•

1917-thftt-1949
•
.
99410-93
 PROLOGUE

This fifth book in our Antique Service Literature series covers the primary
source of service information to our dealer network during the early years.
This is the era when service manuals, as such, did not exist.

You will find the bulletins are not in numerical order, but are arranged accord-
ing to date. Unfortunately, not every bulletin was available for reproduction.

We are pleased with the results and trust that this book will be beneficial to
you in your restoration work.

©COPYRIGHT 1984
HARLEY-DAVIDSON MOTOR CO., INC.
CMI-250-12/95 ALL RIGHTS RESERVED
 Nv. 44

Service Dept. Bulletin

Service 'Department Bulletin

tively easy to change a motor around at naturally remain cooler under heavy pull-
any time, but for the reasons explained ing than the solo motor. The difference
No. 44. Feb. 15, 1917 Harley-Davidson Motor Co., Milwaukee hereinafter, it is always advisable to spec- in the speed of the motors is slight, while
ify the proper type motor when ordering. the sidecar motor has this advantage that
The difference in the compression of it will pull for miles without overheating
the two motors makes the sidecar motor and losing power. This motor is also
Sidecar Motor and Gear Number ideal for double duty, whether with tan- longer lived than the solo motor in double
dem, sidecar or van. This motor will duty service.
Wh:Y the Sidecar Motor is Logical for How to Change a Sidecar Motor to the
Sidecar Service. Solo T:!)pe.
The Difference in Construction Be- Do Not Use the Standard Gear for
tween the Sidecar and Solo Motor. Sidecar Service.
The Correct Sprocqet Combination for What to Do When it is Desired to Change a Motor
What to do When it is Desired to Sidecar Service.
Change a Motor. Wh:Y it is Important to Use the Proper If it is desired to change a solo motor chine, if the importance of distinguishing
How. to Change a Solo Motor to the T:!)pe Motor and Gear. to the sidecar type, a set of Ys" steel between the solo and sidecar type motors
Sidecar T:!)pe. Summar:!) of Essential Facts. plates are to be fitted between the cylin- is taken into consideration.
ders and crank cases. This change can A sidecar type motor should not be
be made at any time desired. Therefore, changed to the solo type after one thou-
Why the Sidecar Motor is Logical for Sidecar Service you need not hesitate to sell a sidecar to sand miles, or more, service. The reason
an owner of a solo machine, because his for this is apparent. In the first few hun-
You want your riders to obtain the see that a motor built especially for side- motor can be converted to the sidecar type dred miles of service the cylinders and
maxim11m in pleasure and service from car duty will give longer satisfaction and at very small cost. pistons "wear in," especially at the upper
their Harley-Davidsons. One excellent longer life than a motor built for the re- If a machine is fitted with a sidecar end of the piston travel. If the plates are
means to help this good cause is to provide quirements of solo service. after it has seen a season's service or more,
them with motors adapted to their require- removed, the pistons travel higher on the
We recommend the sidecar motor for it is advisable to have the cylinders re-
ments. We refer here to the solo and sidecar and sidevan service. In this con- cylinder walls and the motor will knock.
ground and fitted with oversized pistons
sidecar motors. Each motor is designed nection, please note that whenever refer- If it is desired to change a sidecar
and rings at our factory and then to fit
for particular services. ence is made to the sidecar, the sidevan is the compression plates. It can be under- motor to solo, after one thousand miles or
It is clear that sidecar service requires also included. The sidecar motor can stood that a motor will not develop full more, t~e cylinders should be reground at
different qualities in a motor than solo or also be used to advantage for solo or sin- efficiency with slightly worn cylinders, pis- our factory and the plates then removed.
single service. The big difference is the gle service on rough roads, in deep sand, tons and rings. It is seldom necessary to make a change
added weight of the sidecar equipped ma- or in extremely hilly country. Provision It is generally possible to specify the of this kind since the sidecar motor can
chine and the passenger or passengers, as is made on the machine order blank to type motor desired when ordering the rna- be used successfully for solo service.
the case may be. In sidecar service,
specify the type motor wanted. Do not
power is of more importance than speed.
make the mistake to specify the solo motor
The motor that will pull at an even pace
for miles, or as long as necessary, without on a machine that will be used for side-
heating is better adapted to sidecar service car or sidevan service. These recom- How to Change a Solo Motor to the Sidecar Type
than the motor that is somewhat faster at mendations are based on our engineering
department's tests as well as on three sea- The accompanying illustrations make Take care to see that the pistons do not
the outset bu't that is bound to heat up and
clear how to change a solo motor to the strike sharply against the connectin11 rods,
lose power sooner or later. It is easy to sons' experience with both types of motors.
sidecar type and a sidecar motor to the or they may be put out of round, causing
solo type. unnecessary friction in the cylinders after
To change a standard or solo motor to
The Difference in Construction Between the Sidecar the sidecar type, proceed as follows:
assembling. Be careful that the paper
gaskets are not lorn, or they will have to
and Solo Motor Take the motor out of the frame, loosen
be replaced to make the motor oil tight.
the intake manifold packing nuts a few
It is well known that the only differ- the sidecar motor, to lower the compres- turns, then turn the manifold nipples out Fit the Ys" steel plates, one below each
ence between the solo and sidecar motors ston. Both motors are fitted with the of the cylinders and remove the carburetor cylinder. Then lit a set of paper gaskets
is the set of Ys" steel plates, fitted be- same type pistons and are identical in and manifold complete. Remove the between the plates and the cylinders. In
tween the cylinders and crank cases on every respect. It is therefore compara- cylinder stud nuts as well as the washers other words, the original gaskets are not
"B" and "C" and take off the cylinders. removed and another set is fitted. This
Suvi« 'Deparlmml Bulletin No. 44 No. 44 s.,vice 'Department Bullelln

the way before beginning to draw up the

others.
Do Not Use the Standard Gear for Sidecar Service
The exhaust lifter pins and intake push Another essential for successful sidecar ers understand this and use the correct
rods must be readjusted to take care of service is that of correct gearing. The gear for sidecar service. Furthermore,
the difference in the position of the cylin- standard solo gear is too high for sidecar every sidecar motor machine is geared for
ders, as follows: use. We are glad to say that most dl'al- sidecar service when it leaves the factory.
Raise the exhaust valve spring covers.
Turn the motor until one of the exhaust
valves is raised. Then adjust the other
which in that position is closed. Allow The Correct Sprocket Combination for Sidecar Service
.008" to .010" clearance between the Sometimes a machine is equipped with Heretofore a 14-tooth engine sprocket
exhaust lifter pin and valve stem. Before a sidecar after it has been in service; and with 40-tooth rear wheel sprocket have
adjusting the second exhaust valve, turn it then becomes necessary to make the been used for sidecar service-gear ratio
the motor, bringing the valve to the closed proper change. The standard solo gear 4.39 to I. When gearing a machine for
position. Try the adjustment of both ratio is 3. 90 to I on high with the follow- sidecar service, this- combination can be
valves. Replace the spring covers. ing sprockets: 15-tooth engine, 4 3-tooth used, although it is not quite as well suited
clutch, 28-tooth countershaft and 40-toolh as the 15-tooth and 44-tooth r.:ombina"tion.
Adjust the inlet push rods as follows:
Figure One
rear wheel. It ~hould seldom be necessary to use a
Remove the silencer spring covers. Ad- The sidecar gear ratio is 4.50 to I on lower than 4.50 to I gear ratio on high,
just both push rods so that there is .004" high with the following sprockets: 15-
is necessary to keep the motor oil tight. for, with a gear reduction of I Y2 on in-
Replace the cylinciers and fit the stud nuts clearance between the inlet valve stem and tooth engine, 4 3-tooth clutch, 28-tooth termediate and 2Y4 on low, this ratio is
securely, drawing them up evenly all inlet lever. The inlet valves must be countershaft and 44-tooth rear wheel.
6. 75 to I on intermediate and I 0.12 to I
around instead of tightening one nut all closed while making the adjustment. It will he noted that instead of using a
smaller engine sprocket as heretofore, a on low. However, if very heavy loads
larger rear wheel sprocket is employed, are carried, or if the roads are exception-
giving a slightly lower gear than was pos- ally rough, or the sand unusually deep, a
sible with a 14-tooth sprocket, making 14-tooth engine sprocket ·with a 44-tooth
this sprocket combination particularly rear wheel sprocket will alford a gear ratio
How to Change a Sidecar Motor to the Solo Type satisfactory for sidecar service. of 4.83 to I on high.

If a sidecar motor is changed to the

solo type, the steel plates "A" are re-
moved and the cylinder stud nut washers Why it is Important to Use the Proper Type Motor and Gear
"C" and cylinder plug washers "B" fitted
to take up the space occupied by the plates The standard solo gear remains un- whether a machine is used for solo or side-
"A." The washers can be obtained from changed, viz., 15-tooth, 43-tooth, 28- car service, with the above facts in mind.
us at small cost. The above instructions tooth, 40-tooth. Never use a sidecar with This bulletin has been prompted with the
on removing the motN. taking off the car- the standard gear. The motor will not knowledge that solo motors ar~ being used
buretor, etc., are to be followed carefully. develop the power necessary for sidecar for sidecar service and in some cases with
The exhaust lifter pins and inlet push service. It will be necessary to shift to standard gearing. Such mc''lrs cannot
rods must also be readjusted, but instead intermediate and low gears in places give satisfaction.
of raising the lifter pins and lengthening where the motor, if properly geared, For the good of the service, and to see
the push rods, both are shortened until the would travel on high. The motor will that your riders obtain the maximum in
proper adjustment is obtained. overheat, lose power and serious trouble pleasure and service, which we know is
will be experienced. what every dealer is working for, see that
It is important that the adjustment of
the exhaust lifter pins and inlet push rods It may be that in the past you have not your machines are geared for the service
is absolutely accurate. Use one of our considered the questions of proper motor they are expected to render and equipped
feeler gauges to measure the clearances. equipment and gearing, depending on with the correct type motor.
Figure Two
No. 44 Scrolce t'lJepartmenl Bulletin

tively easy to change a motor around at naturally remain cooler under heavy pull-
any time, but for the reasons explained ing than the solo motor. The difference
hereinafter, it is always advis_able to spec- in the speed of the motors is slight, while
ify the proper type motor when ordering. the sidecar motor has this advantage that
The difference in the compression of it will pull for miles without overheating
the two motors makes the sidecar motor and losing power. This motor is also
ideal for double duty, whether with tan- longer lived than the solo motor in double
dem, sidecar or van. This motor will duty service.

What to Do When it is Desired to Change a Motor

If it is desired to change a solo motor chine, if the importance of distinguishing
to the sidecar type, a set of Vs" steel between the solo and sidecar type motors
plates are to be fitted between the cylin- is taken into consideration.
ders and crank cases. This change can A sidecar type motor should not be
be made at any time desired. Therefore, changed to the solo type after one thou-
you need not hesitate to sell a sidecar · to sand miles, or more, service. The reason
an owner of a solo machine, because his for this is apparent. In the first few hun-
motor can be converted to the sidecar type dred miles of service the cylinders and
at very small cost. pistons ..wear in,.. especially at the upper
If a machine is fitted with a sidecar end of the piston travel. If the plates are
after it has seen a season's service or more, removed, the pistons travel higher on the
it is advisable to have the cylinders re- cylinder walls and the motor will knock.
ground and fitted with oversized pistons If it is desired to change a sidecar
and rings at our factory and then to fit motor to solo. after one thousand miles or
the cotqpression plates. It can be under-
more. the cylinders should be reground at
stood that a motor will not develop full
efficiency with slightly worn cylinders, pis- our factory and the plates then removed.
tons and rings. It is seldom necessary to make a change
It is generally possible to specify the of this kind since the sidecar motor can
type motor desired when ordering the rna- be used successfully for solo service.

How to Change a Solo Motor to the Sidecar Type

The accompanying illustrations make Take care to see that the pistons do not
dear how to change a solo motor to the strike sharply against the connecting rods,
sidecar type and a sidecar motor to the or they may be put out of round. causing
solo type. unnecessary friction in the cylinders after
To change a standard or solo motor to assenibling. Be careful that the paper
the sidecar type. proceed as follows: gaskets are not .tom, or they will have to
Take the motor out of the frame, loosen be replaced to make the motor oil tight.
the intake manifold packing nuts a few
Fit the Vs" steel plates. one below each
turns. then turn the manifold nipples out
of the cylinders and remove the carburetor cylinder. Then fit a set of paper gaskets
and. manifold complete. Remove the between the plates and the cylinders. In
cylinder stud nuts as well as the washers other words, the original gaskets .are not
"B .. and ..C .. and take off the cylinders. removed and another set is fitted. This
Service Dept. Bulletin
No. 44. Feb. 15, 1917 Harley·Davidson Motor Co., Milwaukee

Sidecar Motor and Gear Number

Why the Sidecar Motor is Logical for HoD1 to Change a Sidecar Motor to the
Sidecar. Service. Solo TJ;pe.
The Difference in Construction Be~ Do Not Use the Standard Gear /Of'
tJ»een the Sidecar and Solo Motor. Sidecar Ser»ice.
The Correct Sprocket Combination for
What to do When it is Desired to Sidecar Service.
Change a Motor. Why it is Important to Use the Proper
Hot» to Change a Solo Motor to the Type Motor and Gear.
Sidecar Type. Summary of Essential Facts.

Why the Sidecar Motor is Logical for Sidecar Service

You want your riders to obtain the see that a motor built especially for side-
maximum in pleasure and service from car duty will give longer satisfaction and
their Harley~Davidsons. One excellent longer life than a motor built for the re-
means to help this aood cause is to provide quirements of solo service.
them with motors adapted to their require- We recommend the sidecar motor for
ments. We refer here to the solo and sidecar and sidevan service. In this con~
sidecar motors. Each motor is designed nection, please note that whenever refer-
for particular services. ence is made to the sidecar, the sidevan is
It is dear that sidecar service requires also included. The sidecar motor can
different qualities in a motor than solo or also be used to advantage for solo or sin-
single service. The big difference is the gle service on rough roads, in deep sand,
added weight of the sidecar equipped ma~ or in extremely hilly country. Provision
chine and the passenger or passengers, as is made on the machine order blank to
the case may be. In sidecar service. specify the type motor wanted. Do not
power is of more importance than speed.
make the mistake to specify the solo motor
The motor that will pull at an even pace
foJ miles, or as long as necessary. without on a machine that will be used for side-
heating is better adapted to sidecar service car or sidevan service. These recom-
than the motor that is somewhat fa.Ster at mendations are based on our engineering
the outael but that is bound to heat up and department's tests as well as on three sea-
lose power sooner or later. It is easy to sons" experience with both types of motors.

The Difference in Construction Between the Sidecar

and Solo Motor
It is well known that the only di1fer~ the sidecar motor, to lower the compres-
·ence between the solo and sidecar motors sion. Both motors are fitted with the
is the set of Ya" steel plates, fitted be- same type ·pistons and are identical in
tween the cylinders and crank cases on every respect It is therefore compara-
Service 'Department Bulletin No. 44

the way before beginning to draw up the

others.
The exhaust lifter pins and intake push
rods must be readjusted to take care of
the difference in the position of the cylin·
ders. as follows:
Raise the exhaust valve" spring covers.
Turn the motor until one of the exhaust
valves is raised. Then adjust the other
which in that position is closed. Allow
.008'' to .01 0'' clearance between the
exhaust lifter pin and valve stem. Before
adjusting the second exhaust valve. tum
the motor. bringing the valve to the closed
position. Try the adjustment of both
valves. Replace the spring covers.
Adjust the inlet push rods as follows:
Fieure Oae Remove the silencer spring covers. Ad·
is necessary to keep the motor oil tight. just both push rods so that there is .004"
Replace the cylinders and fit the stud nuts clearance between the inlet valve stem and
securely. drawing them up evenly all inlet lever. The inlet valves must be
around instead of tightening one nut all closed while making the adjustment.

How to Change a Sidecar Motor to the Solo Type

If a sidecar motor is changed to the
solo type, the steel plates "A" are re-
moved and the cylinder stud nut washers
..C .. and cylinder plug washers ''B .. fitted
to take up the space occupied by the plates
'"A,. The washers can be obtained from
us at small cost. The above instructions
on removing the motor. taking off the car~
buretor. etc.• are to be followed carefully.
The exhaust lifter pins and inlet push
rods must also be readjusted. but instead
of raising the lifter pins and lengthening
the push rods, both are shortened until the
proper adjustment is obtained.
It is important that the adjustment of
the exhaust lifter pins and inlet push rods
is absolutely accurate. Use one of our
feeler gauges to measure the clearances. Fiarure Two
No. 44 Service Ve(Xlrtmeni Bulletin

Do Not Use the Standard Gear for Sidecar Service

Another essential for successful sidecar ers understand this and . use the correct
service is that of correct gearing. The gear for sidecar service. Furthermore,
standard solo gear is too high for sidecar every sidecar motor machine is geared for
use. We are glad to say that most deal- sidecar service when it leaves the factory.

The Correct Sprocket Combination for Sidecar Service

Sometimes a machine is equipped with Hereto fore a 14-tooth engine sprocket
a sidecar after it has been in service, and with 40-tooth rear wheel sprocket have
it then becomes necessary to make the been used for sidecar service--gear ratio
proper change. The standard solo gear 4. 39 to 1. When gearing a machine for
ratio is 3. 90 to I on high with the follow- sidecar service, this- combination can be
ing sprockets: I 5-tooth engine, 4 3·tooth used, although it is not quite as well suited
clutch, 28-tooth countershaft and 40-tooth as the 15-tooth and 44-tooth combination.
rear wheel. It ~hould seldom be necessary to use a
The sidecar gear ratio is 4.50 to I on lower than 4.50 to 1 gea! ratio on high,
high with the following sprockets: 15- for; with a gear reduction of 1Yz on in-
tooth engine, 4 3-tooth clutch, 28-tooth termediate and 2 !;4 on low, this ratio is
countershaft and 44-tooth rear wheel. 6. 75 to I on intermediate and 10.12 to I
It will be noted that instead of using a on low. However. if very heavy loads
smaller engine sprocket as heretofore, a
larger rear wheel sprocket is employed. are carried, or if the roads are exception·
giving a slightly lower gear than was pos- ally rough, or the sand unusually deep, a
sible with a 14-tooth sprocket, making 14~tooth engine sprocket with a 44~tooth
this sprocket combination particularly rear wheel sprocket will afford a gear ratio
satisfactory for sidecar service. of 4.83 to I on high.

Why it is Important to Use the Proper Type Motor and Gear

The standard solo gear remains un· whether a machine is used for solo or side-
changed, viz., 15-tooth, 43~tooth. 28- car service. with the above facts in mind.
tooth, 40-tooth. Never use a sidecar with This bulletin has been prompted with the
the standard gear. The motor 'will not knowledge that solo motors are being used
dejllelop the power necessary for sidecar for sidecar ~rvice and in some cases with
ser¥ice. It will be necessary to shift to standard gearing. Such mc~'lrs cannot
intermediate and low gears in places give satisfaction.
where the motor, if properly geared. For the good of the service. and to see
would travel on high. The motor will that your riders obtain the maximum in
overheat, lose power and serious trouble pleasure and service, which we know is
will be experienced. what every dealer is working for, see that
It may be that in the past you have not your machines are geared for the service
considered_t}l_e_guestions of proper motor they are expected to render and equipped
equipment and gearing, depending on with the correct type motor.
Sen>ice D<parlm<nl Bulletin No. 44

Summary of Essential Facts

Summarizing this bulletin briefly, the over the motor and to lower the gear,
important facts are these: when the sidecar is attached.
When you order a new machine give When you equip a machine that has
the question of correct motor equipment been in service for some time with a side-
careful thought and make your decision car, make sure that the gear ·ratio is cor-
with the facts just covered in mind. rect. The standard solo combination of
If the machine is to be used with a sprockets is I 5-tooth, 43-tooth, 28-tooth,
sidecar immediately or in the near future, 40-tooth-high gear ratio 3.90 to I.
specify the sidecar type motor. There To change to the sidecar gearing, you
can be no doubt in regard to this question. can either lit a 44-tooth rear wheel sprocket
Every sidecar motor equipped machine and use a I 5-tooth engine sprocket, or
is geared for sidecar service at our factory, a 14-tooth engine sprocket and 40-tooth
so you need make no change. This is an- rear wheel sprocket. The high gear ratio
other reason why you should specify the with a 15-tooth engine sprocket and 44-
sidecar type motor for sidecar ~ervice. If tooth rear wheel sprocket is 4.50 to I,
a solo motor is ordered, the standard gear with a 14-tooth engine sprocket and 40-
is of course furnished, unless otherwise tooth rear wheel sprocket 4.39 to I.
specified. The sidecar combination of Never use the standard gear on a sidecar
sprockets is 15-tooth, 4 3-tooth, 28-tooth equipped machine.
and 44-tooth-high gear ratio 4.50 to I. When you equip a machine that has
Remember that whether the motor is been in service for some time, with a side-
sidecar or solo type, the sidecar gear ratio car, change the motor to the sidecar type
must be used if the machine is used with a if possible, besides changing the gear.
sidecar. Change the motor to the sidecar type,
When you order a machine for solo either by merely fitting a set of compres-
service, specify the solo motor, unless the sion plates between the cylinders and
machine will be used on very bad roads, crank cases, if the motor has seen lillie
in deep sand, or on steep hills, where service, or by having the cylinders re-
power is of more importance than speed. ground at our factory and then fitting the
In that case, the sidecar type motor should compression plates.
be specified. The same holds true if the Do not change a sidecar motor to the
purchaser is a likely sidecar prospect. You solo type after extended service, without
will be saved the time required to change first having the cylinders reground by us.
Service Dept. Bulletin No. 46 Service 'Department Bulltlln

No. 46. March 20, 1917 Ha.rley-Davidson Motor Co., Milwaukee

earlier roller arms. For this reason it is Rollers and roller bushings can be
recommended that when roller arm repairs ordered for the new type roller arms. The
are needed, the whole fitting be exchanged roller turns on the bushing which fits sta-
General Parts and Repair Number for the later type. Any roller arms being tionary on the roller pin. The only fit-
carried in stock can be returned for ex- tings that can wear are the rollers and
change. bushings.
Sleeve for Muffler Inner Tube. Rem)} Generator Drive Shaft and Gear
1917 Inlet and Exhaust Roller Arms. Furnished Assembled.
Renerval of Mechanical Oiler Pari$- When Ordering a Chain Guard for a
Alrvays Ship Drive Case and Drive 1913 Model.
Case Cover to Factory When One or 44- Tooth Rear Wheel Sprocket for Side- Renewal of Mechanical Oiler Parts- Always Ship Drive
MMe Nerv Parb are Needed. car Service. Case and Drive Case Cover to Factory When One
The 1917 Head Fittings Are Adapted to Use the 1917 Manual as a Reference
all Models. or More New Parts are Needed
Boolt--lts Value From a Selling
Fittings Required to Attach Different Standpoint.
Sidecar Models to Various Model The mechanical oiler is practically chanica! oiler assembled on the drive
Horv the 1917 Manual is Placed in the trouble and fool proof and it is seldom case. The drive case cover is naturally
Machines. Hands of the Rider.
1915 Parts for 1914 Trvo Speed Hub. that a part must be replaced. When an distorted very slightly when assembled
Special Clamp for 1914 Sidecar. Register Sales of Used Machines. operating shaft, operating shaft bushing or with the drive case and if the mechanical
The Repairing of Worn Carburetors-· Oil and Gasoline Tanks on N erv M a- chamber cap needs renewing, the oiler oiler is assembled and lapped in with its
Charge Reasonable. chines Norv Drained. and drive case should be returned to us own drive case and then tested with its
Rebuilding Generator on 1915 Electric A Plan to Spread Harley-Davidson own worm gear, a perfect fit is insured.
for the necessary repairs. Owing to the
Model. Knorvledge. If a new drive case cover is ordered,
accuracy required in the fitting of the just remove the drive case before fitting and
listed parts, renewals sre made only at assemble the cover with it to test the oiler
Sleeve for MufHer Inner Tube our factory. by hand. Fit the intermediate worm gear
The good running of the motor depends and intermediate gear. Then turn the in-
If you notice that the exhaust of your must be removed. Take off the exhaust to a great extent on the efficiency of the termediate gear by hand. The operating
early 191 7 machines is not as quiet as pipe connection which has a right thread. mechanical oiler. Parts such as the oper- shaft should turn freely. If there is a
that of the later machines, and you wish If necessary, soak the joints with kerosene ating shaft or bushing, operating shaft and bind, or if the operating shaft turns with
to quiet it, we will be glad to furnish you and use a piece of pipe inserted in one of plunger chamber caps must be fitted with difficulty, send the drive case and cover
with a sleeve to fit over the muffier inner
tube, free of charge. The object is, of
the openings to turn the connection. Re-
move the nuts on both ends of the muffier
extreme accuracy; therefore, even though to the factory to be "run in." Take r.o
your repair facilities are of the best, refer chance on causing the mechanical oiler to
course, to close some of the ports and this stud and the muffler shell can be taken mechanical oiler to us. seize. The most practical plan is to ~nd
is accomplished without any back pres- apart. The sleeve is split and can be The reason why it is necessary to send the drive case and cover to the factory
sure. The factory number of the sleeve spread enough to slip over the muffler inner in the mechanical oiler and the drive case when any mechanical oiler part needs re-
is FH-36, and we suggest including as tube, without removing the cutout valve assembly is that it is advisable to lap newing and we will lap in the oiler and
many as you need with your next parts stem. Place the sleeve on the inner tube in the operating shaft with the me- return it ready for service.
order. Machines shipped from the fac- as far as possible and turn it to the left
tory approximately after October 25th do until the split is over the seam of the tube.
not need the sleeve. If the sleeve is not turned, the ports are
To fit the inner tube sleeve, the muffler only partly closed. The 191 7 Head Fittings Are Adapted to all Models
When it becomes necessary to fit new both a new cup and cone, the small extra
I 91 7 Inlet and Exhaust Roller Arms head fittings to an earlier than 1916 ma- expense will be more than offset by the
When it becomes necessary to repair a Beginning with this motor number on chine, the imprt>ved 1916 and 191 7 con- longer service the new parts will render.
set of 1917 exhaust or inlet roller arms, February 8th, a change has been made in struction can be taken advantage of. The When a head cup or cone must be re-
return them to us for exchange, instead the roller arms. enabling the fitting of new 1916 and 191 7 head fittings are of the newed, inspect all head fittings and if any
of attempting to repair. This applies to rollers and roller bushings when needed. two point bearing type and are better con- wear is found, replace the parts with the
all motors up to No. 17T-8927. This cannot be done practically on the structed than the earlier head fittings. 191 7 type. If the balls are 0. K., fit
There is no difference in the price of two extra balls in each new cup, twenty
the fittings and while it is necessary to fit balls being used in the 191 7 cup, instead
Service 'Department Bulletin No. 46 No. 46 · Sorotce 'Doparlmenl Bulletin

of eighteen as before 1916. The ball It is not necessary to replace both ball these facts, we wish to say that the 1915 parts. This will, of course, be wrong,
retainers are discarded, the bearings being cups and cones to take advantage of the parts are an advance in design, a double since all you need is one new 1915 part.
assembled with good cup grease which 1916 and 191 7 construction. If one cup set of roller bearings being used in place Therefore, when ordering an actuating
serves as a retainer. and cone are not worn, they need not be of ball bearings and a thrust ball bearing worm cone, bearing, or driving hub gear,
The parts needed to replace a com- discarded while the worn parts can be re- being added to take up the end thrust of be sure to specify the 1915 parts number,
plete set of 1909 to 1916 head fittings the drive gear. The regular retail price if the part you are replacing is of the new
placed with the 1917 style. Most deal-
are as follows: of the 1915 assembly of parts is $7.00. type. If you repair a two speed hub that
2 EE-64 Head cups, each ... $ .40 ers are fitting the 191 7 head fittings Since a large number of the original is still fitted with the original parts, return
I EE-65 Upper head cone... .35 whenever a b~ll cup must be renewed on 1914 cones and driving hub gears have them to our factory, that is, the actuating
I EE-66 Lower head cone . . . . 18 an earlier than 1916 model and lind it already been exchanged, it is important worm cone and driving hub gear and we
40 B0-543 Head cup balls, each .01 well worth while to make the change, for when ordering a new 1915 actuating will exchange them for the 1915 assembly
Two extra balls are used in each 191 7 the new fittings are exceptionally long worm cone, driving hub gear, roller or for $3.50 net. The factory number of
head cup. lived. thrust bearing or retainer to specify the this assembly is DG-170.
correct part number. Foil ow these suggestions to obtain the
You may overhaul a 1914 two speed benefit of the 1915 improvements when
hub that is fitted with the 1915 parts and replacing an original 1914 cone or gear,
Fittings Required to Attach Different Sidecar Models to lind that the cone or driving hub gear is and to avoid duplication and misunder-
Y arious Model Machines worn. If you order a new part from a standing when ordering a new style part
1914 parts list, we will send you a com- to replace one of the same type. You
Inquiries are frequently received rela- I DQ-60 Frame brace eye bolt.$ .45 plete set of the 1915 parts, since we no will lind the 1915 parts listed on page 3 7
tive to parts needed to connect, say a I E0-276-W Spacer washer . . . . .05 longer furnish the original 1914 style of the new 191 0 to 191 7 parts price list.
191 7 sidecar to a 1914 or 1915 model,
or a 1915 or 1916 sidecar to a 191 7 To attach a 191 7 sidecar to a 1916
model. To make the subject clear, we model, the following part is required:
are herewith listing the parts needed for I EQ-60 Frame brace eye bolt.$ .60 Special Clamp for 191 4 Sidecar
the various combinations. It will be noted It is generally known that we furnish over all and distributes the sidecar strain.
To attach a 1915 sidecar to 1916
that the sidecars are interchangeable on a special clamp for the 1914 sidecar. We furnish this fitting at actual cost,
models, the following parts are required:
all models at small cost. When ordering This clamp fits on the lower rear fork of $1.25, because it should be fitted to every
a set of parts, specify the factory numbers. I EQ-53 Frame brace clevis .. $ .60
I F0-536 Frame brace clevis the frame, replacing the original clamp. 1914 sidecar equipped machine. The
To attach a 191 7, 1916 or 1915 side- The special clamp measures 6 3-4 inches number of this clamp is CK-774.
car to a 1914 model, the following parts bolt .. . . . .. . . . .05
are required: I EQ-60 Frame brace eye bolt .60

I DQ-60-A Frame brace eye bolt.$ .45 To attach a 1915 sidecar to 1917
1 E0-276-W Spacer washer . . . . .05 models, the following parts are required: The Repairing of Worn Carburetors-Charge Reasonable
I DE-95 Rt. stand stop.. . . . .08 I FQ-60 Frame brace eye boit.$ .60 When you overhaul motors you fre- fitting a bushing or an oversized shaft.
Rt. luggage carrier I EQ-53 Frame brace clevis.. .60 quently lind the carburetor worn at vari- Instead of attempting to do this, we rec-
I DE-43 stud . . . . . . . . . .06 I F0-536 Frame brace clevis ous points. The compensating air valve ommend referring a carburetor in this con-
2 B0-683 Stud nuts at 5c each .1 0 bolt .. . . . . . . . . .05 is in poor condition and generally the dition to the Wheeler-Schebler Carburetor
To attach a 1916 sidecar to 1917 throttle shaft is loose in the carburetor Co., Indianapolis, Indiana, for thorough
To attach a 191 7 or 1916 sidecar to body.
models, the following part is required: overhauling. The average charge for a
1915 models, the following parts are re-
A carburetor in this condition cannot complete overhauling including the repairs
quired: I FQ-60 Framebraceeyebolt.$ .60 be adjusted accurately, for the wear at necessitated by wear at the throttle shaft
the throttle shaft spoils the mixture. Gen- is $2.50 net, according to a recent quota-
erally the carburetor cannot be adjusted to tion from the manufacturers. This does
1915 Parts for 1914 Two Speed Hubs throttle down. The amount of wear at not include a new bowl or body. It is
the throttle shaft can best be learned by very seldom that either of these fittings
Most of our dealers understand that with roller bearings for $3.50 net, $4.25 raising the lift lever clear of the cam, tak- needs renewing because of wear. Acci-
when the original actuating worm cone or retail, in exchange for the original' parts. ing hold of the shaft and moving it back dent or abuse is generally responsible for
driving hub gear of a 1914 two speed This exchange price has been in force and forth. serious damage to the body and bowl.
hub needs renewing, we furnish a 1915 since the fall of 1914. To take up wear at the throttle shaft This price does not apply to every job,
type cone and driving hub gear complete To those dealers not familiar with requires reaming the carburetor body and of course, any more than you or we can
SenJice Depar/menl Bulle/in No. 46 No. 46 Serolce Deparlmen/ Bulle/In

quote a flat price on all motor overhaul- Heretofore, some dealers have referred
ing. However, in every case the charge worn carburetors to us for exchange. 44-Tooth Rear Wheel Sprocket for Sidecar Service
is reasonable. The carburetor is placed However, since we return all worn carbu-
Bulletin No. 44 explains the change in times in the past. The new 44-tooth
in as good shape as new for all practical retors to the manufacturers, every dealer
should refer his carburetors directly to the
the combination of sprockets for sidecar sprocket is not listed in the parts liat, while
purposes, and since it is not a simple mat- service; namely, the use of a 15-tooth en- the 44-tooth clutch sprocket ia.
ter to repair a badly worn carburetor, we Wheeler-Schebler Carburetor Co. Al-
gine sprocket and 44-tooth rear wheel Attention is also called to the fact that
know that you will welcome the oppor- ways tag shipment plainly with your name
sprocket in place of 14-tooth and 40-tooth bulletin No. 44 gave the standard three
tunity to get first class work at very rea· and address and write a letter of instruc-
sprockets. The number of the 44-tooth speed gear ratio as 3.90 to I. This is
sonable cost. tions under separate cover at the time.
sprocket is DK-783. When ordering, do incorrect. The gear ratio is 4.10 to I.
The Wheeler-Schebler people are able Prepay transportation charges.
Parts such as the manifold, union, inlet
not make the mistake to specify the 44- The 3. 90 to I gear ratio is mentioned on
to make prompt repairs and we urge every
nipples, packing bushings, gaskets, etc.,
tooth clutch sprocket used on the single pages 4 and 5 of the bulletin just referred
dealer to take advantage of this service.
geared machines, as has happened several to. Correct your copy.
The rebuilding of badly worn carburetors are not manufactured by the carburetor
can be compared with such work as re- people and therefore should not be in-
grinding cylinders and rebushing connect- cluded with carburetors that are to be re-
ing rods-an operation that can be done paired. If new parts are needed they Use the 191 7 Manual as a Reference Book-Its Value
best and cheapest by the manufacturers. should be ordered from us.
From a Selling Standpoint
You have already received your copy read the manual carefully as a means to
of the 191 7 manual. We have tried to become more familiar with Harley-David-
make the manual very complete and com-
Rebuilding Generator on 191 5 Electric Model prehensive. Keep your copy on hand for
son design and construction. You may
not have regarded the manual from this
easy reference when you want information
If you have a 1915 electric model on at a reasonable price. The 191 and u on a particular subject. A careful study
viewpiont in the past. Its value as a means
which the generator has not been over- 1917 generators embody a number of im- of improving your and your employees'
of the manual is an education in itself, not
hauled and fitted with the 1916 improve- provements in addition to the manually only on repair work, but on the construc- knowledge of the machine and presenting
ments, refer it to the Remy Electric Co., operated switch that will be applied to the tion of the machine. such knowledge to the prospect as con-
Anderson, Ind. The work will be done 1915 generator at a reasonable price. Every person connected with your or- vincing sales argument, should not be
ganization should make it his busineaa to overlooked.

Remy Generator Drive Shaft and Gear Fumished Assembled How the I 91 7 Manual is Placed in the Hands of the Rider
The drive gear and shaft for the Remy if a new gear were fitted to an old shaft, All riders who have registered 191 7 information with which every rider must
generator are furnished assembled, not or an old gear to a new shaft. The num- machines to date will receive copy of the be acquainted to derive satisfactory
separately. The gear is a .003-inch press 191 7 manual within the next few days. serv1ce.
bers of the parts are EX-I 056, drive Prior to this season the manual has always Another reason for forwarding the
fit on the shaft, besides being keyed. A
shaft and EX-I 059 drive gear. been included with the machine. 1 his manual directly to the rider is this: We
perfect fit would be almost out of question
year, this will not be done. Instead, the believe that the rider will appreciate the
manual will be mailed the rider as soon manual more if he receives it after he has
as his registration card is received. This taken delivery of the machine, and if in-
is an added inducement to the rider to reg- stead of receiving it with the machine it is
ister his machine immediately. Please re- sent to him by mail. The manual is an
When Ordering a Chain Guard for a 191 3 Model member that unless the machine is regis- expensive piece of workmanship and we
tered, the rider does not receive a manual. wish to avoid all duplication and waste.
On every order for a 191 3 chain being a larger opening for the counter- Therefore, the more promptly the regis- Therefore, kindly read this carefully so
guard, a 1914 guard is furnished. The shaft. Remember that we always furnish tration card is mailed us, the sooner the you will know just how the manual will
1914 chain guard is padded and quiets the 1914 chain guards on all orders for manual will be in the hands of the rider. be distributed.
the action of the drive chain. It fits the We want to see the manual in the hands If you know that some of your 1917
chain guards for 191 3 machines.
191 3 models, the only difference in shape of every 191 7 owner because it coven riders have not registered their machines,
Seroiu Department Bulletin No. 46 No. 46 Ser~>/ce Department Bullel/n

please send us the registration cards or see Mention the same fact to every purchaser subject of motor overhauling-How to will be covered with which you and the
that the riders forward them at once. If of a new machine. It is costing extra time place a motor in perfect running order, repair man are already familiar; all the
you will tell the rider that every registered and postage to place the manual directly whether it needs no more than· to have the more reason why you should get the most
owner receives a copy of the 191 7 man- in the hands of the rider by mail, but we carbon removed and the valves ground or out of the new material. Since the bulle-
ual, we feel sure that there is not one that are glad to absorb this expense because
whether it requires a thorough overhaul- tins are now filed conveniently, they can
will not send us his registration card. the results obtained make it worth while.
ing. Another bulletin will be devoted to be studied at leisure. One enterprising
the electrical system-Generator, battery, dealer says he intends to take the loose
lamps, horn and wiring-How to test for leaf binder along on his Sunday country
Register Sales of Used Machines short circuits, how to test the output of trips and read and study under a shady
the generator; in other words, a clear and tree.
Every sale of a used machine should for a new machine. Furthermore, it is to
be registered so that copy of the manual simple explanation with illustrations, of the It is going to take time and effort on
your and our interest to keep every ma-
can be mailed the purchaser. It is just care and repair of the electrical system. the part of all concerned to carry out this
chine in good running order and we can bulletin service plan, hut by working to-
as important in its way to register used For the dealers and repair men who
machines as to register new sales, for we help the rider by sending him the manual have taken a course at our factory, the gether, we are sure to accomplish big re-
are interested to keep in touch with the and other instructive literature, as well as service bulletins will be an excellent check sults. Service is the bridge !o success in
purchaser of a used machine. That rider the Enthusiast. Extra sets of registration up and a constant reminder of the subjects many lines today and nowhere doe~ servic~
in a year is generally an excellent prospect cards will be furnished on request. covered by the course. There is nothing count bigger or produce greater results than
better than to see work actually done and in the motorcycle business. Satisfied rid-
to do it personally, but a certain amount ers are real assets. They advertise you
and your goods. The abo;-e plan is a
Oil and Gasoline Tanks on New Machines Now Drained of the work of the training course was
means to give your riders efficient service,
necessarily covered by instructions and
Beginning February I st all machines If the motor overoils, make the follow- those who took the course, will find the to keep your machines in first cla5?, running
are shipped drained to conform with the ing adjustment: Remove the vent screw order and to be able to do good work at
bulletins a great help in their work.
ruling of the railroad companies. Hereto- in the operating shaft chamber cap. If reasonable cost. "The sale of a machine
This bulletin service is one of the big- is but the beginning of relations betw~:er,
fore you have been used to receiving ma- oil does not overflow readiiy, tum the
gest helps we have ever given our dealers. you and the rider.
chines with oil in the tanks and attention motor slowly until it does. Replace the
is therefore called to the new system so vent screw firmly. Then remove the vent There isn't a dealer or repair man that All bulletins herein referred to are ~.erv­
that there is no danger of running a new screw in the cap over the plunger chamber is not eager to improve his knowledge. ice bulletins. Various other departments
motor without filling the oil tank. Run until the oil overflows. Replace the screw There are no "Know it Ails" or "I will also issue bulletins that merit your
the motor slowly the first time, so as to firmly. This adjustment is fully covered should Worrys" among Harley-Davidson best attention, but only service bulletins
distribute the oil. on page 4 3 of the I 9 I 7 manual. dealers. We are therefore going ahead are referred to here. If you employ a rf'-
and will issue the bulletins at reasonable pair man, see that he specialize3 on study-
ing the service bulletins. In that case it
intervals. There is a great deal of ground
isn't necessary that you devote as much
to be covered and while a fine start has personal attention to the study of the bul-
A Plan to Spread Harley-Davidson Knowledge already been made, there is no time for letim as if you do your own repair work.
lagging behind. You will receive every If you have any subject in mind of gen-
A large number of dealers and dealers' to give every Harley-Davidson dealer and
bulletin as quickly as it is issued. Place eral interest to you and your fellow deal-
repair men took advantage of the recent repair man a course of training at the fac-
training course at our factory. Every one tory would require several years. It is
it in your loose leaf binder and it cannot ers that has not been covered by a ~ervice
get away from you. Study each bulletin bulletin, that i~. a subject pertaining !o
returned home with increased enthusiasm, therefore our intention to make the 191 7
carefully. the care and repair of the machines or
a more intimate knowledge of the reasons service bulletins as helpful as possible. some other phase of service, let us hear
To make this plan a success, every
for Harley-Davidson quality, acquired by We will try to cover practically all of the
dealer's co-operation is necessary. If you rrom you. you prohabiy have ideas on
study in various factory departments and work taken up in the repair course, so that service and are using n1ethods in rep11ir
employ a repair man; see that he studies
last but not least, with greater ability to every dealer and repair man has the op- work that will interest other dealer~. Do
do first class repair work and render A- I portunity to acquire a factory training. the bulletins. The man that does the not forget that we always welcome sug-
service. Several bulletins have already been is- work is directly interested. There is a gestions. An interchange of ideM is al-
Many dealers and repair men could not sued and others are in preparation with difference between looking over a bulletin ways helpful to ail concerned. Let us
come to the factory, of course. In fact, this in mind. One bulletin will cover the or reading and studying it. Some ground hear from you.
 No. 47

Service Dept. Bulletin a rider wants a first class job, both within
and without, we will refinish the cylinder Relining l set (2) clutch
No. 47. March 24, 1917 Harley-Davidson Motor Co., Milwaukee at the just quoted price. A cylinder discs . . . . . . . . $1.75 $1.40
should never be refinished with aluminum Relining l set ( 2) clutch
discs in lots of ten sets
paint or other preparation, because of the
and over . . . . . . 1.25
danger of overheating and rusting.
Please note these prices carefully since
Factory Repair Work Number The charges for relining clutch discs they differ in some cases from the pnces
are as follows: in effect prior to Feb. l 5, 191 7.
Prices on Regrinding C}!linders, Rebush- Oversized Piston Pins Fitted if Specified.
ing Connecfing Rods and Relining How to Distinguish and Order Rings for
Clutch Discs. a Reground C}!linder.
Wh}! and When C}!linder Regrinding is Sidecar Motor Should be Fitted with
Recommended. Compression Plates.
Why and When Cylinder Regrinding IS Recommended
H alP to Measure Cylinders and Pistons. Some Dealers Carr}! Exchange C}!linders. If you have had cylinders reground at lower end of the piston travel and the
Wh}! C}!linder.s Should be Reground at Wh}! Connecting Rods Should be Re. the factory before, this operation needs wear cannot be taken. up by fitting a new
Our Factor}!. bushed at Our Factor}). no recommendation. In some cases the piston either standard or oversized. Nat-
Pacq C}!linders Care{ull}! to Avoid A ccurac!J is N eccssary in Assembling impression still prevails that after a motor urally a slight shoulder is worn at the
Breaqage. Motor. has seen several seasons' service, it can be upper end of the piston travel, against
Regrinding Does Not Weaqen a C}!l- Never Usc a Piston Pin Locq Pin Twice. thoroughly overhauled and placed in per- which a new piston will strike, making the
indcr. Clutch Discs Should be Relined at Our fect running condition without regrinding motor noisy. The same condition applies
Regrinding Increases Power Factory. the cylinders. The repair man will fit to fitting wider than standard piston rings,
new . bearings,· piston pins and rings, but when the ring slots in the piston are worn.
unless the cylinder walls are cut or The top ring will strike the shoulder which
Most dealers are familiar with the fact reasonable to enable every dealer to take burned will not think of having the cylin- the orginal ring had worn in the cylinder
that certain operations in repair work can advantage of factory work where neces- ders reground. and the rider will wonder why his motor
be done most satisfactorily at our factory sary for results. Cylinder and piston wear is normally is noisy. The oversized rings will more-
and that our prices on this work are very very gradual, but because of the accurate over not fit perfectly in the piston grooves.
fit necessary for smooth, quiet running and When speaking here of a shoulder, we
full power development, regrinding is ad- do not necessarily mean a great deal of
visable when the cylinder and piston wear wear. The shoulder may be so slight as
Prices on Regrinding Cylinders, Rebushing Connecting Rods may seem very slight. to be barely felt by the sense of touch,
To measure the cylinder and piston lit, but if the accuracy necessary for smooth,
and Relining Clutch Discs a set of 3 to 4 inch inside and outside quiet running is considered and the speed
The operations that come under this List Net micrometers are necessary. A perfect fit of the piston travel, it can be appreciated
heading are regrinding of cylinders, re- Rebushing one set twin means a clearance not to exceed .003 that if a piston or ring that has "worn in"
bushing of connecting rods and relining (three thousandths) inch between the cyl- is replaced with an oversized part, the
connecting rods at low-
of clutch discs. Beginning Feb. 15, inders and pistons. This is no more than motor is likely to be made noisier rather
er end ............ 2.35 1.70 the thickness of a hair or of this paper. This
191 7, the following prices, including ma- than quieted. There is also the dang...r of
terial and labor, are effective: Rebushing one single cyl- does not mean that a motor will not run breaking the new piston by striking the
inder connecting rod at satisfactorily unless fitted perfectly, but shoulder constantly.
List Net rather that after covering many thousand
both ends, 1914, '15. Cases have come to our at!Pntion where
Regrinding one cylinder miles and an overhauling is necessary, a
'16 and '17. . . . . . . . 1.60 1.1 0 several pistons broke in one motor and
and fitting piston, rings, first class job is impossible without re-
piston pin and lock pin.$4.75 $3.50 Rebushing one single cyl- the dealer was at a loss to understand the
grinding.
Refinishing one cylinder, inder connecting rod at cause. The fact is that the cylinder was
Sometimes the repair man will make
including sand blasting lower end, 1914, '15, the mistake to figure that a new piston, worn and that the pistons were broken by
and nickelplating . . . . I. 00 . 75 '16 and '17 ........ 1.25 .90 standard or oversized, will take up the striking the shoulder at the end of the pis-
Rebushing one set twin wear and make a perfect fit. This is ton travel. rr such a cylinder is ceground
connecting rods at both A cylinder need not be nickdplated, erroneous, for the cylinder wears taper, and fitted with the correct size piston, a!!
ends . . . . . . . . . . . . . 3.00 2.25 of course, when reground. However, if that is, more at the upper than at the further trouble is obviated.
Service Department Bulletin No. 47 No. 47 Service Depatlm~nl Bulldin

A new piston should never be fitted to able, so that the question of cost need not inder will wobble and the result will be an Then there is the job of turning up
a motor without regrinding the cylinder. stand between the rider and a first class out of round grinding job. Each grinder oversized pistons if you do not have your
This statement applies to practically every job. We are also able to give prompt represents an investment of better than cylinders reground at our factory. This
case, and if the repairman is guided ac- service on regrinding cylinders, so that a $1 ,000.00. means ordering the piston castings and
cordingly, he will be able to turn out first motor overhauling is not unnecessarily de- Do not be satisfied to have your cylin- turning them up or ordering finished over-
class motor work and make satisfied rid- layed because the cylinders are reground. ders reground elsewhere, for absolute ac- sized pistons and rings and taking a big
ers. A motor that is overhauled and re- It has been the experience of many re- curacy is necessary or the work is worse chance on getting an accurate fit.
ground will run smoother and more quiet- pair men to overhaul a motor without than useless. Our cylinders are ground Our price for regrinding is, we believe,
ly, the compression will be better and the being able to eliminate a knock or pound, the lowest ever offered and all work j,
taper and unless the exact limits are
power and speed greater, than if it is at- although new bearings were fitted and all handled promptly, so that there 15 cverv
tempted to make a job without regrinding. known, the operator cannot make a per-
fits seemed to be 0. K. Maybe even new incentive to having your cylinders rP.·
A cylinder should be reground when it pistons and rings were fitted and the repair fect fit. Generally when cylinders are ground by us. If a cylinder has been cu!
is worn, if it is scored or cut from lack of man was at a loss to know what to do. ground outside of our factory, they are by a loose piston pin. it can generally be-
oil, as well as when the walls have been In all probability, the piston fit was not ground straight and, of course, results are reground. Do not attempt to havf' the cut
damaged by the piston· pin. Do not think accurate as above explained and if the far from what they should be. filled and to use the same piston.
that a good fit can be made by lapping cylinders had been reground, the motor
in a new piston. would have run as sweet and smooth as a
Our charge for regrinding is reason- new job.
Pack Cylinders Carefully to Avoid Breakage
Pack cylinders carefully for shipment. make the latter as near the dimensions o!
How to Measure Cylinders and Pistons Remember that all merchandise is sub- the cylinder as possible, '" that tlw cy 1w
jected to rough handling in transit and der cannot be thrown acound. Protect
The correct way to determine the pis- is fitted with not more than .003 inch that cylinder flanges are easily broken. If with excelsior or paper.
ton fit is to measure the piston at the bot- clearance. When a motor is taken apart you pack a set of cylinders in one box or Address every facto~y shipment wry
tom, the cylinder Y4 inch from the upper for overhauling, measure the cylinders and package, place excelsior, paper or burlap plainly-Service Department. TI.e rea-
end of the stroke. The piston is largest pistons as just explained and if the clear- between them so that they cannot strike. son for this is explained in biJI!etin N0
at the bottom, the cylinder at the top ance is found to exceed .008 inch, have If a cylinder is shipped in a wooden box, 42.
after considerable wear. Therefore, they the cylinders reground if a first class job
is specified.
are to be measured as just suggested.
When a set of micrometers is not at
A set of inside and outside micrometers hand for measuring, try the piston fit in Regrinding Does Not Weaken Cylinders
are necessary to do accurate work and the cylinder. If there is more than three
since accuracy is necessary for good re- paper thicknesses of play between the Sometimes we are asked whether re- cylinder is generally not enlarged more
sults, every first class repair shop should cylinder and piston walls, the cylinder grinding weakens a cylinder. The answer than .0 I 0 inch. At that rate, the cylin-
have a set of micrometers. First class in- should be reground. The motor will re- is NO. A cylinder can generally be re- der can be reground a number of times
struments can be bought at a well stocked tain its power, speed and quiet running, ground a number of times and with the This is based on the assumption that good
hardware or tool supply house. if cylinders are reground about every two exception of cases where a piston pin had
oil is used and that the motor is kept free
A new motor or a reground cylinder seasons. cut the cylinder walls, we do not know
from carbon, dust and grit by frequent
of an instance where a cylinder had to be
replaced because it had been reground. flushing. Hard carbon, dust, sand and
We never remove more stock than other foreign matter will cau'e unneces-
Why Cylinders Should be Reground at our Factory necessary. On the first regrinding, the sary wear if the motor is not kept clean.

Most dealers are in a position to do Our facilities for regrinding cylinders

first class repair work and we urge that are the very best. Two special grinders
you do your own motor work, unless a have been installed in our repair depart- Regrinding Increases Power
rider specifies a factory job. However, ment in the service building. These grind-
when it comes to regrinding cylinders and ers are equipped with special fixtures for Sometimes a rider wishes to increase the the limit, the walls would, of course, be
similar operations, as explained herein- counterbalancing the valve chamber of horsepower of his motor by cylinder re- weakened. If a motor is enlarged .0 I 0
after, be satisfied only with the best and the cylinder. Without this fixture a true grinding. This is not recommended be- inch or .020 inch, the cubic displacement
send your work to our factory. grinding job is impossible because the cyl- cause if the cylinders were ground out to is increased very slightly. The displace-
Seroice 'Department Bulletin No. 47 No. 47 Service Dtparlmenl Bulle lin

ment of a twin motor is 60.34 cu. in. If do so by having his cylinders reground, new connecting rod is also furnished at a ton should be specified, since this was
the cylinders are ground .010 inch over, even though the horsepower of his motor reasonable price to enable using the 191 7 standard in our 1916 ~idecar motor con-
sized, the displacement is increased to only is not increased. piston. struction. If the cylinders are reground
60.69 cu. in. When it is desired that the pistons be Twin cylinders should be reground in
in sets, three ring p1stons with \ 8 inch
Naturally, regrinding and the fitting of lapped in after regrinding, which is the sets whenever possible. although this is not
oversized pistons increases the power of a same as running them in, we will do so at necessary. When one cylinder of a 1916 compression plates, as already referred to,
motor, because a perfect lit is made and an additional charge of 50 cents per cyl- sidecar motor is reground, a two ring pis- will be fitted.
lost compression restored. Therefore, a inder. If the pistons are to be lapped in,
rider who wants to increase his power can specify in your letter of instructions.

Some Dealers Carry Exchange Cylinders

Some dealers carry one or two sets of cylinders fitted with pistons, rings and
Oversized Piston Pins Fitted if Specified reground cylinders in stock, so that when pins, on hand, for all practical purposes
If on taking a motor apart, it is found ton pins, when furnishing new pins on a a motor is brought in for overhauling, the as good as new, that we will dispese of
that the piston pin bushings are slightly regrinding job. Of course, if a bushing rider can be given immediate service by at reasonable prices to such de~lers as
worn, a perfect lit can generally be made exchanging cylinders. As already slated, wish to carry an extra set or two. You
is worn considerably, it is best to renew it,
by fitting slightly oversized pins. There- our service on regrinding cylinders is very may have a set or two of old cylinders on
fore, when specified, we will be glad to for it is not advisable to fit a considerably prompt, but it pays when you do consid- hand that if reground. would be made
lit .002, .003 or .004 inch oversized pis- oversized pin to a new piston. erable motor overhauling to carry one or serviceable and could be used for ex-
two extra sets of cylinders, so that you changes. When exchanging cylinders, th~
can give the rider who does not want to rider's cylinders must be examined care-
lay up his machine more than 24 hours, fully to see that he does not get a better
How to Distinguish and Order Rings for a Reground Cylinder as good a job as the rider whose cylinders set than his. If the cylinders are about
you can refer to the factory. alike, they can be exchanged at the price
Cylinders are always reground to· cer- size, the standard cylinder measurement We have a number of sets of reground of regrinding plus express charge,.
tain standard sizes. No more stock is re- being 3.309 to 3.310 inches. A cylinder
moved than necessary. All reground cyl- measuring 3.330 inches, or .020 inches
inders are therefore .0 10, .020, .030 oversized is marked R-3, 3.340 inches
inches, etc., oversized. This simplifies R-4, et cetera. Therefore, when order-
carrying oversized rings in stock. Odd ing new rings for a reground cylinder, it
Why Connecting Rods Should be Rebushed at our Factory
sizes need not be carried. is only necessary to specify the number The fitting of steel connecting rod bush- ing, rods can be exchanged and the worn
The bore of a reground cylinder is dis- ings is as specialized as cylinder regrind- bushings replaced at the factory. The
on the cylinder base. If the motor is one
tinguished by a number stamped on the ing and should only be done at our fac- bushings should be repiaced when the con-
that you have not seen before, inspection
cylinder base, sprocket side, near the for- tory. The bushings are ground on a spe-
will show whether it has been reground necting rods have up and dov.-n play.
ward edge. A cylinder measuring 3.320 cial grinder after they are fitted, since they
at our factory. This method of marking W'hen the bushings are worn badly, they
inches is marked R-2. R indicating that naturally distort when pressed in the rods
it has been reground, the number 2 being has been in effect for about 16 months. are grooved or ringed. Generally when
and a perfect fit is impossible without
the second number of the decimal. There- Of course, standard rings are not to be grinding after fitting. For this reason, the the bushings need renewing, the roller
fore R-2 really means .010 in..n over- fitted to an oversized piston. steel connecting rod bushings are not fur- bearings and crank pin shculd also be re-
nished on parts orders. It pays to carry placed. Oversized rollers are furnished
an extra set of connecting rods, so that in sizes from .000 I (one ten thou·
when a motor is brought in for overhaul- sandth) inch up.
Sidecar Motor Should be Fitted with Compression Plates
A motor used in sidecar service should retail each. See service bulletin No. 44
be fitted with Ys inch compression plates for further particulars.
between the cylinders and pistons, the All reground cylinders are fitted with
Accuracy is Necessary m Assembling Motor
same as the 191 7 sidecar motor. There- 19 I 7 pistons. These pistons have larger In assembling cylinders, pistons and attention where pistons were put out of
fore, when having such a motor reground, bearing surfaces than the pistons of some connecting rods with the motor after re- round and never were trued and rounded
specify three ring pistons and compres- of the earlier seasons. When an earlier grinding and rebushing, great care must up, so that they would not travel true and
sion plates. The latter sell at 20 cents than 1912 single cylinder is reground, a be taken. Instances have come to our the advantages of regrinding were there-
Suvia D~parlm~nf Bulletin No. 47

fore lost. The same holds true if a con- is recommended. It would be unfortunate
necting rod is sprung very slightly. to lose the brnefits of a regrinding job by
In a service bulletin to be issued in the some slight carelessness in overhauling or
n~ar future, every operation pertaining to in assembling. The use of the factory
motor overhauling will be covered thor- piston squaring plate is strongly recom-
oughly. Most Harley-Davidson repair- mended for accurate work in lining up
men appreciate the importance of abso- pistons and connecting rods. The use of
lute accuracy in motor work and a careful this plate will be described in the bulletin
reading of the motor overhauling bulletin just referred to.

Never Use a Piston Pin Lock Pin Twice

I I will be noted that a new piston pin closing, the lock pins are naturally weak-
lock pin is furnished with every reground ened and it does not pay to take a chance
cylinder. The reason for this is that a on a piston pin working loose and cutting
lock pin should never be used twice. As the cylinder walls because as inexpensive
soon as you take a motor apart, throw the a part as a piston pin lock pin was not
lock pins away. From spreading and renewed.

Clutch Discs Should be Relined at Our Factory

Relining clutch discs is another opera- his own relining, but it is cheaper to send
tion that can be done best at our factory. the discs to the factory. In addition to
Smooth clutch action is essential to good this, a perfect job is made. Most dealers
clutch service. Every clutch disc that we are referring their clutch discs to the fac-
reline passes through one of our giant tory and we know that everyone will, once
presses, "bumped" as we call it, giving it the advantages of factory relining are un-
the perfect, even friction surface, so derstood. Excellent service is given on
necessary for smooth clutch action. When this work, for all discs received at the fac-
a set of discs need relining, return them tory are exchanged for discs already re-
or exchange for a set from your stock,
lined, so that there is no delay. The sub-
then return to the factory for relining, or
hold them until you have accumulated a ject of fitting clutch discs and adjusting
sufficient number to get the benefit of the the clutch bearings will be covered in a
quantity price. near future bulletin and reference to these
Clutch linings and rivets can be ob- instructions is recommended in this con-
tained from us, if a dealer prefers to do nection.
Service Dept. Bulletin No. 51 Service Department Bulletin

No. 51. April 25, 1917 Harley-Davidson Motor Co., Milwaukee A Suggestion Regarding Service to Commercial Users
It has been suggested that we furnish will be glad to have you give us your
public service corporations and others who ideas of this plan. We would not fur-
use Harley-Davidsons in large numbers nish all the service bulletins but only such
Mention the Motor Number To Increase Confidence in the Dtaler as would be of direct interest and would
t'sing old Mode~ for Their Parts Regarding Timer Uller Scretv DX-10/2 and maintain their own service depart-
ments, with such service bulletins as will help the cause of good service.
A Suggestion Hegarding Sm•ice to Com- Oiling the Inlet V al"Ve Stems The above suggestion was made by a
mercial Users be of direct interest to the men responsible
dealer after reading the recent bulletin on
for the good running of the machines. Service to Commercial Users. This dealer
Large corporations such as telephone,
Mention the Motor Number electric and gas companies generally main-
believes that since the people that he has
in mind do their own service and repair
Whe11ever you write us regarding a formation given, bec~use the motor num- tain a repair department to look after their work, it will pay to give them the benefit
madune, mention the number of the motor. ber was not mentioned. machines. If you number one or more of such service bulletins as will be of
Tf,;, information is frequently necessary Sometimes a dealer will refer to a ma- of such concerns among your users we direct help. Let us hear from you.
to answer a letter promptly and intelli- chine as "my demonstrator" or "the ma-
chine I sold Mr. so and so." If the rna- To Increase Confidence in the Dealer
gen!ly. ~lith the different models in ser-
chine is registered as the dealer's demon-
vice it is no! sufficient to refer to a ma- Your attention is called to the article ter and that by means of our bulletin ser-
strator or if the rider has registered it,
rhinP .1s a 1917 or 1916 model. it is of course a simple matter for us to in the current issue of The Enthusiast vice each dealer is kept in touch with the
Thi5 may seem to be a small point but headed: Do You Know What is Being most efficient means of keeping all of his
look up the motor number; otherwise,
;, in fact v~ry important. It has happened there may be a delay or inaccurate in- Done to Give You Service~ This article machines in good working order.
mc're than once that important informa- formation may be rendered. The sure tells the rider why he should go to his The effect of this message is sure to be
dealer when his machine needs attention. felt, for The Enthusiast reaches every
: ,,~, '"'' been delayed, or inaccurate in- way is to mention the motor number.
There are still some riders who have their registered Harley-Davidson rider and is
machines overhauled at some other shop read with interest and attention. This
Using Old Models for Their Parts than their dealer's, because some one else was brought home by the avalanche of re-
offers to do the work cheaper. turns received from the mailing card en-
::;.~•metimes a machine taken in trade is The carburetor can generally be over- This article explains that the dealer's closed with the last number of The En-
wo,•h more if stripped for its parts than hauled at considerably less than the cost facilities are the very best, that every thusiast, asking the riders whether they
,j rf'sold. Generally such a machine of a new one. The makers will do this dealer is furnished with factory tools and wanted their names continued on the mail-
mml be repaired to place it in good run- work at reasonable cost as explained in wrenches at reasonable cost, that a large ing list. Everything done to bring the
ning order and the dealer in some cases service bulletin number 46. The magneto number of dealers and repairmen took a dealer and rider together to cement their
hnds 11 difficult lo break even. If such a course of training at our factory last win- relations is sure to help business.
as a rule is 0. K., or can be placed in
machine is stripped for its parts it i~ very
serviceable condition at reasonable price.
likely that thf! dealer will more than
We could go on this way through the Regarding Timer Lever Screw DX-1 012
break even on his investment. That this
plan is practical is best attested by the whole machine. Do not use the wrong length screw in a result the circuit breaker was thrown
fact that it is being used by a number of Of course good judgment must be used fitting the timer lever on the Remy gen-. out of adjustment, the points did not break
in sizing up a machine. There may be erator. It has happened several times with an equal gap and the motor did not
dealers.
run satisfactorily.
Generallv. a considerable amount of little call for parts of a certain model be- that a longer than the regular screw was
material of a machine that has seen sev- This is a small item but just because it
cause there aren't many machines of that used. This screw protruded through the
eral seasons' service is found in service- seems unimportant may easily cause the
model in the dealer's territory. You can, cover so that the nut on the end of the repairman a lot of worry. Always use
able condition or can be placed in such however, appraise a machine for its parts circuit breaker shaft would strike it. As the regular screw DX-1012.
condition at small expense. This ma- value after careful examination. It may
terial can be used in repairing other ma-
chines. Cylinders can be reground, con-
happen that it will cost more to place a Oiling the Inlet Valve Stems
necting rods rebushed and be used ad- machine in first class mechanical condi- Wear of the inlet valves and housings of light oil-regular motorcycle oil--to
vantageously for exchange service, espe- tion than it can be sold f,or. In that case can be reduced to practically nothing_ if the inlet valve stems every week during
cially if a dealer does considerable over- the machine should by all means be used the following suggestions are applied .. the first four or five weeks of service and
hauling. for its parts. Applying a little oil to the inlet valve every two or three weeks thereafter. The
stems will lengthen the life of the valves oil will tend to glaze the valve stem and
and the valve guides. Apply a few drops gilide, thereby reducing wear.
 Service Dept. Bulletin No. 52 Ser1>ice Department :IJulletin

No. 52. May 10, 1917 Harley-Davidson Motor Co., Milwaukee part with a metal tag, stamped with the only the parts that are to be refinished
repair order number, as there may be one and make your instructions clear. Also
hundred or more jobs en route through our bear in mind that any quotations on re-
M oke Your Instructions on Every Repair HoD> to Apply Harley-Davidson Tram- enameling department at the same time. enameling do not include the labor for
job Complete fen Whenever possible, do your own strip- tagging the parts and other incidental
Instructions far Altaching Sidecar Top Important Notice ping and ship to us only the parts that are
operations. This labor will not exceed
to be refinished. This means to take
apart forks and transmissions, remove a few hours on most jobs.
Make Your Instructions on Every Repair job Complete frame and tank fittings, etc. Wheels need While the above instructions apply
not be stripped if the hub shells and especially to re-enameling, they hold true
Parts that are returned to us for re- Taking your own experience in repair spokes are to be re-enameled, as is now of all repair work. Make your instruc-
enameling _nearly always need repairing of work into consideration, you will agree done very frequently. However, the hub, tions on each jQb complete. Leave noth-
!lOme kind before the job can be com- with us that a definite system of giving brake and clutch parts must be removed ing in doubt.
pleted in first class shape. Frames and complete instructions on re-enameling and, Irom the hub shells. When you return a set of forks to be
forks are frequently found bent, tanks and in fact on all repair work, is necessary in In stripping parts for re-enameling we, repaired, instruct us whether or not to re-
mud guards dented, and verv often other order to avoid misunderstanding and en- often find fittings worn or damaged be- enamel them. Do not take it for granted
parts arri>e in a damaged co~dition. able us to give you prompt service. yond repair. Head fittings, front hub that because a set of forks are scratched
It has been our experience that if a It has already happened that the repair cones or rocker plate bushings are found we will re-enamel them. We must have
rider goes to the expense of shipping his work on a re-enameling job exceeded the worn, fork springs broken, sprockets worn your instruction to that effect. When you
machine or certain parts to the factory cost of the enameling itself. If the dealer and so on. Frequently it is out of the ship to us a cylinder for regrinding and
for re-enameling, he expects a first class has no previous understanding with the question to assemble the job with such want the valves ground in or refaced, in-
job and does not want us to re-enamel his rider and the factory, a misunderstanding parts. There is also a natu!al disinclina- struct us accordingly. If you return a
frame and forks without straightening and is apt to result. When you quote a rider tion on our part to assemble a machine or number of parts for re-enameling and cer-
lming, if such work is necessary. It is out an approximate price on re-enameling or parts with damaged parts. If the rider tain nickelplated fittings are included, tell
of question to write for specific instruc- when you ship to us parts of machines afterwards finds such parts he would feel us whether or not to renickel them. If
tions on every re-enameling job that needs from your used stock, always take the that the factory did not make a first class you want to leave a job to our best judg-
additional attention. To do so would foregoing into consideration. As we re- job. Therefore, when parts are found ment or want an estimate, instruct us ac-
mean considerable delay and extra detail ceive parts for re-enameling from dealers beyond service, new parts are fitted and cordingly.
work. On the other hand, when you all over the country, you can understand charged for. If, in such cases the dealer It is necessary to have a definite work-
quote a rider on a re-enameling job, you how important it is to give us definite in- and rider figured on the actual re- ing plan, as outlined, on each repair job;
naturally must know about how much the structions and to estimate the job care- enameling only, the charge would be first, to save time and make good service
factory work will cost you. To avoid mis- fully for the rider. larger than expected. possible; second, to be able to turn out
understanding the following plan will be Our current prices on re-enameling For these reasons we prefer that on a every job exactly as you and the rider ex-
put into effect at once with your help. parts and complete machines do not in- straight re-enameling job you ship to us pect it.
When you ship to us a job for re- clude any labor for taking apart, reas-
enameling. whether it consists of one part sembling and making repairs. The labor
or a complete machine, word your in- necessary to tag each part before referring
structions according to the following, de- the job to our enameling department, for Instructions for Attaching Sidecar Top
pending on what you want done: collecting the parts for shipment after re-
When a sidecar is ordered equipped the forward top irons ·or props. figuring
I. Re-enamel only. Make absolute- enameling, and doing other incidental
ly no repairs. with top, the latter is attached without from the front end of the upholstering.
wor,k, is charged for extra. It is not in-
2. Re-cnamel and make all necessary extra charge. When a sidecar top is and about 4 inches to both sides of the
cluded in the charge for re-enameling.
repairs. ordered separately, it is furnished com- corners on the rear of the body for the
Since this labor varies on practically every
3. Re-enamel and make the follow- plete with fittings and if the following in- rear rod.
job it is impossible to give a definite quo-
ing repair~. (Then specify what work structions are carried out carefully it will Fit the rear rod first. It will be nece&-
tation excepting on the actual re-enamel-
you want done.) be a simple matter to make a first class sary to twist the rod back and forth in
ing. Bear in mind that there is other
4. Re--enamel and make necessary job of attaching it. order to pass it along under the uphol-
labor besides re-enameling connected with
small repairs. If considerable work is Be careful not to damage the uphol- stering. Be sure to have the rod rest on
every job. For instance, in order to pre-
needed, submit estimate. stering while removing it to fit the top the sides of the body and draw it back.-
vent confusion, we must distinguish each
irons to the body. Loosen just enough ward against the rear of the seat. After
upholstering to be able to fit the irons. the rod has been passed through properly.
This will amount to about 10 inches for cut a small hole in each side of the up-
 No. 52 No. 52 Service Department :Bulletin

bolstering just large enough to pass the Drill two holes with a No. 28 drill at
rod through. Center the rod properly on these points. Fasten both front strap loops
How to Apply Harley-Davidson Transfers
the wooden strips of the body by using with one bolt and nut. Line the loops This is a subject with which most deal- careful that the transfer is not wrinkled.
the holes in the rod as a guide. Then up with the edge of the cowl away from ers and repairmen are familiar but for the Press the transfer firmly in place.
with a 3/ 8-inch drill or auger put the the center glove fastener. Drill the other benefit of those who have not applied The transfer is made up of two thick-
clamp bolt holes into the wood strip. holes and fit the screws and nuts. transfers before, or who have not been nesses of paper, the top layer of which
Place the bushings or collars on the can be removed at once without wetting,
Make the rod secure by passing the 3/8- successful in every case, we offer the fol-
front top irons, fit the sidecar top, the by loosening the edge and slowly pulling
inch bolts through the wood strip from lowing instructions:
spring nut locks or lock washers and the it off. This leaves a thin layer of paper
the bottom and then through the rod and After the final coat of enamel has dried over the transfer. Moisten with water
drawmg the nuts tight. Replace the up- nuts. Bend part of the nut lock or lock thoroughly, rub lightly with mineral wool until saturated. Then remove the paper
hobt.ering as carefully as possible to make washer against the shank of the nut, there- or fine sand paper. Then dust carefully carefully.
a neat appearing job. by locking it secure. and make sure that the surface to which Have a piece of cheese cloth that has
Spread the top, cross the front straps the transfer is to be applied is perfectly been dipped in gasoline ready and rub
To fit the front irons, loosen the top
and pass them through the loops on the clean. lightly over the transfer and surrounding
of the upholstering from the front end as
cowl. Adjust the straps so that the dis- surface. This will take off all surplus
already explained. Measure forward Apply a thin coat of quick drying var-
I 9 I 2 mches from the outside rear end tance from the highest part of the cowl varnish or sizing. Dry off the gasoline
nish or gold sizing to the face side of the
to the bottom of the top is 19 I /2 inches. with a clean piece of cheese cloth and the
of the body, being sure to have the ruler transfer and allow to dry until it becomes
Fit the fasteners or clasps for the rear enameled surface is ready for the varnish.
or scale in line with the rear rod. Mark tacky, that is, so that it will not stick to
top straps on the rear of the body imme- If these instructions are followed care-
the wood strip at this place. This mark the lingers when rubbed lightly, but will fully, a first class job will result. Trans·
1s to he the center point of the front iron diately below the padding and about 3
stick if pressed firmly. Then place the fers for the tanks, frame head and tool
or prop when it is fitted. Be sure to get inches from the outer edge so that the
straps hang perfectly straight. Firmly transfer on the enameled surface being box are furnished free of charge.
this measurement accurate or the top will
not f,~ properly. press the rear strap eyelets over the fast-
ener screws.
Hold the non against the side of the
wood strip with the stud in line with the
To lit the rear curtain fasteners draw IMPORTANT NOTICE
the curtains reasonably tight so as to get The design of the 1917 motor requires that from .008 inch to .010 inch
mark and drill two I 1 4-inch holes. It is all wrinkles and looseness out of them.
advisable to drill these holes so that they clearance be allowed· between the exhaust valves and lifter pins. On the
Note carefully where the eyelets are and 1916 and earlier models a closer adjustment was recommended. The 191 7
will line up with the upper holes in the fit the curtain fasteners. push rods are adjusted with .004 inch clearance, the same as heretofore.
side iron. Cut holes into the upholster- Attach the front curtain to the top and It has frequently happened that in checking over the exhaust valves
ing the same as was done for the rear top to the fastener on the cowl. Then note of a 191 7 motor dealers and riders have readjusted them with the clearance
rod. Fit the bolts with the heads on the
where the eyelets are and mark the posi- recommended for the 1916 and earlier motors. This is wrong and we
outside and draw the nuts secure. Then recommend that you see that the exhaust and inlet valves on your 191 7 motors
tion for the two curtain fasteners. The
fit the two wood screws and replace the are adjusted correctly. If the adjustment is too close by only .001 or .002
proper place will be about 7 I /2 inches
upholstering carefully. inch, the valves are likely to be held open after expansion and exposed to
from the outer edge of the strap loops.
Place the bow rests on the bow rod Do not draw the front curtain too tight the direct heat of the charge. Furthermore, the timing of the motor is
and adjust them properly after the top over the cowl and use the same No. 28 changed. This will result in unsatisfactory motor service.
has been fitted. Several cases have come to our attention in which it was believed that
drill for drilling the rivet holes into the
The threaded glove fastener or clasp carburetor trouble was being experienced but investigation showed that the
cowl. The rivets which clamp the cur-
with the hexagon head is to be fitted on trouble was due to too close adjustment of the exhaust and inlet valves. The
tain fasteners are split and can easily be inlet push rods should be adjusted to allow .004 inch clearance between
top of the cowl about I inch from the spread with a screw driver. the valve stems and inlet levers. This adjustment is the same as in previous
edge exactly in the center. Drill a hole Attach the left side curtain to the top seasons.
at this point with a No. 28 drill. The and fit the fastener to line up with the If you have a 191 7 motor that spits and misses at high speed, regardless
fastener is firmly held with a clamp nut eyelet in the side curtain. The remaining of changes in the carburetor adjustment, check over the inlet and exhaust
placed under the cowl. curtain fastener is to be placed on the adjustments and you will most likely find that they are not correct. The
Measure 4 I /2 inches to both sides right side of the sidecar body so that it exhaust and inlet valves must be adjusted and the clearance measured when
from the center of this fastener and about lines up with the eyelets in the right side the motor is cold.
2 3 4 inches from the edge of the cowl. curtains.
 No. 53 Savio· 'D~parfmenl Bulletin

Importance of Correct Shifter Rod Adjustment

No. 53. May 21, 1917 Harley-Davidson Motor Co., Milwaukee
Very often little thought is given to the two-speed mechanism is in neutral po-
shifter rod adjustment. As long as the sition the shifter handle on the tanks
shifter handle on the tanks will not jump must be in a perpendicular position,
The Harley-Davidson T rva-Speed Hub Inspection a/ Parts to neutral automatically while riding the shifter lever "4 3" must be in line
Lubricate the Trvo-Speed Hub every Fit Roller Bearing Cone and Driving along in either high or !ow speed, the
Hub Gear with the rear axle "24" and the shifter
1,500 Miles average rider is inciined to take it for
Horv to Remove the Driving Hub Gear rod lever "26" must be at equal angles
Importance of Correct Shifter Rod Ad- granted that e\erything is in proper ad-
Horv to Fit the Hol!er Bearing Driving justment. This, however, is not neces- with both shifter rods. This adjust-
justment Hub Gear ment will allow the dogs to engage
sarily true, because it is very important
To Adjust tl1e Shi/lcr Rods H orv Ia Assemble the T rvo-Speed Hub to have the dogs of the clutch collar entirely, insure easy shifting, reduce wear
Horv to Strip the Trvo-Speed Hub Inspecting and Overhauling the Clutch "20," right cone "21" and of the inner and allow the clutch collar pin "9" to
hub shell "2" engage fully. If only the enter the lock holes "H" in the clutch
edges of the dogs engage there is great gear cone "13." If the clutch collar
The Harley-Davidson Two-Speed Hub danger of chipping off the corners and if pin cannot enter these holes, if the
this practice is c0ntinued long enough, pin and cone are worn, or if the clutch
This bulletin covers the care and ad- or low speed, nor lubricate the two-speed these parts of the two-speed mechanism collar spring screw (not shown in illus-
justments of the Harley-Davidson two- hub at other intervals than recommended. will be ruined.· tration) is loose, it will be impossible to
speed hub as well as instructions for strip- Never try to force the shifter lever into To make sure that the adjustment is get the shifter handle to slay in either high
ping, repairing and assembling. high or low speed when the machine is 0. K. apply the following: When the or low speed.
standing still and the motor is not run-
While the two->peed model is no longer
ning. The dogs may not be in line and
manufactured, there are many thousand to force the lever may bend the shift
two-speed machines in service. The two- mechanism. If the clutch is engaged to To Adjust the Shifter Rods
speed hub naturally needs attention from the point where it has the slightest trace
time to time and while its care was out-
It will be understood from the above lever forward and backward. If the
of a drag, the dogs will line up readily that generally when the two-speed does lever will not line up, loosen the shifter
lined in the 1914 manual, frequent in- and allow easy shifting. The time to
quiries from dealers ar.d riders show that not shift readily, or when the speeds do pinion nut on the shifter pinion sufficiently
make adjustments is generally after the to allow moving the shifter lever as may
there is need of a clear explanation of how position of the rear wheel has been not engage properly, the shifter rods are
to take apart, repair and re-assemble the out of adjustment. Re-adjust the long rod be found necessary. After the long
changed in adjusting the chains. Then shifter rod and the shifter lever have been
two-speed mechanism. This bulletin is do not change the position of the shifter first. This rod has right threads and
written with that in mind. should be adjusted so that the shifter adjusted place both in neutral position and
lever "4 3" on the shifter pinion washer
adjust the short shifter rod so that the end
Never make any unnecessary adjust- "42" but adjust the short shifter rod handle on top of the tanks is perpendicu-
will just fit over the stud of the shifter
ments, nor force the shifter lever into high "38" as explained hereafter. lar in the neutral position and at the same lever.
time the shifter rod lever should be at After the proper rod adjustment has
equal angles with both shifter rods. been obtained note whether the lugs or
Disconnect the shifter rod end "4 5" stops on the shifter bracket "22" are pre-
Lubricate the Two-Speed Hub Every I ,500 Miles from the shifter lever "43" so that the venting the shifter arm "23" from fully
The two-speed hub should be lubri- shifter lever can be properly adjusted on engaging in either high or low speed. If
heating. Let the lubricant cool before
cated with Harley-Davidson non-fluid using the machine. Never put in more the shifter pinion washer. The shifter the arm strikes these stops before low and
lubricant or a good grade of medium grease than just specified and do not use lever must be in line with the axle when high speed are fully engaged, file off the
heavy cup grease every 1,500 miles. To a thm lubnca;Jt, because the lublicant the mechanism is in neutral position. To stops on the shifter bracket as may be
lubncale the hub remove the axle end find the neutral position, move the shifter required.
will have a tendency to work out of the
screw "25." Load a grease gun, such hub and into the brake, preventing the
as is listed in our accessory catalog, about brake from holding. After adding the
one-fifth full, place the nozzle in the end lubricant replace the axle end screw firm- How to Strip the Two-Speed Hub
of the axle and discharge the contents ly. To insure easy shifting put a drop of
into the hub. In cool weather when the oil on the various bearings of the shifting If for some reason the two-speed hub used at the factory is recommended. Tak-
lubricant is thick and hard, thin it by rods daily, or at least once each week. must be taken apart, as for fitting a new ing ior granted that the rear wheel has
axle, the following method of stripping been removed from the machine, proceed
Sen>ice Department Bulletin No. 53 No. 53 Suvicc D~parlmenl Bul/t!lin

by removing both axle clamp nuts "34," found to stick tight, lightly tap the spoke
left side spacer washer "32" and rear side of the clutch hub shell with a rod or
axle adjusting clip. Remove the actuat- hammer handle. Push the axle toward
ing nut "A" and collar "C" by turning the right to release the nineteen steel balls

• 0
this assembly to the right, then take off at "F," taking care not to lose any.
the actuating ball retainer with balls "B" Remove the right cone "21," .take off
and the actuating plate "D." the two screws clamping the hub shell
4 5 6
2 3

/
/
E

/
F - e 9 10 12
I" 13 I.

IB 16 17 18 19
00 20 2!

22 23
=· 24

Crose Section of Two-Speed Hub

0
25
i
26
y 27
I
26
-·- 29
(f) ...,Jo_)/

30
0
31
0
32
0
33
0
34

Remove the hexagon I/ 4" x 24 nut band "39" and then the band. With a
clamping the shifter lever and take off dull chisel remove the six woodruff keys
the lock washer, lever "43" and shifter "8" which lock the inner and outer hub v ~ 37
pinion washer "42." The shifter pinion shells "1," "2" and "7." To remove 35 36
"41" can be removed from the shifter
body "40" by lightly forcing it down-
ward. Withdraw the shifter body from
the keys take a dull drift or chisel. Place
the drift or chisel against the left edge
of the keys, strike the chisel with a ham- 38 -
0 ......., ...
the axle and remove the adjusting clip mer and the keys can be rocked out of
L,
~
(not shown in illustration), washer "30" the key ways. 0 ~) ~ ~
and brake side cover assembly "E." With factory wrench CK-6 furnished
40 41 42 4!1 44 45 4$ 47
Remove the left cone lock nut "33," especially for the purpose, remove the
bushing "36" and the actuating worm inner hub shell assembly from the outer ----·----- . ---------- --
cone "14." The entire clutch assembly hub shell by turning to the right. The
Component Parts of Two--Speed Hub
with the driving hub gear "S" can then wrench fits the dogs of the clutch collar
be removed from the rear hub. If it is which is locked by dogs to the inner hub
Service Dept. Bulletin
No. 53. May 21, 1917 Harley-Davidson Motor Co., Milwaukee

The H arle:y-Davidson Two-Speed Hub Inspection of Parts

Lubricate the Two-Speed Hub e"Ve7)1 Fit Roller Bearing Cone and Driving
1.500 Miles Hub Gear
How to Remove the Driving Hub Gear
Importance of Correct Shifter Rod Ad~ H on> to Fit the Roller Bearing Driving
justment Hub Gear
To Adjust the Shiftet Rods How to Assemble the Two-Speed Hub
How to Strip the Two-Speed Hub Inspecting and Overhauling the Clutch

The Harley-Davidson Two-Speed Hub

This bulletin covers the care and ad~ or· low speed, nor lubricate the two-speed
justments of the Harley-Davidson two- hub at other intervals than recommended.
speed hub as well as instructions for strip- Never try to force the shifter lever into
ping, repairing and assembling. high or low speed when the machine is
standing still and the motor is not run-
While the two-speed model is no longer
ning. The dogs may not be in line and
manufactured, there are many thousand to force the lever may bend the shift
two-speed machines in service. The two- mechanism. If the clutch is engaged to
speed hub naturally needs attention from the pomt where it has the slightest trace
time to time and while its care was out- of a drag, the dogs will line up readily
lined in the 1914 manual. frequent in~ and allow easy shifting. The time to
quirics from dealers and riders show that make adjustments is generally after the
there is need of a clear explanation of how position of the rear wheel has been
to take apart, repair and re-assemble the changed in adjusting the chains. Then
two-speed mechanism. This bulletin is do not change the position of the shifter
written with that in mind. lever "4 3" on the shifter pinion washer
Never make any unnecessary adjust- ''42" but adjust the short shifter rod
ments, nor force the shifter lever into high "38" as explained hereafter.

Lubricate the Two-Speed Hub Every 1,500 Miles

The two-speed hub should be luhri- heating. Let the lubricant cool before
c.ated with Harley-Davidson non-Buid using the machine. Never put in more
lubricant or a good grade of medium grease than just specified and do not use
heavy cup grease every 1.500 miles. To a thin lubncant. because the lublicant
lubricate the hub remove the axle end will have a tendency to work out of the
screw .. 25." Load a grease gun. such hub and into the brake, preventing the
as is listed in our accessory catalog, about brake from holding. After adding the
one~fifth full, place the nozzle in the end lubricant replace the axle end screw firm~
of the axle and discharge the contents ly. To insure easy shifting put a drop of
into the hub. In cool weather when the oil on the various bearings of the shifting
lubricant is thick and hard, thin it by rods daily, or at least once each week.
No. 53 Service 'Department Bulletin

Importance of Correct Shifter Rod Adjustment

Very often little thought is given to the two-speed mechanism is in neutral po-
shifter rod adjustment. As long as the sition the shifter handle on the tanks
shifter handle on the tanks will not jump must be in a perpendicular position,
to neutral automatically while riding the shifter lever "43" must be in line
along in either high or low speed, the with the rear axle "24 .. and the shifter
average rider is inclined to take it for
rod lever "26" must be at equal angles
granted that e' erything is in proper ad~
justmenl This, however, is not neces- with both shifter rods. 1lUs adjust·
sarily true, because it is very important ment will allow the dogs to engage
to have the dogs of the clutch collar entirely, insure easy shifting, reduce wear
•'20," right cone "21" and of the inner and allow the clutch collar pin "9" to
hub shell .. 2" engage fully. If only the enter the lock holes "H'' in the clutch
edges of the dogs engage there is great gear cone ··13." If the clutch collar
danger of chipping off the corners and if pin cannot enter these holes, if the
this practice is continued long enough. pin and cone are worn. or if the clutch
these parts of the tw~speed mechanism collar spring screw (not shown in illus-
will be ruined. tration) is loose, it will be impossible to
To make sure that the adjustment is get the shifter handle to stay in either high
0. K. apply the following: When the or low speed.

To Adjust the Shifter Rods

It will be understood from the above lever forward and backward. If the
that generally when the two-speed does lever will not line up, loosen the shifter
not shift readily. or when the speeds do pinion nut on the shifter pinion sufficiently
not engage properly, the shifter rods are to allow moving the shifter lever as may
out of adjustment Re~adjust the long rod be found necessary. After the long
first. This rod has right threads and shifter rod and the shifter lever have been
adjusted place both in neutral position and
should be adjusted so that the shifter
adjust the short shifter rod so that the end
handle on top of the tanks is perpendicu~ will just fit over the stud of the shifter
lar in the neutral position and at the same lever.
time the shifter rod lever should be at After the proper rod adjustment has
equal angles with both shifter rods. been obtained note whether the lugs or
Disconnect the shifter rod end "4 5,. stops on the shifter bracket .. 22 .. are pre~
from the shifter lever "4 3" so that the venting the shifter arm .. 23" from fully
shifter lever can be properly adjusted on engaging in either high or low speed. If
the shifter pinion washer. The shifter the a1111 strikes these stops before low and
lever must be in line with the axle when high speed are fully engaged. file off the
the mechanism is in neutral position. To stops on the shifter bracket as may be
find the neutral position, move the shifter required.

How to Strip the Two-Speed Hub

If for some reason the two~speed hub used at the factory is recommended. T ak-
must be taken apart, as for fitting a new ing for granted that the rear wheel has
axle, the following method of stripping been removed from the machine, proceed
5erl!ice Department Bulletin No. 53

by removing both axle clamp nuts "34," found to stick tight, lightly tap the spoke
left side spacer washer ''32" and rear side of the clutch hub shell with a rod or
axle adjusting clip. Remove the actual· hammer handle. Push the axle toward
ing nut "A" and collar "C" by turning the right to release the nineteen steel balls
this assembly to the right. then take off at ''F :· taking care not to lose any.
the actuating ball retainer with balls "B" Remove the right cone "21." take off
and the actuating plate "D.., the two screws clamping the hub shell

Crou Section of Two-Speed Hub

Remove the hexagon I/ 4" x 24 nut band "39" and then the band. With a
clamping the shifter lever and take off dull chisel remove the six woodruff keys
the lock washer. lever "43" and shifter "8" which lock the inner and outer hub
pinion washer "42." The shifter pinion shells "1." "2 .. and ·'7." To remove
.. 41 .. can be removed from the shifter the keys take a dull drift or chisel. Place
body "40" by lightly forcing it down- the drift or chisel against the left edge
ward. Withdraw the shifter body from of the keys, strike the chisel with a ham-
the axle and remove the adjusting dip mer and the keys can be rocked out of
(not shown in illustration), washer "30" the key ways.
and brake side cover assembly "E." With factory \vrench CK-6 furnished
Remove the left cone lock nut "33," especially for the purpose. remove the
bushing "36" and the actuating worm inner hub shell assembly from the outer
cone "14:· The entire clutch assembly hub shell by turning to the right. The
with the driving hub gear "5" can then wrench fits the dogs of the clutch collar
be removed from the rear hub. If it is which is locked by dogs to the inner hub
No. 53 Service Department Bulletin

~· ?
.

2 3
fj
...
a 0 5 6

.....
8 -
9
"--""
10 --- 11
__,
12
uA 13 14

7
Q) 0 0 0 0
15 16 17 18 t9
0 0 20 21

h:.
23
•. - B;::$
24
!II !! !!

0
25
&y
26 27
I
28
- 29
30
0
31
0
32
0
33
0
3.4

~ =- 37
_;

35 36

36

0
L______
rJ
40
~
A1
0
42
~
4'
Component Part. of Two--Speed Hub
...
44
~~

45
~

46
~

47
Setllice Department Bulletin No. 53

1 BG207 Inner hub shell (left half)

When ordering two-speed 2 BG207 Inner hub shell (rig~t half)
parts always specify the 3 DG218 Bevel pinion shaft
Factory Number, and not 4 BG217 Bevel pinion
the Photo Number. 5 DG215 Driving hub gear
6 BG213 Driving packing ring
7 BG200a Outer hub shell
8 BG202 Hub shell keys
9 BG224 Clutch collar pin
JO BG223 Clutch collar spring (lower)
II BG222 Clutch collar spring (center)
12 8G22J Clutch collar spring (upper)
13 BG225 Clutch gear cone ( 1914)
DG225 Clutch gear cone ( 1915)
14 DG210 Actuating worm cone
15 DG177 Roller bearings
16 DGI75b Ball race inside
17 DG176 Ball retainer and balls
18 DG175a Ball race outside
19 BG264 Clutch shifter collar
20 8G219 Clutch collar
21 BG220a Right cone
22 8G273a Two-speed shifter bracket
23 BG278a Shifter arm
24 DG262 Rear axle ( 191 5)
CG262 Rear axle ( 1914)
25 80153 Axle end screw( right)
80151 Axle end screw (left)
26 BG286 Shifter rod lever
27 BG297 Shifter lever bracket
28 BG208 Clutch shifter bar
29 8G209b Clutch shifter plunger
30 80328 Axle washer (inside frame)
31 CG265 Axle lock washer
32 80315 Axle washer (outside frame)
33 80696 Left cone lock nut
34 B0693 Rear axle nut
35 CG253 Axle support washer
36 DG248 Axle bushing
37 CGI90 Long shifter rod (IOC)
CG289 Long shifter rod (I OF)
DG190 Long shifter rod ( 11 C)
38 CG288a Short shifter rod
39 8G201 Hub shell band
40 CG189 Shifter body
41 BG199a Shifter pinion
42 BG 19.3 Shifter pinion washer
43 BG258a Shifter lever
44 BG299 Shifter rod clevis pin
45 CG284 Shifter rod end
46 CG296 Shifter rod clevis
47 CG294 Shifter rod link complete
No. 53 Service Department Bulletin

shell. The entire hub shell assembly is the wrench is $1 .25. If the axle is to
removed from the left side of the outer be changed for some reason the clutch
hub and can very easily be taken apart. shifter bar .. 28" can easily be withdrawn
Without the special wrench it is not easy
to remove the inner hub shell. Its use after the shifter plunger "29" has been
is therefore recommended. The price of screwed out.

Inspection of Parts
If the two-speed wheel has seen con- wise any other part showing considerable
siderable service, the parts should be care- wear.
fully inspected for wear. To enable care- If it was difficult to move the shifter
handle on the tank while shifting speeds
ful inspection, the parts must be washed and all the bearings along the control rods
thoroughly. After washing. inspect all were free and well lubricated, the trouble
the bearing surfaces of the various parts. may be due to a bent axle. Examine
Pitted or worn balls, cups and cones the axle where the shifter plunger is fitted.
should be replaced with new parts, like- The axle may be binding on the plunger.

Fit Roller Bearing Cone and Driving Hub Gear

The original style driving hub gear and and should for that reason replace the
actuating worm cone should in every case earlier type. The original ball bearing
be replaced. These parts were fitted with cone and driving hub gear can be ex-
changed for the new parts at a charge
ball bearings which have since been re- of $4.25 provided the old style parts are
placed with the well known Harley-Dav- sent to us. The regular price of the new
idson roller bearing. This style bearing assembly is $7.00. The new assembly
is trouble-proof as well as very long lived goes under part No. DG-170.

How to Remove the Driving Hub Gear

To fit the new style driving hub gear ing hub lock nut and the driving hub nut.
to the clutch will of course require taking With special factory wrench CK-800 re-
the clutch apart. After the clutch as- move the driving hub lock nut and the
sembly with the driving hub gear has been driving hub nut. Lift the hub shell and
removed as has been explained previously, sprocket assembly from the friction disc
mark the driving disc and the outer edge assembly, being careful not to lose any of
of the clutch hub shell with a scratch awl the 68 i ;'4-inch balls.
or pencil because it is of great importance Clamp the teeth of the gear in vise jaws
to have the discs fit the same feather keys covered with sheet copper to protect the
of the hub shell when again assembled. teeth and with factory wrench No. CK-1 7
Lay the clutch on the bench and hold remove the driving disc lock nut. If the
it secure by driving three spikes into the friction assembly sticks slightly on the
bench equally spaced around the sprocket driving hub gear, tap the gear lightly. In-
and as close to the clutch sprocket as pos- spect all bearing surfaces for wear and
sible. This will make it easy to hold the pits, including the steel balls, and replace
clutch assembly while unscrewing the driv- all that are not in good condition.
Service Department Bulletin No. 53

How to Fit the Roller Bearing Driving Hub Gear

When assembling the driving hub gear hub lock nut. Try the bearing adjust-
and clutch assembly it is advisable to fit ment by turning the hub shell on the driv.
the clutch hub shell on the driving hub ing hub gear. This must run perfectly
gear before the friction assembly. This free with just the slightest trace of a
will allow an accurate bearing adjustment shake. If the bearing adjustment is not
just right, tighten or loosen the driving
and is recommended for that reason.
hub nuts as may be found necessary.
Pack the hub shell cone with a good Place this assembly in a vise, clamp-
grade of thick cup grease and place the ing the gear and fit the friction assembly
I /4-inch balls in two rows of 34 each. in such a manner that the marks placed
using the grease as a retainer. Place the on the driving disc and hub shell before
driving hub gear into this as,sembly in the the clutch was taken apart, line up.
same way the other gear was fitted. Screw Lightly tap the driving disc to force it
the driving hub nut down tight on to the over the spline fittings of the driving hub
driving hub gear. then back it off about gear and draw the driving disc clamp nut
I I 4 turn and firmly tighten the driving down tight.

How to Assemble the Two-Speed Hub

Pack the clutch gear cone .. I 3" bear- Fit the shifter collar ''19'" over the
ing grooves with grease which will lubri- axle. Place the clutch shifter bar "26••
cate and act as a retainer to hold the balls through the shifter collar and the pnr-
while assembling. This bearing consists vided slot in the axle. Screw the clutch
of a double row of 5/ 16-inch balls of 18 shifter plunger "29" into the shift~r
balls each. Place the clutch gear cone with bar. When this is done care should
balls into the right half of the inner hub be taken to get the teeth of the plunger
''2." Since this bearing is only a free to line up evenly and properly with the
rwming fit and no play is allowed, the slot in the axle so that the shifter pinion
balls will not enter the inner hub shell can move the shifter bar the full travel
easily and it generally will be found of the slot. Refer to "c.·· illustration
necessary to press firmly with the hands No. I.
to get the parts together. Place the clutch collar ''20.. over the
Lubricate the bevel pinion shaft "3" right end of the axle in such a position
with regular motor oil and place the four that the lock pin is to the left of the
pinions "4" on the shaft. Place this as- feather key of the clutch collar and that
sembly in position on the right half of the the high side of the lugs or dogs of this
inner hub "2"• and fit the left half .. 1, collar is to the right. Place the axle
of the inner hub against the right half so assembly into the inner hub shell assembly
that the marks on the inner hubs line up. and with a screw driver press in the clutch
The marks are either center punch marks, collar pin "9"' so that the clutch collar
numbers or letters. It is very important can be placed over the clutch gear cone.
to match up the inner hub shells because Be sure that clutch collar pin is in line
these parts are machined in pairs to insure with the three lock holes. at "H .. in the
a perfect fit over the bevel pinion shaft. clutch gear cone.
For this reason it is necessary to renew Engage the dogs of the clutch collar
both halves when one-half must be re- and the right side of the inner hub. Lubri~
newed. cate the entire assembly with a little cylin-
No. 53 Service Department Bulletin

der oil. hold it together carefully and packing ring "6" into the driving hub
place it into the outer hub "7" from the gear recess with the square edge toward
left side. With wrench CK-6 placed the clutch. Pack the driving hub gear
over the clutch collar, the inner hub shell bearing with thick cup grease and fit the
assembly is screwed into the outer hub eighteen 3,18-inch balls. Place the clutch
by turning to the left. It is very im- assembly over the axle and onto the rear
hub.
portant to turn the inner hub very tight Pack the ball thrust bearing "1 6,"
into the outer hub. If it is impossible to "1 7" and "18." and roller bearing parts
line up the key ways after the inner hub "1 S" with grease and fit them into the
is turned in tight by hand. do not back driving hub gear in the following man-
the inner hub outward slightly but force ner: First fit the beveled race "16;·
it tight with a hammer. then the ball retainer with the balls "I 7,"
After the inner hub has been properly the outer race "18" and the roller bear-
tightened and the key ways line up, fit ings with retainers "l S ...
the six woodruff keys "8." These keys Be sure that the felt washer in the re-
fit tight and it will be found necessary to cess of the actu_ating worm cone "i 4" is
use a hammer to drive them way down: in good conditioil and will retain the lubri-
Be sure to drive them way down and see cant and prevent dirt from entering this
that no dirt remains in the key ways or bearing. Then screw the actuating worm
it will be impossible to fit the hub shell cone in place. First screw this down
band .. 39." tight. then back it off possibly 1I 4 turn
Place the hub shell band over the rear or just enough to allow the wheel to turn
hub and fit the two hub shell band screws. perfectly free and make sure that the bear-
If trouble is experienced in fitting the ing is not being cramped.
screws use a soft thin punch or nail. Place Fit the bushing "36" over the left axle
this through two holes one on each end end with the large diameter toward the
in the band and into one of the outer hub actuating worm cone. Then place the
holes, then pull the band in place, hold axle support washer "35" over the axle
it and fit one of the screws. against the bushing. This washer was
Pack the right cone bearing .. 21" with not used on two-speed hubs manufactured
thick cup grease and fit the nineteen 3 18~ before June 1st. 1914. but should be
inch balls. Lubricate the inner hub fitted to these two-speeds also, because it
mechanism with a few drops of thin oil greatly adds to the strength of the axle.
and screw the cone on the axle. Screw Next to the axle support washer fit the
the right cone 1I 16-inch beyond the rear keyed lock washer "31 ;• then fit the lock
axle clip grooves and line up the square nut "33" and draw this very tight.
shank of the cone with the grooves in the Again tr:y the wheel to see that it turns
axle. If this is done the brake arm will freel:y and that the bearings are not
line up properly with the brake arm clamp aamped. Fit the brake side cover so
and then there will be no danger of spoil- that the brake arm is in line with the bral(e
ing the bearing adjustment when fitting arm cl.:1mp. Remember that this is very
the wheel in the frame. Push the axle important because if the brake end cover
inward toward the left by hand. were either forced up or down in lining
Pack the left side of the two-speed up the brake arm with the clamp, the
mechanism with thick cup grease. Force bearing adjustment of the rear wheel
this grease in well between the pinion would be changed and there would be
gears. Allow ~ufficient room for the driv- great danger .of ruining the actuatin~
ing hub gear or an over-supply of grease worm cone, driving hub gear and the com·
will be put into the hub causing it to work plete bearing in a ver:y few miles of driv
out on the brake side. Fit the driving in g.
Service 'Department :lJulletin No. 53

If the brake shell has been removed, Do not draw the clamp nut tight because
inspect it for wear before replacing. To the shifter lever will have to be adjusted
fit the brake shell force it over the feather properly when the wheel is set into the
keyways of the rear hub by tapping and frame. This has already been fully ex-
hold it securely by drawing the brake shell plained under Importance of Correct
nut down tight. Shifter Rod Adjustment. Replace the
After the brake side cover has been axle clamp nuts and the axle end screws.
properly fitted, place the large plain
When clamping the wheel in the frame
washer "30'' which fits on the inside of
by tightening the clamp nuts, be careful
the frame over the axle with the large flat
bearing surface toward the brake. Then fit not to allow the shifter pinion to come
the axle washer and clip· which go on the in contact with the axle. To overcome
outside of the frame. Place the shifter this danger, turn the shifter body forward
body "40" over the axle with the lock and backward to find the central position,

Brake Side Cover Showina

Shifter Lever in Low Speed

pin toward the outside. Grease the shifter then tighten the right clamp nut while
pinion "41 •• with thick grease and place holding the shifter body.
it into the shifter body. If too much play develops at the rear
Replace the remaining parts in the fol- wheel or clutch, adjust the left cone only
lowing rotation on the shifter pinion: and be sure that the bearings are not
Shifter pinion washer "42" with knurled cramped after adjusting. A very little
side up, shifter lever "43" with knurled shake and a free running wheel indicate
side down, lock washer and clamp nut. proper adjustment.
Service Dept. Bulletin
No. 62. November 1, 1917 Harley-Davidson Motor Co., Milwaukee

Care of the Commutator-Electrically Equipped Model

Causes of Quzck Wear To A Jjust the Tension of the Brush
Hard Carbon Brushes Springs
To Fit and A cljust new Carbon Brushes To Repair a Grooved Commutator
Proper Pressure of Brushes against Com" Poorl')l Fitting Circuit Breaqer Cover
mutator

A commutator which is grooved, show- Neglect will in time render the commu-
ing that the brushes are gradually cutting tator and armature useless. A careful
periodic inspection for wear and the ap-
into it, should not be neglected. Inspec-
plication of the proper remedy when wear
tion of the commutator is recommended is found, will make renewal of the com-
whenever the circuit breaker or distribu- mutator unnecessary during the life of the
tor points are inspected and adjusted. machine.

Causes of Quick Wear

Quick commutator wear can generally against the commutator, or failure to
be traced to one or more of the following clean the commutator if the machine is
three causes: Hard carbon brushes, used in very sandy or dusty country,
especially if sand and dust can get under
brushes bearing with too much pressure
Lhe circuit breaker cover.

Hard Carbon Brushes

If a commutator is found grooved and brush cannot be seen with the eye. There-
inspection of the brush tension, as de- fore. when a faulty brush is suspected,
scribed hereinafter, proves that the springs all three brushes and brush holders should
are properly adjusted and the mechanism be replaced.
on the inside of the circuit breaker cover Never replace a brush without replac-
is clean, hard brushes are the cause of ing the holder because it is very important
the commutator wear. to have a perfect circuit between the two,
The reference to hard brushes does not and to obtain this circuit very careful
mean that the brushes are as hard as a soldering and tinning are required. The
piece of steel, but rather that the com- cost of a brush holder is less than the cost
position of the material in the brush lacks of the labor required to solder and tin
graphite. The amount of graphite in a a new brush to an old holder.
No. 62 Seroice Department Bulletin

To Fit and Adjust New Carbon Brushes

Trim the new brushes to con form with Follow the n:.dius of the commutator with
the radius of the commutator. Place the sandpaper as much as possible. Refer
the brush holders on the studs. Cut some to illustration. To obtain a good bear-
"00" sandpaper (never use emery) into ing of the brush against the commutator
strips 3~8 inch wide. Place this sand- may require pulling the strip of sandpaper
paper between the commutator and brush through several times, but the operation
with the coarse side toward the brush. 'should be repeated only as often as is
necessary.
When trimming the forward brush, be
sure to pass the sandpaper between the
lower bearing housing support and the
commutator if the strip is long enough,
and pull upward and backward so that
the edges of the brush will not be trimmed
off. When trimming the two rear brushes
pass the strip of sandpaper under the
upper housing support, then under the
upper and lower brushes, and draw the
sandpaper toward the front.
After the brushes have been properly
seated. remove all traces of grit by wi~
ing the commutator with a gasoline soaked
rag and then drawing plain writing paper
After the sandpaper has been properly between the brushes and commutator. For
placed, bear down lightly on the brush instructions on adjusting the brush springs
holders and pull out the sandpaper. Be refer to instructions under .. Proper Pres-
careful when pulling out the sandpaper sure of Brushes against Commutator" and
not to damage the near edge of the brush. "To Adjust Tension of Brush Springs."

Proper Pressure of Brushes Against Commutator

The proper brush pressure against the the commutator and the scale is balanc-
commutator is six ..ounces. Determine the ing. Never let a brush bear with greater
proper pressure with a small spring scale pressure, nor have it considerably less.
or hook the end of the brush holder with Too much pressure will cause quick wear
a piece of wire to a scale graduated to of both the commutator and brushes,
ounces. Then pull the generator away, while too little pressure will affect the
the exact brush pressure is determined at conductivity of the brush and interfere
.the point when the brush is just leaving with the current output of the generator.

To Adjust the Tension of the Brush Springs

When inspection proves that the brush lowing instructions should be applied:
springs are improperly adjusted, the fol- The cotter pins holding the brushes on
Set"))ice Department Bulletin No. 6.

their studs should be withdrawn, so that If it is impossible to obtain the proper

the brushes and springs can be removed pressure by turning the spring one~ half
from the studs far enough to release the turn, one way or the other, proceed as
springs from the slots in the studs. A follows: Release the spring entirely by
piston pin lock pin, or something similar withdrawing the brush holder part way
to it, should then be placed through the from the stud. Then replace the brush
outside opening of the brush holder and holder and spring on the stud without
over the straight end of the spring. Wind having any pressure on the brush. With
up the spring to the proper tension by a pair of narrow-jawed pliers take hold
turning the piston pin lock pin. Push of the end of the spring which bears
the brush holder back over the stud. against, or is hooked on to the brush
When this is done, the spring will have holder. Pull this end of the spring out
to follow and no trouble will be experi~ until the proper tension has been obtained
enced if the slot of the lock pin lines up and cut off the spring, leaving just enough
with the slot in the brush holder stud. of the spring to overcome all danger of
Again test the tension of the brush it slipping off the brush holder. Be sure
against the commutator. If the brush to try the pressure of the brush from
seems to be bearing with too much pres- time to time while pulling out the spring
sure, release the coil spring one-half tum, so that no more is pulled out than is neces-
or if the pressure is too little, give the coil sary. After the spring has been properly
spring another half turn. adjusted, replace the cotter pin.

To Repair a Grooved Commutator

A grooved commutator can be repaired After the commutator has been turned
if the groove is not more than 1/16 inch down, remove all copper chips from be-
deep. Place the complete armature in tween the segments and re-assemble the
a lathe, holding it between centers, and instrument. Careful inspection will show
turn down the face of the commutator. that the brushes have only a little bearing
on the commutator, necessitating ret rim~
When turning the commutator down, be
ming of the brushes as already explained.
sure to take off light cuts at a time, and If a commutator is cut too deep to be re-
under no circumstances turn off any of faced, the generator should be referred
the shoulder of the commutator which is to the Remy Electric Co., or to their
toward the armature end of the commu- nearest branch or service station, for re-
tator and is about I j8 inch wide. paus.

Poorly Fitting Circuit Breaker Cover

If grit and dirt are found on the cir- and commutator unnecessarily and may
cuit breaker and distributor mechanism get on the breaker and distributor mechan-
whenever the circuit breaker cover is re- ism, causing irregular running of the
moved, examine the felt washers and note motor.
whether the cover is bent. The cover Make sure that the felt washer is se-
must fit well enough against the generator curely shellaced to the generator and that
to prevent the entrance of dirt or grit. it fits properly between the cover and the
If dirt can enter, it will wear the brushes generator. If the cover is bent, even only
No. 62 Service Department :Bulletin

slightly, be mre to straighten it carefully. properly adjusted spring tension ·and the
If the small, round felt washer between fact that the manufacturers are unable to
the spider and the cover has been lost, govern absolutely the composition of the
replace it. Otherwise considerable dirt brushes, makes inspection important. This
will enter at this point the same as at a inspection can conveniently be made at
this time of the year when many machines
poorly fitting cover.
are overhauled and the others can be
Our experience proves that periodic in~ spared easier than in the summer riding
spection of the ccmmutator and brushes season. We advise inspecting the com~
according to these instructions is neces- mutator and brushes whenever the circuit
sary. Natural wear, dust and dirt, im- breaker cover is removed.

Inspect the screws in the right bearing plate from time to time to make
sure that they are drawn up tight. It is extremely important that these screws
be kept tight. This insures proper alignment of the armature and pole
pieces and will prevent injury to the armature. A. loose fitting right end
plate will cause the motor to misfire, due to variation in the gap between
the breaker and distributor points. If the screws work loose, clean the screw
holes, see that the lock washers and lock plate are fitted and shellac the
screws and screw holes.
Service Department Bulletin No. 62 No. 62 Service Department ~7Julletin

their studs should be withdrawn, so that If it is impossible to obtain the proper slightly, be wre to straighten it carefully. properly adjusted spring tension and the
the brushes and springs can be removed pressure by turning the spring one-half If the small, round felt washer between fact that the manufacturers are unable to
rrom the studs far enough to release the turn, one way or the other, proceed as the spider and the cover has been lost, goverp absolutely the composition of the
springs from the slots in the studs. A follows: Release the spring entirely by replace it. Otherwise considerable dirt brushes, makes inspection important. This
piston pin lock pin, or something similar withdrawing the brush holder part way will enter at this point the same as at a inspection can conveniently be made at
to it, should then be placed through the from the stud. Then replace the brush this time of the year when many machines
poorly fitting cover.
outside opening of the ·brush holder and holder and spring on the stud without are overhauled and the others can be
over the straight end of the spring. Wind Our experience proves that periodic in- spared easier than in the summer riding
having any pressure on the brush. With
up the spring to the proper tension by spection of the commutator and brushes season. We advise inspecting the com-
a pair of narrow-jawed pliers take hold
turning the piston pin lock pin. Push of the end of the spring which bears according to these instructions is neces- mutator and brushes whenever the circuit
the brush holder back over the stud. against, or is hooked on to the bru>h sary. Natural wear, dust and dirt, im- breaker cover is removed.
When this is done, the spring will have holder. Pull this end of the spring out
to follow. and no trouble will be experi- until the proper tension has been obtained
enced if the slot of the lock pin lines up and cut off the spring, leaving just enough
with the slot in the brush holder stud. of the spring to overcome all danger of
Again test the tension of the brush it slipping off the brush holder. Be sure Inspect the screws in the right bearing plate from time to time to make
against the commutator. If the brush to try the pressure of the brush from sure that they are drawn up tight. It is extremely important that these screws
seems to be bearing with too much pres- time to time while pulling out the spring be kept tight. This insures proper alignmen! of the armature and pole
sure, release the coil spring one-half turn, so that no more is pulled out than is neces- pieces and will prevent injury to the armature. A loose fitting right end
or if the pressure is too little, give the coil sary. After the spring has been properly
plate will cause the motor to misfire, due to variation in the gap between
spring another half turn. adjusted, replace the cotter pin.
the breaker and distributor points. If the screws work loose, clean the screw
holes, see that the lock washers and lock plate are fitted and shellac the
screws and screw holes.
To Repair a Grooved Commutator
A grooved commutator can be repaired After the commutator has been turned
if the groove is not more than 1/16 inch down, remove all copper chips from be-
deep. Place the complete armature in tween the segments and re-assemble the
a lathe, holding it betweel! centers, and instrument. Careful inspection will show
turn down the face of the commutator. that the brushes have only a little bearing
on the commutator, necessitating retrim-
When turning the commutator down, be
ming of the brushes as already explained.
sure to take off light cuts at a time, and
If a commutator is cut too deep to be re-
under no circumstances turn off any of faced, the generator should be referred
the shoulder of the commutator which is to the Remy Electric Co., or to their
toward the armature end of the commu- nearest branch or service station, for re-
tator and is about 1/8 inch wide. paus.

Poorly Fitting Circuit Breaker Cover

If grit and dirt are found on the cir- and commutator unnecessarily and may
cuit breaker and distributor mechanism get on the breaker and distributor mechan-
whenever the circuit breaker cover is re- ism, causing irregular . running of the
moved, examine the felt washers and note motor.
whether the cover is bent. The cover Make sure that the fell washer is se-
must fit well enough against the generator curely shellaced to the generator and that
to prevent the entrance of dirt or grit. it fits properly between the cover and the
If dirt can enter, it will wear the brushes generator. If the cover is bent, even only
 No. 63 Sert1ice Depatlmf.'nt Bullttin

Service Dept. Bulletin To Charge Batteries with the F-F Rectifier

No. 63. December 5, 1917 Harley-Davidson Motor Co., Milwaukee When you receive a rectifier you will paint the positive binding post red or dis·
note that the instruments are arranged dif- tinguish it from the negative post in some
ferently than in the accompanying illus- simple manner to avoid any chance for
A Practical Means of Doing Your Own Battery Charging tration and that the wmng is concealed. confusion.
When D. C. Current is Not Available 0 1
To Charge Batteries n•ith the F-F Rec- To Charge more tlwn one Bali<"Ty
tifier To Adjust the Rectifier
To Adjust the Charging Rate
Regulating Charging Rate Fuse Protection
For some time there has been a demand Because these conditions exist and
for a reliable battery charging apparatus. knowing that many dealers wish to do
The increasing popularity of the electric- their own battery charging, we are fur-
ally equipped model brings with it the nishing a rectifier that is ideal for the
question of battery charging and in many charging of small batteries. Wlih the rec-
cases the dealer wishes to make provisions
tifier is furnished a rheostat, or resistance,
to do this work himself. For the dealer
with which the current can be regulated
who has direct or D. C. current available,
the problem of charging batteries is a sim- to charge from one to eight batteries.
ple one as explained later in this bulletin. The rectifier can be used by every
It is the dealer who can only get alternat- dealer who does his own battery charging
ing or A. C. current, who must have- a and cannot get direct current. Various
means of convertin!! this current to direct apparatuses were tested by our engmeer-
current. This is th.e field of the rectifier, ing department and the rectifier that was
an instrument to change A. C. c~rrent to
best suited to our needs was adopted.
D.C.
Quality, efficiency, life and cost of in-
The motorcycle battery is almost in a
class by itself. Its charging rate is so low stallation were considered.
that it cannot be charged 011 the same line The rectifier is designed for use with
with automobile batteries without being 11 0 volt alternating current 60 cycle fre-
damaged. The life of a battery is short- quency. This is the type current com-
ened very materially by charging at a too monly used, but before ordering a rectifier Rectifier with Resistance and Arnm~1er
high rate, as many dealers and riders have we suggest making sure that your voltage for Charging horn A. C. Line

learned to their regret. We have exam- and cycle frequency are 1 I 0 and 60, re-
ined numbers of batteries that were ruined spectively. The instrument is furnished
by this cause. Many garages and even mounted ready for service. The panel can
battery charging stations, through ignor- be attached to a wall, the charging wire Another way to determine the polarity
ance or carelessness, charge small batteries fitted into a socket and the leads are ready
of the charging wires or the polarity of
at high rates. to be connected to the battery.
the battery leads is to dip the ends of the
wires into a glass of water in which a little
salt' has been dissolved. Bubbles will form
The price of the rectifier comJ!Iete with resistance and ammeter on the negative wire. Once the positive
is as follows: Type 1636, F-F Magnetic Rectifier, mounted on wire has been determined, place a knot in
panel, with rheostat, ammeter and wiring as shown in illustration, The letters "P" and "N" are stamped it, according to common practice, and
$28.00, list, (west of the Rockies $30.00, list), f. o. b. Cleveland. on the mounting panel above the positive paint the "POS" ( +) and "NEG"
Shipping weight about 20 pounds. Write for discount. and negative binding posts, respectively, (-) marks on the panel to simplify dis-
and the positive binding post is also indi- tinguishing the charging wires for all the
cated with a tag. We suggest that you time.
Seroice Department :Bulletin No. 63 No. 63 Seroice 'Department Bulletin

Regulating Charging Rate connected to the positive lead of the recti- When one battery is to be charged al-
fier. The negative battery wires must be low two amperes of current to flow
When charging a battery make sure It has always been recommended to connected in like manner with the negative through the battery and cut out more re-
that the positive wire of the rectifier is charge the motorcycle ba!lery at a one am- lead of the rectifier. sistance by moving the resistance clip from
connected to the positive pole of the bat- pere rate. However, with the F ranee rec- If the rectifier is being used to charge "I" to "2," for each battery that is
tery. marked "POS," ( +) or indicated tifier the charge can be started at two or one battery and another battery is con- added to the charging line. Since one
in red. Connect the negative wire of the three amperes. In fact when a rider is in nected, connect the batteries in parallel battery can be started off at two amperes,
rectifier to the negative pole of the bat-
need of his battery. a higher than one am- and change the position of the resistance two batteries can be started at a four am-
tery marked "Neg" (-). After the
pere charging rate is recommended. The clip so that a greater charging rate will pere charge, three batteries at six amperes,
battery has been connected properly. in-
sert the plug into a lamp socket and note battery begins to warm up and charge flow through the ammeter. Adjust the bearing in mind always that the charging
the charging rate on the ammeter. sooner. There is no danger of overcharg- flow of current with the resistance when- rate must be reduced when the battery be-
ing because as the battery becomes ever another battery has been added to, or gins to gas and the temperature of the so-
The ch11rging rate is regulated by mov- charged, its resistance cuts down the removed from, the charging line. lution rises above I I 0° F.
ing the clip "3" between the points "2"
charging rate until, when the battery is
and "I " on the resistance unit, as shown
in illustration. With the clip at point "I" fully charged, the current automatically
the entire resistance is cut in or the charg- tapers off to a fraction of an ampere, as To Adjust the Rectifier
ing rate is at a minimum. At point "2" will be indicated on the ammeter.
Do not charge one battery at a higher To adjust the rectifier the knurled There should be a sma!l gap at "D"
the entire output of the rectifier enters the
rate than three amperes and as soon as the screws "A" should first be turned out- between both of the carbon and copper
battery. The resistance allows for a
wide range of battery charging rates. battery begins to bubble or gas, reduce ward or away from the armature. Then electrodes when the rectifier is not in use.
From one to eight or even ten batteries the charging rate to one ampere. If a bat- screw them inward. By proceeding in This prevents any back flow of current
can be charged at one time. No fixed tery is not in healthy condition, that is, this way pressure will be applied to both from the battery when idle and will allow
position for the resistance clip can be given if it is internally damaged, its resistance carbon brushes which will prevent them the armature to' vibrate freely when in use.
to charge a certain number of batteries. will not cut down the charging rate. from backing up and getting out of ad- It is very important to have the carbon
By connecting the clip in various positions Therefore when the temperature of the justment automatically. Be sure to have brushes seat squarely against the copper
on the carbon bars, varying charging rates solution rises above I I 0° F .• or the bat- the armature "B" central between the electrodes. The cover for the rectifier should
will be obtained and can readily be noted tery begins to bubble or gas, reduce the pole pieces "C" of the magnets. always be kept in place.
on the ammeter. charging rate.

To Charge More than One Battery To Adjust the Charging Rate

When more than one battery is to be as shown in illustration below. All posi- The charging rate is regulated by slid-
tive wires of the batteries must be inter- weight, however, is set by the factory for
charged, connect the batteries in parallel
ing the small brass weight "E" on the best results and should not be moved un-
Ocr., armature spring, up and down. This less conditions warrant.

Fuse Protection
The rectifier is provided with a fuse will also blow. This of course does not
"F" per illustration. The fuse is of 20 apply to a dead battery because such a
ampere capacity and protects the instru- battery has no opposing current. If a fuse
ment should the load be excessive, that is, burns out do not replace with a fuse of
over 20 amperes. If with the resistance more than 20 ampere capacity. Should
clip "3" on contact with carbon rod at the vibrator be working and the ammeter
"2" end, a battery were connected in not show any deflection or there is no
reverse with the charging wires, that is current at the charging wires, it is pos-
"POS" (+) to "NEG" (-) and sible that the binding posts which hold the
DiagTam of Batteries Connected in Parallel 'NEG" (-) to "POS" (+).the fuse fuse are loose, or that the fuse is blown.
Scroie< Dcparlmcnl Bulletin No. 63

The dealer who can rely on a battery depot for careful and
prompt service does not need a rectifier, but there are times
when the ability to give immediate service on battery charg-
ing will prove an asset to every dealer's service department.
The dealer who is not convenient to a battery service station,
or who knows from experience that his service station cannot
be relied on to do careful work, is directly concerned in a
means of doing his own battery charging.

Battery charging with the F -F Rectifier can be done at a

profit. Battery charging is not an item of free service. The
rider is willing to pay for the work and will in addition ap-
preciate that the dealer can do his battery charging promptly,
instead of having to refer the work to a service station.

Read Carefully Both Bulletins No. 63 and 64

The thought may occur that because you are not concerned with the bulletin
you use D. C. current, the bulletin on on charging from a D. C. line. Both
charging with alternating current does not bulletins contain important information on
battery charging and every dealer and
interest you, or you may be interested in
mechanic will lind it to his interest to read
charging from an A. C. line and feel that both bulletins carefully.

Battery Manual for Dealers and Mechanics

The Electric Storage Battery Co. pub- copy to every dealer who is interested in
lish an excellent volume on the subject of improving his knowledge of battery con-
battery repairing. We have secured a struction, or who is doing or intends to do
supply of these books and will furnish battery charging and repairing.

Of Interest to All Harley-Davidson Dealers

We wish to obtain complete informa- many will do their own charging with the
tion as to the number of Harley-Davidson F-F rectifier as well as their battery re-
dealers that are already doing battery pair work. If you are in the class of the
charging and repairing, or that are con- dealers who are charging and repairing
templating doing such work. A consid- batteries, or if you decide to do your own
erable number of dealers are already charging and repairing in the future,
charging and repairing batteries, while please notify us.
 Oil Bulletir1
January 2, 1918 Harley-Davidson Motor Co., Milwaukee, Wis.

Oil in Cans
List Net

J~;:.:: :~ 1~
$1.25 $ .87!4
12.00 8.40
1c.nd,. 16.00
ls Crates of I 0.................... . 37.80

I ............................. . 5.25 3.67!1

6 ............................. . 3.50
S Gallon Size

~. ~~;~~~ ~~s~ . ~;_~; ·. ·. ·. ·. ~ ·. ·. ·. ·. ·. ·. ·. ·. ·. ·.

{ 3.30
:
10.25 7.15

Oil in Barrels
One-Half Barrel (28 to 32 Gal.) .............. per gal. .59
Full Barrel ( 48 to S4 Gal.) . . . . . . . . . . . . . . per gal. .56
The above prices are for both medium and heavy oil.

Special Racing Oil

Gallon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . $I .40 $1.05
5 Gallon . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5.75 4.52!1
I 0 Gallon .. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00 8.15
One-Half Barrel (28 to 32 Gal.) .............. per gal. .78!1
Full Barrel ( 48 to 54 Gal.) .............. per gal. .73!1
 No. 68 Service /)eparlmC'nf Ru/letin

cause the crank pm never wears equally bushings. When the bushings are worn,
all the way around. Generally, renewal the rods should be sent to the factory for
of the crank pin is found necessary. The rebushing and regrinding. If the closed
same holds true of the bushings in the end of the retainers is worn by the rollers,
connecting rods. The wear is not evenly the tetainers should be replaced with new
No. 68. February 20, 1918 Harley-Davidson Motor Cq., Milwaukee distributed over the entire area of the ones.

When and How to Overhaul Crank Pin Bearings Why Connecting Rods Should be Re-Bushed at the Factory
Special fixtures are required to remove little as .0001 (one ten thousandth) inch,
To Test 1he Wear How to Lap the Connecting Rod Bush-
the worn steel bushings and to press in a perfect fit cannot be obtained and care-
To T alec Apart and Inspect Bearings ings
new ones to prevent bending or .damaging ful lapping will be required. Some deal-
Why Connecting Rods should be Re- Description of Connecting Hod Lapping the rods. In addition to this it is very im- ers have their connecting rods only re-
Bushed at the Faciory Arbor portant to grind the bushings to size a Iter bushed at the factory and do their own
To Repair !1 Slightly Worn Bearing they have beeen pressed in, because the fitting of roller bearings and crank pin.
How to Obtain a Good Roller Bearing M agneio Gear Puller
bushings are distorted during the opera- This is satisfactory, provided the dealer
Fit New Service Literature tion and must be trued up accurately. has .the proper equipment.
otherwise they will be no better than the
worn bushings. This grinding operation
To Test the Wear also requires special machines. Therefore The rollers used in the connect-
it is important to have the factory do this ing rods are made in twenty assorted
When a motor is overhauled, the fit of To test the clearance or fit of the crank
work. sizes varying from .00 I inch over-
the crank pin bearing is seldom over- pin bearing, wash out all oil and try the It is recommended to have the factory size, to .001 inch undersize, each
looked. In many cases the mechanic will rod for up and down play. Have the fit the rebushed connecting· rods to a new size varying .000 I inch in diameter.
lit a larger size set of rollers to overcome upper end of the rod in line with the crank set of rollers, retainers and crank pin, be- Unless ordered otherwise, standard
a little play at the crank pin bearing, pin and fly wheel shafts, when the rods came various sizes of rollers may have to
which he believes may cause a knock. size rollers are furnished on parts
are near their upper dead center. The be tried to obtain a good fit. Sometimes orders.
Nothing can be further from the actual even with the rollers varying in stze as
bearing should be overhauled only when
fact, because there must be considerable
play at this bearing to cause a knock. If the clearance is sufficient to be felt or to
the upper end of the rods can be moved make a thumping noise. Therefore, do
sideways, as much as 3-16 inch, the crank not overhaul a crank pin bearing just be-
pin bearing is not too loose a fit and need cause the upper ends of the rods can be To Repair a Slightly Worn Bearing
not be overhauled. moved sideways slightly.
If inspection of the Bushings finds them the shop equipment includes one of these
worn only very slightly, they can be laps, the work can be taken care of by
the dealer's mechanics as well as at the
placed in good condition by lapping them
To Take Apart and Inspect Bearings with the special connecting rod lapping
factory. The worn crank pin and rollers
with retainers should of course, be re-
If according to the foregoing tests the cov~r over the crank pin and on the roller arbor, described and illustrated herein. If placed with new ones.
bearing is found too loose, place the lly retainers. With one hand bear down on
wheels in a vise, clamping the sprocket the cover while removing the rods with the
shaft and remove the lock washer and other hand to prevent dropping and pos-
clamp nut on the gear side. To remove sibly losing the rollers when removing the
rods. How to Obtain a Good Roller Bearing Fit
the gear side /ly wheel from the tapered
Remove the retainers with the rollers When renewing the whole bearing, or connecting rod bushings, the bearing fit
crank pin, strike the rim of the wheel with
from the crank pin. Inspect the rollers, should of course be made so that the rods
a hammer about 90'0 from the crank pin, only fitting a new set of rollers with re-
retainers, crank pin and the hardened have no shake and can be turned perfectly
or strike the crank pin squarely, being steel bushings in the rods for wear. Pay tainers and crank pin and lapping the
free.
careful not to damage the threads during special attention to the grooves that may
the latter operation. be worn into the crank pin by the rollers.
Before removing the rods from the If the pin is grooved, do not try to over-
rollet s place a lower exhaust valve spring come the play by fitting larger rollers, be-
Service Dept. Bulletin
No. 68. February 20, 1918 HarleyMDavidson Motor Co., Milwaukee

When and How to Overhaul Crank Pin Bearings

To Test the Wear How to Lap the Connecting Rod Bush-
To Take Apart and Inspect Bearings ings
Wh:y Connecting Rods should be Re~ Description of Connecting Rod Lapping
Bushed at the F actor;y Arbor
To Repair a Slightl:y Worn Bearing
How to Obtain a Good Roller Bearing Magneto C ear Puller
Fit New Service Literature

To Test the Wear

When a motor is overhauled, the fit of To test the clearance or fit of the crank
the crank pin bearing is seldom over- pin bearing, wash out all oil and try the
looked. In many cases the mechanic will rod for up and down play. Have the
fit a larger size set of rollers to overcome upper end of the rod in line with the crank
a little play at the crank pin bearing, pin and fly wheel shafts, when the rods
which he believes may cause a knock.
are near their upper dead center. The
Nothing can be further from the actual
bearing should be overhauled only when
fact, because there must be considerable
play at this bearing to cause a knock. If the clearance is sufficient to be felt or to
the upper end of the rods can be moved make a thumping noise. Therefore, do
sideways, as much as 3-16 inch, the crank not overhaul a crank pin bearing just be-
pin bearing is not too loose a fit and need cause the upper ends of the rods can be
not be overhauled. moved sideways slightly.

To Take Apart and Inspect Bearings

If according to the foregoing tests the cover over the crank pin and on the roller
bearing is found too loose, place the fly retainers. With one hand bear down on
wheels in a vise, clamping the sprocket the cover while removing the rods with the
shaft and remove the lock washer and other hand to prevent dropping and pos-
clamp nut on the gear side. To remove sibly losing the rollers when removing the
rods.
the gear side fly wheel from the tapered
Remove the retainers with the rollers
crank pin, strike the rim of the wheel with
from the crank pin. Inspect the rollers.
a hammer about 90:.> from the crank pin, retainers, crank pin and the hardened
or strike the crank pin squarely, being steel bushings in the rods for wear. Pay
careful not to damage the threads during special attention to the grooves that may
the latter operation. be worn into the crank pin by the rollers.
Before removing the rods from the If the pin is grooved, do not try to over~
rollers place a lower exhaust valve spring come the play by fitting larger rollers, be-
 68 Service Department Bulletin

cause the crank pin never wears equally bushings. When the bushings are worn,
all the way around. Generally, renewal the rods should be sent to the factory for
of the crank pin is found necessary. The rebushing and regrinding. If the closed
same holds true of the bushings in the end of the retainers is worn by the rollers,
connecting rods. The wear is not evenly the retainers should be replaced with new
distributed over the entire area of the ones.

Why Connecting Rods Should be Re~ Bushed at the Factory

Special fixtures are required to remove little as .0001 (one ten thousandth) inch,
the worn steel bushings and to press in a perfect fit cannot be obtained and care~
new ones to prevent bending or damaging ful lapping will be required. Some deal-
the rods. In addition to this it is very im- ers have their connecting rods only re-
portant to grind the bushings to size after bushed at the factory and do their own
they have beeen pressed in, because the fitting of roller bearings and crank pin.
bushings are distorted during the opera~ This is satisfactory, provided the dealer
tion and must be trued up accurately, has the proper equipment.
otherwise they will be no better than the
worn bushings. This grinding operation
also requires special machines. Therefore The rollers used in the connect~
it is important to have the factory do this ing rods are made in twenty assorted
work. sizes varying from .001 inch over·
It is recommended to have the factory size, to . 00 1 inch undersize, each
fit the rebushed connecting rods to a new size varying .0001 inch in diameter.
set of rollers. retainers and crank pin, be. Unless ordered otherwise, standard
cause various sizes of rollers may have to size rollers are furnished on parts
be tried to obtain a good fit. Sometimes orders.
even with the rollers varying in size as

To Repair a Slightly W om Bearing

If inspection of the Bushings finds them the shop equipment includes one of these
worn only very slightly, they can be laps, the work can be taken care of by
the dealer's mechanics as well as at the
placed in good condition by lapping them factory. The worn crank pin and rollers
with the special connecting rod lapping with retainers should of course, be re~
arbor. described and illustrated herein. If placed with new ones.

How to Obtain a Good Roller Bearing Fit

When renewing the whole bearing, or connecting rod bushings, the bearing fit
only; fitting a new set of rollers with re- should of course be made so that the rods
tainers and crank pin and lapping the have no shake and can be turned perfectly
free.
 Sel1!icc Department Bulletin No. 68

~'hen the bushings have been lapped shake but prevent the connecting rods from
but not replaced by a new set, although spinning freely, or cause the rods to climb,
a new crank pin is being used, do not tiT the bearing fit is too tight. In this case,
a standard size set of rollers and expect ~ the roller retainers should be reversed.
good fit. Try a set of rollers that are To reverse the roller retainers, remove the
about . 000 3 inch oversize. If the ro<h connecting rods and roller retainers. Re-
have any play, try the next larger size of place the latter so that the retainer which
rollers, .0004 inch oversize. Be sure to was at the top is at the bottom. Then
place the .0003 inch oversize rollers in try the bearing fit. If reversing the roller
their original containers to avoid dropping retainers will not allow a loose enough fit.
or mixing them with some other size rol- the connecting rod bushings should be
lers. lapped with the lapping arbor furnished
If the next size larger rollers, in this by us until they fit the . 0004 inch over-
case, .0004 inch oversize, eliminate all size rollers.

How to Lap the Connecting Rod Bushings

To lap the bushings, clamp the arbor If no lathe is available the connecting
in the chuck of the lathe, place the lap rod bushings can be lapped by clamping
over the arbor and by means of the two the lapping arbor in a vise and turning
adjusting nuts on the arbor, adjust the
diameter of the lap to fit the bushings. the rods in a true arc by hand. Another
Run the lathe at a speed of about 200 method would be to drill a 3~8 inch hole
to 300 r.p.m., place some emery com- centrally through the end of the arbor

pound such as is used in grinding valves, and to fit a 3~8 inch rod about 1 6 inches
on the lap, put the rods over the lap for long to serve as a handle. The connect~
a few seconds and enough stock should ing rod could then be clamped in a vise
be removed from the bushings to make a and the arbor could be turned by means
good fit on the rollers. The bushings are of the handle. Exercise great care while
of course to be cleaned before trying them
lapping a connecting rod bushing. Very
on the rollers.
little lapping makes a decided difference in
Never attempt to lap connecting rod
bushings with any other kind of a lap the inside diameter of the bushings. The
than is illustrated here, because it is bearing fit is good when the rods can be
very important to lap both sides of the spun perfectly free with possibly the very
bushings and both bu!'hings to the same slightest trace of a side shake noticeable at
diameter. the upper end of the rods.
No. 68 Serllice Department Bulletin

Description of Connecting Rod Lapping Arbor

The connecting rod lapping arbor is justing collar and an iron lap. In Ser-
made up in two sizes; one to fit all crank vice Bulletin No. 55 the lapping arbor is
pin bushings prior to 191 5, and the other described as though it included two sizes
of laps. It was later decided, however,
to fit the 1915 and later model bushings.
to furnish separate arbors and laps for the
Each lapping arbor consists of a taper two sizes of bushings. The price of the
shank arbor, two adjusting nuts, one ad- lapping arbor complete is $7.50 list.

Magneto Gear Puller

This illustrates the new magneto or model 25 0 generator with the exception
generator gear puller. The puller will of the gear used on the 1915 motor.

facilitate removing the magneto gear from Price of the puller is $2.25 list. Order
19 I 6, 191 7 and 1918 motors. It is also by number FK-831.
adaptable to the drive gear used on the
 Seroice D"paTfmenl BulleUn No. 68 No. 68 Sen>ice Department Bulletin

When the bushing' have been lapped shake but prevent the connecting rods from
but not replaced by a new set, although spinning freely, or came the rods to climb, Description of Connecting Rod Lapping Arbor
a new crank pin is being used, do not try the bearing fit is too tight. In this case,
a standard size set of rollers and expect a the roller retainers should be reversed. The connecting rod lapping arbor is justing collar and an iron lap. In Ser-
good lit. Try a set of rollers that are To reverse the roller retainers, remove the made up in two sizes; one to fit all crank vice Bulletin No. 55 the lapping arbor is
about . 000 3 inch oversize. If the rods connecting rods and roller retainers. Re- pin bushing3 prior to 191 5, and the other described as though it included two sizes
have any play, try the next larger size of place the latter so that the retainer which of laps. It was later decided, however,
to fit the 1915 and later model bushings.
rollers, . 0004 inch oversize. Be sure to was at the top is at the bottom. Then to furnish separate arbors and laps for the
place the .0003 inch oversize rollers in try the bearing lit. If reversing the roller Each lapping arbor consists of a taper two sizes of bushings. The price of the
their original containers to avoid dropping retainers will not allow a loose enough lit, shank arbor, two adjusting nuts, one ad- lapping arbor complete is $7.50 list.
or mixing them with some other size rol- the connecting rod bushings should be
lers. lapped with the lapping arbor furnished
If the next size larger rollers, in this by us until they fit the .0004 inch over-
case, .0004 inch oversize, eliminate all size rollers.

Magneto Gear Puller

How to Lap the Connecting Rod Bushings This illustrates the new magneto or model 250 generator with the exception
generator gear puller. The puller will of the gear used on the 19 I 5 motor.
To lap the bushings, clamp the arbor If no lathe is available the connecting
in the chuck of the lathe, place the lap rod bushings can be lapped by clamping
over the arbor and by means of the two the lapping arbor in a vise and turning
adjusting nuts on the arbor, adjust the
diameter of the lap to fit the bushings. the rods in a true arc by hand. Another
Run the lathe at a speed of about 200 method would be to drill a 3-8 inch hole
to 300 r.p.m., place some emery com- centrally through the end of the arbor

facilitate removing the magneto gear frpm Price of the puller is $2.25 list. Order
19 I 6, I 9 I 7 and I 9 I 8 motors. It is also by number FK~83 I.
adaptable to the drive gear used on the
pound such as is used in grinding valves, and to fit a 3-8 inch rod about 16 inches
on the lap, put the rods over the lap for long to serve as a handle. The connect-
a few seconds and enough stock should ing rod could then be clamped in a vise
be removed from the bushings to make a and the arbor could be turned by means
good fit on the rollers. The bushings are of the handle. Exercise great care while
of course to be cleaned before trying them
lapping a connecting :od bushing. Very
on the rollers.
little lapping makes a decided difference in
Never attempt to lap connecting rod
bushings with any other kind of a lap the inside diameter of the bushings. The
than is illustrated here, because it is bearing fit is good when the rods can be
very important to lap both sides of the spun perfectly free with possibly the very
bushings and both bushings to the same slightest trace of a side shake noticeable at
diameter. the upper end of the rods.
 No. 7 I Sen>ice Department Bulletin

Service Dept. Bulletin Correct Gear Ratios for Sidecar and Solo Service
No. 71. March 5, 1918 Harley-Davidson Motor Co., Milwaukee While it is important that the proper will not develop the power of a machine
type motor be used according to the serv- properly geared. It will overheat and
ice expected, it is of still greater import- serious injury to the motor will be the re-
The Advantage$ of the Solo Motor and Sprocket Combinations for Sidecar Service ance that the proper sprocket combination sult.
the Sidecar Motor or gear ratio be used. Sidecar service We are giving herewith a table of
Sprocket Combinations for Solo Service
Correct Gear Ratios for Sidecar and Solo requires the use of a lower gear than solo proper gear ratios for 1915 to 1918
Service Delays in Transit service. A machine fitted with a sidecar three speed models, according to the serv-
motor at our factory is geared for sidecar ice expected. The use of the now stand-
service, another reason for specifying the ard 48 tooth rear wheel sprocket is recom-
type motor needed when placing the ma- mended because it enables using a larger
chine order. Unless a machine is ordered engine sprocket than the smaller sprockets,
The Advantages of the Solo Motor and with a sidecar motor, or the sidecar gear is
specified, the gear must be lowered if a
which naturally means longer chain and
sprocket life. The 44 and 40 tooth
the Sidecar Motor side attachment is used. The machine used
with a sidecar but geared for solo service
sprockets can, however, be furnished on
parts orders.
The sidecar or parcelcar owner requires and fitted with oversize pistons and rings.
a motor that has abundant power at low The valves may also have to be reground
motor speed, and that will pull a heavy or refaced. After the cylinders have been Sprocket Combinations for Sidecar Service
load as long as necessary, without over- placed in first class shape the compression Number Number Number Number
heating. The sidecar type motor is espe- plates are fitted. of Teeth of Teeth of Teeth of Teeth
cially built for this purpose. Its combus- For the same reason the plates should Motor Clutch. Countershaft Rear Wheel High
tion chambers are larger and its compres- Sprocket Sprocket Sprocket Sprocket Gear Ratio
not be taken from a sidecar motor after
sion therefore lower than that of the solo it has seen a thousand miles or more serv- I5 43 28 48 standard 1918 sidecar gear~ I to 4.91
type motor. It will continue to pull and 14 43 28 44 I to 4.83
ice, because the cylinders and pistons have
maintain an even speed under conditions 14 43 28 40 I to 4.39
worn in by that time, especially at the I to 5.20
that would overtax the solo motor. I3 43 28 44
upper end of the piston travel. If the 13 43 28 40 I to 4.73
Both motors are furnished as standard plates are removed, the pistons travel
eqUipment and are identical excepting that higher on the cylinder walls and the motor Sprocket Combinations for Solo Service
the sidecar motor is fitted with a set of will knock because the pistons will strike 17 43 28 48 standard 1918 solo gear I to 4.34
I -8 inch compression plates between the the shoulder in the cylinders. Therefore, 16 43 28 44 I to 4.22
cylinders and crankcase, which make before such a change is made the cylin- 15 43 28 40 I to4.09
the difference in the size of the combus- ders should be reground.
tion chambers. Therefore, to convert a When placing a machine order specify
solo motor to the sidecar type is simply the type motor needed, (specification
a matter of fitting a set of compression blanks are provided on the machine order Delays in Transit
plates between the crank cases and cylin- form), and you and the rider will be Freight and express are moving
ders, while to change from sidecar to saved the trouble of making a change very slowly especially from Eastern
solo type, requires nothing more than the later. The sidecar motor can be used points. Express is frequently en-
removal of the compression plates. for solo service and should be given the route twice or three times the length
preference for severe solo service, especi- of time required ordinarily.
It should be understood that in some ally if the machine is placed in the hands
cases after a motor has been run for a This fact should be taken into
of a new rider. When the motorcycle
year, its efficiency cannot be increased by consideration when acknowledgment
is not used constantly with a side· attach-
lowering the compression because of wear. of material shipped us for repairs is
ment or when it is intended to use a side-
Therefore, when it is desired to remodel a not received as promptly as expected.
car at a later date, the sidecar motor
motor, the cylinders should be reground should be specified.
No. 53 Service Department Bulletin

If these instructions are noted carefully there is no need to take the hub apart.
together with the accompanying illustra- It will generally be found that difficult
tions, it will be found comparatively easy shifting and poor meshing are due to poor
ly adjusted shifter rods.
to make any necessary repairs. If it is If this bulletin does not answer all of
only necessary to adjust the shifter rods, your two-speed questions, write us briefly.

Inspecting and Overhauling the Clutch

In connection with overhauling the two- If the six clutch screws must be re~
speed hub, the proper method of inspect~ moved. it is advisable to mark all discs
ing and overhauling the clutch can also in line with the driving disc because it is
well be covered, especially since the fitting very important to have the friction discs
of the roller bearing driving hub gear re~ fit the same spline fittings of the key ring
quires stripping the clutch partly. In- in the hub shell when the clutch is again
specting the clutch while the two-speed
assembled. If the position of the discs is
hub is apart may save having to remove
it at some future date. changed. they may stick in the key ring
The clutch is to be taken apart as al~ and the clutch will take hold jerkily with
ready explained under How to Remove a tendency to stall the motor.
the Dri'ving Hub Gear. The driving and Remove and measure the springs to see
friction disc assembly can be held very whether they have contracted. When new
conveniently in a vise. Before removing the 1915 springs are 1 inch long and the
the screws, note how far they extend 191 4 springs 11 I I 6 inch. If measuring
through the clutch spring nut sectors. If the springs shows that they have contracted
the dutch has been holding well and these more than 1I I 6 inch, or if they appear
screws are found to just extend through to be weak, replace them.
the sectors, all discs and springs are in If the friction disc linings are covered
good condition and the assembly should with oil or grease they should be thorw
not be taken apart. oughly cleaned. To clean the discs, first
If the adjusting screws extend quite a wash them in gasoline. Then soak them
way through the sectors and the clutch with gasoline and lay them on a gas plate
slips with a properly adjusted lever, it is to burn out the remaining traces of lubri-
not necessarily true that the discs are cant. · The discs may require several
worn. The six springs may have con- soakings in gasoline and burnings before
tracted due to overheating the clutch from all grease will be removed. If the disc
considerable slipping. Again the slipping linings are less than I I 16 inch thick, the
may be due to grease or oil having gotten discs should be sent to us to be relined
onto the discs. or a new set should be fitted.

To Fit New or Relined Friction Discs

Before assembling the clutch with a been assembled. If the discs stick when
new or relined set of discs, be sure to fit they are fitted in the key ring, they should
be turned so that the same spline fittings
the discs in the key ring of the hub shell
do not line up. Find the position where
and mark them when a good fit has been the best fit is obtained and if the discs
obtained so that there will be no danger stick only slightly they can be worked in
of the discs sticking after the clutch has to be a good fit by forcing them way in
SeriJice Department {Bulletin No. 53

and out several times. Do not grind off grind off only enough to allow the discs
any stock. from the disc feather keys unless to work in and out freely without any for-
absolutely necessary and then be sure to ward and backward play.

Mark the Discs and Key Ring

After a good fit has been obtained, mark discs and releasing· friction disc have been
the discs and key ring with chalk marks removed, proceed as follows:
so that these marks can be referred to Fit and chalkmark the hub friction
discs in the clutch hub shell, fit and mark
when assembling. If the position of the the releasing friction disc on the releasing
releasing friction disc has been changed disc, fit and mark the releasing disc on
on the releasing disc, find the position the studs of the driving disc. The fric-
where it does not stick and mark both tion assembly now being fitted, the dutch
discs. If the releasing disc, hub friction is ready for assembling.

How to Assemble the Clutch

Place the lower hub friction disc on the others, the clutch will not release as it
releasing disc, fit the releasing friction disc should and give poor service.
so that the marks on this disc and on the To make sure that the assembly will
releasing disc line up, then fit the other work freely, lay it on a surface plate with
hub friction disc so that the marks line the driving disc down and strike the re~
leasing disc lightly but squarely all the
up with the first hub friction disc.
way around with a hammer. The assem-
Carefully place these parts in a vise bly is now ready to be fitted into the
and clamp them together. Put the six clutch hub shell but since an accurate
clutch screws through the driving disc and bearing adjustment is necessary, it is ad-
the releasing disc. Place the six coil visable to fit the clutch hub shell on the
springs on the screws and tum the screws driving hub gear as is explained under
into the clutch spring nut sectors. If How to Fit the Roller Bearing Driving
trouble is experienced in starting the Hub Gear. If new discs were fitted, be
screws in the sectors, the springs can be careful not to assemble the friction disc
compressed sufficiently by hand. The and huh shell assemblies according to the
screws must be tightened an equal number marks placed on these parts before they
of turns to obtain equal pressure over all were taken apart. Assemble according to
friction surface. If one adjusting screw the marks placed on the parts after the
is st:rewed into a sector further than the proper fit had been obtained.
s..oice 'D•partm<nt JJulldin No. 53 No. 53 Sert•ice Department Bull<tin

If the brake shell has been removed, Do not draw the clamp nut tight because If these instructions are noted carefully there is no need to take the hub apart.
inspect it for wear before replacing. To the shifter lever will have to be adjusted together with the accompanying illustra- It will generally be found that difficult
fit the brake shell force it over the feather properly when the wheel is set into the shifting and poor meshing are due to poor·
tions, it will be found comparatively easy
keyways of the rear hub by tapping and frame. This has already been fully ex- ly adjusted shifter rods.
hold it securely by drawing the brake shell to make any necessary repairs. If it is If this bulletin does not answer all of
plained under Importance of Correct
nut down tight. Shi/lcr Rod Adjustment. Replace the only necessary to adjust the shifter rods, your two-speed questions, write us briefly.
After the brake side cover has been axle clamp nuts and the axle end screws.
properly fitted, place the large plain When clamping the whl"el in the frame
washer "30" which fits on the inside of
by tightening the clamp nuts, be careful
the frame over the axle with the large flat
not to allow the shifter pinion to come
Inspecting and Overhauling the Clutch
bearing surface toward the brake. Then fit
the axle washer and clip which go on the in contact with the axle. To overcome
In connection with overhauling the two- If the six clutch screws must be re-
outside of the frame. Place the shifter this danger, turn the shifter body forward
speed hub, the proper method of inspect- move<:~, it is advisable to mark all discs
body "40" over the axle with the lock and backward to find the central position, ing and overhauling the clutch can also in line with the driving disc because it is
well be covered, especially since the fitting very important to have the friction discs
of the roller bearing driving hub gear re- fit the same spline fittings of the key ring
quires stripping the clutch partly. In-
in the hub shell when the clutch is again
specting the clutch while the two-speed
assembled. If the position of the discs is
hub is apart may save having to remove
it at some future date. changed, they may stick in the key ring
The clutch· is to be taken apart as al- and the clutch will take hold jerkily with
ready explained under H otv lo Remove a tendency to stall the motor.
the Driving Hub Gear. The driving and Remove and measure the springs to see
friction disc assembly can be held very whether they have contracted. When new
conveniently in a vise. Before removing the I 9 I S springs are I inch long and the
the screws, note how far they extend 19 I 4 springs I I I 16 inch. If measuring
through the clutch spring nut sectors. If the springs shows that they have contracted
the clutch has been holding well and these more than I I 16 inch, or if they appear
screws are found to just extend through to be weak, replace them.
the sectors, all discs and springs are in If the friction disc linings are covered
good condition and the assembly should with oil or grease they should be thor-
not be taken apart. oughly cleaned. To clean the discs, first
If the adjusting screws extend quite a wash them in gasoline. Then soak them
way through the sectors and the clutch with gasoline and lay them on a gas plate
slips with a properly adjusted lever, it is to burn out the remaining traces of lubri-
not necessarily true that the discs are cant. The discs may require several
worn. The six springs may have con- soakings in gasoline and burnings before
Brake Side Cover Showing tracted due to overheating the clutch from all grease will be removed. If the disc
Shifter Lever in Low Speed considerable slipping. Again the slipping linings are less than I/ 16 inch thick, the
may be due to grease or oil having gotten discs should be sent to us to be relined
onto the discs. or a new set should be fitted.

then tighten the right clamp nut while

To Fit New or Relined Friction Discs
pin toward the outside. Grease the shifter
pinion "4 I " with thick grease and place holding the shifter body. Before assembling the clutch with a been assembled. If the discs stick when
it into the shifter body. If too much play develops at the rear new or relined set of discs, be sure to fit they are fitted in the key ring, they should
Replace the remaining parts in the fol- wheel or clutch, adjust the left cone only be turned so that the same spline fittings
and be sure that the bearings are not the discs in the key ring of the hub shell
lowing rotation on the shifter pinion: do not line up. Find the position where
Shifter pinion washer "42" with knurled cramped after adjusting. A very little and mark them when a good fit has been the best fit is obtained and if the discs
side up, shifter lever "43" with knurled shake and a free running wheel indicate obtained so that there will be no danger stick only slightly they can be worked in
side down, lock washer and clamp nut. proper adjustment. of the discs sticking after the clutch has to be a good fit by forcing them way in
Service Dcparlmenl :Bulle/in No. 53

and out several times. Do not grind off grind off only enough to allow the discs
any stock from the disc feather keys unless to work in and out freely without any for-
absolutely necessary and then be sure to ward and backward play.

Mark the Discs and Key Ring

After a good fit has been obtained, mark discs and releasing friction disc have been
the discs and key ring with chalk marks removed, proceed as follows:
Fit and chalkmark the hub friction
so that these marks can be referred to
discs in the clutch hub shell, fit and mark
when assembling. If the position of the the releasing friction disc on the releasing
releasing friction disc has been changed disc, fit and mark the releasing disc on
on the releasing disc, find the position the studs of the driving disc. The fric-
where it does not stick and mark both tion assembly now being fitted, the clutch
discs. If the releasing disc, hub friction is ready for assembling.

How to Assemble the Clutch

Place the lower hub friction disc on the others, the clutch will not release as it
releasing disc, fit the releasing friction disc should and give poor service.
so that the marks on this disc and on the To make sure that the assembly will
releasing disc line up, then fit the other work freely, lay it on a surf ace plate with
hub friction disc so that the marks line the driving disc down and strike the re-
leasing disc lightly but squarely all the
up with the first hub friction disc.
way around with a hammer. The assem-
Carefully place these parts in a vise bly is now ready to be fitted into the
and clamp them together. Put the six clutch hub shell but since an accurate
clutch screws through the driving disc and bearing adjustment is necessary, it is ad-
the releasing disc. Place the six coil visable to fit the clutch hub shell on the
springs on the screws and turn the screws driving hub gear as is explained under
into the clutch spring nut sectors. If How to Fit the Roller Bearing Driving
trouble is experienced in starting the Hub Gear. If new discs were fitted, be
screws in the sectors, the springs can be careful not to assemble the friction disc
compressed sufficiently by hand. The and hub shell assemblies according to the
screws must be tightened an equal number marks placed on these parts before they
of turns to obtain equal pressure over all were taken apart. Assemble according to
friction surface. If one adjusting screw the marks placed on the parts after the
is screwed into a sector further than the proper fit had been obtained.
5ei1Jice Department Bulletin No. 53 No. 53 Service Department Bulletin

I BG207 Inner hub shell (left halt)

Inner hub shell (right ld f .i
shell. The entire hub shell assembly is the wrench is $1.25.. If the axle is to
When ordering two-speed 2 BG207
Bevel pinion shaft removed from the left side of the outer be changed for some reason the clutch
parts always specify the 3 DG218
hub and can very easily be taken apart. shifter bar "28" can easily be withdrawn
Factory Number, and not 4 BG217 Bevel pinion
Driving hub gear Without the special wrench it is not easy
the Photo Number. S DG21S after the shifter plunger "29" has been
Driving packing ring to remove the inner hub shell. Its use
6 BG213 screwed out.
is therefore recommended. The price of
7 BG200a Outer hub shell
8 BG202 Hub shell keys
9 BG224 Clutch collar pin
10 BG223 Clutch collar spring (lower) Inspection of Parts
II BG222 Clutch collar spring (center) wise any other part showing considerable
If the two-speed wheel has seen con-
12 BG221 Clutch collar spring (upper) wear.
13 BG22S Clutch gear cone ( 1914) siderable service, the parts should be care-
fully inspected for wear. To enable care- If it was difficult to move the shifter
DG22S Clutch gear cone ( 191 S) handle on the tank while shifting speeds
14 DG210 Actuating worm cone ful inspection, the parts must be washed and all the bearings along the control rods
IS DG177 Roller bearings thoroughly. After washing, inspect all were free and well lubricated, the trouble
16 DGI7Sb Ball race inside the bearing surfaces of the various parts. may be due to a ·bent axle. Examine
17 DG176 Ball retainer and balls Pitted or worn balls, cups and cones the axle where the shifter plunger is fitted.
18 DGI7Sa Ball race outside should be replaced with new parts, like- The axle may be binding on the plunger.
19 BG264 Clutch shifter collar
20 BG219 Clutch collar
21 BG220a Right cone
22 BG273a Two-speed shifter bracket Fit Roller Bearing Cone and Driving Hub Gear
23 BG278a Shifter arm
The original style driving hub gear and and should for that reason replace the
24 DG262 Rear axle ( 191 5)
actuating worm cone should in every case earlier type. The original ball bearing
CG262 Rear axle ( 1914)
be replaced. These parts were fitted with cone and driving hub gear can be ex-
25 BOI53 Axle end screw( right)
changed for the new parts at a charge
B0,51 Axle end screw (left) ball bearings which have since been re-
Shifter rod lever of $4.25 provided the old style parts are
26 BG286 placed with the well known Harley-Dav- sent to us. The regular price of the new
27 BG297 Shifter lever bracket idson roller bearing. This style bearing assembly is $7.00. The new assembly
28 BG208 Clutch shifter bar
is trouble-proof as well as very long lived goes under part No. DG-1 70.
29 BG209b Clutch shifter plunger
30 B0328 Axle washer (inside frame)
31 CG26S Axle lock washer
32 B0315 Axle washer (outside frame) How to Remove the Driving Hub Gear
33 B0696 Left cone lock nut
34 B0693 Rear axle nul To lit the new style driving hub gear ing hub lock nut and the driving hub nut.
35 CG253 Axle support washer to the clutch will of course require taking With special factory wrench CK-800 re-
36 DG248 Axle bushing the clutch apart. After the clutch as- move the driving hub lock nut and the
37 CGI90 Long shifter rod (I OC) sembly with tbe driving hub gear has been driving hub nut. Lift the hub shell and
CG289 Long shifter rod ( I OF) removed as has been explained previously, sprocket assembly from the friction disc
DGI90 Long shifter rod ( I I C) mark the driving disc and the outer edge assembly, being careful not to lose any of
38 CG288a Short shifter rod of the clutch hub shell with a scratch awl the 68 I ,'4-inch balls.
39 BG201 Hub shell band or pencil because it is of great importance Clamp the teeth of the gear in vise jaws
40 CGI89 Shifter body to have the discs fit the same feather keys covered with sheet copper to protect the
41 BG199a Shifter pinion of the hub shell when again assembled. teeth and with factory wrench No. CK- I 7
42 BGI93 Shifter pinion washer Lay the clutch on the bench and hold remove the driving disc lock nut. If the
43 BG258a Shifter lever it secure by driving three spikes into the friction assembly sticks slightly on the
44 BG299 Shifter rod clevis pin bench equally spaced around the sprocket driving hub gear, tap the gear lightly. In-
45 CG284 Shifter rod end and as close to the clutch sprocket as pos- spect all bearing surfaces for wear and
46 CG296 Shifter rod clevis sible. This will make it easy to hold the pits, including the steel balls, and replace
47 CG294 Shifter rod link complete clutch assembly while unscrewing the driv- all that are not in good condition.
Service Department Bulletin No. 53 No. 53 S.r~ice Department Bulletin

der oil, hold it together carefully and packing ring "6" into the driving hub
How to Fit the Roller Bearing Driving Hub Gear place it into the outer hub "7" from the gear recess with the square edge toward
hub lock nut. Try the bearing adjust- left side. With wrench CK-6 placed the clutch. Pack the driving hub gear
When assembling the driving hub gear
ment by turning the hub shell on the driv- over the clutch collar, the inner hub shell bearing with thick cup grease and fit the
and clutch assembly it is advisable to fit
ing hub gear. This must run perfectly assembly is screwed into the outer hub eighteen 3, 8-inch balls. Place the clutch
the clutch hub shell on the driving hub assembly over the axle and onto the rear
gear before the friction assembly. This free with just the slightest trace of a by turning to the left. It is very im-
shake. If the bearing adjustment is not hub.
will allow an accurate bearing adjustment portant to turn the inner hub very tight
just right. tighten or loosen the driving Pack the ball thrust bearing "16,"
and is recommended for that reason. into the outer hub. If it is impossible to "I 7" and "18," and roller bearing parts
hub nuts as may be found necessary. line up the key ways after the inner hub
Pack the hub shell cone with a good Place this assembly in a vise, clamp- "15" with grease and fit them into the
grade of thick cup grease and place the is turned in tight by hand, do not back driving hub gear in the following man-
ing the gear and fit the friction assembly the inner hub outward slightly but force
I /4-inch balls in two rows of 34 each, in such a manner that the marks placed ner: First fit the beveled race "16,"
it tight with a hammer.
u~ing the grease as a retainer. Place the on the driving disc and hub shell before then the ball retainer with the balls "17,"
After the inner hub has been properly the outer race "18" and the roller bear-
driving hub gear into this assembly in the the clutch was taken apart, line up.
tightened and the key ways line up, fit ings with retainers "15."
same way the other gear was fitted. Screw Lightly tap the driving disc to force it
the six woodruff keys "8." These keys Be sure that the felt washer in the re-
the driving hub nut down tight on to the over the spline fittings of the driving hub
fit tight and it will be found necessary to cess of the actuating worm cone "14" is
driving hub gear, then back it off about gear and draw the driving disc clamp nut
use a hammer to drive them way down.
I 14 turn and firmly tighten the driving down tight. in good condition and will retain the lubri-
Be sure to drive them way down and see cant and prevent dirt from entering this
that no dirt remains in the key ways or bearing. Then screw the actuating worm
it will be impossible to fit the hub shell cone in place. First screw this down
band "39." tight, then back it off possibly I ;4 turn
How to Assemble the Two-Speed Hub Place the hub shell band over the rear or just enough to allow the wheel to turn
Pack the clutch gear cone "13" bear- Fit the shi her collar "19" over the hub and fit the two hub shell band screws. perfectly free and make sure that the bear-
ing grooves with grease which will lubri- axle. Place the clutch shifter bar "28" If trouble is experienced in fitting the ing is not being cramped.
cate and act as a retainer to hold the balls through the shifter collar and the pro- screws use a soft thin punch or nail. Place
Fit the bushing "36" over the left axle
while assembling. This bearing consists vided slot in the axle. Screw the clutch this through two holes one on each end
end with the large diameter toward the
of a double row of 5/ 16-inch balls of 18 shifter plunger "29" into the shifter in the band and into one of the outer hub
actuating worm cone. Then place the
holes, then pull the band in place, hold
balls each. Place the clutch gear cone with bar. When this is done care should axle support washer "35" over the axle
balls into the right half of the inner hub be taken to get the Ieeth of the plunger it and fit one of the screws.
against the bushing. This washer was
"2." Since this bearing is only a free to line up evenly and properly with the Pack the right cone bearing "21" with not used on two-speed hubs manufactured
running fit and no play is allowed, the slot in the axle so that the shifter pinion thick cup grease and fit the nineteen 3 j8- before June I sl, 1914, but should be
balls will not enter the inner hub shell can move the shifter bar the full travel inch balls. Lubricate the inner hub fitted to these two-speeds also, because it
easily and it generally will be found of the slot. Refer to "G," illustration mechanism with a few drops of thin oil greatly adds to the strength of the axle.
necessary to press firmly with the hands No. I. and screw the cone on the axle. Screw Next to the axle support washer fit the
to get the parts together. Place the clutch collar "20" over the the right cone I/ 16-inch beyond the rear keyed lock washer "31," then fit the lock
Lubricate the bevel pinion shaft "3" right end of the axle in such a position axle clip grooves and line up the square nut "33" and draw this very tight.
with regular motor oil and place the four that the lock pin is to the left of the shank of the cone with the grooves in the Again try the wheel to see that it twns
pinions "4" on the shaft. Place this as- feather key of the clutch collar and that axle. If this is done the brake arm will freely and that the bearings are not
sembly in position on the right half of the the high side of the lugs or dogs of this line up properly with the brake arm clamp cramped. Fit the bral(e side cover so
inner hub "2" and fit the left half "I" collar is to the right. Place the axle and then there will be no danger of spoil- that the bra/re arm is in line with the bra/re
of the inner hub against the right half so assembly into the inner hub shell assembly ing the bearing adjustment when fitting arm clamp. Remember that this is very
that the marks on the inner hubs line up. and with a screw driver press in the clutch the wheel in the frame. Push the axle important because if the bral{e end cover
The marks are either center punch marks, collar pin "9" so that the clutch collar inward toward the left by hand. were either forced up or down in lining
numbers or letters. It is very important can be placed over the clutch gear cone. Pack the left side of the two-speed up the bral{e arm with the clamp, the
to match up the inner hub shells because Be sure that clutch collar pin is in line mechanism with thick cup grease. Force bearing adjustment of the rear wheel
these parts are machined in pairs to insure with the three lock holes at "H" in the this grease in well between the pinion would be changed and there would be
a perfect fit over the bevel pinion shaft. clutch gear cone. gears. Allow sufficient room for the driv- great danger of ruining the actuating
For this reason it is necessary to renew Engage the dogs of the clutch collar ing hub gear or an over-supply of grease worm cone, driving hub gear and the com-
both halves when one-half must be re- and the right side of the inner hub. Lubri- will be put into the hub causing it to work plete bearing in a very few miles of driv-
newed. cate the entire assembly with a little cylin- out on the brake side. Fit the driving ing.
 To Adjust the Circuit Breaker Poinls
The fibre block on the circuit breaker clutch engaged), until the steel cam hits
arm is subjected to a certain amount of the fibre block and separates the contact
wear in service, and after several thou- points as far as they will go. The lock
sand miles it will be necessary to readjust nut "I I" should then be loosened with
the contact points to make up for this the generator wrench, and the adjusting
wear. As a matter of precaution, an in- :crew "I 0" should be turned out or in
spection and adjustment if necessary, by turning the hexagon head until it is
should be made, say, every 1,500 miles. just possible to insert the flat steel gauge
If the high side of one of the steel cams on the wrench between the points at "9."
is not in contact with the fibre block, it After the points are correctly adjusted,
will be necessary to turn over the generator carefully tighten the lock nut and measure
slowly by means of the rear wheel (trans- the clearance again to be sure that the
mission must be in high gear and the adjustment is correct.

To Reseat Brushes and Clean Commutator

Inspect the commutator and brushes when drawing it out follow the radius
every month or every I ,500 miles. If the of the commutator to prevent trimming off
commutator is found blackened, not dark the edges of the brushes. It is extremely
brown, it should be cleaned by burnish- important to have the entire surface of the
ing with No. 00 sandpaper. Never use brush bear against the commutator, to
emer:J) paper. Normally the commutator receive full efficiency from the generator.
reqmres no attention. To clean the com- Bear down lightly on the brush holder
mutator, cut a strip of No. 00 sandpaper and withdraw the sandpaper. After clean-
into strips about ~,i\" wide. Run the motor ing the brushes and the commutator, re-
slowly and hold the sandpaper with the move any particles of sand with a gasoline
coarse side against the commutator until moistened cloth. This is important, for
the latter is bright and clean. Be careful sand will cut the commutator. Do not
not to gel a linger caught in the drive chain take for granted from the above instruc-
during this operation. See that the brushes tions that it is necessary to clean the com-
have a good and clean bearing surface mutator and reseal the brushes every
against the commutator. If they have not, 1.500 miles. Clean these parts only when
insert a strip of the same sand paper be- conditions warrant. If the commutator is
tween the commutator and the brush, with found cut or worn by the brushes, even
the coarse side towards the brush. Be though the damage seems to be only slight,
sure to pass the strip of sandpaper around refer your machine to the dealer immediate-
the commutator as far as possible and ly.

Lubricating the Generator

Never use thin oil on any part of the cup will require filling about every 1,000
generator. Once a year put a little vase- miles. If the generator has a regular
tine about half the size of a pea on the grease cup here instead of a vaseline cup,
lop of the fibre block of the interrupter give this one-half turn every 500 miles and
lever and keep the cup on the right side keep it filled with a good grade of cup
of the generator filled with good vaseline grease.
if the cup is provided with a wick. This
Service Dept. Bulletin NtJ. 76 Servie< Department Bulletin

No. 76 August 10, 1918 Harley-Davidson Motor Co., Milwaukee To Repair 191 6 and Later Inlet Valves
Before an inlet valve stem can be cen- ed, make sure to clamp the valve centrally
To Repair Inlet Housings and Valves tered and trued up, the key end of it must so that the valve stem will be at equal
centers to the valve head.
be annealed, because the stem is hardened
In a recent letter it was suggested that he can buy the inlet housing bushings for a distance of I /2 inch. Turn the stem down to about .264"
from us and save sending the valves and After machining, harden the stem again diameter. Polish it with No. 00 emery
inlet housings and valves with worn guides
and stems, respectively, be referred to the housings to the factor:~-. The repair oper- by heating the end in molten lead and cloth and try the fit of the stem in the
ations are described below. housing guide. The fit is right when the
factory for repairs. quenching in oil.
Housings and valves of all models later stem is perfectly free with just a slight
If a dealer has a lathe or can have re- than I 912, but exclusive of I 915, can be Center the valve stem and valve head
trace of shake noticeable.
repaired. accurately. The valve head is already
liable work done at a local machine shop, After truing up the stem, refa~e the
centered, while the valve stem can be held valve seat again, making sure that the
The list prices of the bushings are as follows: List Price in a bell center, or a fixture can be made valve stem is absolutdy central. Valves
DA 834 1913-1914 Inlet Housing Bushing ............. . $ .20 with which the valve stem can be accu- which are worn so that the taper face runs
DA 834R 1916 Inlet Housing Bushing (Standard Size) .. .30 rately damped to facilitate turning the flush with the top, or within I j32" from
DA 834RA 1916 Inlet Housing Bushing (Undersize) .... .30 stem doW!l. Whichever method is adopt- the top, should be scrapped.
HA 834 1917-1918 Inlet Housing Bushing (Standard Size) .. .30
GA 834 1917-1918 Inlet Housing Bushing (Undersize) .... .30
To Repair a 191 3 or 191 4 Inlet Housing
To Repair Woro. 1916 and Later Inlet Housings Worn 1913 and 1914 housings are held by a .002" press fit. If the bush-
also repaired by boring out the guide and ing is too long, the inside end of it is faced
Center the inlet housing in the chuck of After a new guide has been turned in off so as to give sufficient clearance be-
place, the valve seat in the housing should fitting a bushing, but because of the de-
a lathe and bore .it out 33/64". This tween the guide and the valve head.
be trued up if it is worn. To have this sign of the housing, a different style bush-
will remove the entire guide. Lay a
seat true with the guide hole is very im- ing is used. If the valve is replaced with a new one,
straight edge or a depth gauge across the
portant, and will tht'cefore require plac- center the housing accurately, and ream
bottom of the housing, and turn the lower The housing guide is bored out to
ing the housing on a mandrel. Before out the guide with a 9;32" reamer. The
end of the guide boss off until the distance .378" and is not threaded. The bushing valve seat of the housing is then faced off
turning the housing seat down, be sure to
between the straight edge and boss is obtain the proper taper ( 30° or 45 °, de- is then pressed into the housing from the square with the guide by supporting it on
11/16". pendiQg upon the model); then set the inside, flush with the top of the guide, and a mandrel.
Tap this hole with a 9jl6"x24 V tap, compound head accordingly, and turn the
entering the tap from the bottom. This seat down just as much as may be neces-
tap, GX743, retails for $1.95. If a sary.
new valve is to be used, place a little After the housing seat has been trued
To Repair a 191 3 or 191 4 Inlet Valve
white lead on the threads and screw in a up, the extreme lower end may have to
guide or bushing with a standard hole. If be turned off slightly so as not to reduce If the valve stem is only slightly worn, These inlet valve stems are not faced
the valve stem is worn only slightly and lhe valve opening. Never turn this lower it can be made serviceable by facing off off as easily as the later than 1916 inlet
is to be faced down, screw in an under- flange off so that it is less than 3/ 16" the stem to true it up and then boring the valve, because the heads of them are not
size guide. Be sure to screw in the guide deep, and turn off only enough to have centered. For this reason, extreme care
from the bottom of the housing and to the lower taper edge of the valve come bushing to give the stem about .00 I"
clearance. must be taken in chucking the valve head,
place a little white lead on the threads he- Hush with the bottom of the housing. If so that the stem is trued up square with
fore turning it in tight; otherwise there will these limits cannot be followed, the hous- Before attempting any machine work,
be a leak; and the result will be nearly ing is worn too much and should be the seat.
the same as with a worn guide and stem. scrapped. anneal the valve stem, and after machin- It is understood that inlet housings and
ing, harden it as explained under, To Re- valves can continue to be referred to the
pair 1916 and Later Inlet Valves. factory for repairs, if preferred.
 The Warning Signal
To Adjust a Faulty Manual Ignition Switch
If previous tests and impcctions prove .Switch." Remove the three screws hold- One feature much appreciated by Har- pressing the horn button while the motor
that the centrifugal switch, horn, battery. ing the fibre base and spider cover as- ley-Davidson owners of electric models, is running, there is a short circuit either
wiring and connections are 0. K. and the is the fact that the warning signal or horn in the horn switch on the handle bar, in
sembly together, and bend the end of
horn cannot be sounded when the motor can only be sounded when the motor is the wire from the horn switch to the horn,
the contact blade. This will be only very running. If the horn can be sounded con- or in the horn itself. If the horn cannot
is cranked, the motor will be hard start- slightly, as may be found necessary. Be
ing because the manual ignition switch is stantly when the motor is idle, prevent be sounded while the motor is running, re-
careful not to bend the contact blade too complete discharging of the battery by re- move the horn cover and make sure that
faulty.
much because it will then be impossible moving the ignition key from the switch the vibrator contacts are not pitted or
Since the manual ignition switch is in-
tegral with the light in 5 switch, refer to in- to lock the ignition when the key is re- or by disconnecting the batteryt ground stuck together. The points should break
structions covering the removal of this moved. This same blade grounds or short wtre. at least a I j64" when the armature is
switch on pages 4 and 5, under "To In- circuits the generator when the key is re- Examine the fuse in the horn circuit. bearing against the diaphragm stem. If
spect and Correct a Faulty Lighting moved from the switch. Of course with a burned out or a loosely the points are not at fault, see that the
held fuse the horn could not be sounded. wiring from the switch box to the horn,
The cause of the short circuit must be and from the horn switch to the horn
When ·Motor Keeps on Running with Ignition Key Removed found and remedied before the fuse is re- is not damaged or loose. If these instruc-
placed. tions do not cover the trouble refer to
This trouble can be traced to two frame work after removing the enamel at If the horn sounds continually without service bulletin No. 61.
causes which are: the points of contact. If a sgark occurs,
I. Failure of entire switch assembly it will be necessary to remove the enamel
to make a connection or ground to the so that switch clamp can make contact To Run With a Discharged Storage Battery
frame. with the frame.
2. Contact blade failing to make The motorcyCle cim be run with a dis- tery box and repeat the above instruc-
If no spark occurs, it will be necessary
contact or ground against the lug of the charged or disabled battery, but it is very tions. After starting the motor, be sure
to remove cover and bend contact blade
spider assembly cover when key is re- important to have the battery recharged to reconnect the battery ground wire at
moved. ur;til it makes contact with the lug of the or repaired immediately, because if the once or the generator may be ruined. Al-
To determine whether entire assembly spider assembly cover. If the tempe1 battery is left in a discharged or disabled ways see that the battery ground wire is
ts grounded, start the motor and touch should be burned out of this blade, it condition for any length of time it will connected while the motor is running, be-
a screw driver to the switch and the should be replaced. be ruined. If the battery is disabled or cause the battery acts as a safety valve and
partly discharged, turn the lights off when protects the generator. It is possible to
starting motor. ruin the generator if the motor is driven
To Test Whether the Generator is Charging the Battery Switch on the ignition, put the gear at a speed greater than 15 miles per hour
shifting lever in either low or second gear, unless the storage battery remains con-
If the storage battery is exhausted and If the above tests prove that the gen-
engage the clutch, raise the exhaust valves nected.
it is suspected that the generator is not erator is charging, that. the circuit between and push the machine at a good pace by Before disconnecting any of the wues
charging, have the battery recharged and the generator and battery is closed, that running alongside, drop the valves, and other than the spark plug wires to make
5tart the motor in the regular way. Then there is no short circuit, and that the bat- jump on or quickly disengage the clutch a repair, disconnect the battery ground
disconnect the ground connection. If the tery is not at fault, the output of the as soon as the motor starts. If the ma- wire from the battery box cover to pre-
motor continues to run, the generator is
generator most likely is not normal due chine will not start, disconnect the bat- vent burning out of fuse or short circuiting
furnishing current. If the motor stops, the
to a dirty commutator and brushes. In tery ground wire on the outside of the bat- the battery.
generator is faulty and the matter should
be referred to your dealer. During thi~ that case, clean the commutator and re-
seal the brushes as explained under that
lest the motor must not be run at a speed
exceeding 15 miles per hour. heading.
If Battery Discharges Without Apparent Cause
Should the top of the battery become the lighting switch turned to the OFF
dirty and saturated with electrolyte, a slow position and the motor idle, being sure that
Hard Starting discharge will be the result. Likewise, the horn cannot be sounded. Then dis-
Ha.rd starting of the motor can gen- discharged battery, refer to instrm:tions the battery box and the terminals will connect the ground wire on the outside of
erally be traced to a discharged storage "To Run With A Discharged Battery." be eaten and destroyed. Keep the battery the battery box and rub it against some
battery or failure of the ignition switches If the switches are suspected refer to clean. metallic part of the machine. If sparking
to make a good connection between the instructions under "To Test for and Re- Test for a short circuit between the occurs, there is a short circuit. To find
generator and battery. In the case of a pair a Faulty Ignition Switch." generator and battery as follows: Have out where the short circuit is, remove the
ignition key from the manual igmhon during this tc't would indicate that the
switch and repeat the above test. If short circuit is in the wiring, or connec-
sparking occurs the same as before, the tions leading from the manual ignition
short circuit is between the battery and switch to the centrifugal switch.
the manual ignition switch. No sparking

How to Test a Suspected Battery

If this test and the above explained twenty-four hours. Then take a second
conditions do not apply, the battery itself hydrometer reading of each cell. If the
may be at fault. Take the battery out battery is 0. K., the readings will prac~
of the box and have it charged. After tically be the same. If there is a de-
charging tape the ends of the wires. Take cided difference in the reading the battery
a hydrometer reading and make note of is at fault and should be referred to the
the specific gravity of each cell. Set the nearest Exide Battery Service Station.
battery in a cool, clean and dry place for

To Clean Circuit Breaker Points

To clean the circuit breaker points, it points at "9" are slightly pitted or burned,
is necessary to remove the bakelite cap of they should be cleaned with No. 00 sand-
the distributor. If the circuit breaker paper. Never use emery paper.

Ignition Mechanism of the Harley-Davidson Remy Generator

I. Distributor cap locating lug, or cam; 9. Circuit breaker points; I 0. Ad-
stop, should interlock with the slot at "6" justing screw with which the gap at the
whenever the distributor cap "3" is re- circuit breaker points "9" are adjusted;
placed. Failure to fit the distributor cap I I . Adjusting screw lock nut, prevents
properly may mean a damaged generator; adjusting screw "I 0" from turning auto-
2. High tension terminals which alter- matically. The lock nut must be loosened
nately collect the ignition current from before an adjustment is made, and must
segment "5" and carry it to the spark plug be securely tightened after adjusting; 12.
wires. These high tension terminals clear Primary wire connects primary winding of
the segment by about I ;64" and should coil "16" to ground through circuit break-
never be adjusted ; 3. Distributor cap; er points at "9"; I 3. Distributor cap
4. Distributor segment contact spring spring (2 used) securely holds the dis-
which carries the ignition current from car- tributor cap "3" in position; 14. High
bon contact "I 4" to segment "5" ; 5. Dis- tension carbon contact insert which carries
tributor segment distributes the ignition the ignition current from wire "15" to dis-
current from the distributor segment con- tributor segment contact spring "4"; 15.
tact spring "4" to the high tension termi- High tension wire which carries the ignition llluatration of Ian ltlon Mechanlam
nals at "2"; 6. Slot in timer head cast- current from the seconda{y winding of the
ing lines up with lug "I" when the dis- coil to the carbon contact insert ''14" in
tributor cap "3" is properly fitted; 7. Cir- the distributor cap; 16. Coil only one
cuit breaker lever; 8. Circuit breaker used.
 ·1 he trouble l;nnp or sidecar lamp con- light either the trouhle or the sidecar lamp,
nection hole is offset to the right o! the the lighting switch must be turned on be-
Fluctuating Lights
switch. Refer to illustration which plain· cause this connection is in circuit with the If the lamps burn bright when the mo- the battery to the terminal block on the
ly shows where to plug in. In order to tail lamp. tor is running at moderate speed, but vary battery box to the lighting switch. See
and flicker when the motor is running slow- that the upper fuse is 0. K., that it is held
When Lights Do Not Burn When Motor IS Idle ly, the cause is a discharged battery or securely and that the wire connections on
a poor circuit between the battery, gen- the switch clamp screws are clamped firm-
Failure of the lamps to burn while th<" out and the short circuit has been remc· erator and lights, at one or more of the
mota• is not running, generally indicates died, the horn fuse can be safely used in ly. Examine the contact spider of the
following points.
that the battery is discharged, or that the the lighting circuit. If tinfoil can be ob- lighting switch as explained under "To
• Carefully inspect the ground wire which
lighting fuse is burned out due to a short tained a temporary repair of a burned out is clamped under the cover clamp screw Inspect and Correct a Faulty Lighting
in the lamp circuit. In the latter case lo- fuse can be. effected by wrapping a double of the battery box, and leads to the nega- Switch." Examine the wiring leading to
cate and remedy th•: short circuit before thickness of tinfoil around it. tive pole of the battery. In like manner the lamps and the connections on the in-
replacing the fuse. Two fuses are mount- To ascertain whether the battery is dis- examine the positive wire leading from side of the lamps.
ed in the switch box for the horn and light- charged, test it as explained under the bat-
ing circuits 1o prevent discharge and possi- tery instructions. If the fuse and battery
ble injury to the battery should a short are found to be in good condition, the To Inspect and Correct a Faulty Lighting Switch
circuit occur in the lamp or horn wiring. trouble lies in the lamps or in the wiring.
Remove the two hexagon nuts which the three screws which pass through the
See that the fuses are held firmly in the Inspect the bulbs and examine the wiring clamp the entire switch box assembly to side of the spider cover have been re·
holders. In case a fuse burns out do not for a break. Also look over the lamp the studs of the switch base. Take hold moved. Inspect the four spider contacts
use a piece of wire as a substitute. Lo- connections to see if any are loose or of the black switch box cover and re- inside of this cover. Make sure that they
cate and remedy the cause of the trouble
broken. If the battery is discharged have move the entire assembly from the switch bear against the contact inserts in the fibre
and replace the fuse with a new Harley-
it recharged immediately. If the trouble base. If the cover sticks it can easily be base· with sufficient pressure to insure a
Davidson fuse. By using a piece of wire,
was due to a loose or broken connection, forced off by placing a screw driver closed circuit, and that they cannot slide
the short circuit that was responsible for
or a short circuit in the wiring, repair ac- against the edge of the cover from the beyond the insert contacts. To see wheth·
the fuse burning out, may cause serious
cordingly. Investigation shows that most left side of the machine and then striking er the spider contacts slide beyond the in-
injury to the switch or wiring, and dis-
charge the battery. In an emergency, if discharged batteries are caused from ex- the screw driver with the fist or palm sert contacts, turn them to the various posi-
the fuse in the lighting switch is burned of the hand. Remove the two round head tions and with a pencil, mark the exact lo-
cessive or careless use of the lights.
screws which clamp the black switch box cation of the contacts on the metal cover of
cover to the switch assembly and remove
If One Lamp Fails to Burn the cover. If an inspection proves that
this assembly. Then put the fibre switch
base assembly into the switch cover as-
If ell the lamps but one burn, the fault lamp to burn may be due to a burned out the wires are connected firmly and prop-
erly as per illustration showing switch wir- sembly and note whether each mark lines
lies in that particular lamp, or in the wir- bulb, and the test of inserting a good bulb
ing diagram, the fibre switch base to which up with its respective clamp screw. If
ing thereto. It may be that the contact in place of the suspected one immediately
the wires are attached should be removed they do not line up properly, bend the
spider for that particular hmp is making suggests itself. If the good bulb fails to
a poor circuit with the insert contact in the burn, the wiring and the connections to the from the cover and spider assembly. These spider contacts as may be found neces-
switch. In this case, see switch instruc- lamps should be carefully examined. two assemblies can be taken apart after sary.
tions pages 4 and 5. The failure of a
To Test for and Repair a Faulty Ignition Switch
If Neither Headlight Will Burn
The following symptoms can be traced period of a few seconds after the motor
If neither head lamp bulb lights, but point of contact with the reflector, with to the ignition switches of which there are stops.
the tail lamp bulb does, the trouble must a scraper or screw driver. If it is neces- two: The centrifugal switch which is en- 3. The horn cannot be sounded when
lie either in the headlight bulbs, wiring, sary to remove the reflector, use the 'great- tirely automatic and built into the gen- cranking the motor vigorously. (See that
lighting switch or the double connector in est care not to touch the reflecting surface. erator; and tire manual switch which is in- fuse is 0. K.)
the headlight. Sometimes trouble with the To open the lamp for replacing a bulb, tegral with the lighting switch and op- The Manual Switch is Out of Order
small headlight is caused by failure of the loosen the screw in the bottom of the .erated with a key. When:-·-
reflector to make a good connection or front flange about 'It". Remove the glass The Centrifugal Switch is Out of Or- 4. The motor does not stop when the
ground to the lamp body, especially if retainer, glass and packing washer. To der When:- ignition key is removed.
the entire interior of the lamp is covered replace a bulb in a new type headlamp 1• The horn can be sounded when 5. The horn cannot be sounded when
with enamel. If the enamel is the cause it is necessary to remove one hinge pin the motor is idle. the motor is cranked and the centrifugal
of the trouble, scrape the lamp at the and swing door outward. 2. The horn can be sounded for a switch is in good working order.
 To Adjust the Centrifugal Switch
To gam access to the centrifugal they are finely tempered and "set" on the
switch it will, of course, be necessary to switch blade suppo~t. Always bend the
remove the left foot board, short chain switch blade support when changing posi-
guard and chain. Under the cover at tion of blade. Adjust the long blade sup-
the lower left end of the generator is a port first.
\o L,....l\4~ "'~····."~\..\G..~,. set screw. With a screw driver loosen When bending the long blade support,
RI!.D WIRE.
this about one turn: This cover which is care must be taken to bend it so that the
held by a bayonet type connection, is then steel insert in the thrust button is in line
\o SM"-1..'- I-\£AO\.I~>H removed by turning it to the left as far with the thrust ball in the switch housing.
~LA<>< VIIRE. as it will go and pulling it from the gen- This is very important, because, if the ball
comes in contact with the bakelite of the
button, it will wear a pit into the button
in a short time.- After the large blade
is in the proper position, obtain the clear-
ance at the contact points by bending the
lower or short blade support. A definite
clearance for these points cannot be given
because of the variation in the stiffness in
To Sw1TC>\ Ol?AC~£.1\e.RI'IINAI.. some of the blades. However, it is safe
\T"'IL- .1"--'"'"tl 5•t>E C,-..~ \..I">{T")
to aswme, that I /32" clearance is about
A right. Bend this blade support accord-
ingly, being careful that the points line
Switch Wiring Diagram of Model 18-J
Equipped with Model 235 Generator
B up, and make a good square contact.
c The switch should now be tested to see
whether or not the adjustment is correct.
D Replace the short chain and battery
ground wire, raise the valves, press firmly
on the handle bar horn button and give
the starter crank a vigorous stroke. If the
1..1&1\T FU~E
centrifugal switch blades are properly ad-
justed, and the circuit between the gen-
erator and battery, and the battery itself
is 0. K., the horn will sound for just a
erator. Be sure that the clearance "A" fraction of a second.
TO ~MA\.\. 1\I:Ml\.IG.ltT
BL"C:.l\ y'!\ ftl between thrust button "B" and cover "C" Watch the action of the centrifugal
of the centrifugal switch does not amount switch blades. See if they make contact.
to more than a few thousandths of an inch. Then if the horn does not sound while
If there is too much clearance at this point, pressing the horn button, check for the
ball action will be lost which will prevent following possible troubles:-
a good contact if any, at the points "D." 1. Battery is discharged. 2. Faulty
manual switch. 3. Loose wire connec-
If the blades require adjusting, disconnect
tions, 4. Faulty horn or the wire itself
the ground wire from the battery box cover is broken at one or mote places.
screw to prevent a short circuit, which if It is well to get into the habit of at-
only for an instant would remove the tempting to sound the horn after stopping
temper in the switch blades making them the motor, to determine whether the cen-
useless. Never bend the switch blades as trifugal switch is functioning properly.
 No. 48A Service Department Bulletin

Service Dept. Bulletin How to Adjust the Bearings by Means of the Driving Hub Nut
No. 48A. July 10, 1918 Harley-Davidson Motor Co., Milwaukee Fit the left threaded driving hub nut possible, the bearings will be damaged
after seeing that it is a perfect lit. Draw or the driving hub nut may be backed off
(Revised Edition of Service Bulletin No. 48) automatically, even though a lock washer
the nut tight and then back it off the dis-
tance between three rivets on the sprocket is fitted between it and the lock nut. The
hub shell. This distance can easily be driving hub nut acts as a cone to adjust
determined with the wrench. If the the bearings. The bearing must be free
Inspection and Lubrication of Clutch Bearings driving hub nut is drawn up as tight as without any perceptible shake.

Clutch Bearings of 1917 and earlier The following instructions apply espec-
style clutches should be repacked with ially to the 1915 to 191 7 three-speed
How to Fit the Driving Hub Lock Washer and Lock Nut
good cup _grease every 3000 miles for model clutch, although in a general way After fitting the driving hub nut, lit the hub; then with wrench CK I 7 lit the right
average service and oftener if the machine they apply to the clutches on direct geared lock washer. The washer is made with a threaded driving hub lock nut. Draw this
is subjected to exceptionally severe service. models as well. key that fits in a keyway in the driving nut up as tight as possible.
We recommend that the dealer lubricate
this style clutch bearing rather than the The 1918 three-speed clutch is lubri-
cated with a few drops of oil through the
How to Test the Adjustment of the Bearings
·rider, because special wrenches are re-
quired to handle the driving hub nut and actuating plate every I 000 miles, as ex- Test the adjustment of the bearings be- adjustment slightly. If this does not rem-
lock nut, and also because perfect adjust- plained in the 1918 manual. fore locking the lock washer or fitting the edy the trouble, the six clutch adjusting
ments are necessary to get good results. clutch to the machine. Lay the clutch screws may be screwed in too far.
on the driving hub lock nut, lit the actuat- After the proper bearing adjustment
ing plate and with some suitable leverage, has been obtamed, lock the lock nut by
bear squarely down on the actuating plate. forcing a punch or chisel between the
How to Take the Clutch Apart WheR the plate is forced downward, the clutch shell and lock washer opposite one
friction discs are released. While holding or two of the milled grooves in the lock
In order to lubricate the driving hub rawhide hammer or block of wood. Re- the actuating plate in this position, it nut. This will force a part of the lock
bearings of other than 191 8 three-speed move the driving hub lock nut with wrench should be an easy matter to turn the clutch washer into the milled slots or grooves in
clutches it is necessary to remove the CK I 7. Take off the lock washer if one sprocket with the lingers. If the clutch the lock nut and prevent this nut turning
clutch complete from the machine and is fitted, and with wrench CK800 tum off sprocket turns hard, loosen the driving hub automatically.
then to strip it. Do this as follows: the driving hub nut. With a scratch awl
On three-speed models remove the cot- mark the driving disc and clutch shell, be-
ter pin and both nuts from the clutch pull Driving Hub, Nuts and Lock Washer Furnished Assembled
cause it is essential that the spline fittings
rod, then the actuating plate and spring. When a driving hub must be replaced, the earlier driving hubs. If difficulty is
With the special clutch wrench DK806 or keyways of the discs and the key ring
of the hub shell are assembled as taken we include a nut, lock nut, and lock experienced with the lock nut and nut of
remove the left threaded lock nut and the washer with the new driving hub. This
apart. Remove the disc assembly from an earlier type driving hub working loose,
clamp nut which hold the clutch on the is done to insure a perfect lit. The lock
main shaft. If the clutch sticks tight on the driving hub assembly, being careful not a new style driving hub with which will
washer on the driving hub has been used
the main shaft, strike one side of it with a to lose any of the 64 I /4 inch balls. since May, 1916, and since to use it, a be included a nut. lock washer and lock
keyway must be provided in the driving nut should be liaed. Order by part
hub, the lock washer cannot be fitted to DG534.
How to Lubricate the Bearings
How to Fit the Clutch
Carefully clean and inspect the bearing travel of the balls ~oe~ not indicate wear. Before fitting the clutch on the shaft, clutch clamp nuts with wrench DK806.
surfaces of the driving hub and hub shell Repack the bearings with Harley-David- make sure that the shaft, keyways, and Adjust the clutch pull rod nuts so that
cone. If a part is found pitted or worn son non-Huid lubricant or a good grade of driving hub are clean. Fit the key prop- there is about one-half inch free motion at
badly, it should be replaced. If a new erly; that is, see that it fits snugly in both the top of the hand lever when it is in the
hub shell cone is required, send the clutch cup grease. The lubricant also acts as a
keyways but that it is not too high and extreme forward position. This is im-
hub shell assembly to the factory to have a retainer while assembling the clutch bear-
prevents the driving hub from resting prop- portant to get the proper clutch adju~t­
new cone fitted. A ring showing the ing in two rows of 32 balls each. erly on the shaft; then firmly tighten both ment.
 The Harley~Oavidson Remy Electric Lighting and
Service Dept. Bulletin Ignition System
This remarkably efficient system con- tension current for ignition by the coil on
No. 67. Revised. Harley-Davidson Motor Co., Milwaukee fists of a compact direct current generator, lop of the generator.
storage battery, headlight with two bulbs, It should be understood that the bat-
tail light, signal and switch. The gen- tery is not provided as an independent
erator furnishes low tension 6-8 volt direct system for lighting and ignition, although
current for lights, signal system, and for the storage battery will provide ignition
charging the battery. . This current is and lighting current for a short time when
"stepped up" or transformed into high the generator itself is not generating.

Care of the Harley~Davidson Remy Generator

The electrically equipped model re- veniently refer his machine to a dealer we
quires reasonable attention. It is advisa- are covering the care of this model here-
ble to have your dealer make any neces- with. If the instructions are followed
sary inspections, tests and adjustments be- closely and care is exercised any necessary
cause extreme accuracy is, of course, essen- adjustments can be made successfully.
tial. For the rider who cannot con-

Do Not Overload the System

.
.. .
0 Never overload the electrical system by give just so much current; the storage bat-
r~
-.
equipping with accessories not approved tery capacity is limited: therefore, care
- c by the Harley-Davidson Engineering De- must be exercised when adding electrical
~"
o., partment. The generator is designed to equipment.
~::I

Why the Battery Must Always Be Kept in Circuit

The battery acts as an accumulator and serious damage may result to the arma-
governor holding the voltage down to 8 ture, spark coil, or condenser. Bulbs will
volts. The current produced by the gen- burn out at any voltage higher than 6-8
erator at 30 miles per hour, with the bat- volts. Therefore, even though the stor-
tery out of circuit, is above 30 volts. This age battery should be exhausted and not
high· voltage produces a serious overload capable of giving off current, it must be
on the generator and will burn and pit left in its place, connected up.
the breaker points in a Short time. Other

The Lighting System

The headlight contains two bulbs- Never leave the machine standing with
the larger bulb is twenty-one candle the bright headlight turned on as the bat-
power and nitrogen filled. The dimmer tery will be discharged in a short time.
and tail light bulbs are each two candle H any of the lamp bulbs need renewal,
power and have tungsten filaments. The replace ·with lamps ·of the same candle

r
lighting switch has three positions; all power and voltage. This is extremely im-

~· ~~·~~·~-···-···-· OFF, bright headlight and tail light, and

dim headlight and tail light.
portant; 6-8 volt bulbs should be used.
In ordering, specify single point bulbs.
~
I
iI
"
'I
MO
••J I
~ lf
Se11>ice Deparlmenl Bullelin No. 72

The Importance of Proper Push Rod and Exhaust

Lifter Pin Adjustment
Some mechanics give little thought to of an inch after grinding the valves. This
oversight is extremely dangerous because
the importance of readjusting the pushrods
the lift mechanism and cylinders do not
and lifter pins to the one-thousandth part expand evenly when the motor gets hot.

The Exhaust Valves Expand More Than the Cylinders

There is a tendency for the exhaust valves will be held open after the motor
valve stems to expand more than the cylin- has warmed up. If the one fact that the
ders after the motor has warmed up. exhaust valve stems expand more than the
Therefore, if sufficient clearance is not cylinders is taken into consideration, the
allowed between the lifter pins and valve importance of adjusting the lifter pins ac-
stems when the motor is cold, the exhaust curately will be appreciated.

The Cylinders Expand More Than the Push Rods

Trouble will also be experienced with fore, if the inlet push rods are adjusted
the inlet mechanism if the adjustment is -while the motor is hot, the inlet valves
not accurate. However, instead of the will be held open when the motor cools
down, because the cylinders will contract
push rods expanding more than the cylin-
more than the push rods. For these rea-
ders and getting tight against the inlet sons it is very important to adjust the ex-
valves, they will loosen up gradually as haust lifter pins and inlet push rods with
the motor gets hot, because the cylinders great accuracy and when the motor is
expand more than the push rods. There- cold.

Table of Valve Clearances

The following are the proper clearances and inlet levers and inlet valves according
between the exhaust valves and lifter pins to model:
1918 and 19f7 twin ex. lifter pins, .008" to .010" clearance for both cylinders
1916 twin ex. lifter pins, .006" clearance for front cylinder
1915 twin ex. lifter pins, .006" clearance for front cylinder
1916 twin ex. lifter pins, . 004" clearance for rear cylinder
1915 twin ex. lifter pins, .004" clearance for rear cylinder
I 914 and prior twin ex. lifter pins, .004" clearance for both cylinders
Single cylinder ex. lifter pins, .004" clearance for all models

Allow .004" clearance between the Be sure that the valves are in the low-
inlet levers and inlet valve stems on all est position before making any adjust-
models. ments.
 Service Department :JJullelln No. 73A

Service Dept. Bulletin After a new guide has been turned in After the housing seat has been trued
No. 73A June 17, 1918 Harley-Davidson Motor Co., Milwaukee place, the valve seat in the housing should up, the extreme lower end may have to
be trued up if it is worn. To have this be turned off slightly so as not to reduce
seat ·true with the guide hole is very im- valve opening. Never turn this lower
portant, and will therefore require placing flange off so that it is less than 3/ 16"
To Repair Inlet Housings and Valves To Repair an Inlet Housing
1916 and Later Models To Repair an Inlet Valve the housing on a mandrel. Before turn- deep, and turn off only enough to have
ing the housing seat down, be sure to ob- the lower taper edge of the valve come
tain the proper taper (30° or 45° de-
flush with the bottom of the housing. If
pending upon the model); then set the
these limits cannot be followed, the hous-
To Repair Inlet Housings and Valves compound head accordingly, and turn the
ing is worn too bad and should be
seat down just as much as may be neces-
191 6 and Later Models sary. scrapped.

Worn inlet housing guides and seats pending upon the model. If a new inlet
and worn inlet· valve stems and seats of valve is to be fitted, a standard size bush-
1916 and later models can be repaired ing is screwed into the housing. To Repair an Inlet Valve
outside of the factory wherever a lathe is The price of the bushing is 25 cents
available. A worn inlet housing is re- list, subject to the regular discount. Order Center the valve stem and valve head Turn the stem down to about .264"
paired by boring out the housing to a diameter. Polish it with No. 00 emery
as follows: accurately. The valve head is already
diameter of 33;64"; then threading the cloth and try the lit of the stem in the
· 1916 Inlet housing bushing standard centered, while the valve stem can be held housing guide. The lit is right when the
bore with a 9/16"x24 V tap, and se-
size-DA834R. in a bell center, or a fixture can be made stem is perfectly free with just a slight
curely screwing a bushing into the hous- trace of shake noticeable.
1916 Inlet housing bushing undersize with which the valve stem can be ac-
ing. After truing up the stem, reface the
-DA834RA. curately clamped to facilitate turning the
Worn seats and stems of inlet valves valve seat again, making sure that the
stem down. Whichever method is valve stem is absolutely central. Valves
are repaired by turning down the stem 191 7 and 1918 Inlet housing bushing
adopted, make sure to clamp the valve which are worn so that the taper face
so that it will be about .002" loose in an standard size-HA834.
centrally so that the valve stem will be at runs flush with the top, or within lj32"
undersized bushing, and then facing off 191 7 and 1918 Inlet housing bushing equal centers to the valve head. from the top, should be scrapped.
the seat with a 30" or 45 ° angle, de- undersize-GA834RA.

To Repair an Inlet Housing

Center the inlet housing in the chuck new valve is to he used, place a little
of a lathe and bore the housing out white lead on the threads and screw in a
33/64". This will remove the entire guide with a standard hole. If the valve
guide. Lay a straightedge or a depth- stem is worn only slightly and is to be
gauge across the bottom of the housing. faced down, screw in an undersize guide.
and tum the lower end of the guide boss Be sure to screw in the guide from the
off until the distance between the straight- bottom of the housing and to place a little
white lead on the threads before turning
edge and boss is II/ 16".
it in tight; otherwise there will be a leak,
Tap this hole with a 9jl6"x24 V tap, and the result will be nearly the same as
mtering the tap from the bottom. If a with a worn guide ancl stem.
 No. 72 Service Department Bulletin

Service Dept. Bulletin and reamer are standard s1ze and one
each 1-32 inch oversize. The oversize
necessary, the cutter can be sent to us.
It is removed after taking off one nut.
No. 72. March 5, 1918 Harley-Davidson Motor Co., Milwaukee
guide reamer and pilot are used on cylin- Another important feature of the tool
ders with badly worn valve stem guides is that the pilot is held stationary, being a
Cylinder Exhaust Seal Reaming Tool How to Fit and Grind Exhaust Valves
in which the standard size pilot would fit press fit in the cylinder guide. The
Why the Valve Seals should be Reamed How to Te.sl Whether a Valve Seals very loosely. The tool is well designed reamer turns on the pilot. This gives the
How to Use the Exhaust Seat Reamer The Importance of proper Pushrod and and the material and workmanship are of reamer an accurate guide, insuring a good
and Facer Exhaust Lifter Pin Adjustment the best. The price is $1 0. 00 list. Order seat and preventing chattering of the cut-
Clean and if Necessary Ream the Valve The Exhaust Valves Expand more than the tool by No. FK824. ter.
Guide the Cylinders
The reamer is demountable and in- Carefully read the following, explain-
How to Use the Reamer The Cylinders Expand more than the
Push Rods cludes a specially heat treated tool steel ing why and how to use the reamer.
Do N ol Lap a Pitted, Burned or Warped
cutter. It will give a long period of serv- Keep these instructions for reference and
Valve Table of Valve Clearances
ice before sharpening of the cutter is nec- follow them carefully to get the best re-
essary. When sharpening does become sults.
[ Reviaed Edition of Service Bulletin No. 54]

Cylinder Exhaust Seat Reaming Tool

and How to Use Why the Valve Seats Should be Reamed
The tool shown in the accompanying necessity for first class valve seating work.
illustration should be part of the equip- The tool consists of the reaming cutter When a motor ·has been run for some haust valve and cylinder seat when the
ment of every repair shop. It can be complete with detachable handles, two time with a poorly seating exhaust valve, valve is in its raised position is 3-8 inch.
used practically on all models and is a pilots and two guide reamers. One pilot the cylinder and valve seat will be found Assuming that a pitted valve and seat are
pitted considerably. A seat in this con- ground in, it can be understood that this
dition should not be ground with a valve clearance will be reduced by the time the
grinding compound to regain a good seat, valve seats and, combining with this the
for the following reasons:: natural wear caused by the closing of the
I. Excessive grinding will be neces- valve, it is easy to see that the size of
sary to remove the pits in the cylinder and the opening will be cut down consider-
on the valve. ably. A reduced opening will prevent
free escape of the exhaust gases and
2. The valve being considerably therefore reduce the power and speed.
harder than the cylinder, the cylinder seat
will naturally be considerably lower after 3. Excessive g1inding or lapping will
such grinding. This will allow the valve ruin the straight face of the valve and
to seat deeper in the valve chamber. As cylinder seat and allow only a very nar-
a result the clearance between the valve row seat. This can be understood if it is
and the cylinder when the valve is in the considered that during the operation of
raised position will be reduced, the motor grinding, the compound is forced away
will not be properly scavenged and will considerably more from the center of the
load up with burnt gases. By using the seats than from the outer edges. The
reamer, no more stock than absolutely greater amount of compound on the outer
necessary need be removed. edges naturally will remove more stock
On the 1917 and 1918 twin motor and make the seats oval instead of a
the approximate clearance between the ex- straight 45 ° taper.
Ser~>iu Department Bulletin No. 72 No. 72 Service Department :Bulletin

How to Use the Exhaust Seat but is due to the hard scale which the of the reamer while giving it about three
heat forms on the exhaust seat. To save or four complete turns, depending on the
Reamer and Facer the cutting edges of the reamer, do not condition of the seat.
attempt to force the reamer through this Care should of course be exercised
The cylinder exhaust valve seat cannot scale by pressing squarely. Instead, ex- when re-reaming a seat not to remove too
be re-reamed while the motor is in the ert a slight pressure on one end of the much stock, because the exhaust valve
frame. Remove the motor, take off the wrench handle, (being careful not to press may at no time be below the bottom of
cylinder and strip it of the exhaust valve hard enough to spring the pilot), then give the valve chamber. If the seat is deep
and inlet housing assembly. To properly the wrench one complete revolution and enough to allow the valve to rest too low,
hold the cylinder during the process of the hard scale should be cut through. the bottom of the valve chamber should
reaming, clamp it in a vise as in the illus- After the scale has been cut, the seat be turned down. This requires special
tration. Note that the cylinder is resting should be trued up. This is done by tools and a cylinder in this condition
pressing lightly and squarely on the center should be referred to us.
on a block of wood and that the cylinder
base is clamped in the vise jaws. This
is the best method for holding the cylinder
to safeguard against damage, if no cylin-
der clamping plate is available. Do Not Lap a Pitted, Burned or Warped Valve
A valve that is badly pitted, burned or grinder. Very often a grinder will be
or warped should not be lapped in a cylin- found most convenient because the very
Clean and If Necessary Ream the Valve Guide der with a re-reamed valve seat. Such hard scale which forms on the valve seat
lapping will have the effects on the seats will quickly dull the lathe tool. If you
After inspecting the seal and determin- pilot to be held centrally and firmly which already described. are not equipped to reface exhaust valves,
ing that re-reaming is advisable, inspect is essential to good reaming. A 6 inch refer them to us. A valve that is very
the cylinder valve guide. If the guide A valve that is badly pitted, burned badly worn, burned or warped should be
tap wrench will enable turning the guide
does not appear badly worn, clean it of reamers easily. or warped should be dressed off in a lathe replaced.
carbon with the standard guide reamer. The design of the tool is such that the
Be careful not to ream the large or top pilot must be held stationary. The reamer
diameter of the guide any deeper than or cutting tool must turn on the pilot.
I 3-8 inch. If the cylinder guide is very This construction will hold the reamer ab- How to Fit and Grind Exhaust Valves
badly worn, ream it with the 1-32 inch solutely true, thereby eliminating all chat-
oversize guide reamer. This will allow the tering and making a smooth job. After the seat has been properly operation not to grind too much, other-
reamed and the valve placed in good con- wise the straight tapers of the valve and
dition or a new one selected, proceed to cylinder will be ruined. Give the valve
grind in the valve. If the oversize guide only a few turns, take it out of the cylin-
How to Use the Reamer reamer was used to true up a badly worn der and inspect the seats. Do not expect
cylinder guide, be sure to fit an oversize to find a polished ring around the valve
After the guide has been reamed, select Place the seat reamer over the pilot. valve; 1-32 inch oversize valves are car- seat from this little-grinding, but make
the pilot which is a good snug fit in the Use the reamer to cut through the hard ried in stock at the factory. Great care sure that the valve seats properly before
cylinder guide. Force the pilot in by scale as shown in the illustration and ex- should be taken during the valve grinding assembling.
hand as far as possible, to hold it firmly. plained in the following paragraph. Be
These instructions are very important be- careful never to turn the reamer in the re-
cause if the reamer is allowed to "wob- verse direction and when stopping a cut to
ble" while the seat in the cylinder is being change position so that you can reach the How to Test Whether a Valve Seats
reamed, an uneven and poor job will be other handle, be sure the same cut is kept
made. The exhaust valve must seat right on. Never allow the reamer to stop One of the simplest and most accurate Place ihe valve in the cylinder and with a
squarely and firmly, otherwise the motor without completing the cut. screwdriver give it 1-4 turn. Remove
means of testing whether a valve seats is
will not be flexible and the burning gases The fact that the reamer will not cut the valve and inspect the marks. If the
passing by will again burn the seat in a when you first attempt to ream the seat to mark the seats of the valve and cylinder
marks are erased equally the valve is seat-
very short time. does nof indicate that the reamer is dull, with pencil marks about 1-8 inch apart. ing properly.
 given a coat of asphaltum paint, to meet directly from the II 0 volt line to the neg-

Service Dept. Bulletin with the lire underwriters' rules. When

wiring the panel, put the resistance (or
lamps) in series with the positive ( +)
ative (-) of the battery.
An ammeter is not necessary in the
charging circuit because the lamps them-
selves are sufficient indication of the ap-
No. 82. july 5, 1919 Harley-Davidson Motor Co., Milwaukee wue. Connect the negative (-) wire proximate rate of current Rowing.

Charging Rate Table with Lamp Resistance

To Charge Storage Batteries ··-

Approximate Amount of Current That will

Number Size- of Lamps
Flow Through Lamp at t 10 Volt Pressure
To Charge Batteries from a D. C. Line
A rectifier is not needed to charge stor- requirement is the neccssuy re,istance to
I 60 walt (16 CP) Y2 ampere
age batteries from a D.C. line. The only obtain the proper charging rate. The I 120 watt (32 CP) I ampere
lamp bank is the simplest resistance and
the most economical to construct and use. The charging panel just described is sary to have two lamps in series for each
This type of resistance is illustrated and for a 110 volt D.C. line only. To charge one on the board as illustrated, to obtain
described herewith. from a 220 volt circuit it will be neces- the correct charging rate.

To Determine Polarity of Charging Wires

In arranging the panel be careful that battery, the needle would read backward.
the positive ( +) charging wirt. is con- When a voltmeter is not at hand, the
polarity of the charging wires can be de-
termined as follows: We refer here to
the wires from the socket that bring the
current to the panel, rather than to the
battery wires, although the polarity of the
latter can be determined in the same man-
ner. Without bringing the wires together,
place the ends of the charging wires into
a glass of water in which a tablespoonful
of salt has been dissolved and turn on the
Voltmeter Test. Showing Polarity of Storage current. The wire on, or from which, the
Battery Wires
greater amount of bubbles will form is
nected to the "POS" ( +) terminal of the negative wire.
the battery, and the negative (-) charg-
Switchboard tCharRing Pane{) for Ch&rging frtJm a D. C. Line ing wire to the "NEG" (-) terminal of
the battery. If a voltmeter is at hand,
the polarity of the charging wire can
readily be determined. The positive
Making a Charging Panel binding post of the voltmeter is marked
·- -
0
. ..D 0
( +) and when connected to the ( +) --- ··o o·
The charging panel can easily be con- seldom necessary to use more than 6 battery terminal, or to any direct current
structed by anyone at an expenditure not amperes in one circuit while charging the line, providing the voltage does not ex-
- - - 0 0.
exceeding $10.00. The complete lamp small motorcycle battery, a larger lamp ----o o
ceed that of the voltmeter, the movement 6 0
bank consists of the following: One 220 bank is not necessary. of the needle showing the voltage will
volt, I 0 or 20 ampere, snap or double Carbon lamps should be used because indicate that the current is Rowing through
pole knife switch; six 120 watt, and two they are inexpensive, allow more current the meter in the proper direction. If the Salt Water Teat ShowinR Polarity of Storage
60 watt carbon lamps; about I 0 feet of to How and the danger of breakage is less "POS" ( +) of the voltm~ter were con-
Battery Wire•
No. 14 wire; 2 porcelain cleats, and 8 than with tungsten lamps. For the panel, nected to the "NEG" (-) of a charg- To make this test safe, screw a Iamp,
porcelain screw base sockets. Since it is use a well seasoned board which has been ing wire, or "NEG" (-) terminal of a either 16 or 32 C.P., into a socket and
 !\s soon as the polarity of tl•<> charging
To Charge More than One Battery
then connect the socket in srnrs with one
of the wires !eading f1om the II 0 volt wires has bern detc1mincd, make a knot
When more than one battery is to be charge has been allowed to run and how
circuit that is to be tested for polarity. in the positive lead and place the lamp.>
charged, connect the batteries in series, long the battery has been discharged.
This will prevent any trouble should the in series with that wire. The negative
tha.t is, positive to negative, negative to
lead connects directly with the negative Keep on charging the battery until the
ends of the I I 0 volt line wires be touched positive, etc., as shown in the illustration
battery cable. Mark the places where the specific gravity reaches a maximum, that
together. Place the end of this wire with below. The two remaining ends, one pos-
wires leave the panel ( +) and (-). is, a point when two hydrometer readings
the end of the other charging wire into itive ( +) and one negative ( ~) must taken at about a two hour interval, show
The arrangement of the wires and the con-
a glass of salt water as described, and be connected to the "POS" ( +) and
nections are clearly shown in the ac- no rise in specific gra~ity. If a voltmeter
the "NEG" (~) wire will be easily "NEG" (~) of the line respectivel)J.
companying illustration. Wire the switch- is used to ascertain the condition of the
When more than one battery is being
indicated. board accordingly. battery, charge at a I ampere rate until
charged in one circuit, do not depend on
the voltage of each cell reaches a max-
the exact current rate because the internal
Regulating the Charging Rate resistance of the cells causes the current
imum. With I ampere flowing, the volt-
age per cell will read from 2.45 to 2.50
When charging a 3ZAS Exide battery Remember that the normal clwrging to drop slightly. If I ampere is to flow
volts when the battery is fully charged.
from a II 0 volt line, using carbon lamp rate is the same whether one or several through 4 batteries, screw in I, 32 C.P.
If more than I ampere is flowing through
resistance, bear in mind that the normal batteries are charged because the full and I, 16 C.P. lamp. To fully charge
the battery when this reading is taken, the
charging rate is I ampere. This means charge passes through each batter)]. When an average battery requires from 24 to 36
voltage reading will be misleading.
the finishing rate at which a battery of charging from an A.C. line, the charging hours, depending on how low the dis-
this type should be charged. When the rate is increased one or two amperes for
battery is first put on the line it may be every battery added to the line because
charged at 2 or 3 amperes, but just as
soon as the battery begins to gas or the
the batteries are connected in parallel, but Important Facts When Charging Batteries
for charging from a D.C. line with bat-
electrolyte to bubble, the battery is near-
teries connected in series, one ampere will Never charge a battery at a high cur- electrolyte and combines with the plates.
ing a complete charge and the 2 or 3
ampere rate ot current is not being flow through six batteries as well as rent rate because this only causes injury. This explains the difference in the hydrom-
utilized. Then the current rate should through one and the charging rate should High charging rates overheat the battery eter readings. In a discharged battery
be cut down to I ampere or even Yz am- never be raised above 3 amperes at the and cause excessive gassing which wears the electrolyte is practically free from
pere to finish the charge. To get a cur- highest unless an automobile battery is and loosens the active material of the acid, therefore light, and the hydrometer
rent of 2 amperes through the battery, charged. Of course, the 3ZAS battery plates unnece;sarily and will also buckle reading is low. In a fully charged bat-
screw 2 of the 32 C.P., (120 watt), may not be charged at the rate of charge and weaken them. 70°F. is the normal tery the acid has been driven out of the
lamps into the sockets. Screw out the of an automobile battery. •emperature of the electrolyte when charg- plates by the charging current and re-
other lamps far enough so that they do ing, but up to I I 0° F. is permissible. stored to the electrolyte, making the lat-
not burn. Never allow the temperature to get over ter heavier and giving a greater hydrometer
II0°F. reading.
While a battery is charging, the tem- The specific gravity of a normally dis-
perature rises, naturally causing the elec- charged battery is 1.125 to 1.150.
trolyte to expand. Therefore after a The specifis; gravity of a half charged
battery has been recharged and allowed battery is 1.200.
to cool, it may be found that the solution
The specific gravity of a fully charged
is below the top of the separators. Add
battery is 1.275 to 1.300.
disstilled water to cover the separators by
Y4 to Ys inch. Always charge a battery If the specific gravity reading is under
with the vent plugs in place and turned I. 125 the battery is abnormally dis-
down tight, or remove them entirely. charged and will require considerable
charging to put it in first class shape.
When a battery begins to gas, it is
nearing a complete charge, provided it is
If acid has been added to the battery,
a greater reading than 1.300 will be ob-
in good mechanical condition, and the
tained and the battery should be charged
charging rate should be reduced to nor-
until a maximum is reached. If this max-
mal, I ampere.
imum is over 1.300, draw off some of the
When a battery is fully charged, very electrolyte and add distilled water until

+ SERIES CONNECTIONS
Diaaram of Three Batteries Connected in Series
little of the acid remains in the plates.
\Vhen it discharges, the acid leaves the
a niaximum of from 1.275 to 1.300 is
obtained.
 To Charge Batteries from an A. C. Line To Charge Batteries with the F-F Rectifier
The dealer who ran gel only alternating gin~l'ring department and the reclllier that In charging storage batteries through charging wires to make sure which really
(/\.C.) current mw:t haYe a means of was best suited to our needs was adopted. the use of a rectifier it is also important is the positive and negative. If no volt-
converting this current to direct current Quality, efficiency, life and cost of m- to connect the positive, ( +), wire of the meter is at hand, the simple salt water test
(D.C.) to charge batteries because direct stallation were considered. rectifier with the positive, ( +). wire of described under "Direct ·current Charg-
current only may be used for this purpose. The rectifier is generally made for use the storage b~ttery. and the negative ing,'' should be applied. However, do
This is where the rectifier is used, an in- with I I 0 volt alternating current 60 cycle charging wire with the negative battery not connect a lamp in series with one of
strument which changes A.C. current to frequency. This is the type current com- the wires because this is only used when
w1re.
D.C. monly used, but before ordering a rectifier determining the polarity of direct current.
As explained under D.C. charging, the we suggest making sure that your voltage The positive and negative rectifier
and cycle frequency are II 0 and 60, charging wires, (wires thai connect rec- Once the positive wire has been de-
motorcycle battery is almost in a class by
itscl f. ils charging rate is so low that it respectively, and if they are not, to state tifier to battery), can generally be iden- termined, place a knot in it, according to
so when ordering. tified as follows: the positive wire is red common practice, thereby doubly safe-
cannot be charged on the same line with
automobile batteries without being dam· The instrument is not furnished mounted and the negative wire is black. guarding against making the wrong con-
aged. Many garages and even battery as illustrated, but anyone can make a first It is, however, advisable to test the nection.
charging stations, thr:mgh ignorance or class job of mounting with a I inch board
carelessness, -charge small batteries at and a few screws. The assembled panel Regulating Charging Rate
hi!<h rates. can then be attached to a wall, and be When charging a battery, make sure ber of batteries. By connecting the clip
-Because these conditions exist and out of harm's way. The wires are fitted that the positive wire of the rectifier is in various positions on the carbon bars,
knowing that many dealers wish to do into a socket and the charging leads are connected to the positive pole of the bat- varying charging rates will be obtained
their own battery charging, we are fur- ready to be connected to the battery. tery, marked "POS," ( +). or in~­ that can readily be noted on the am-
cated in red. Connect the negative wire meter.
of the rectifier to the negative pole of the It has always been recommended to
battery marked "NEG," (-). If the charge the motorcycle battery at a one
"NEG," and "POS," marks on the bat- ampere rate. However, with the F-F
tery poles cannot be seen, the polarity of Rectifier the charge can be started at two
The Illustration Shows the Recliw the battery can be ascertained in identical- or three amperes. In fact when a rider
fi~r and Ammeter Mounted on .a
Panel. This ln11trument i• Used ly the same manner as the polarity of the is in need of his battery, a higher than
for A. C. CharRing. one ampere charging rate is recommended,
rectifier.
After the battery has been properly because the battery begins to warm up
connected, insert the plug into the lamp and charge sooner. There is no danger
socket and note the charging rate on the of overcharging because as the battery be-
ammeter. The charging rate is regulated comes charged, its resistance cuts down
by moving the clip "3" between the points the charging rate until, when the battery
"2" and "I" on the resistance unit. The is fully charged, the current automatically
end of point "2" cannot be seen because tapers off to a fraction of an ampere.
it points to the extreme end of the re- Do not charge one battery at a higher
sistance on the right side of the instrument rate than three amperes and as soon as
where the highest charging rate is obtained. the battery begins to bubble or gas, re-
With the clip at point "I" the entire re- duce the charging rate to one ampere or
sistance is cut in or the charging rate is at less. If a battery 1s not in healthy con-
a m1mmum. At point "2" the entire out- dition, that is, if it is internally damaged,
put of the rectifier enters the battery. The its resistance will not cut down the charg-
resistance allows for a wide range of bat- mg rate. Therefore, when the tem-
nishing a rectifier with an improved re- tery charging rates. From one to eight perature of the solution rises about II 0°
sistance that is ideal for the charging of or even ten batteries can be charged at one
The price of the rectifier com- F., or when the battery begins to bubble
small batteries. With the resistance, the time. No fixed position for the resistance
plete with resistance and ammeter is or gas freely, reduce the charging rate.
current can be regulated to charge from clip can be given to charge a certain num-
one to eight batteries and the charging as follows: Type 166-R, F-F Mag-
rate lor one battery can be held at less netic Rectifier with rheostat, am-
than one· ampere. meter and sufficient wmng for To Charge More than One Battery
The rectifier can be used by every mounting as shown in illustration, When more than one battery is to be nected to the positive lead of the rectifier.
dealer who does his own battery charg- $30.00, F.O.B. Cleveland. charged, connect the batteries in parallel The negative battery wires must be con-
ing and cannot get direct current. Various Shipping weight about 20 pounds. as shown in the illustration. All positive nected in like manner with the negative
apparatuses were tested by our en- wires of the batteries must be inter-con- lead of the rectifier.
 D

If the rcctifrer is being used to charge the battery and cut out more resistance
one hattery· and another battery is con- by moving lht' resistance dip foom "I"
nected, connect the batteries in parallel towards "2," for each battery that is
and change the position of the resistance added to the charging line. Since one
clip so that a greater charging rate will battery can be started off at two amperes,
Aow through the ammeter. Adjust the two batteries can be started at a four
Aow of current with the resistance when- ampere charge, three batteries at six am-
ever another battery is added to, or re- peres, bearing in mind always that the
moved from, the charging line. charging rate must be reduced when the
When one battery is to be charged, al- batteries begin to gas and the temperature
low two amperes of current to Aow through of the solution rises above I I 0" F.

000

PRRRLLEL CONNECTIONS

Diagram of Three Batteries Connected in Parallel

+
To Adjust the Rectifier
To adjust the rectifier the knurled There should be a small gap at "D" Fuse Protection
screws "A" should first be turned out- between both of the carbon and copper
ward or away from the armature. Then electrodes when the rectifier is not in use. The rectifier is provided with a fuse not show any deflection or there were no
Krew them inward. By proceeding in This prevents any back flow of current "F" per illustration. With the II 0 volt current at the charging wires, it is pos-
this way pressure will be applied to both from the battery when the rectifier is idle rectifier the fuse is of 20 ampere capacity sible that the binding posts which hold
carbon brushes which will prevent them and will allow the armature to vibrate and protects the instrument should the load the fuse are loose, or that the fuse is
from backing up and getting out of ad- freely when in use. It is very important be excessive, that is, over 20 amperes. blown.
justment automatically. Be sure to have to have the carbon brushes seat squarely If with the resistance clip "3" on con-
The thought may occur that because
the armature "B" central between the pole against the copper electrodes. tact with carbon rod at "2" end, a bat-
you use D.C. current, the subject of
pieces "C" of the magnets. tery in fair condition were connected in
charging with alternating current does not
reverse with the charging wires, that is
interest you, or you may be interested in
"POS" (+) to "NEG" (-) and
charging from an A.C. line and feel that
To Adjust the Charging Rate "NEG" (-) to "POS" (+). the
you are not concerned with the subject
fuse would blow. This of course does
The maximum output of the rectifier and down. This weight, however, is set of charging from a D.C. line. On the
not apply to a dead battery because such
is regulated by sliding the small brass by the factory for best results and should contrary,- both subjects contain im-
a battery has no opposing current. If a
weight "E" on the armature spring, up not be moved unless conditions warrant. portant information on battery charging
fuse burns out do not replace with a fuse
and every dealer and mechanic will find
of more than 20 ampere capacity. Should
it to his interest to read them carefully.
the vibrator be working and the ammeter
Service Dept. Bulletin Engine Clamp Plates on Repaired Frames
Effective May I st, engine clamp plates orden~d from the Parts Department or
No. 86. June 15, 1920. Harley-Davidson Motor Co., Milwaukee and bolts will no longer be furnished with fitted to repaired frames if sprcif1ed on the
1epai•ed frames. However, they can be repair order.

Use Our Order Form No. 13 15 for .Replacements The Three Plate Type of Exide Battery
and Repairs The Exide 3KZ3 type of battery has
been used as standard equipment on all
battery cannot be determined by striking
the terminals together and observing the
Us,. a separate sheet for repairs, ex- your instructions explicit; this will pre- 1920 J models. Owing to the design arcing or "spark." When the terminals
change or replacement as the case may vent errors and confusion, and will also and construction of the battery it is of a three plate type of battery are
be. Numbt>r each order and keep a help greatly to get your goods returned ~uperior to the live plate type, its life being brushed together, the "arc" is not so in-
duplicate copy for your file. If it is de- more promptly. tensive as that of a live plate battery.
rnuch longer.
sired that a number of orders be shipped However, this does not indicate that the
together, mark them accordingly. Ex- These forms will be furnished f1ee There are three cells, each cell contain- battery is not in a normal condition.
ample: Ship orders, 846, 847, 852 upon request, therefore, see that you have ing an element, each element consists of
The proper method of determining the
and 854 together. by express, freight or a supply on hand and usc them for h<'ller three heavy duty plates, one positive and exact condition of a storage battery, is to
parcel post. as the case may be. ·Make serVICe. two negatives. The plates are identical use a battery hydrometer.
with those used in automobile starting and
The ampere hour capacity of the 3KZ3
lighting batteries; they are !;4 inch thick battery (engine not running) is 7Yz
The Reason for a Steel Plate Under One and are insulated with perforated rubber
and thick wood separators.
hours. Meaning that one ampere can be
drawn from the battery for 7Yz hours be-
Cylinder Only The capacity or condition of a storage fore recharging is necessary.
All Harley-Davidson motors are me- (Shim) under the cylinder having the
chanically balanced in order to elimi- smallest compression chamber. For this
nate vibration and to produce the highest
efficiency. Uniform combustion in both
reason you may get motors with a plate
under either cylinder or no plates at all.
Fitting The Sport Model Manifold
cylinders is first in ·line for obtaining me- Side car motors may have an addi- \Vhen assembling the sport motor, care Fit the manifold and securely tighten
chanical balance. The design of the slope tional plate, besides the customary YH inch must be exercised in fitting the manifold. the two nuts holding it in place. The rea-
head type of cylinder, now used as compression plates, under one of the cylin- The flat surface of the cylinder inlet and son for leaving the front cylinder base
standard equipment, is such that the foun- ders. nuts loose is to permit the cylinder to turn
exhaust ports must perfectly align with
dry men cannot keep within the correct When disassembling a motor, note the and align the ports with the manifold face.
the flat port surfaces of the manifold to
compression limits in the course of manu- The cylinder base stud holes are a little
number and thickness of plates under each prevent leakage at the junction. Examine
facturing. larger than the base studs, therefore,
cylinder. It may be well to mark the plates the copper gaskets and see that they are
To equalize the combustion, makes in order to put them back in their respective allowing the cylinder to turn slightly. As-
in a good condition.
necessary the use of a thin steel plate places. suming that the manifold has been properly
Assemble the rear cylinder to the crank fitted, securely tighten the front cylinder
case and securely tighten the base nuts, base nuts.
Sprocket Combination for Double Sidecar then put the front cylinder in place and
tighten the nuts just enough to hold the
Test the manifold and cylinder junc-
tures by squirting gasoline over the joint
In order to have a well balanced com- This set of sprockets gives a l:ll''lr ratio cylinder in position without binding it. when the motor is running.
bination, especially when driving in a of 5.27 to I.
rough or mountainous country, the follow- Under the most favorable condi•;nns a
ing ·~t of sprockets have proven satisfac-
tory:
I 5 tooth engine sprocket may he used;
however, we advise the· lowl'r gf'ar as it
Sport Model Carburetor
Engine sprocket, 14 Ieeth. will relieve the motor of unnecessary If the carburetor overloads (chokes) Lower the float level to ~ 1 ::~ inch and
Countershaft sprocket, 28 Ieeth. strain. when accelerating the motor, or the motor try the result. The characteristics of dif-
Clutch sprocket, 4 3 Ieeth. is sluggish in pick up, it may be necessary ferent motors may make it necessary to try
Rea, wheel sprocket, 48 Ieeth. to change the carburetor float levi!( to several float settings before the required re-
remedy the cause. sult is obtained.
 Assemble chain guard.
Sport Model Assemble flywheel cover (outer).
Assemble left fool board and adj·~sl clutch control.
Assembling Sport Model Motor Into Frame Place washer and caller pin in clutch control coupling.
Place exhaust pipe in position and assemble mumer.
Set the motor in the frame and assemble the motor clamp plates and pass the The mumer is supported to starter frame by the front mumer bolt, and IS sup-
studs through from the left side. Fit the right side clamp plates and securely tighten ported in the rear by a frame bracket that al>o clamps the mumer tail piece.
the stud nuts. Do not force the studs through the lugs.
Assemble the foot board support rod bracket on the right side of the crank case.
The studs holding this bracket pass through the crank case. One stud is 5 ~-:! inches
long and the other is 2''·1 t: inches long. Tool for Replacing Recoil Spring Guide Rod
Assemblies to be Made From Left Side.

l .~
- -- - /0~ --····-
Fit and adjust drive chain.
Assemble chain guard front end, place lock washers under nuts and tighten.
Assemble and clamp front foot board support.
Assemble and adjust three speed shifter rod. "'lt!
Fit hand oil pump pipe.
Assemble starter with rear foot board support rod in position, and tighten lock
nut on support rod.
Place rock plate rear clamp bracket on the rear foot board support rod, and
place the entire· assembly in position on the crank case.
Place two lock washers on crank case starter clamp bolts, followed by two nuts
which should be permanently tightened.
Fit and adjust magneto control.
Remove all the screws in the felt washer retainer at the left side mam bearing
and fasten the inner flywheel cover in position.
To get this cover in position the starter crank pedal must be held down at its
lowest point. The detailed drawing is self-explanatory, and with material found in the average repair
Assemblies to be Made From Right Side. shop a satisfactory assembling jig can easily be made.
Remove the two lower front cylinder stud nuts and assemble rock plate on these It is not essential that 24 V threads be used; for that matter, use any standard ~I,;
studs. Replace nuts and tighten. inch die you may have.
Fasten the rock plate in the rear to the clamp on the rear foot board support rod.
Fit the compression release rod.
Put spark plugs in cylinders.
Assemble manifold with copper gaskets between manifold and cylinders.
(See special manifold instructions.)
Place two lock washers, followed by two nuts on manifold clamp studs and
tighten.
Assemble carburetor to the manifold, placing a paper gasket between the union.
Assemble and tighten right foot board and brake assembly.
Place cotter pin in rear brake rod coupling.
Fit mechanical oiler pipe.
How To Use the Jig
Fit gasoline pipe. Hold the assembly in the jav's of a vice (see illus-
Make the throttle control connections. tration) and turn each nut only a little at a time until
Be sure the strain on the carburetor throttle shah is relieved, that is, adjust the the spring has compressed enough to allow the spring
control so that when the right grip is turned entirely off there is a slight shake in the guide rod to be screwed into the bracket.
throttle shaft. This reduces the amount of wear on the carburetor shaft to a minimum.

Assemblies to be Made From Left Side.

Place pin in mam shaft and place starter gear spring washer on shaft with ptn
fitting into recess.
Place starter gear spring on ~.haft, followed by starter gear, flywht>el key, fly-
wheel. flywheel tongue washer and flywheel lock nut.
Tighten flywheel lock nul and bend washer over one flat side of nut with a chisel. 3233
 No. 66 Service Department Bulletin

were placed into the underside of the front sides in back of window, roll apron up to
bow to get the curtain to hang properly. window, swing entire curtain up and
No. 66. Revised Sept. 15, 1920. Harley-Davidson Motor Co., Milwaukee The remainder of the fasteners c;an now against inside of top. Attach tabs by
be fitted. It is necessary to place an eye- means of tacks to center bow so that eye-
let into each lower corner of side curtains. lets in tabs will line up with fasteners in
How to Attach Top and Windshield to Two short tabs (or straps) with eye-
curtain. Care must be taken not to buckle
or crack celluloid window when fold-
1918-19-20-21 Sidecars lets to hold curtain in place under top when ing top. If desired the curtain can be en-
Locate side prop sockets along the out- Place the taper bushings on prop studs not in use are furnished. To fold curtain tirely detached and be carried in pro-
side edge of the arm rests and cut away with the widest part toward the upholster- disconnect from cowl and sides, fold the vided bag.
just enough leather to expose the threaded ing. Place the top on the front studs.
hole in the props. Turn the threaded
square shank studs into the side prop sock-
Hold secure with round headed square
shank nuts. Pass the long hinged rods
To Attach the Wind Shield
ets with the square shank toward body. over the short rear bracket studs and se- Drill the 21-64 inch holes which are snugly against front of top. Tighten all
Attach the rear bow rest brackets to cure with washer and cotton pin. Unfold already in the I 1-4 x 1-4 inch iron strip bracket bolts. Remove the upper left
the wooden strip which extends around the the top, and bring it to shape. Pass the ahead of and opposite sidecar door, all hand bracket bolt nut, pass front end of
edge of the body. Remove the large rear straps past the rear end of rear brack- the way through the body. side shield over bolt and replace nut. Lo-
headed upholstering tacks which will come ets, around under the brackets, through Temporarily clamp the slotted brackets cate position of small dip with three holes
under the brackets. Substitute a few ordi- the slot in the bracket and then buckle marked "L" and "R" to their respective on side arm by drawing side shield to
nary tacks in place of those removed. them. Adjust the straps equally so that side of the body. Put the longer round proper tension and lining side shield up
H9ld bracket in position on body making they are just tight when the long hinged bolt through the upper left hole, the with windshield frame. Fasten small
sure that lower edge lines up with wooden rods are straightened. shorter round bol.t through the upper right bracket to side arm using the two coun-
strip, and that distance between long stud hole. Put the bolts with the square head tersunk holes with plain hole extending
on bracket and prop stud is about 12 3-8
If the front wind shield has previously in lower holes, passing all bolts from inside. downward, first drilling wood rib one-half
been fitted, be sure to adjust the stop inch deep with 1-8 inch drill. Attach
inches. Mark position of rear screw hole Place fittings on large studs of brackets
screws as explained under "To Attach spring clip to wind shield frame by means
on side of bracket and drill the wooden in following relation: fibre washers, wind
Wind Shield." of screws and nuts. at the same time ad-
strip with a 1-8 inch drill about 1-2 or shield frame, friction springs and castel-
5-8 inch deep and turn the screws in Draw the curtains downward reason- justing it to line up and hold side shield
lated nuts. Adjust nuts until sufficient securely. If necessary, bend side shield
place. Then drill the other screw holes ably tight with straps used to hold top friction is obtained to prevent the wind
and turn the screws in place. No trouble when folded. Adjust side curtains s"O that at lower end so as to have it bear firmly
shield moving from vibration and still be
will be experienced when turning in the opening for back curtain is square and against the top. Readjust wind shield
able to move it readily. When adjust-
wood screws if a little soap is placed on that sides hang properly. Fit both rear as needed by moving it up or down to
ment is obtained lock castellated nuts by
the threaded part of the screws first. curtain fasteners to the body and attach have the fop, wind shield and side shield
means of cotter pins. in proper relation to each other. lightea
Under no circumstances, use a hammer to side curtains. Locate the position for
Attach four curtain and four glove all nuts and fittings securely and adjtDt
drive the screws in place or fit a, larger front curtain fasteners and attach to the
fasteners to wind shield frame by means set screws in square bolt for wind shield
screw if a screw has been lost, because body. When side curtains fit properly,
of provided nuts. stop so that wind shield bears against set
this will split the wood rib. locate and fit eyelets into rear curtain.
Place wind shield curtain on frame and screws when it comes in contact with top..
adjust shield by moving it up or down to Locate proper po~ition for wind shield
IMPORTANT line up properly with top. Proper ad- apron fittings on cowl being careful not
Ascertain whether or not the sidecar prop socket brackets along the justment is obtained when the curtain fits to draw wind shield apron too tight.
outside edge of the arm rests are directly opposite each other. /f they are
not in line the top tvill not fit the body perfectly. Measuring from the rear To Fit Right Side Curtain
bow bracket studs to the side prop socket centers, the distance should be Snap lower rear glove fastener into wind shield frame and cowl. Mark loca-
13 1-2 inches. If they are not of equal distance, shift one of the prop place. Locate position for upper glove tion of eyelets and insert latter in place.
socket brackets by removing the wood screws and making new screw ho.les. fastener screw in center bow. Screw When in use right curtain is to be placed
same in place and attach curtain. Remove under wind shield curtain. To enter or
right side of wind shield· curtain, draw leave sidecar loosen only rear end of right
To Fit the Storm Curtain right curtain snugly in place and over side curtain and push wind shield forward.
Locate the posJ!Jon for the cowl fast- side of the top and should be dra~ fairly
eners by drawing curtain into shape over tight. Adjust curtain by means of these To Fold Top
cowl and temporarily fasten the side cur- tacks until assured the entire curtain sets Roll up rear curtain and fasten with when folding top to keep these in place.
tains to the center bow and arm rests with properly. It may be necessary to move provided straps. Loosen the s_ide curtains Do not overlook to strap lop down se-
small tacks. These .side curtains fit out- one or more of the three fasteners that and throw them over the top. Be careful curely and use slip cover to keep top elean.
 Sport Model Gasoline Dirt Trap
Owing to the dirt and sediment in the clogged. It is recommended that the dirt
present market gasoline, the filter scre<"n· trap be cleaned at least e\'ery I 000 miles.
No. 88. October 15, 1920. Harley-Davidson Motor Co., Milwaukee ing surf ace in the dirt trap easily become•

Sticking Exhaust Valves

With cool mornings comes the stickin~ the wax from the oil congeals and gums
Instructing your Riders on Cold Weather Starting exhaust valves. No other trouble vexes up the piston rings, bearings and exhaust
By the time cold wenther sets in, the priming the sport model motor, is to open the rider more. However, with a little valve stems, preventing good lubrication
;werage riders' cylinder priming cocks are the auxiliary air shutter on the carburetor effort on the riders' part, sticking exhaust and causing the riders endless troubles. .
completely closed with carbon. The cocks and with the throttle wide open, inject a valves can be made a .thing of the past. Advise your riders to flush out their
should be removed and cleaned with a fine priming gunful of gasoline into the car- More motorcyclists should appreciate the motors with kerosene to thoroughly clean
wire, also the holes in the cylinders should buretor mixing chamber. Partially close value of flushing the motor with kerosene. out all the gum and wax. Remove the
be opened to permit gasoline to enter. the throttle, pull out the starting button After lubricating oil has been used un- spark plugs and make sure that the kero-
A quick and satisfactory method of and crank the motor. der great heat and pressure it becomes un- sene reaches the exhaust valve stems. Re-
desirable for further use in an internal fer them to the Harley-Davidson Instruc-
Worn Carburetors combustion engine. Such oil is divided, tion book which fully covers motor flush-
more or le;s, into two elements, wax and ing. They will be repaid by better motor
Carburetors-that have been functioning leak into the mixture and weaken it. Most an oil with no body or lubricating prop- service and less starting trouble.
properly in warm weather may cause all carburetors after one year's service are erties. Such an oil is usually called a When grinding exhaust valves always
trouble when the cold weather arrives. The subjected to this trouble. To overcome "cracked lubricant." Such lubricant will clean out the valve stem guides with our
main re~son is due to the throttle shafts, such trouble, an oversize throttle shaft not properly care for the rapidly ·moving reamer FK-826.
air valves and air valve adjusting screw must be fitted and a new air valve and ad- pistons, rings and other bearing surf aces ;
stems being worn and permitting air to justing screw installed.
Importance of correct Motor Timing
Fitting an oversize T rottle Shaft From our service men's observations we his machine. We recently revised our
Separate the throttle disc from the shaft screw stem, renew the air valve and air learn that a number of our dealers are timing bulletin No. 65, bringing it up to
by melting the solder. After the disc has valve adjusting screw. The air valve not paying enough attention to the motor date, therefore we urgently request that
been removed the shaft can be pulled out spring should hold the valve closed with timing when repairs are made. Every every dealer and repairman take more in-
of the body casting. A good method for a pressure of 6 ounces. Do not .stretch one should realize that to get the efficiency lerest in timing motors.
soldering or removing throttle discs, is tC' the spring to g1ve this tension; use a new from a motor, it must be correctly timed. Keep your riders' circuit breaker points
use an old "brilliant burner" and a Prest- spnng. One may put in new pistons, rings, piston set according to the proper gauge. Show
O-Lite tank. Invert the carburetor .bowl and measure pins and a roller bearing set, yet, however, them how to adjust exhaust and inlet valve
Enlarge the throttle shaft hole in the the float level. The measurement should if the motor is not timed correctly, the cus- tappets. Help them to derive the horse
body casting by using a \<! inch drill. Fit be taken from the cork float, opposite the tomer l;,ses the benefit of the new parts and power built into every Harley-Davidson
the oversize shaft, throttle disc and throttle float lever bearing. From the edge of the consequently does not feel satisfied with motor.
disc washer. Remove the cam casting bowl to the cork float should measure 1% 2
from the original shaft by driving out the inch. The float level can be corrected by Oversize Cylinders used on Standard Motorcycles
small pin. Ascertain the correct location bending the float lever. Care must be
of the cam casting on the new shaft and exercised when bending the float lever to Owing to the scarcity of material, we Oversize pistons to fit oversize cylinders
drill a %~ inch hole through the shaft. prevent breaking the cork float. have been compelled to use oversize cylin- can be obtained from the facto.ry. Specify
Key the cam casting to the shaft by means By overhauling the carburetor as just ders from time to time. However, in the size of piston wanted when ordering.
of a suitable pin. outlined, cold weather difficulties will be each case an oversize piston was fitted and Allow .00:1" clearance when fitting a pis-
If there is more than .010 inch clear- overcome and all the difference in the mo· the standard clearance maintained. ton to the cylinder.
ance between the air valve and adjusting lor's operation will be noticed. When fitting pistons to a motor, ascer- A standard cylinder should measure
tain whether or not the cylinders are over- 3. 31 0" at the bottom diameter, and
size. Oversize cylinders are stamped on 3. 307" at the top diameter.· A standard
Exchange Carburetors the base, on the sprocket side. The cylin· piston should measure 3.305" at the skirt
The Service Department exchanges car- have been replaced and the carburetors ders will be stamped as follows: A cylin- diameter and have the same meas1.1rement
buretors at a remarbbly low price, the tested according to Schebler standards. der that is .002" oversize will be stamped between the second and third ring&.
average carburetor exchange being $5.00. Every dealer should avail himself of this 2; one that is .006 will be stamped 6 and Consult your "Motor Repair Manual"
These service carburetors have been over- opportunity. Send your carburetors in so on. The largest oversize cylinder used for correct piston fitting.
hauled by the Schebler factory and are and have them exchanged; give your cus- is .008 inch, the smallest .002 inch.
in perfect working order, any worn parts tomers real factory service.
Service Dept. Bulletin
No. 89. November 1, 1920. Harley-Davidson Motor Co., Milwaukee

I I I I

===~~====~====~~~r-===
tOl ttif----~~-!UJ

Fitting 1920-1921 Motor to Dealers' Racing Frame

Fitting 1920 or 1921 motors to the No. 3 (3/8") and the No.4 (29 ;32")
dealers' racing frame can be easily ac- ~ushings to the casing studs on the right
complished by following these instructions s1de of the motor. See illustration. Fit
Fitting 500 Type Motor to Dealers' Racing Frame and closely observing the above illustration. the right frame tie plate and make sure
The 500 type motor base whether casings studs on the right side of the mo- Fasten the crank case lugs to the frame that the casing studs will pass thru the
used with single cylinder or twin cylinders tor. · See illustration. Fit the right side motor bracket in the usual manner. Draw tie plate freely. If the casing studs do
can be fitted to the frame by carefully frame tie plate and make sure that the cas- up the motor clamp bolts tight. Remove not line up with the right side frame tie
following these instructions. · ing studs will pass thru the tie plate freely. the 5 motor casing studs in ·order to per- plate, it will be necessary to elongate the
Fasten the crank case lugs to the frame If the casing studs do not line up with the mit the use of the long casing studs a:nd holes with a round file. Secure the right
motor brackets in the usual manner. Draw right side tie plate, it will be necessary to bushings as shown in the illustration. As- frame tie plate by drawing up all nuts.
up the motor damp bolts tight. Remove elongate the holes with a round file. Se- semble the "left side" frame tie plate After the casing is securely damped to
the S motor casing studs in order to per- cure the right side tie plate by drawing up first, passing the hexagon head bolts 5 the frame, fit the cylinder plug extension·
mit the use of the long casing studs and all nuts. and 7 and the ftat head bolts 6 thru from brackets and securely tighten them to the
bushings as shown in the illustration. As- the left side. Do not attempt to fit the frame. Owing to difference in motor con-
After the casing is securely damped to
semble the "left side" frame tie plate right frame tie plate at this stage of as- struction it may be necessary to enlarge the
the frame, fit the cylinder plug extension
first, passing the hexagon head bolts 5 and semblage. Pass the long casing studs thru bracket holes in order to make a perfect
brackets and securely tighten them to the
7 and the flat head bolts 6 thru from the the left frame. tie plate and thru the 3 No. fit.
frame. Owing to difference in motor con-
left side. Do not attempt to fit the right I (1-19/32") and the 2 No.3 (3jtW) With this type of frame, the cyGnden
struction it may be necessary to enlarge
frame tie plate at this stage of assemblage. bushings and casing lugs. See illustra- may be removed without removing the
the bracket holes in order to make a per-
Pass the long casing studs thru the left tion. Fit the 2 No. I (1-19 j32"), 2 whole motor.
frame tie plate and thru the S No. I fect fit.
( 1-19 ;32") Bushings and casing lugs. With this type of frame the cylinders
Fit the 4 No. I ( 1-19 132") bushings may be removed without removing the
and the No. 2 ( 1-S/ 32") bushing to the whole motor.
 High Compression ("8") Type Motors
High compression motors are built up motors have 1/8" longer pistons. They
for exceedingly high altitudes, such as Den- are marked as follows: L-20-T-IOOOB,
ver or the Utah mountains. The atmos- also 21-JB-1 000 and up. The letter "B"
No. 90. Feb. 25, 1921. Harley-Davidson Motor Co., Milwaukee pheric values at such high altitudes se- is also stamped on each cylinder base
riously affect the efficiency of any gasoline flange. The clearance between pistons
and cylinders of "B" type motors is the
engine; therefore special consideration is
same as that of the standard 61" motor,
I-I ow to Measure Cylinders and Pistons For a Proper given motors for high altitudes, and they
are built accordingly. High compression
or from .0025" to .0035".
This model is no longer being built.
Fit. New Method of Marking Over~
size and Reground Cylinders
Fast Stock, or ("E") Type, Motors
(These instructions on piston and cylinder fitting supersede those in Service Bulletin This motor is built up according to
No. 47) "E" type motors are assembled with the
specifications that will make it both pow- greatest of care and are. block tested to
Harley-Davidson cylinders since I 914 edge of such work or authentic instruc- erful and fast. It is built up about the insure their efficiency. "E" type motors
have been taper ground, that is, the top tions. same as the "A" motor, i. e., all working are marked as follows: L-20-E.- I 000 and
diameter is smaller than the bottom dia- parts are perfectly free, the gear shaft is up. The cylinders have the letter "E"
meter by three thousandths of an i!lch Since accuracy is necessary for good
.0005" looser than standard and the pis- stamped on their base flanges. When or-
(.003"). This taper grinding is done to results, an inside and an outside microm-
ton and cylinder clearance (at top of the dering pistons for the "E" motor, please
allow for the excessive heal caused by eter are the essential instruments used
stroke) is from .004" to .005". All specify IA-736A.
combustion of the gasses at the upper end when fitting pistons to cylinders. The cyl-
of the cylinder and to make the cylinder inders should be measured at the top of
walls parallel under normal ~orking c?n- the bore and the pistons should be measured
ditions. Owing to the cylmders bemg between the second and bottom rings for Measuring Instruments
taper ground, it is con fusing for one to the proper clearance diameters. See chart
No. 2, for standard cylinder and piston Every first class motorcycle repair shop calipers may be used wi_th fairly satisfac-
properly measure cylinder diameters or lit
pistons to cylinders without a good know!- measurements. should be equipped with a. full set of in- tory results. Do not tr:y to fit pistons· to
side and outside micrometers. They are cylinders rvithout the proper measuring in-
the only instruments available that will struments as the result at best rvould be onl:y
Standard Motors actually tell you the sizes of the pistpn and a guess.
When the piston is properly fitted to the cylinder. This clearance is between the cylinder and other accurately ground parts. To correctly fit pistons to cylinders that
cylinder there should be from two thou- second and bottom rings of the piston and have been .reground at our factory and are
sandths (.002") to three thousandths When a set of micrometers is not avail-
the top of the cylinder bore, rvhen the pis- marked with the letter "R," refer to the
(.003") clearance between it and the ton is at the top of the cylinder. able, a reliable set of inside and outside instructions in the following paragraphs.

Police ("A") Type Motors Original Method of Regrinding Cylinders

This motor is in every respect a stock The letter "A" is stamped on each cyl-
inder base flange. The pistons fitted to Since we are changing our method of the bottom and 3.307" diameter at the
motor with somewhat looser fits through-
new "A" motors at the factory are marked marking reground cylinders, a few words lop. Ti> regrind in uniform steps of
out the reciprocating action, and is block
"A" on the piston heads. Pistons fur- briefly explaining the method effective un- .0 10", the top of the cylinder was selected
tested. The clearance between the pis- til the present time, are in order. In 191 7
nished for "A" motors on parts and re- for the various regrinds and symbols rep-
tons and cylinder walls at the upper end we started to identify reground cylinders
pair orders are not marked with the letter resenting the diameters. The following ex-
of the stroke should be from .003" to "A." When ordering pistons to fit an with a code, or set of symbols. This code ample will illustrate the "R" or symbol
.004" after the pistons arc lapped in. The "A" type motor, be sure to specify that was based on the following principles: A method of marking reground cylinders and
marking of these motors is as follows: they are to be used in an "A" (police) standard cylinder is 3.31 0" diameter at the proper piston sizes for a perfect fit.
L20-T-1000A. also 21-JA-1000 and up. motor.
 "R2" stamped on the cylinder base the first reground size is .0 13". All others, nish you with a piston that will correctly ure "20" on the rear left side of the
flange indicates that the "top" diameter of "R3," "R4," etc., are in multiples of ten lit such cylinders. Example: Assuming flange; these symbols mean that this cyl-
the cylinder is 3. 320" and that it is re- thousandths; the lop of cylinders measuring that the letter "A" is stamped on the front inder is for an "A" (police) motor and is
ground .0 13" larger than a standard cyl- 3.330", 3.340", etc. The distinguish- left side of the cylinder flange and the fig- reground .020" oversize (over standard).
ing feature of this system is that the over-
inder. The bottom diameter of the cylin-
size pistons are .013", .023", .033",
der would measure 3.323", or .013"
larger than a standard cylinder.
etc., oversize and that new pistons sho1,1ld All Oversize Pistons Will Be Marked
be ordered by these sizes or by the symbol
A piston to fit this cylinder would be stamped on the cylinder base flange and It has been our policy in the past to en- For example: If a piston has the figure
.0 I 3" larger than standard, or 3.318". not by specifying .010", .020", .030", case oversize pistons in the regular carton "I 0" stamped on its head, it means that
''1"{2'' cylinders are the only ones in which etc., oversize. and to designate their sizes cin the carton. this piston is .0 I 0" larger than standard
This method was all right as long as the (standard 61" piston 3.305"). This pis-
piston was kept in the box, but upon re- ton when fitted to a cylinder that has the
New Method of Marking Oversize and moving it and mixing it with other pistons, figure "I 0" stamped on its flange (.0 10"
Reground Cylinders its identity became lost. oversize) will insure a perfect lit, assuming
that the cylinder is not worn.
In order to simplify the fitting of pis- in direct reading ligures on the cylinder Any piston that is oversize (larger
tons to cylinders and to enable dealers to base flange. For example : A 61" motor than standard, 61" motor, 3.305") will The letter "F" is stamped on the head
carry a limited stock of assorted oversize be marked with a figure, designating just of every front cylinder piston fitted to a
cylinder flange has the figure "5" stamped
how many thousandths of an inch it is new motor, and to front cylinders reground
pistons that will meet all requirements, we on the left (sprocket) side, meaning that
oversize. This method of marking will at the factory. This is mentioned so that
have changed our method of marking all this cylinder is .005" oversize (larger than enable you to arrange your stock of pist\)ns the finding of this mark will cause no con-
oversize pistons and cylinders. The meth- standard), or its bottom diameter is to suit your needs and will eliminate the fusion. "E" motor pistons are not special-
od of regrinding cylinders heretofore ef- 3.315". In ordering a piston for this par- possibility of giving the customer the wrong ly marked, since their design differs from
fective was such that pistons had to be ticular cylinder, you should specify one piston. that of the standard pistons.
specially ground to fit each cylinder. This that is .005" oversize (larger than stan-
meant, for instance, that a piston ground dard) to insure a perfect fit.
for an "R2" cylinder (3. 323'' bottom How to Use the New Cylinder, Piston
diameter, 61 " motor) would not fit any Cylinders with number "20" or a larger
other than an "R2" cylinder. The new number stamped on their base flanges have and Ring Chart
method of marking cylinders will not re- been reground at our factory. A cylinder
The chart on page 5 very clearly cov- ments are to be taken for correct piston
quire pistons ground to speciai .sizes for with "20" stamped on its base flange is
ers the new method of marking cylinders fits .
proper clearances, but will use a straight
.020" oversize (reground .020" larger and pistons that are oversize and shows
than standard) and its llange end diameter The following example will illustrate
run of .010", .020", .030", etc., oversize the correct size piston rings to use in each
1s 3.330". Other sizes of reground cyl- the new method of 'marking oversize cylin-
pistons. case. The drawings of the cylinder and
inders read accordingly.
Instead of regrinding cylinders and the pistons designate points where measure- ders and pistons and how to use the ~hart :
identifying them with the symbols "R2," This change became effective on factory
"R3," "R4," etc., all cylinders that are reground cylinders january 23, 1921, and
will become effective on new motors in Legend Cylinder Bore
over standard size (bottom cylinder to be Sizes
diameter 3.31 0" for 61") will be marked the near future. Stamped on Amount Piston Piston
Cylinder Oversize Top Flange Size Ring
Flange End End
...., - - -- - - · - - -- - -
Cylinder Markings for Special Motors "d
5
New motor ................. Standard 3.307
New motor ................. .005+ 3.312
3.310
3.315
3.305
3.310
Standard
.005+
a
be stamped on the cylinder base flange.
~ 10 New motor ................. .010+ 3.317 3.320 3.315 .Q10+
All special motors such as the "A," ~ - - -- - - - - - - - -
"B," and "E" types, will have corre- When ordering pistons for "A," "B," ~nd "' 20 Reground oversize ........... .020+ 3.327 3.330 3.325 .020+
~0 30 Reground oversize ........... .030+ 3.337 3.340 3.335 .030+
sponding letters stamped on the left "E" motors, specify which motor (letter) 40 Reground oversize ........... .040+ 3.347 3.350 3.345
;:;:l .040+
side of the cylinder base flange. These they are for, and mention any oversize lig-
letters, "A," "B," and "E," will be in ures that may be stamped on the cylinder Chart No. I
addition to any oversize figures that may base flange. This will enable us to fur- (Text Ccm.tinued on Page 6)
 Chart of Cylinder, Piston and Ring Sizes
Assuming that we have an F model cyl- sketch, or stamped with the number "40"
LL4L,von /'?nav-vr CY.o::. Ll.:>,(!e S;zt:J on its head. . Under the heading Piston
&Jr,-9~,P~p
inder with "40" stamped on its base
pNCyL/.4/D~~ iovER.f/Zc /.:>P rUI/V'i~ RJroN' A Jr.:>~'<' flange, we can determine from the last row Ring, we find that a ring that is .040"
hA?..-,;4 END E/Y:o J;z£ ,$/Vij of figures in chart No. I what this oversize must be used.
~LJ<I/%roR "40" means. It comes under the re-
~
ifrA'/Y:OA'.<'.O .1.307 .J.,J/0 J ..JOf ~rA'/VCW.f'O In the same manner we can determine
.s .,- ' ground oversiz? heading, meaning that it what cylinders and rinl!' should be used
,(J(J .5 .. ~-.312 ,3.)/$ .].3/0 .tJtJf ...
tl /P ___...,.,__;_" __ ----
II ,tJ/0,. l!./Z __ -----
.J. .J&o :!-.:1!..5_- --~:.!_:t __ has been reground at our factory. From the with a certain size of piston or vice versa.•
~ 2() RLf-<'"vNt> tlrF,f:tl~ . tJZO,. next heading, amount oversize, it is shown
<.,
. .J.JzJ .J...J3o 3-JZf .ozo,..
.040" oversize. According to the heading
Special type motor markings are placed

~13
.J()
4P
"
.. ,
.tJ.JO,.
.o4o.,.
3337
3347
J .•Uo
.:1..3.50
.fJ,J.!J.S
.!}• .34.5
,IJJ?,.
.()40 ..
Cylinder Bore Sizes, its top diameter is
3.347", and its flange end, (bottom) di.a-
on the front end of the left side front
cylinder flange, and on the rear end of the
fp .o.so .. .3-357 .!JJ6o .J.3S.S left side rear cylinder flange, Oversize
, . ,(!J() ..
meter is 3.350". The correct piston to
\ 6o
7P ' . .1760 ...
.o7or
~·-''7
J ..J77
.J.J7o
,J.,J,/0
3 . .]65
.3.37-f
.()6Pf'
.tJ7tN·
use for this cylinder, under the heading,
Piston Size, is one measuring 3.345" at
markings are placed on the rear end of the
left side front cylinder flange, and on the
front end of the left side rear cylinder
~
IY'r.w ~rPR rA'#DA?.f'o .J.4Z4 34&7 J.4ZZ 5rA'N'OA'RP flange.
. .PO$',-
the point shown on the 3 ring piston in the

~
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." .J.4Z9 3.4.JZ 3.4.?7 .:>os..-

"
~
/P
Zo
1---------
"
IP.r~,f"ov,v.r:>(lv.r.('J'IZE
----- 1-3..:.~~-
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A-·~·!.7
.J-447
__ _.t_4_.},!-- r-.:.!'..!'2~ --
J.44Z .tJzo,.
- .
~ 30 .030 .. .1.41.$'4 .J.457 .3.452 .o3o-r
4o " .040 ... .].464 3.467 3.46Z ,04171'
~lj 50 " " .ofof" 3474 .3477 .J.47Z PSO-.'
,
~
6o .!.4,/4
70 . ." .060 ...
.070,. 3.494
.J.4,!7
3497
.3.4.!2
.3492
.()60-.>
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Chart No.2
 Spark Plugs
Service Dept. Bulletin In all cases use a mica ~park plug for
racing, because the extreme heat generated
trouble. We have had good results with
Wright spark plugs after they have been
No. 81. Revised. May 10, 1921 Harley-Davidson Motor Co., Milwaukee by the motor will have disastrous effects used for about 25 miles ( 40 K M). Do
on other type plugs. In some cases the not use a new plug.
spark plugs are the direct cause of a motor Adjust the spark plug electrodes so that
overheating, and trying another type of the gap is no wider than .0 30" (. 76 M
CARE OF THE "E" TYPE MOTOR plug will suggest itself. M). nor less than .025" (.64 M M).
Do not use spark plugs which have more Too great a gap will cause overheating,
The fast "E" type motor is gradually Remember that attention to details may than one core electrode and one base while too small a gap may cause the spark
coming into general use. Such a motor mean the winning of an important contest. electrode, because such plugs will cause plugs to foul.
must receive special care, particularly be- The following information should also be
fore entering a race or hill climb, and it is passed on to owners of motors of this
with this in mind that the following sug- type. Additional copies of this bulletin Carburetor Adjustments
gestions are offered. will be mailed upon request.
The carburetor should be adjusted so and is driven about 45 m. p. b. (72 K M)
that the motor receives a fairly rich mix- the ports can be opened one-half way,
How to Tune Up and Take Care of the "E" Type Motor lure. Of course, too rich a mixture will without turning the needle valve. This
cut down the speed of a motor, while too will permit a greater speed than could be
To be abfe to obiain maximum speed shipped to any place and give the same obtained without the ported sleeve.
lean a mixture will cause over-heating. If
from any motor, it must be kept in first satisfaction. To lind out whether or not If the highest possible speed is desired,
the compression is right, and whether or it is impossible to obtain an adjustment to
class condition by a careful inspection the ports should be opened wide and im-
not the proper gear ratio (sprocket com- get satisfactory speed without overheating, mediately thereafter the carburetor needle
and cleaning at least every I 00 miles the spark plugs are at fault, the sprocket
bination) is being used, motors should valve given from one to two complete turns
( 160 K M). In addition to the periodic always be given careful tests where the combination is not right, or the compression extra. The exact number of turns the
inspection and cleaning, the compression contest is to be held. of the motor is too high. needle valve should be given can only be
and gear ratio must be in accordance with Other items which must be given care- The use of the ported air sleeve, which ascertained by trying various adjustments.
the climatic and track conditions of the ful consideration are; lubricating oils, is standard equipment on the fast stock When the speed is again cut down to
place where the contest is to be held. grade of gasoline, spark plugs, carburetor motor, can brieRy be explained as follows: normal, the ported air sleeve is to be closed
Do not take it for granted that a motor adjustment, wheel, chain, and frame align- Keep the ports closed for ordinary run- and the carburetor needle valve turned
built and tested in Milwaukee can be ment, bearing lubrication and adjustments. ning. After the machine has warmed up down to its origina,l position.

Lubrication Gasoline
Use nothing but Harley-Davidson rac- smoke from both cylinders. This is very Low test gasoline (62° Baume) should any circumstances use · ether, naptha,
ing oil. Our Parts Department can sup- easily determined because the motor emits be used in preference to high test gasoline picric acid or any other highly volatile
ply this in one and live gallon cans. Under a regular haze when properly lubricated. because the motor will not heat up as much fuels. The Harley-Davidson motor is not
extreme conditions, mix one pint of castor When cutting out the ignition, as men- with the lower test. Note: Never under designed for such fuels.
oil with one gallon of this oil. tioned, also try for heat in the motor. If
After warming up the motor drain the either cylinder fires when ignition is cut out,
crank case, put in two hand pumps of oil the motor is overheating. This can be Overheating
and run the motor slowly for one or two overcome by making the mixture a little
laps. After this the mechanical oiler will rich, causing it to burn a little slower and There are several conditions that prove give the carburetor needle valve another
take care of the motor, providing it is overcoming the premature explosion. whether or not a motor overheats, such as one-half turn of gasoline, and again test
properly vented. To vent the oiler, dis- bucking, slowing down, and keeping on the motor for overheating. While testing,
We suggest inspecting the hand pump for
connect the oil pipe at the mechanical oiler running with the magneto short-circuited. cut the gasoline down again, and if the mo-
leaks before entering a race of any i.m-
connection on the crank case letting oil Row Under these conditions lind out which tor still overheats, place a I j32" (.79 M
portance, as we have had cases where dirt
through the pipe; forcing out the air. This cylinder is really doing the overheating by M) thick compression plate under the
or some foreign substance would hold the
will allow a full Row of oil through examining both spark plugs. If the mica cylinder or cylinders, whichever the case
ball open, and the oil would keep dripping
the pipe. To determine whether or core of a plug is puffed out, blistered or may be. If this will not eliminate all over-
in the crank case; this in turn would cause
not the mechanical oiler is taking care rough, overheating in that cylinder is indi- heating, substitute a l/16" (1.5 M M)
t!Je motor to over!Jeat, due to excessive oil.
of the motor, use the cut-out button, cut- This detail should not be overlooked be-
cated. Whether this condition is found or a !/s"" (3.1 M M) thick compression
ting out the ignition and watching for cause it is important. in both cylinders or only in one, replace the plate in place of the I j32" (.79 M M)
puffed or blistered plug with a new one, thick plate.
 where the carburetor has a tend~ncy to ing it out of the cam casting, the mixture is
spit back. If such a point is located, .try made lean. Full instructions for setting

Service Dept. Bulletin and eliminate the spitting by re-adjusting

the needle valve. If the needle valve ad-
justment will not eliminate the spitting at
this certain point, increase the tension of the
the low speed cam adjusting screw are con-
tained in the Harley-Davidson Instruction
Book.
With the low and intermediate s~ed
No. 91. March 1, 1921 Harley-Davidson Motor Co., Milwaukee adjustments set so that the carburetor will
air valve spring until the motor fires evenly.
not load up or spit, set the high speed ad-
Close the throttle and allow the motor
justment by moving the indicator between
to idle. If the slow speed (idling speed) one and three on the dial until smooth ac-
Lubrication and Carburetion of the 7 4 11 Motor adjustment is not correct, do not move the
needle valve, but vary the cam track ad-
celeration at high speed is obtained.
Oftentimes the motor will choke at high
Because of the longer stroke and larger into use, and about ~;1 of a pumpful of oil justment until the motor fires evenly with a speed and it will be no fault of the car-
bore of the 74" motor, its pistons cover injected into the motor base every few closed throttle. The slotted cam track ad- buretor's adjustment; such an occurrence is
more feet per minute than the standard, or miles. This ruling also holds good for 74" justing screw controls the needle .valve rise caused by air pockets forming in the gas-
6 I" motor; therefore it requires special motor lubrication when negotiating muddy, and fall. By screwing it into the cam oline line and temporarily shutting off the
lubrication at the higher motor speeds. sandy or gradient roads, or under any cir- casting the mixture is made rich; by screw- fuel.
Between 35 and 40 miles an hour we cumstances that require special attention as
recommend that the hand-pump be brought to oiling.
Carburetor and Motor Valve Springs
Operating New 7 4" Motors Just Out of the Crate The air valves on the carburetor are especially the exhaust, and replace them
The very thought of driving a Super The 74" motor, like any other new used to maintain a normal velocity of if shrunk %/' or more. See that the
Powered 74" makes the motorcyclist for- air through the primary or venturi tube. tappets are adjusted accurately ; viz., with
motor, must be "run-in" gradually and not
set that a aew motor must be "run-in." At low motor speeds the maj~rity of air from . 008" to . 0 I 0" clearance between·
subjected to any severe use during the first the exhaust valves and lifter pins, and
He wanJs to "open-it-up" immediately passing through the carburetor is taken in
and "see-what-it-will-do." Such cases fre- few hundred miles. The motor should be .004" between the inlet valves and inlet
by the hot air, or primary opening, and as
quently happen, with the rider never giving "run-in" for at least 200 miles. During levers.
the motor speed increases the additional air
his new mo.tor a thought, other than "she's that time the motorcycle should never ex- is drawn in through the auxiliary air valve. The exhaust valves should be inspec:ted
a dandy." Scored cylinders and pistons and ceed 30 miles an hour ; also care should be It is essential that the air valve springs have from time to time to make sure that they
damaged valves are the likely result. The exercised to insure plenty of oil for lubri- are not gummed with oil. If a motor has
rider forpll that the metals in a new motor the proper tension. Weak air valve springs
cation. Advise your riders of these facts, been run for some time with poorly ad-
are green (not accustomed to working will cause hard starting, will make low
and tell them that the future life and serv- justed tappets or sticking valves, it will he
teJRperafures and other existing conditions) , speed adjustments hard to obtain and will necessary to reface the valve seats in the
that the bearing surfaces are not worn in, ice of their mounts depend entirely upon the cause loss of power. The air valve spring cylinders and the valves, and then to grind
aad ~t all parts were fitted at the factory treatment received during the first few should have from 6 to 7 ounces tension to in the latter carefully and thoroughly. It
to allow for aay initial wear. hundred miles. insure a perfect working carburetor. is best to send exhaust valves needing re-
Weak valve springs and poorly ad- facing directly to the factory. The exhaust
Adjusting Schebler Carburetors justed, or poorly seating valves are {re- valve seat facing tool, FK824, is to be
It is only natural that the proper The following outline should, in every quently responsible for loss of power and used for refacing the cylinder valve seats.
functioning of the carburetor has been a f- case, enahle properly adjusting a car- very unsatisfactory motor performanct>. It is especially important to watch the valve
fected by the present low quality of gas- buretor to any motor. ' If a motor, particularly a 74•'', does action of tht> 74'; motor with the foregoing
oline motor fuel. Perfect carburetion is Set the idler, or low speed adjusting not run right, inspect the valve springs, in mind.
absolutely essential if one expects the mo- screw so that it is approximately I I 16"
tor to respond to every move of the throt-
tle and to give out all of the power which
open. Get a favorable mixture· at low Fitting the Manifold to a 7 4" Motor
speed with the motor idling by adjusting
is built into it. the needle valve. Drive the machine on The manifold used on the 7 4" motors manifold ends and will not be "crimped"
It may often be necessary to resort to the road at about 20 m.p.h. or until the does not project into the cylinder nipples as when the packing nuts are drawn up tight.
precision carburetor adjustments in or~er throttle is open far enough so that cam on far as in the case of the 61" motor. This Any ill fitting at the manifold packings will
to get a flexible control over the motor ; in the casting has moved 3I 16" under the result in a leaking jcint and will affect the
other words, each motor should be put to makes it necessary to exercise more care mixture to such a degree that the motor will
roller of the lift lever. With this throttle
a test under its normal working conditions position adjust the needle valve until the when fitting the manifold so that the inlet be "hard starting" and will not run prop-
and the carburetor then adjusted to func- motor fires uniformly. Open and close the packing bushings will correctly fit on the erly at low speeds.
tion properly in the following Yarious tests. throttle a trifle and try to locate a point
 Caution Valve Seats
Under no condition reduce the com- get hot enough to work at its best. From Always inspect valve seats when the should be ground in. If the valve seats
pression by adding too many plates be- this it can be understood that the motor motor is taken apart, and be careful that show that they bear all around, do not
tween the cylinders and crank case, or must be allowed to get as hot as possible, the valves are not mixed. If the seats are grind them, because the seals may be dam-
add plates to tune up a stock motor for without overheating, in order to get best re- not in good shape, grind the valves. If aged. When fitting a valve into a cylinder,
speed, because this will not let the motor sults. the seats are badly burned, the cylin_der put a film of oil and graphite on the valve
seals should be rereamed and other valves stem.

To Tune Up for Long Races

When tuning up a machine for long sprocket so that the motor will not over- Scored Cylinders
races, add a 1/16" (1.5 M M) thick heat and slow down if driven at its maxi-
compression plate to those· already under Inspect the cylinders for scores. If the the scores are less than .002" (.05 M M)
mum for a considerable length of time.
the cylinders, and lit a larger motor cylinders are scored more than .002" deep, another piston and set of rings can
(.05 M M) deep, send them to us for re- be lapped in to make a fairly good job.
grinding and new pistons and rings. If
To Tune Up for Short Races
When tuning up a machine for short In addition to this a smaller motor sprocket
can be used. This combination will have
Removing Carbon
races, i. e., two or three miles ( .3 to 4 K a good pick-up and will give good results
M); the compression ean generally be Always make a perfect job of removing underside of the piston, from the piston rjng
if the machine is slowed down momentarily
carbon. Do not let any particles of car- grooves, from under the rings, the valve
raised by removing the compression plates. at times so that it cannot overheat.
bon or grit fall into the crank case. In ad- chamber and th~ exhaust port of the
dition to scraping the carbon from the pis-
ton and cylinder heads, remove it from the cylinders.
Missing at High Speed
If the motor runs without missing up to free length. Inlet springs should be be-
a good speed, but sputters and misses at tween I~" (44.4 M M) and 2" (51.8 Gear Ratios for Fast Stock Motors
extremely high speed, and if no change in M M) long free length.
carburetor adjustment nor any other ad- After the oiling of the motor has been Standard for high speed track, or road
justment will eliminate this condition, in-
If the valve springs are 0. K., the mo-
tor may be geared too low, or may be in tested and the motor runs without over- work: Motor 18, dutch 43, countershaft
spect the valve springs. The exhaust valve healing, try out for proper gearing; this 28, rear wheel 48, high ratio 4.10: I.
springs should be 2!/z" (64. M M) long serious need of an overhauling. is about half the battle in racing on mile For long level stretches, etc. : Motor
( 1.6 K M) dirt tracks. It requires some 18, clutch 43, countershaft 28, rear
Piston Rings experimenting to learn the best and quick- wheel 44, high gear ratio 3.76: I.
est way to come out of a turn on a mile If a fast motor is used with a sidecar,
When stripping the motor, pay special gap at the slot. This gap should be be- ( 1.6 K M) track. Some riders use the the gear ratio will generally have to be
attention to the condition of the top piston tween 1/64" (.39 M M) and I ,132" throttle to control their speed going into changed. If the machine and sidecar are
rings. These rings must be in first class (.79 M M). If necessary, file the slots and coming out of a turn; others ute the to be used for demonstrating speed on a
condition and a good fit. A loose fitting, carefully to obtain the proper gap. It is cut-out button and let the motor act as good level road, do not change the
burned, or scored ring should be repJaced. also important to have this ring just a free a brake. The latter is the quickest and spro,ket combination until the machine has
When ordering new rings, specify the tpo- fit in the piston groove Dlithout any sha~e. easiest way and works very well if the car- been accurately timed for speed. Then
tor number. When fitting one of the lower rings, the buretor is so adjusted that the motor dpes remove the 18 tooth motor sprocket and
Before placing a ring on a piston, put gap at the slot should be between I /32" not load up with gas, making it slow to try a I 7 tooth sprocket. Again test the
it squarely in the cylinder and gauge the (.79 M M) and 1,116" (1.5 M M). pick up. machine to see whether it will cover the
The rider will have to determine which same course under the same conditions in
method is best by trying out both on the less time.
Tappet Adjustments track because the kind of turns have a For bill climbing and other tests for
Adjust the exhaust valve tappets so that the motor is hot. The inlet push rods bearing on the subject. - power, a 15 or even a 14 tooth motor
there is a clearance. of from .006'' (.15 Three speed gear ratios for "E" motors: sprocket may be found better suited.
should be adjusted so that they are just Motor 16, clutch 43, countershaft 28, Questions pertaining to other types of
M M) to .008" (.21 M M) between
the lifter pins and exhaust valve stems when free when the motor is cold. rear wheel 44, high gear ratio 4.22: I. fast motors will be answered by letter.
 spent gases are driven out, these hot gases take \'alve opens, the rr.otor starling on

Service Dept. Bulletin coming in contact with the atmospheric

pressure cause the report commonly heard
from the gas engine. At the top of this
stroke the exhaust valve closes and the in-
another cycle.
BrieRy the cycle of events may be
termed, I, intake; 2, Compression; 3,
Ignition; 4, Exhaust.
No. 65. Revised june 1, 1921 Harley-Davidson Motor Co., Milwaukee

Complete Timing Instructions for Harley-Davidson Motors

Working Principles of the Harley- Davidson Motor To insure the most <~ccurate results in (I 50 m/m) scale graduated to at least
The Harley-Davidson motor is of the wheel travel is one event or stroke. The valve and ignition timing, the motor should I ~132 inch (.5 m/m), and measure the
conventional four-stroke-cycle principle. Rywheel must make two revolutions to be taken out of the frame and the front piston positions through the cylinder plug
The power stroke being the chief cycle complete one power cycle of the motor. cylinder plug removed. opening. The exact location of the pis-
of the motor. It is made up of four Each cylinder of a four-stroke-cycle en- The close relation between the piston ton can be determined by this method.
events, or strokes:· hence the term "four- gine goes 'through the following cycle of travel and the valve operation requires ex" Since accuracy is essential for correct tim-
stroke-cycle." Each 180 degrees of Ry- events. treme accuracy in measurements when ing, we do not recommend the practice of
timing an internal combustion motor. For locating the piston through the inlet hous-
an example: With a difference of only ing chamber.
Intake
one thousandth of an inch (.03 m/m) be- Piston positions are determined from
The intake valve opens at the proper through the carburetor and manifold. The tween the exhaust valve iifter pin and the either upper (top) or lower (bottom)
time by means of cam and gear acllon. atmospheric pressure &t sea level is 14. 7 valve stem, will cause the Rywheel to dead centers. Dead center is the point at
The piston being on a downward stroke pounds per square inch at 60 degrees F. travel approximately 3/16 inch ( 4.7 the extreme upper or lower end of piston
creates a partial vacuum in the cylinder. m/m) to make up the difference. FQr travel-the point where the piston Is
A gaseous vapor passes into the cylinder The intake valve closes as the piston starts
the best results in timing, use a 6 inch "dead."
due to the atmospheric pressure passing on the upward stroke.

Compression The Valve Lift Clearances Must Be Accurate

With both the intake and the exhaust when the piston is at the upper extremity Before retiming the valves, make sure Allow .004 inch (.1 0 m/m) clearance
valves closed, th; cylinder chamber is now of its stroke. The sidecar motor has a that the exhaust lifter pins and the inlet between the inlet levers or rocker arms,
comparatively air tight. The piston on its compression of 55 pounds per square inch, push rods are set accord:ng to the follow- and valve stems on all models.
upward stroke compresses and squeezes the and the solo motor 60 pounds per square
ing specifications. On the 1915 and 1916 twin motors,
gaseous vapor iato a small space. This inch. The compressed gases at this point
compression heats the mixture to a very are ready for ignition by an electric spark. On all the twin cylinder models prior allow .004 inch (.1 0 m/m) exhaust lift-
much higher temperature and makes it After ignition takes place the gases expand to 1915 and all the single cylinder models er pin clearance for the rear cylinder and
more volatile. The ratio of compression from three to four times their initial com- (except model 21 CD) , allow . 004 inch .006 inch (.15 m/m) for the front cylin-
in a motorcycle motor i~ usually 3. 75 to pression pressure, that is, with a compres- der.
(.1 0 m/m) clearance between the exhaust
I , meaning that when the piston is at the sion of 60 pounds per square inch, the
lifter pins and the valve stems or caps. On the 191 7, and all later "V" type
lower most extremity of its stroke the gases would expand to 240 pounds per
chamber above it is 3.75 times greater than square inch after ignition. The earlier models had small steel caps motors, allow from .008 inch (.21 mlm)
placed over the ends of the exhaust valve to .010 inch (.26 m/m) clearance for
Ignition or Power Stroke stems to prevent the stems from wearing both front and rear cylinder exhaust valve
The generator or magneto being timed The connecting rod transmits this power and to provide a mea'ls for taking up tappets. This also holds good for the
to produce an electric spark at the oppor- to the Rywheels, driving the. vehicle and wear. These caps are made in various "500," "A," "B" and "E" type fast
t•ne time, ipites the highly compressed storing up kinetic energy to carry the pis- thicknesses and should be ground until the stock motors.
gases and starts combustion. The piston The sport model lifter pin clearance for
ton through the three minus strokes of the correct clearance is obtained.
being the only movable part subject to the both the inlet and elthaust valves and for
combustion starts on its downward stroke. cycle. Model 21 CD should have .004 inch
both cylinders is .006 inch (.15 m,lm).
(.1 0 m/m) clearance between the inlet Whenever making any adjustmen.ts to the
Exhaust and Scavenging Stroke rocker and valve stem, and .008 inch valve tappets, be sure that the motor is
At the end of the power stroke the these gase~ and prepare for the next series (.21 ~~Vm) to .010 inch (.26 m/m) cold, because the expansion of the cylin-
burnt gases still remain in the cylinder, so of events. On the upward stroke of the between the exhaust lifter pin and valve ders and valve lifting mechanism varies
some provision must be made to expel piston the exhaust valve opens and the stem. when the motor is hot.
Service Dept. Bulletin No. 17 Service 'Department Bulletin

No. 77. August 12, 1918 Harley-Davidson Motor Co., Milwaukee, Wis. Discontinuation of Road Repair Work
As far as possible, the repairing of mo- dealer's possession on a public highway or
torcycles on the road should be eliminated. even at the curb in front of his store.
There is no objection to performing work
Increase in Repair Labor Rates In the majority of states, the lien law re-
quires that equipment undergoing repairs
on the road if a man's credit is good or
the transaction is cash. We suggest that
Beginning August I 5, I 9 I 8, the fol- a minimum rate of $1.00 per hour is rec- be in the possession of the dealer or re- every dealer look up the lien law of his
lowing rates are effective on factory repair ommended. Labor C'f all kinds, especi- pairman. A motorcycle is not in the state.
labor: ally skilled labor, is scarce, and the dealer
must pay good wages to keep or engage
Motor and electrical re- Education of Owners
first class men. The rate of repair labor
pair wo~k .......... $1.25 per hour
must advance accordingly.
Transmission, frame, fork, The purchaser of a new or used ma- tion and fewer calls for small adjust-
The average owner is willing to pay a
wheel, and tank repair chine should be given the instructions ments and repairs. Some dealers have al-
fair rate for repair work, in preference to
work . . . . . . . . . . . . . I . I 0 per hour ready conducted schools for both new and
receiving indifferent or poor work at a low necessary for its successful operation and
Floor work, including strip- old riders, placing the work in charge of
rate. If the quality of the labor is in care. He should be urged to study the
ping and assembling. . . 1.00 per hour a competent man. ·The owners are taught
proportion with the rate, there will be no manufacturer's manual so that he can help
Brazing and welding. . . . I .50 per hour how to use their tools and how to make
dissatisfaction. The dealer's problem, himself. This may require a little more
Enameling and nickelplat- the simple adjustment~ and repairs, especi-
therefore, is to pay wages that will enable
mg . . . . . . . . . . . . . . . I .50 per hour of the dealer's or salesman's time when ally those adjustments needed at definite
him to keep or engage competent repair
the sale is made, but there will be intervals. Classes are conducted one
Increases in the cost of labor make men, and charge for his labor at a rate
these changes necessary. that will pay the repair wages, his over- fewer comebacks for additional· informa- night a week.
A number of dealers are charging from head expenses and net him a fair return on
$1.00 to $1.25 per hour for labor, and his investment. Repairs on Cash Basis
The sale of parts, accessories and sup- On another page we are reprinting the
Changes in Dealer's Service Policies Become a Patriotic Duty plies, as well as all repair work, should regulations adopted by the Milwaukee
The shortage of competent mechanics commercial use of motorcycles can con- be put on a strictly cash basis. This will Motorcycle, Bicycle and Sporting Goods
and the consequent rise in the cost of labor tinue and even expand. The third object result in a saving of help and protection Dealers' Association. They are printed
affecting both dealer and rider, make is the saving of light and fuel by evening against losses. on a heavy cardboard poster measuring
and Sunday closing. Similar regulations 22"x27", which is displayed in every
necessary, and in some cases have already Other means of conservation of labor,
have been adopted nationally by the Na- dealer's window.
brought about, reforms in service prac- material and fuel may suggest themselves,
tional Automobile Dealers' Association. Be the leader in this movement in your
tices by individual dealers and dealers' depending upon local conditions. The city. The other df'alers will readily see
The plan requires every dealer's atten-
associations. regulations can be adopted by all dealers the necessity and advantages of the plan,
tion. A set of regulations should be
The object is three-fold: first, to re· drafted, agreed to, and adopted by the in a city by mutual agreement. Those and your riders will gladly abide by the
lease as many men as possible for military motorcycle and bicycle dealers of every pertaining to the elimination of free ser- service regulations, because they will re-
or essential industrial service; second, to city. The following should be among the vice, Sunday closing, night work, and gard them as a patriotic movement.
retain sufficient skilled help to handle the important features of the plan and agree- cash for all repairs can be issued in printed Two other important considerations
important motorcycle work so that the ment. form and posted in each dealer's store. that need not appear among the regula-
They should be issued with a note that tions printed for public notice, but should
they are made necessary as a patriotic be agreed upon by the dealers and lived
Elimination of Free Service movement. up to, are the following:
Ordinarily the giving of a certain ter advantage. The use of free service
amount of free service with the purchase cards should be discontinued. Free road
of every new machine is commendable. service should be eliminated, and the time
Preferred Service for Industrial Users
At present, the purchaser should not ex- required to call for and deliver a machine The rider who uses his motorcycle for a commercial machine is put ahead of his
pect it. Labor must be employed to bet- should be charged for. pleasure will not resent a delay in the fin- job. It is one of his ~acrifices to help win
ishing of his repair work if a repair job on the war.
Service Department Bulletin No. 77

Conservation of Parts
This subject has been mentioned be- cessful prosecution of the war has already
fore. If a part can be salvaged, it should caused delays and shortage. To conserve
not be discarded. The demand made
upon material of every description for sue- material is as patriotic as to save food.
Service Dept. Bulletin No. 56 Service Department Bulletin

No. 56. June 11, 1917. Harley-Davidson Motor Co., Milwaukee

To Adjust the Carburetor on a 191 7 Motor
Important Adjustments on 1917 Motors Why Cran~ Cases overheat and Motor It is very important not to have the low carburetor gets too rich a mixture, do not
Motor Misses at certain Speeds loses Por»er and Speed speed adjusting screw turned in too far. turn the needle valve down but open the
To Adjust the Carburetor on a 1917 The motor will run slowly when the screw auxiliary air lever on the side of the car-
Motor Pre-ignition is turned out I j 16 inch, providing the buretor. The indicator should not be
throttle control is adjusted so that the but- turned for any other adjustment than for
terfty valve is shut when the right grip is open throttle work.
Important Adjustments on 191 7 Motors turned to the right, and providing there
are no leaks around the manifold, car-
If the motor seems to be getting too
rich a mixture when the throttle is opened
It frequently happens that in trying to the chart on pages 97, 98 and 99 of the buretor and inlet housings. half way, the auxiliary air lever on the
correct an imperfect running motor, the 1917 manual will be found of valuable Let the motor warm up as it does from side of the carburetor should be opened
cause is looked for in the out of the ordi- assistance. It was prepared under the regular driving before changing the needle enough to get the proper mixture and be
nary places. In almost every case, how- supervision of our engineering department valve adjustment and have the motor run- closed when driving slowly or when the
ever, the cause is poor adjustment or a and follows the natural sequence already ning idle with spark advanced and the motor .has been stopped.
slight imperfection and the remedy not suggested-to look for a fault at the ob- throttle closed. Then cut down the mix- If the motor will spit and backfire when
far to seek. It is true that the seemingly vious point and having located it, to apply ture by turning the needle valve to the it is cold, with the carburetor adjusted as
serious difficulty is generally traceable to the remedy. This chart is an excellent right. The correct adjustment is reached just explained, do not change the needle
a small cause. A very slight change in basis of operation for the repair man in when the motor will just fire evenly and valve adjustment but run the machine for
the adjustment of a carburetor may make seeking the cause of and remedy for prac- will start to miss or stop if the needle a short distance with the air valve closed
the difference between a motor that will tically any form of unsatisfactory motor valve is turned down another notch. This by pulling out the starting stem. Leave
run poorly and one that will operate per- performance. is the correct low speed adjustment. Do the stern in this position until the motor
fectly. If the small items are taken care of, not adjust for low speed when the motor has warmed up slightly or until it starts
When a. motor does not hit right at the large ones will take care of them- is cold for in that case the mixture will to miss due to the rich mixture.
all speeds, when a machine lacks speed selves. The small causes are generally be too rich when the motor gets warm. When driving a machine up a steep
or loses power, when a motor overheats the most important and motor adjustments A cold motor naturally needs a richer grade and the motor seems to die down,
or does not perform right in some other and repairs practically without exception, mixture than a motor that is warm. the trouble is invariably due to a poor
respect, the fault should be looked for should be made on that basis. Below are To obtain the proper adjustment for carburetor adjustment. When a car-
in the places where it is likely to be covered a number of conditions that may high speed the machine should be taken buretor is adjusted wrong, the motor re-
found, hefore out of the ordinary tests arise especially in 191 7 twin motors and on a good road and be driven in high ceives a mixture which will be slow in
are made. If the ignition, carburetion, we recommend that in seeking the cause speed for at least a mile. Do not adjust exploding thereby reducing power and
lubrication and valve action are 0. K., and remedy for a certain trouble these for high speed while the motor is run- speed and causing the motor to overheat.
every motor will run as it should. In recommendations be followed carefully ning idle. If the carburetor seems to get If the carburetor adjustment is 0. K.
locating and correcting a fault in a motor, and closely with the above in mind. too learn a mixture when the throttle is for both high and low speed but the motor
opened, the proper adjustment can be ob- seems to load up with gasoline when
tained by moving the indicator on the cam driven open for long distances at low
casting on top of the carburetor toward motor speed, the air lever on the side of
Motor Misses at Certain Speeds figure No. 3. the carburetor can be used to good ad-
If the indicator is over No. I and the vantage.
If a motor misses at certain speeds and 84 and 85 of the 191 7 manual. The
the suggestions in the chart on page 98 following should also be read carefully,
of the 191 7 manual have been carefully bearing in mind that the adjustment of Why Crank Cases Overheat and Motor Loses Power and Speed
applied, the cause is a poorly adjusted the carburetor needle valve must be ac-
carburetor to which the chart makes ref- curate to the notch. One notch either If the crank cases of a motor gel so hot A motor that is oilfilled, is bound to
erence. However, since the 191 7 car- way will affect the running of the motor. that the hand cannot be placed on them heat up, in fact the oil will reach the boil-
buretor is sensitive and the adjustment Prior to 191 7 several notches either way after the motor has been run for some ing point, greatly retarding the pistons on
must be very accurate to get proper re- did not seriously affect the running of the time, the motor is almost invariably full their downward stroke. Loss of power
sults, we advise a careful reading of pages motor. of oil. Generally an oilfilled motor will and speed are natural results.
not smoke a particle. For that reason Several cases of too much oil in the
do not try to determine the amount of oil crank cases have come to our attention.
in the crank case by watching the exhaust. The crank cases had turned bh>Wn from
Scnllcc 'DePGrlmenl :Bulle/in No. 56

the heat. The riders complained of over- To safeguard against overoiling the
heating and lack of power and speed. hand pump should not be used too freely
After the crank cases had been drained and the mechanical oiler should be ad-
and the correct quantity of oil refilled, justed so that the machine will cover at
the motor developed normal power and least 600 miles per gallon. The 191 7
speed. Overoiling is a more prevalent manual covers the adjastment of the me-
cause of unsatisfactory motor service than chanical oiler very thoroughly and will
is generally supposed. therefore not cover the same ground here.

Pre-ignition
The causes of pre-ignition vary. The machine. If set too far apart, they will
chart on pages 98 and 99 covers the get red hot and cause pre-ignition.
causes and remedies. Attention is called All of the above recommendations ap-
here to the fac~ that pre-ignition is fre- ply especially to the 1917 twin motors.
quently due to poorly adjusted or faulty It will be noted that no out of the ordi-
spark plugs. If a motor pre-ignites, over- nary causes and remedies for overheat-
heats or does not work properly at high ing, choking, missing, loss of power, lack
speed in other respects, try a new set of of speed and pre-ignition have been men-
good spark plugs or a set that is giving tioned. Yet, the causes and remedies
satisfaction in another motor. have been covered and with the assistance
The quality of even the best spark of the manual chart, every case of un-
plugs has been affected in some cases by satisfactory motor service can be cor-
the present unusual condition of the ma- rected.
terial market; therefore, faulty plugs will Attention is also called to the import-
be found a more prevalent cause of pre- ance of accurate adjustment of exhaust
ignition with resultant overheating and
and inlet mechanism. For I 00 per cent
other evils, than even a year ago.
To use good spark plugs and to have efficient motor service these adjustments
them properly adjusted is of vital im- must be accurate widain .00 I inch. This
portance for satisfactory motor perform- subject was fully covered in service bul-
ance. The electrodes should be spaced letin No. 52 under the heading "Impor-
according to the gauge furnished with the tant Notice."
 No. 59 SenJiu Department Bulletin

Service Dept. Bulletin the illustrations and instructions on pages

42 and 43 of the 1917 manual.
than 1917 motor, remove the cap itself.
If the oil does not overflow, tuni the motor
No. 59. July 24, 1917 Harley-Davidson Motor Co., Milwaukee Before venting the oiler, which simply slowly a few times until it does. Replace
means to expel any air in the oil cham- the screw or cap firmly. Then remove
bers, see that there is oil in the tank and the screw in the plunger chamber cap, or
that the feed pipe is connected. Remove the cap itself, and turn the motor slowly
Special Notice the vent screw in the forward or operat- until the oil overflows. Replace the screw
At this time of the year Harley-Dav- the riding season. No ~aler or rider ing shaft chamber cap. On an earlier or cap.
idson dealers and riders sometimes ride to should therefore ride to the facto~ with
the factory to have work done on their the expectation of having his motor over- 17-J Style Battery Box Furnished for all Models
machines. We are always glad to give hauled within a few hours, say for in-
such work our best attention but cannot stance on a Saturday with the factories The 191 7 battery box is now fur- although the job is a very simple one. The
promise to complete an extensive overhaul- closing at noon. We gladly offer our best nished for 1915 and 1916 electric mod- advantages of the 191 7 battery box are
ing within eight or nine hours, or even less service but will Appreciate taking the els. The battery box complete with fit- that it can be removed easily and is re-
time. Our repair department is naturally above into consideration to avoid possible tings sells for $3.40 list and is furnished inforced with a metal strap running across
very busy right now, during the heart of disappointment. under part number FJ40. Instructions the bottom and up the sides.
for fitting are furnished with each box,
Bending Relief Pipe Away from Drive Chain
Attention is called here to the para- dition exists, bend the relief pipe so that
44 Tooth Rear Wheel Sprocket for 1916 and 1915 Three
graph on page 36 of the 191 7 manual the oil is nof sprayed on the chain." Speed Models
on the above subject. For convenience This is very good advice. We will
we are repeating this paragraph herewith: leave the matter to the discretion of each The 44 tooth rear wheel sprocket has For ordinary solo service:
"The drive chains do not need external dealer. Ordinarily, the oil sprayed on been standard equipment on all 191 7 Counter- Rear Hith
lubrication since the crank case relief pipe the short drive chain by the relief pipe, three speed machines, both solo and side- Engine Clutch •haft Wheel Gear ratio
sprays oil on the chains. In country performs a useful service by lengthening car type, for some time, in place of the
40 tooth sprocket. Beginning july 9th 16 43 28 44 4.22
where deep sand and dust abound, it is the life of the chain. In very sandy or For solo service on rough roads or very
advisable to keep all the oil away from dusty country, on the contrary, thin oil is the 44 tooth sprocket is also furnished
on orders for rear wheel sprockets for hilly country :
the chains because sand and dust will stick positively injurious. The sand, dust and
in the oil, causing excessive sprocket and grit that accumulate in the oil will cause 1916 and 1915 three speed models. The 15 43 28 44 4.50
chain wear. Therefore, where this con- excessive wear of sprockets and chams. only extra fitting necessary to fit the 44 For ordinary sidecar service:
tooth sprocket is a longer rear chain guard 15 43 28 44 4.50
bracket to give the chain guard the proper
For sidecar service on rough roads er
Venting the Mechanical Oiler to Regulate Oil Supply clearance. Thi1 bracket is furnished with
very hilly country:
every 44 tooth sprocket. The use of the
It may happen that a motor will over- On a single cylinder motor it is neces- larger sprocket" will mean longer sprocket 14 43 28 44 4.83
oil with the adjusting screw of the me- sary to remove only the vent screw or cap and chain life. Heretofore the following sprocket com-
chanical oiler raised as far as possible. in the operating shaft chamber. The 44 tooth sprocket can be used for binations have been standard on '16 and
In that case, provided the hand pump After venting, place thtee or four solo or- sidecar service with the same size '15 models:
does not leak, the mechanical oiler should .010" washers on the plunger adjusting engine sprockets used with the 40 tooth For solo service:
be vented as explained below. We know screw, drain the crank cAses and refill sprocket, viz., 14 tooth for sidecar service 15 43 28 40 4.10
of cases where it was attempted to re~uce Vz
I to 2 pumpfuls of oil with the hand and 15 tooth for solo service. If these For sidecar service:
the oil supply by cutting off the head of pump. sprocket combinations give too low a gear-
the adjusting screw or taking a cut off the These instructions can be followed very ing, a 16 tooth sprocket can be used for 14 43 28 40 4.39
oiler. This is not the remedy because easily and will prove effective in every solo service · and 15 tooth for sidecar The 44 tooth rear wheel sprocket will
when the adjusting screw is raised flush case. Do not try to vent the oiler by fill- work. The use of the larger sprockets be supplied on all orders for rear wheel
with the mechanical oiler, the stroke of ing the chambers with oil after removing is recommended whenever possible, be- sprockets for 1916 and 1915 three apeed
the plunger is reduced to nothing. There- the screws or caps. To expell the air, cause larger sprockets mean longer models. The extra long rear chain guard
fore, no good is accomplished by trying the motor must be turned over, if the oil sprocket and chain life. The following bracket will be furnished with every
to raise the ~trew further. does not overftow readily. Also refer to sprocket combinations are recommended: sprocket unless instructed to the contrary.
Service Dept. Bulletin
No. 60 Service Department :Bulletin

To Adjust the Controls

No. 60. August 10, 1917 Harley-Davidson Motor Co., Milwaukee
When the black painted marks on the following instructions should be followed
control coils are no longer visible and the carefully, depending on the model.
entire mechanism is out of adjustment, the
Proper Adjustment of Controls is an Important Factor in
Getting the Most Out of Your Motors
Be Careful when Selling up a new Ma- To Adjust Spark and Relief Control on To Adjust Throttle Control on Twin Cylinder Models
chine Twin Cylinder Models
Turn the throttle grip to the right as Place the control coil clamp over the coil
To Adju5t Throttle and Relief Control! far as it will go. Pass the carburetor and lit the two screws temporarily. Draw
To Adjust the Control! control sleeve over the control wire and the coil out between the forks as far as
on Single Cylinder Models
coil, or if the sleeve is already over the possible (being sure the throttle is closed
To Adjusi Throttle Control on Twin To Adju5t Spark Control on Single Cylinc coil, loosen the two set screws and push and the grip is turned outward). Hold
Cylinder Models der Model! . the coil in this position and tighten the two
the sleeve over the coil as far as it will go.
coil. clamp screws.
Hold the grip in this position while pull- The throttle control should now be ad-
ing the sleeve off about I /8 inch. Then justed properly but it is advisable to open
tighten the two set screws. and close the throttle several times to make
If the throttle lever is not in line with sure that it is working properly and that
Too much emphasis cannot be placed ence that many cases of unsatisfactory the front cylinder push rod when the the provided stops on the cam casting
on the importance of correct adjustment motor service are due to poor adjustment throttle is closed, loosen the nut on the strike the lug on the carburetor body, indi-
of the throttle and spark controls so as to of the controls. Not every one appreciates cating that the throttle can be fully opened
end of the throttle shaft enough to move
that irregular running, loss of power and
have full control over the motor. These the lever to the required position and and closed. If the adjustment is off just
speed and overheating may be directly due
instructions are prompted by the experi- tighten the clamp nut. Pass the stud of slightly, loosen the two control sleeve set
to improper motor control adjustments.
the sleeve through the hole in the throttle screws and slip the throttle to the required
lever and lit the washer and cotter pin. position. Then tighten both screws.

Be Careful When Setting Up a New Machine To Adjust Spark and Relief Control on Twin Cylinder Models
When setting up a new machine make impossible to throttle the motor down to
sure that the controls are connected and a slow pace. If the spark control coil is Before adjusting the control coil or proper spark control rod adjustment, the
not adjusted properly, the spark cannot wire make sure that the spark and relief bell crank bracket which is placed over the
adjusted properly. Follow the instructions
be advanced or retarded far enough. In- rods are adjusted properly. Make sure rear cylinder plug should be moved either
and illustrations in the 19 i 7 manual cov- that the spark can be fully advanced and forward or backward as may be necessary
ering the setting up of machines. The sufficient spark advance will affect the
rnotor in the form of overheating and loss retarded and that the exhaust valves will Place the intermediate control sleeve
control coils should be clamped to the just start to lift after the interrupter has over the control coil as far as it will go.
of power and speed, while too much ad-
frame according to the black marks on reached the retarded position. These ad- Then pull it off about I j8 inch. Hold
vance on twin cylinder model will keep
them. These marks are painted on after the exhaust valves from raising shortly justments are about right when the ex- the sleeve stationary, tum the left grip to
the factory assembler has obtained the after the ignition unit has been retarded. haust lever is in a horizontal and the spark the extreme left and tighten both sleeve
proper adjustment. This is very impor- On the electrically equipped model, the lever in a vertical position when the in- set screws. Place the control coil clamp
tant because if the coils are connected entire interrupter assembly is forced out terrupter is fully retarded. To obtain over the coil and hold it to the Frame with
otherwise, the throttle may not open all of alignment when the spark control has this adjustment lengthen or shorten the re- the two clamp screws. Connect the inter-
the way, interfering with power and speed, too much advance. The result is an un- lief rod so that the exhaust valves will just mediate control sleeve to the intermediate
or the throttle may not close, making it satisfactory running motor. start to lift when the exhaust lever is in a control rod. Hold the grip to the extreme
horizontal position. Then to obtain the left, retarding the spark and lifting the
S<rllice Departm<nl Bulletin No. 60 No. 60 Seroice Department Bulletin

valves as far as they will go, pull the con- advances fully. Be especially careful on press down on the interrupter lever and More cases of unsatisfactory motor ser-
trol coil out toward the fork as far as pos- the electric model. Do not let the gen- slip the sleeve over I I J6 inch of the con- vice are due to faulty adjustment of the
sible and tighten the coil clamp screws. erator advance lever bear down hard trol wire. Then tighten both sleeve set throttle and spark controls than is gener-
Be sure to test this adjustment before enough when in the advanced position, to screws. ally known. A motor can be injured seri-
using the machine. Turn the grip to the push the interrupter assembly out of align- Turn the grip to both advance and re- ously by running with retarded spark for
extreme right, then try the circuit breaker ment, because this would result in the tard positions and take hold of the inter- any length of time or with open throttle
of the generator or magneto, depending motor missing or stopping entirely with a rupter lever to see whether the magneto and retarded spark. This is of course
on the model, to see whether the spark fully advanced spark. can be fully advanced and retarded. If an extreme application of the effects of
the adjustment is not just right, either bend poorly adjusted controls. However, many
the curved sleeve slightly or loosen the cases of uneven running, overheating, miss·
sleeve set screws and change the position ing or skipping at high speed, lack of
of the control wire in the sleeve. Do not power and speed, and inability to throttle
To Adjust Throttle and Relief Controls on Single Cylinder Models overlook to securely tighten the two sleeve
set screws.
down . are directly due to improperly ad-
justed controls.
Make sure that the relief and carbu- by tightening both set screws. Connect
retor control rods are properly adjusted the control sleeve to the magneto lever.
before proceeding to adjust the throttle Place the control coil clamp over the coil
control coil. To do this, turn the motor and hold it in position with the two
screws. Turn the magneto ·lever to the
over until the exhaust valve is in its lowest
position where the exhaust valve will be
position. Close the throttle. The relief raised as far as it will go and hold it in
rod should now be adjusted so that the ex- this position. Then draw the control coil
haust valve will just start to lift. Then out toward the forks as far as possible
open the throttle to make sure that it can and tighten the coil clamp screws.
be opened fully and that everything works Try the adjustment by turning the grip
freely. to all positions making sure that the
After this adjustment has been ob- throttle can be fully opened and closed
tained, pass the control sleeve over the and that the exhaust valve can be raised
coil as far as it will go. Then draw it after the throttle is closed. If the adjust-
off about I 18 inch. Hold the sleeve in ment is off only slightly, get the proper
this position, turn the right grip to the ex- adjustment by first loosening the sleeve set
treme right and then to the left far enough screws and slightly changing the position
to draw in about I I 16 inch of the con- of the control wire in the sleeve. Then
trol wire and fasten the sleeve to the wire tighten the sleeve set screws.

To Adjust Spark Control on Single Cylinder Models

Pass the control coil through the curved neto interrupter housing lever. Pass the
sleeve leaving it extend through about coil clamp over the control coil and draw
I I 12 to I 3/4 inches from the lower both coil clamp screws tight, being sure
clamp nut. Tighten the coil clamp nuts not to allow any slack between the cylin-
on both sides of the curved sleeve and der plug and the clamp. Turn the left
place the loop of the sleeve over the cylin- grip to the extreme left. Pass the mag-
der plug. neto control sleeve over the coil, put the
Tighten the cylinder plug nut while magneto interrupter in the upper or re-
holding the curved sleeve so that the end tarded position and connect it to the con-
of the control coil is in line with the mag- trol sleeve. Hold the grip in this position,
 No. 61 Seroice 'Department Bulletin

Service Dept. Bulletin

No. 61. August 15, 1917 Harley-Davidson Motor Co., Milwaukee To Adjust the Horn
If the horn does not sound right and To make sure that the current con-
the battery and the circuit between the sumption is right, it is advisable to connect
horn and battery are 0. K., the horn an ammeter in series with the horn. If the
How to Adjust and Repair the Electric Horn can be adjusted by bending the vibrator horn is mounted on a machine, connect
assembly. Remember it is very import- the ammeter between the battery ground
To Adjust the Horn To Test the Coil ant to have the battery, wiring and con- wire and the machine. Then turn "on"
/f the Horn Blon>s Without Pressing the To Remove the Coil nections in good shape before proceeding the ignition switch and note the discharge
Button /f the Horn Fuse Burns Out to adjust a horn.
To Repair a Coil through the generator. The additional
To bend the . vibrator assembly, the
M al(e Y o~tr Own Test Lamp To Assemble the Hom discharge when the horn button is pressed
cover "19" must of course, be removed
To Repair the Horn Changes Made on lfoms first. Do not disconnect or loosen any will then indicate the horn's current con-
other part. The horn should be firmly sumption.
bolted to the bracket and the bracket to If the contact points on the vibrator
the forks, because a little distortion of the springs are too close together when the
horn bracket will interfere with the sound armature is bearing against the diaphragm
The electric horn like anything mechan- the various adjustments properly, a care- of the horn. stem, the housing bail "9" should be re-
ical may require adjusting at some time. ful reading of these instructions is recom- Place a monkey wrench such as is fur- moved and the upper spring can then be
Since it is of great importance to apply mended. nished with every tool equipment over the bent outward by forcing a screw driver
vibrator assembly and pull upward or between both contact springs. Be sure
bear downward as may be necessary to
that the contact points break at least 1.'64
improve the sound. Refer to illustration
and be sure to remove the wrench before inch. If the contact points do not make
trying the horn. In most cases, the horns contact at all, the upper spring should be
will sound best and consume the least cur- removed and be bent downward. If this
rent when the armature "7" clears the spring is removed, be sure that the various
diaphragm stem "10" by about 3/32 parts aTe properly replaced before the
inch, and when the contact points of. the clamp screws are tightened. Instructions
vibrator springs "2" and "4" break about covering this subject are given later in this
I .'64 inch when the armature is bearing bulletin.
firmly against the diaphragm stem. Cur-
Make sure that the armature strikes the
rent consumption is an important factor to
consider when adjusting a horn. A horn diaphragm stem and not the horn body.
properly adjusted will not require more If the armature strikes the body, the horn
than I Yz to 2 amperes, whereas a poorly should be stripped and the lower edge of
adjusted horn may consume as much as 7 the disc which is riveted to the armature
amperes. should be ground off taper.

If the Horn Blows Without Pressing the Button

If the horn blows constantly or inter- Remove the switch cover of the horn
mittently without pressing the horn but- button. Examine the insulating block to
ton, the trouble will be found in the horn see whether it is cracked or whether the
or the wire leading from the button to the insulation of the wire is punctured, caus-
horn. ing a ground. The wire should also be
Service Department Bulletin No. 61 No. 61 Service Department Bulletin

examined where it leaves the center of the should be straightened out. To do this punctured insulator "6", causing a short edge has been scraped off. To absolutely
handle bar and under the horn cover. A will not require removing the copper tube circuit between the large vibrator spring prevent any further short circuits at this
cracked or broken insulating block should from the bar. Simply double over one and the armature. In this case, another place, the hole in the armature can be
be replaced with another. If the wire is end of a piece of handle bar control wire insulator should be fitted after the sharp filled with solder.
and pull this control wire through the cop-
the cause of trouble, fit a new one.
per tube. The doubled end of the con-
If trouble is experienced in passing a trol wire is just large enough to straighten
new wire through the copper tubing in the out the kinks sufficiently to allow passing
handle bar, the tubing is kinked and the wire through easily.
To Test the Coil

If a test lamp indicates a closed circuit spring which is soldered to one of the coil
Make Your Own Test Lamp to the horn and the horn will not sound
after a careful inspection of the vibrator
w1res. Then rub the other battery wire
against the coil wire leading to the left
assembly, the coil should be tested. This
can easily be done after the vibrator as- wire clamp screw "20". Light sparking
A lest lamp which can conveniently be to the body of the lamp. Be careful not
sembly has been removed. Connect one indicates that the coil is 0. K. No spark-
used in the following tests can easily be to overheat the globe while soldering. Use
made out of a single point dimmer or tail friction tape generously to protect and in- of the battery wires to the large vibrator ing indicates a faulty coil. If an ammeter
lamp globe. Solder two pieces of wire to sulate the connections. Do not use a
the globe, one to the center point, the other larger than 2 candle power bulb.

To Repair the Horn

If the horn will not sound and a test "4" is placed under the small spring "2"
lamp connected to the horn wire clamp and whether it is hooked under the fibre
screws "20", indicates that the circuit is strip which is riveted to armature "7",
0. K., the trouble should be looked for in making sure that the fibre strip is not torn.
the horn. Make sure that the points This is the proper position for the large
break and that the armature is properly spring.
adjusted as is covered under "To adjust Inspect the springs to see whether they
the Horn." If these points are found have been turned around which would
0. K., inspect the horn to see whether it prevent the large points making contact.
is properly assembled. The vibrator as- It is also important to inspect the vibrator
20 19
sembly must be assembled m the follow- points for pits. If pitted, draw "00"
manner: sandpaper between the points; then fol- --------------------------
Connector plate .. , " low up with plain writing paper to clean
Vibrator spring "2" out all grit. Any insulators which are
Leatheroid insulator "3" torn or only slightly cracked should be
Contact spring "4 .. replaced. If the peaned end of the con-
Leatheroid insulator "5" tact point on the large vibrator spring is is used to test the coil, the discharge will tery wires to one of the coil wires. Then
Middle spring insulator "6" too large or has sharp edges, trim it off amount to from six to seven amperes. rub the other battery wire against the horn
Armature "7" sufficiently to prevent puncturing insula- To test a coil to see whether it is short- body. If arcing occurs, the coil is short-
The armature is not insulated from the tor "6". circuited, do not use an ammeter. Re- circuited and should be repaired as ex-
horn body. The hole in the center of the armature move the vibrator assembly, disconnect plained under "If the Horn Fuse Burns
Note whether the large vibrator spring spring may have a sharp edge which has both horn wires and attach one of the bat- Out," or replaced with another coil.
Servia Department Bulletin No. 61 No. 61 Service 'Department Bulletin

To Remove the Coil To Repair a Coil

To remove the coil take off the housing The coil can then be removed. If the coil A coil which has tested out to show an about I inch wide and 2 inches long and
bail and with a hot soldering iron remove sticks, it can easily be drawn from the iron open circuit will invariably be an easy measuring about .008 inch thick on the
the 2 or 3 drops of solder at "14". The bushing with a pair of pliers or by striking matter to repair. Examine the wires inside of the coil. If two wrappings of
early 191 7 horns or earlier style horns the horn with coil downward, against the closely where they pass the fibre washer fibre will not make the coil fit tightly over
have no solder at this place but should in bench. If the coil must be replaced with "II " and under the rubber tubes "I 3". the bushing, add more sheet fibre. If two
all cases be soldered when they are over- another, disconnect the large vibrator See whether the wires are broken even wrappings are too much, tear off a piece
hauled. With a small screw driver or spring from the wire leading to the coil by though the insulation appears 0. K. If a of the fibre.
tool of some kind the fibre washer "I I " first melting the solder at this connection wire is broken, cut the insulation in two To add this fibre between the coil and
should be pried out of the horn body. with a soldering iron. over the break and solder in another piece bushing is very important, because it will
of wire of the same grade. If the outside .Protect the coil from injury due to friction
winding of the coil shows a break, little with the iron bushing. Therefore, place
trouble will be experienced in making a some of this fibre under every coil of each
If the Horn Fuse Burns Out satisfactory splice. Be sure to thoroughly horn that requires repairing, whether or
insulate the repair with friction or rubber not the coil is in good condition. Care
If the horn fuse constantly burns out, the fuse holder and turn "ON" the igni- tape. should be taken when placing the coil over
carefully inspect the wiring leading from tion switch. If the fuse will not burn If during the test the coil has proven to the bushing to protect the coil from injury
the generator switt:h box to the horn and out, the wiring is 0. K., and all trouble be shortcircuited, examine the inside wind- during this operation.
then test the horn to locate the short cir- is in the horn. If the fuse does burn out, ing carefully to see whether the insulation Place the piece of sheet fibre about one
cuit. To test the wiring, disconnect the the wire is at fault and should be replaced has rubbed through. If the insulation is half way through the coil leaving the other
wire from the horn which leads from the with another. worn or rubbed through, it undoubtedly half extend toward the bushing. Then
generator to the left connection on the If the short circuit is traced to the horn, was due to the coil having fitted loosely on carefully place the coil over the bushing
horn. Hold this wire in such a manner inspect the vibrator assembly and insula- the iron core or bushing. In this case do and turn it back and forth while pressing
that the end cannot ground and cause a tion a;, explained under "To Adjust the not attempt to insulate the exposed wire it in place by hand. After the coil has
short circuit. Then place a good fuse in Horn. but remove the entire layer of inside wind- been pressed over the bushing place a piece

,
ing by pulling it out, saving just enough of pipe just large enough to pass, over the
of this layer to allow for a connection. bushing and with a small hammer lightly
After the coil has been repaired, test it drive the coil down tight. If some of the
to see whether it is 0. K. Before again sheet fibre should extend the full length of
placing the coil over the iron bushing, the bushing, bend the extra length over
place about two wrappings of sheet fibre onto the end of. the coil with a jack-knife.
3
2

...,.
7

To Assemble the Horn

If the vibrator assembly was taken forked wire or spoke measuring 3.132 inch
apart for some reason, be sure to assemble in diameter through holes "12" so as to
9 it by placing armature "7" against the line up these parts properly and accurate-
9 horn body first. Then follow with "6", ly, thereby preventing all danger of a
"5 ", "4", "3", "2" and "I". short circuit. Remove the two· screws.
To line up this assembly, place the Yz Insulate these clamp screws with tape be-
inch clamp screws through the bracket of fore passing them through and clamping
the horn body from the back side and
~
15
fo()C16 17 18
through the numbered parts in above para-
the vibrator assembly. Do this with a
piece of tape I inch long and 3/16 inch
graph. While holding the screws in this wide. Wrap the tape around the threaded
position, place two nails or a piece of part of the screw close to the head.
Service Department (/)ullelin No. 61

Be careful to wrap the tape around the ings. Firmly turn the screws into the horn
screws in the right direction. The best body, clamping the assembly securely and
way is to hold the screw~ and tape be- withdraw the tool used to line up the vibra-
tween two fingers and with a screw driver tor assembly. The washers must be placed
turn the screws to the right, thereby wrap- on the clamp screws as indicated at "I S",
ping the tape around the screws. If the first the lock washer "16", then plain
tape is wound around the screws in the
metal washer "I 7" and fibre insulating
wrong direction, it will unwind and lear
while the screw is turned in place, allow- washer "18". The vibrator mechanism
ing the vibrator springs to short circuit onto is next in line to be adjusted. For instruc-
the screws. If the later style screws are tions refer to ins! ructions under "To Ad-
used, insulate them with the fibre bush- just the Horn."

Changes Made on Horns

Careful inspection of horns on machines hole through the center of the armature
received after about june 1st will show "7'' is filled with solder to prevent the
that they differ slightly from the earlier edge of the hole from puncturing the fibre
horns. These changes do not alter the insulator "6". A metal strip is being
horns to any extent and were maclt' only to riveted over the fibre strip which is riveted
render them more trouble proof. The to the armature, to prevent the fibre strip
changes are as follows: The coil is from tearing and the peaned end of the
shimmed with fibre holding it secure onto contact point on vibrator spring "4" is
the bushing. The thick fibre washer "II " trimmed of sharp edges.
is prevented from working loose by adding To repair a horn it is not necessary to
two or three drops of solder ("at 14") to apply the changes covered in the preced-
the horn body. The screws which clamp ing paragraph, but careful application
the vibrator assembly to~Jelher and turn of the remainder of this bulletin is recom-
into the lapped plate "8" are replaced mended. If il is desiTed to apply the lat-
with regular bolts and nuts, the tapped est changes to a horn as explained in the
plate having been discarded. These clamp preceding paragraph, the necessary fittings
screws are insulated with turned fibre can be obtained from us. Whenever a
bushings which absolutely prevents all certain trouble is experienced refer to the
danger of a short circuit at this place. The various headings and apply the remedies.
 No. 62 Service Department Bulletin

To Fit and Adjust New Carbon Brushes

No. 62. November I, 1917 Harley-Davidson Motor Co., Milwaukee
Trim the new brushes to conform with Follow the radius of the commutator with
the radius of the commutator. Place the sandpaper as much as possible. Refer
the brush holders on the studs. Cut some to illustration. To obtain a good bear-
Care of the Commutator-Electrically Equipped Model "00'' sandpaper (never use emery) into ing of the brush against the commutator
strips 3-8 inch wide. Place this sand- may require pulling the strip of sandpaper
Causes of Quic~ Wear To Adjust the Tension of tlw Brush paper between the commutator and brush through several times, but the operation
Springs with the coarse side toward the brush. should be repeated only as often as is
Hard Carbon Brushes
necessary.
To Fit and Adjust netv Carbon Brushes To Repair a Grooved Commutator \\'hen trimming the forward brush, be
Proper Pressure of Brushes against Com- Poorly Fitting Circuit Brealeer Cot•er sure to pass the sandpaper between the
mutator lower bearing housing support and the
commutator if the strip is long enongh,
and pull upward and backward so that
A commutator which is grooved, show- Neglect will in time render the commu- the edges of the brush will not be trimmed
tator and armature useless. A careful off. When trimming the two rear brushes
ing that the brushes are gradually cutting
periodic inspection for wear and the ap- pass the strip of sandpaper under the
into it, should not be neglected. Inspec- upper housing support, then under the
plication of the proper remedy when wear
tion of the commutator is recommended is found, will make renewal of the com- upper and lower brushes, and draw the
whenever the circuit breaker or distribu- mutator unnecessary during the life of the sandpaper toward the front.
tor points are inspected and adjusted. machine. After the brushes have been properly
seated, remove all traces of grit by wip-
ing the commutator with a gasoline soaked
rag and then drawing plain writing paper
Causes of Quick Wear After the sandpaper has been properly between the brushes and commutator. For
placed, bear down lightly on the brush instructions on adjusting th~ brush springs
Quick commutator wear can generally against the commutator, or failure to holders and pull out the sandpaper. Be refer to instructions under "Proper Pres-
clean the commutator il ;:;c ;n3.c~in" is careful when pulling out the sandpaper sure of Brushes against Commutator" and
be traced to one or more of the following not tu damage the near edge of the brush. "To Adjust Tension of Brush Springs."
used in very sandy or dusty country,
three causes: Hard carbon brushes,
especially if sand and dust can get under
brushes bearing with too much pressure the circuit breaker cover.

Proper Pressure of Brushes Against Commutator

The proper brush pressure against the the commutator and the scale is balanc-
Hard Carbon Brushes commutator is six ounces. Determine the ing. Never let a brush bear with greater
proper pressure with a small spring scale pressure, nor have it considerably less.
If a commutator is found grooved and brush cannot be seen with the eye. There- or hook the end of the brush holder with Too much pressure will cause quick wear
inspection of the brush tension, as de- fore, when a faulty brush is suspected, a piece of wire to a scale graduated to of both the commutator and brushes,
scribed hereinafter, proves that the springs all three brushes and brush holders should ounces. Then pull the generator away, while too little pressure will affect the
are properly adjusted and the mechanism be replaced. the exact brush pressure is determined at conductivity of the brush and interfere
on the inside of the circuit breaker cover Never replace a brush without replac- the point when the brush is just leaving with the current output of the generator.
is clean, hard brushes are the cause of ing the holder because it is very important
the commutator wear. to have a perfect circuit between the two,·
The reference to hard brushes does not and to obtain this circuit very careful
mean that the brushes are as hard as a soldering and tinning are required. The
piece of steel, but rather that the com- cost of a brush holder is less than the cost To Adjust the Tension of the Brush Springs
position of the material in the brush lacks of the labor required to solder and tin
When inspection proves that the brush lowing instructions should be applied:
graphite. The amount of graphite in a a new brush to an old holder.
springs are improperly adjusted, the fol- The cotter pins holding the brushes on
Service Dept. Bulletin No. 79 Service Department Bulletin

No. 79. January 20, 1919 Harley-Davidson Motor Co., Milwaukee The 191 9 Clutch
The simplified construction of the 19 I 9 parts that the power is conveyed from
clutch (which has eliminated ten parts) the friction assembly to the main shaft.
embodies several important features worthy Arrows No. 2 and No. 3 indicate the
of more than passing attention, such as actuating plate and the clutch takeup
the automatic lubrication, accomplished spring, respectively.
through the medium of the transmission,
Arrow No. 4 refers to the special lock
and the elimination of the split ring as-
washer for the main shaft left side nut
sembly, which, of course, now makes it No. 5. The lock washer has three blades
impossible for a novice to put the clutch and secures the clamp nut when one of
out of adjustment by altering the adjust- these blades is bent over one of the fiat
ment of the split ring. sides of the nut. As will be seen, in ad-
Dealers and their repairmen should be dition to holding the clutch on the main
familiar with the new construction to be shaft, nut No. 5 also holds the clutch
able to explain its advantages and to make together. No special wrench is required
repairs when necessary. to reach this nut. Any wrench that can
The lubrication of the new clutch is open I ~" or that has a I ~" hexagon
taken care of entirely automatically opening can be used.
through the transmission. If it is desired to remove the clutch
The cross section reproduced herewith from the main shaft, it will only be neces-
shows the change in the clutch bearing. sary to strike the end of the main shaft
The change made in the actuating mech- squarely with a hammer while pulling on
anism is not shown. It is but a few min- the clutch shell with the other hand after
utes work to gain access to these parts, and the nut has been removed. A rawhide
those who wish to become familiar with mallet, or a copper hammer such as is
the construction, can inspect it after ~e­ recommended for flywheel truing, is best
moving the pull rod. Care should be suited for this work because the shaft or
taken that the pull rod is properly adjusted the threads are easily damaged · with a
when reassembling. The pull rod nuts steel hammer.
should be adjusted so that the top end of
Arrow No. 6 points to the pull rod ad-
the clutch hand lever has a free forward
justing collar. This collar differs from
and backward movement of about Vz inch
the other type in that it is not as thick.
when the lever is forward.
It can be used on the earlier type model,
Explanation of New Parts although it will not be possible to use the
earlier collars on tht~ new clutch, because
All parts that supersede other parts are the pull rod is not long enough.
clearly indicated with arrows and are more Arrow No. 8 directs attention to the
clearly visible, being drawn in heavy clutch sprocket. It shows that the con-
lines. The parts that are illustrated in struction of the sprocket differs con-
a very thin dot and dash outline, have not siderably from that used previously. The
been changed. sprocket is enlarged,-not in diameter,
Arrow No. I points to the driving but the inside area has been increased so
disc. It will be seen that the driving disc as to eliminate the necessity of the clutch
is riveted to a heavy taper .bored bushing shell. There are many other advantages
with ~"rivets, (see arrow No. 7). The to this construction, the most important,
Cross-section of 1919 Clutch. taper bored bushing is in turn keyed to that the former hub shell cone, now the
Parts drawn in heavy lines show changes. the main shaft as was the driving hub on outer roller race, No. 14, is riveted di-
the earlier clutches. It is through these rectly to the sprocket, see No. I 5, where-
Se,-,ia Department Bulletin No. 79

as formerly the parts were held together to the shaft and while being held in this
with solder. position are soldered together. They are
Arrow No. 9 points to the clutch bear- then turned down to give the maiQ drive
ing. The bearing is of the roller type gear .003" clearance.
identical with those used for the crank pin Arrows No. II and No. 12 lead to
in the latest motors. This obviates the the main shaft and clutch pull rod, re-
necessity of carrying a special size re- spectively. The change in the main shaft
tainer and rollers in stock for clutch spares. can readily be seen, while the length of
The rollers run directly on the hardened the pull rod has been increased.
main shaft. This construction helps to Arrow No. 13 points to the roller bear-
eliminate the driving hub, and also per- ing washer. With these hardened steel
mits automatic lubrication from the gear washers the proper end play of the clutch
box. is obtained. They are made in thick-
When the clutch bearing is fitted up, nesses varying .005" from .085" to
the size rollers are selected which will .II 0". If no end play is allowed, the
permit the ;procket assembly to turn per- clutch will not release, because the taper
fectly free without any perceptible shake. bushing which is riveted to the driving
The proper size rollers for this fit are those disc, the clutch roller race, the roller
over which it will be just possible to pass bearing washei, and the main drive gear
the clutch roller race. are in contact.
Arrow No. I 0 points to the bronze Too much play between the clutch and
bushing which is the bearing for the main the main drive gear also has its evils and
drive gear. With this construction there for that reason a clearance of between
will never be any danger of the gear .005" and .010" should be allowed be-
running tight on the shaft with the proper tween the roller bearing washer and the
amount of oil in the gear box. The bush- clutch roller race. It is important to
ing is made in two interchangeable parts, gauge this clearance after the left side
each part being keyed to the shaft so that main shaft nut has been drawn up as
the bushing will turn with the shaft only. tight as possible, or the washer will not
To permit machining an even, true, bear- be free after the clutch is tightened, and
ing, the bushings are clamped securely the clutch will drag.
Service Dept. Bulletin
No. 65• Revised June 1,1921 Harley-Davidson Motor Co., Milwaukee

Working Principles of the Harley-Davidson Motor

The Harley-Davidson motor is of the wheel travel is one event or stroke. The
conventional four-stroke-cycle principle. 8ywheel must make two revolutions to
The power stroke being the chief cycle complete one power cycle of the motor.
of the motor. It is made up of four Each cylinder of a four-stroke-cycle en-
events, or strokes: hence the term .. four- gine goes through the following cycle of
stroke-cycle.'' Each 180 degrees of .A.y- events.

Intake
The intake valve opens at the proper through the carburetor and manifo-ld. The
time by means of cam and gear action. atmospheric pressure «t sea level is 14.7
The pis.ton being on a downward stroke pounds per square inch 'at 60 degrees F.
creates a partial vacuum in the cylinder.
A gaseous vapor passes into the cylinder The intake valve doses as the piston starts
due to the atmospheric pressure passing on the upward stroke.

Compression
With both the intake and the exhaust when the piston is at the upper extremity
valves closed, the cylinder chamber is now of its stroke. The sidecar motor has a
comparatively air tight. The piston on its compression of 55 pounds per square inch,
upward stroke compresses and squeezes the and the solo motor 60 pounds per square
gaseous vapor into a small space. This inch. The compressed gases at this point
compression heats the mixture to a very are ready for ignition by an electric spark.
much higher temperature and makes it After ignition takes place the gases expand
more volatile. The ratio of compression from three to four times their initial com-
in a motorcycle motor i.s usually 3. 75 to pression pressure, that is. with a compres~
1, meaning that when the piston is at the sion of 60 pounds per square inch. the
lower most extremity of its stroke the gases would expand to 240 pounds per
chamber above it is 3.75 times greater than square inch after ignition.

Ignition or Power Stroke

The generator or magneto being timed The connecting rod transmits this power
to produce an electric spark at the oppor- to the 8ywheels, driving the vehicle and
tune time, ignites the highly compressed storing up kinetic energy to carry the pis-
gases and starts combustion. The piston
being the only movable pnrt subject to the ton through the three minus strokes of the
combustion starts on its downward stroke. cycle.

Exhaust and Scavenging Stroke

At the end of the power stroke the these gases and prepare for the next series
burnt gases still remain in the cylinder, so of events. On the upward stroke of the
some provision must be made to expel piston the exhaust valve opens and the
"V" Twin motor with cutaway gear cover, slJOwing how 1915 to 1922 twin magne·to
models should be set acco~ding to gear max:ks

Illustttation No. 1
spent gases are driven out, these hot gases take valve opens, the motor starting on
coming in contact with the atmospheric another cycle.
pressure cause the report commonly heard Briefly the cycle of events may be
from the gas engine. At the top of this termed, I. intake; 2, Compression; 3,
stroke the exhaust valve closes and the in~ Ignition; 4, Exhaust.

Complete Timing Instructions for Harley-Davidson Motors

To insure the most accurate results in ( 150 m lm) scale graduated to at least
valve and ignition timing, the motor should 1!,132 inch (.5 m/m), and measure the
be taken out of the frame and the front piston positions through the cylinder plug
cylinder plug removed. o~~~ Tk6~~~oo~~P~
The close relation between the piston ton can be determined by this method.
travel and the valve operation requires ex~ Since accuracy is essential for correct tim~
treme accuracy in measurements when ing, we do not recommeud the practice of
timing an internal combustion motor. For· locating the piston through the inlet hous-
an example: With a difference of only ing chamber.
one thousandth of an inch {.03 m/m') be~ Piston positiofts are determined from
tween the exhaust valve lifter pin and the either upper (top) or lower (bottom)
valve stem, will cause the flywheel to dead centers. Dead center is the point at
travel approximately 3/16 inch ( 4.7 the extreme upper or lower end of piston
mjm) to make up the difference. For travel-the point where the piston is
the best results in timing, use a 6 inch .. dead."

The Valve Lift Clearances Must Be Accurate

Before retiming the valves, make sure Allow .004 inch (.l 0 m/m) clearance
that the exhaust lifter pins and the inlet between. the inlet levers or rocker arms,
push rods are set accord:ng to the follow~ and valve stems on all models.
ing specifications. On the 191 5 and 1916 twin motors,
On all the twin cylinder models prior allow .004 inch (.1 0 m/m) exhaust lift~
to 1915 and all the single cylinder models er pin clearance for the rear cylinder and
(except model 21 CD) • allow . 004 inch .006 inch (.I 5 m/m) for the front cylin-
(.I 0 m/m) clearance between the exhaust der.
lifter pins and the val 'le stems or caps. On the 191 7. and all later "V" type
The earlier models had small steel caps motors, allow from .008 inch (.21 mlm)
placed over the ends of the exhaust valve to .0 I 0 inch (.26 in/m) clearance for
stems t~ prevent the stems from wearing both front and rear cylinder exhaust valve
and to provide a mea,s for taking up tappets. This also holds good for the
wear. These caps are made in various "500," ·"A," .. B .. and "E" type fast
thicknesses and should b~ ground until the stock motors.
correct clearance is obtained. The sport model lifter pin clearance for
both the inlet and exhaust valves and for
Model 21 CD should have .004 inch
both cylinders is .006 inch (.15 m/m).
(.I 0 mjm) clearance between the inlet Whenever making any adjustments to the
rocker and valve stem, and .008 inch valve tappets, be sure that the motor is
(.21 m/m) to .010 inch (.26 m /m) cold. because the expansion of the cylin-
between the exhaust lifter pin and valve ders and valve lifting mechanism varies
stem. when the motor is hot.
 To Time Inlet and Exhaust Valves
Assuming that the explosion of the fuel opening is when the piston is between ~
has taken place. it can easily be under· inch ( 19. mjm) and 9/16 inch ( 14.2
stood that there must be an outlet for the m/m) before bottom dead center. The
spent gases, at the proper time. in order exhaust valve closes when the piston is
to get the. full benefit of the energy ob~ 1/32 inch (.79 mlm) to 3132 inch
tained by the explosion and to prevent (2.3 m/m) past (after) top dead center.
possible injury to the motor. The exhaust The ·exhaust valve of the Sport Model
valve and its lifting mechanism serves this opens when the piston is between 9/ I 6
purpose. The time of valve opening and inch. ( 14.2 m/m) and 7116 inch ( 11.
dosing can best be determined at the point mlm) before bottom dead center. It
when the push rod or lifter pin begins to should close when the piston is I /32 inch
tighten or loosen when operating the valve (.79 m'/m) to 3/32 inch (2.3 mlm)
stem. This can easily be ascertained by past (after) top dead ct:nter.
turning the push rod while the motor is Since the inlet and exhaust cams are
being turned over. mounted on the same timing gear (made
With the "V.. type and the single cyl~ integral) on all twin motors, the inlet
inder motor, the point of exhaust valve valves do not require independent timing.

Single Cylinder Inlet Timing

AJI 1913 and 1918 si•·gle cylinder mo- valve should close when the piston is from
tors require independent timing of the in~ Ys inch (3.1 mlm) to% inch (9.5 mlm)
let valves, because the inlet cam is mount- pa!t (after) bottom dead center. Single
ed on one of the intermediate timing gears.
The single inlet valve should open 3 I I 6 cylinder motors prior to 191 3 have auto-
inch ( 4. 7 m/m) before the piston reaches matic inlet valves. therefore require no
top dead center, to top center. The inlet timing.

To Time Mechanical Relief Valve

To assure releasing the exact volume of and oil vapor into the crank case and cyl-
crank case compression ·1t the proper time, inders. thereby lubricating all the moving
all motors are fitted with a relief or breath- parts on the interior of the motor.
er valve. All twin motors beginning With The port in the sleeve of the relief valve
the 1914. but excluding the EH model. ( 1915 to 1922) must be open between
are fitted with a mechanically operated ro- 1I 16 inch ( 1.5 m/m) and 3/32 inch
tary relief valve. As the pistons descend (2.3 m/m) when the FRONT piston is
in the cylinders a certain amount of com~ on either top dead center. This port opens
pression is formed in the crank case. Some gradually when the motor is turned in the
outlet for this compression must be pro- direction it runs. and closes when the piston
vided for, in order that the motor can func~ has reached bottom dead center. All sin~
tion properly. The timmg of the relief gle cylinder motors (except 21 CD) • the
valve controls the lubricating system to a EH motor. and all twin motors prior to
large degree. When the pistons rise in 1914. are fitted with an automatic relief,
the cylinders the relief (breather) valve or breather valve which, of course, re~
closes and causes the piston to create a quires no t1mmg. Single cylinder model
partial vacuum in the crank case and cylin- 21 CD, should be timed according to 1915
ders. This partial vacuum draws the oil instructions as outlined above.
 To Time Spark
When the fuel charge is properly com- plode and expand, forcing the piston down-
pressed, it must be ignited. Ignition of ward and giving energy to the rear wheel
the compressed gases is accomplished by a of the motorcycle in the form of power.
storage battery and generator-ignition Since an interval of time is required for
unit, or by a high tension magneto. Igni- ignition to propagate a flame thru the
tion. or the electric spark, occurs at the gases and cause complete combustion, the
time when the generator or magneto cir· timing of the electric sparks occurrence is
cuit breaker points are just separating. At always set before the piston reaches its top
this juncture, a high tension (high voltage) dead center on the compression stroke. The
spark is induced to jump be;tween the spark following paragraphs will enable one to
plug points and ignite the highly com- correctly time the ignition for any Harley-
pressed gases, causing the gases to ex- Davidson Motor.

Magneto Equipped, Standard Solo "V" Twin

High compression solo motors with mag- on the compression stroke. The circuit
neto ignition are timed to spark when the breaker lever must be fully advanced and
piston is 17/64 inch (6.7 m/m) to 5/16 the circuit breaker points just breaking
inch (7.9 m/m) before top dead center when timing all motors for ignition.

Magneto Equipped, Sidecar "V" Twin

To time low compression sidecar motors pression stroke, with the circuit breaker
with magneto ignition, set the piston 13 164 lever fully advanced and the breaker points
inch (5.1 m/m) to 17/64 inch (6:7 just separating.
rn/m) before top dead center on com-

Generator Equipped, Standard Solo "V" Twin

High compression solo motors with gen- inch ( 7. 1 m/m) before top dead center
erator ignition should be timed when the on the compression strokf!.
piston is 15~/64 inch (5.9 m/m) to 9/32

Generator Equipped, Sidecar "V" Twin

Side car motors equipped with generator 13}64 inch (5.1 ml/m) to 17/64 inch
ignition should be timed when the piston is (6.7 mjm) before top dead center.

All Single Cylinder Motors

Time all single cylindci motors (except vanced and the breaker points just break-
21 CD) when the piston is· 3/1 6 inch ing. The 1921 CD, c::»mmercial single
( 4. 7 m/m) to !;:4 inch ( 6.3 m/m) before should be timed with the piston !;:4 inch
top dead center on the compression stroke, (6.3 m/m) to 9 }32 inch (7.1 m/m)
with the circuit breaker lever fully ad- before top dead center.

Sport Model Ignition Timing

Time all Sport Model motors .for igni- center on the compression stroke. On the
tion when the piston is Ys inch (9.5 m/m) magneto models, the front interrupter shoe
to 7 jl6 inch ( 11. mjm) before top dead times for the front cylinder.
 Ignition Timing for Fast "500," "M," "A"
and "E" Type Motors
Ignition timing for special built fast mo- ignition timing alone will not make any mo-
tors should be set with the piston Ys inch tor fast, it must be built for speed in the
{9.5 mjm) to 7/16 inch { 11. m,lm) first place.
before top dead center. Remember that

It. is common practice to set automobile ignition timing with the circuit
breaker lever retarded, pistons located at top dead center and the circuit breaker
points just opening. This method cannot be practiced on motorcycle motors,
because the ignition would occur Ys inch ( 3.1 m/m) late. This, of course,
would cause the motor to overheat and not develop its fullest efficiency.

Circuit Breaker Adjustments

To insure extreme accuracy in ignition Harley-Davidson
ti.ming, make sure that the circuit breaker Generator .. -.020 inch (.51 m/m)
points are set according to the manufactur· Remy model 250
Generator ... -.020 inch (.51 m/m)
ers specifications. An adjusting wrench
Remy model 235
fitted with a thickness gauge accompanies Generator ... -.020 inch (.51 mlm)
each ignition apparatus. If such a gauge Bosch magneto-.015 inch (.4 m/m)
is· not available·, adjust the breaker points Berling magneto--.018 inch (.46 m/m)
according to the following data: D i x i e magneto-.020 inch (.51 m/m)

.Reasons for Advancing and Retarding the Spark

Theoretically the proper time for ex- inch (3.1 m/m) past top center on the
ploding the charge is at ~op dead center on power stroke, and considerable energy will
the compression stroke; when the charge is be lost on account of the lapse of time be-
c~mpressed as much as it can be. How- tween the spark and complete explosion.
ever, there is a slight lapse of time between Then again, running the motor at slow
the sparking and explosion. When the speed with an open throttle and fully ad-
spark occurs, it. first ignites the charge vanced spark will result in injury to the
around the spark plug points. This flame motor in time, because complete combus-
then spreads through the rest of the mix- tion of the charge will take place before
ture. forcing the piston downward. The the piston has reached top dead center on
time between the spark and complete ex· the compression stroke. The effects of
plosion of the mixture is very short, but it this can be more easily noticed in the
can easily be understood that as the speed form of a knock, when driving at low
of the motor is increased, the spark should motor speed with an open throttle on a
be advanced. For this reason, the time of hard pull. Therefore, to get the full effect
ignition is made adjustable with the use of of the explosion, the spark should occur
the left grip. slightly before top center on the compres-
If the motor is run at high speed with a sion stroke.
retarded spark, the spark will occur when The time of sparking is controlled by
the piston is 1I 16 inch ( 1.5 m/m) to Ys turning the left grip to thl." right or to the
left, depending on the speed of the motor Do not form the impression from the
and whether or not under a hard pull. If above explanation that 1t is necessary to
the above is understood. the left grip will carry the spark in retarded position when·
always be carried in the proper position.
Running the motor accordingly will mean ever driving slowly. o~ not do this un·
added life, because the u:plosion is taking less the motor is pulling hard at a low
place when the piston is ja the proper posi~ motor speed.
tion.

To Time Model 2 3 5 Generator for the First Time

When a model 235 generator is fitted Be careful when setting this cam, not to
to a motor for the first time, gear marks use the wrong cam for the cylinder that is
cannot be referred to. to get the timing being timed. The small cam times the.
· correct, because the interrupter cam is front cylinder while the large cam times
loose on the shaft and must be set for .that the rear cylinder. After the earn has been
particular motor. Proceed to time the
properly set and securely damped, check
generator by first placing all the gears with
marks in line in their respective places. An over the timing and if it is 0. K., place
inspection will prove that the front piston the high tensi~n distributor segment over
is near the top center. on the compression the end of the shaft in such a position that
stroke. Turn the motor, whichever way the driving pin on the cam lines up· wifh·
is necessary. to bring the front piston be. the provided hole in the distributor seg..
tween 7;32 inch (5.5 mjm) to 9/32 ment. Later models have a special dip to
inch ( 7. I m/m) before top center on the support the distributor segment. The bake·
compression stroke. Remove the bakelite lite distributor cap can then be plac~d ovt;r.
distributor cap and the high tension dis· the circuit breaker assembly, it being only
tributor segment. Remove the hexagon nut necessary to line up the stop of this cap
clamping the circuit breaker cam, and with with the slot in the upper rear edge of the
the special wrench (see illustration No. 2) timer head and securing it by means of the
pry the cam loose from the tapered timer springs. When placing the ignition cables
shaft. Advance the circuit breaker as far into the distributor cap, be sure to place
as it will go by pushing it forward. Move the short cable, which is for the rear cyl·
the cam on the shaft in the direction it incler, into the extreme left boss. The 'long
runs so that the SMALL CAM is just causing front cylinder cable should be placed into
the circuit breaker points to break contact. the extreme right boss c. f the distributor
Then tighten the cam damp nut securely. cap.

Illustration No. 2
HX-1114 Price $.25

To Time Model 235 Generator According to Gear Marks

Assuming that the pinion. relief, sec· marks as is covered under: To Time
ondary. intermediate, and intermediate Twin Cylinder Motors According to Gear
worm gears have been set according to Marks, only the generatoi intermediate and
generator gears remain to be set. generator gear, and intermediate worm
Place the generator gear and key on gear line up exactly true. Pay special
the generator shaft, fit the washer and attention to this because if one of these
draw up the LEFT HAND clamp nut gears is just one tooth from the proper
temporarily. Remove the distributor cap position, the point of ignition will be off
from the generator. l'um the generator Y.4 inch (6.3 m/m). which would have
drive gear backward or to the left until the a decided effect on the running of the
small cam just touches the fibre block on motor. After having the gears lined up
the circuit breaker lever. This is very im~ properly, securely~ tighten the generator
portant because the generator drive gear gear clamp nut and fit the split t:ings and
and circuit breaker cam are geared three collars on the gear studs.
to one respectively. Place the intermedi~ As a matter of safety. check over the
ate generator gear on the stud so that the timing of the ignition following previOus
marks on the generator gear. intermediate instructions.

To Time the Harley~ Davidson Generator on "V., Type Twins

Owing to the circuit breaker cam and be possible to time the ignition properly by
the timer shaft being made integral, new lifting the timer base from the generator
timing instructions are obvious. It will not body and meshing the spiral gear on timer

lllustration No. 3
shaft with the worm gear on the armature (.4 m/m). Note: The full opening of
shaft. the circuit breaker points when properly
The generator drive gear and the inter- adjusted is between .020 inch (.51 m/m)
mediate compound gear are not marked, to .024 inch (.61 m/m). With the cir·
however, the remainder of the gears; in- cuit breaker points set cis specified (open
termediate worm (oiler) gear, intermedi- .015 inch .38 m/m) and the marked gears
ate, secondary (cam). pinion, and relief in perfect line, hold the small generator
gears retain their original markings. When gear firmly with the thumb of the left
all of the marked gears. are set properly, hand. Insert the compound intermediate
i.e., all marks in line, the front cylinder pis-- gear by turning it and trying to mesh it
ton will be approximately 3/16 inch with the generator and intermediate oiler
( 4.7 m/m) from top center on the com- gears. The construction of the compound
pression stroke. Refer to illustration 3 intermediate gear (one gear being smaller
for proper gear settings. than the other) allows proper meshing of
Advance the timer lever (illustration the teeth at seYeral positions. Do not force
No ... 4) by moving it forward to the .full the compound gear into meshing with the

Illustration No. 4

extent of its travel, as indicating by the other two gears-but keep turning it and
arrow. Since ignition for the front cylin- trying different positions until it slips in
der is in order, select the SMALL END of place freely. After properly meshing the
the timer cam (illustration No. 4) and turn gears put the split lock ring in place; this
it to the right ( clockwtse) until it has prevents· the gear from coming off of the
opened the circuit breaker points .015 inch stud and losing the correct timing just oh-
tained. These timing instructions if prop· be in the same pos1t1on while timing as
erly carried out will be accurate to within when being driven by the motor. Insert
a small margin. Should the motor be out a 6.inch ( 150. m/m) steel scale (ruler)
of the frame. the cylinder plug (found in into the front cylinder and lay some flat
the cylinder head) may be removed with object across the vertical cylinder flanges
to facilitate the reading of the scale. Note
a special wrench, and a steel scale (ruler)
the reading of the scale in this position,
inserted in the hole and the results may then turn the motor (clockwise) and note
be checked as follows: how much the scale rises until it reaches its
Advance the spark lever. Rotate the highest point. When the ignition is pro~
motor in a right hand (clock~wise) direc· erly timed the scale should rise between
tion until the small or front cylinder cam 15,164 inch (5.9 rn/m) and 9/32 inch
just begins to separate the breaker points. ( 7.1 m/m) for standard solo motors, and
If it should be necessary to turn motor 13}64 inch (5.1 m/m) to 17/64 inch
backward (anti-clockwise) in order to get ( 6. 7 m/m) for sidecar motors. Should
the proper setting of breaker points be sure the readings not check according to these
to remove back lash in the timer shaft if figures the first time they are checked, do
any. by trying to tum the timer shaft to not change timing until it has been re·
the left with the hand, as the gears should checked several times.

To Time Twin Cylinder Motors According to Gear Marks

Assuming that all of the gears have After the compression relief valve has
been removed, but that no new gears are been properly fitted and timed, plac:e the
to be fitted, it is a simple matter to re~ secondary gear on the stud in such a man-
time the motor correctly according to the ner that the mark will line up with the mark
following: Place the pinion gear on the on· the pinion gear. In order to get this
fly wheel shaft. and fit the key and the result with the 1914 and 1915 motors,
pinion lock screw. (The lock screw has the motor must first be turned until the
a left hand thread). Fit the compression mark on the pinion gear is in an upward
relief valve in the bronze bushing. On position. The secondary gears on all
19 I 4 and 191 5 motors. line up the marks 1915. 1916, 1917. 1918, 1919. 1920,
on the compression relief valve gear and 192 I and 1922 motors have two marks.
the pinion gear. Be sure to place the gear on the stud in
On 1916, 1917. 1918, 1919, 1920, such a position that the other mark will be
192 I and 1922 motors. line up the mark toward the intermediate drive gear. See
of the compression relief valve gear with illustration No. 1. The exhaust valve tim-
the mark ( .. A .. ) stamped in the crank ing can now be checked over and must
case. See ..A .. illustration No. 3. Be- correspond within the limits already men-
fore fitting this gear, be sure that the motor tioned. Fit the drive case after being sure
is in such a position that the mark on the that the marks of the pimon and secondary
driving pinion is in perfect alignment with gear are in line. Then place the inter-
the secondary gear stud and lifter arm mediate gear so that its mark will coincide
stud as shown in the illustration. It is with the mark on the secondary gear. After
always advisable to check over the timing
the intermediate gear ha::> been placed in
after a gear has been set according to
marks. We therefore urge that the tim- position, the motor should not be turned
ing of the compression relief valve be again. The intermediate worm gear is
checked over to see whether it corresponds then placed on the stud in such a way that
with the timing mentioned previously in one of the marks of this gear and the inter-
this article. mediate gear line up.
 The magneto or 250 model generator gear are not in line, the shaft only may
drive gear (not the 235 or Harley-David- be turned, because gear marks must be in
son generator) is then iined up with the line to have the timing right. Fit the lock
washer and draw the clamp nut tight.
intermediate worm gear after the key has After completing these operations the gear
been properly placed in the keyway of the marks will be in line as shown in illustra-
shaft. If the keyway of the shaft and tion No. 1.

To Time Single Cylinder Motors According to Gear Marks

Place the pinion gear on the fly wheel with the mark on the gear mounted with
shaft. Turn the motor until the mark the secondary gear. Fit the other inter-
on this gear is upward. Then place the mediate gear and then the magneto gear
secondary gear on the stud so that the according to mark.s. When the gears are
marks of this gear and the pinion gear are set according to 'marks. all marks visible
in line. Replace the drive case. Turn the will be in line.
motor until the mark on the gear which These instructions. as already mentioned,
is mounted with the secondary gear will apply to retiming a motor when the origi-
be toward the intermediate cam gear stud nal gears are used. If a new gear is fitted.
(toward the rear of the motor). Place time the motor according to piston posi-
the intermediate or intake cam gear on the tions, as previously explained under: To
stud so that the proper mark will line up Time Inlet and Exhaust Valves.

Timing Ignition for the Sport Model Without Removing

the Generator Drive Gear

Illustration No. 5
 When disassembling generator from the against the flat side of the timer shaft
motor do not remove the generator drive .. B," the flat side of the timer shaft
gear unless generator must be entirely dis~ should be accurately aligned with the filed
assembled. The hole in the rear of gear mark "A" on the outer edge of circuit
case is large enough to permit the passage breaker casting or frame. When aligning
of the gear while on drive shaft. Inspect timer shaft with filed mark on casting, be
sure that the flat !;ide of the shaft is to
circuit breaker points before starting to
the right rear of the shaft center. See il-
time motor, for proper gap which should lustration No. 5.
be .020 inch (.51 m/m) and can be de~ When timer shaft is in the above de-
termined by thickness gauge or by the steel scribed position and the marks on the
gauge on the back of the generator wrench. pinion gear, secondary gear, and inter-
Remove the generator intermediate gear. mediate gear are properly lined up, the
Rotate the motor until pinion gear marks generator intermediate gear will mesh with
"A" and .. B'' are directly in line .with the intermediate gear and the generator
secondary gear and intermediate drive gear. drive gear. Place this gear in position and
See illustration No. 7. secure with split locking ring. After gen-
It is very essential that these marks are erator is correctly timed be sure that out-
acccurately aligned. Every circuit break- side terminal of distributor cap leads to
er casting or frame has a filed mark on the the front cylinder. These terminals being
outer edge of this casting. Remove dis- the same length makes it possible for them
tributor segment and holder. and by plac- to become crossed which would, of course,
ing the edge of a 6 inch ( 150. m/m) scale change the timing. See illustration No. 6.

Timing Sport Model Ignition When the Generator

Drive Gear Has Been Removed
Inspect circuit breaker points before the outer edge of circuit breaker casting
starting to time motor, for proper gap. or frame. See illustration No. 5. When
which should be .020 incA (.51 m/m) aligning timer shaft with filed mark on
and can be determined by a thickness casting be sure that the flat side of the shaft
gauge, or the steel gauge on the back of is to the rear of shaft center. When timer
the generator wrench. The generator shaft is in the above described position
drive gear has three keyways. which are and the marks on the pinion gear, second-
placed in different positions, permitting the
changing of timing by I /3 of a tooth.
2/3 of a tooth or by 1 tooth. Rotate the
motor until pinion gear marks are directly
in line with secondary gear and intermedi-
ate gear. See illustration No. 7. It is FRONT CY/.!NJ)!R
<AJJa
very essential that these marks are accurate-
ly aligned. Every circuit breaker casting
or frame has a filed mark on the outer
edge of this casting aft~r the motor has
once been timed at the factory. Remove
distributor segment and holder, and by
placing the edge of a 6 inch ( 150. m/m)
scale against the flat side of the timer
shaft, the flat side of the timer shaft should
be accurately aligned to ~he field mark on Illustration No. 6
ary gear and intermediate gear are prop- before top dead center. on compression
erly lined up. try the generator drive gear stroke, with interrupter fully advanced. It
in each of the keyways, until it slips in is necessary to remove the front foot board
mesh. without changing the position of support and the front cylinder plug for
timer shaft or without turning the pinion this operation. After generator is correct~
gear. It is advisable to recheck timing by ly timed. he sure that the outside terminal
inserting a 6 inch ( 150. mi/m) scale in of distributor cap leads t;> the front cylin-
front cylinder to determine whether cir- der. These terminals being both the same
cuit breaker points are just beginning to length makes it possible for them to become
separate when piston is from % inch crossed which would entirely change the
(9.5 m/m) to 7 '16 inch ( 11. mjm) timing. See illustration No. 6.

Illustration No. 7
 Summary of All Motor Valve Timing
1912 TO 1916 "v" TWINS SPORT MODEL VALVE TIMING

Exhaust V"alve opens with piston % Exhaust valve opens with pistons 7/16
inch ( 15.8 mjm) to ~ inch ( 19. m /m) inch (11.1 m/m) to 9/16 inch (14.2
before bottom dead centef. , mjm) before bottom dead center.
Exhaust valve closes with piston 1 /32 Exhaust valve closes with piston 1/32
inch (.79 m/m) to 3/32 inch (2.3 m m) inch (.79 m, m) to 3132 inch (2.3 m/m)
after top dead center. after top dead center.
Inlet valve opens with piston 1132 inch Inlet valve opens with piston 1 / 16 inch
(.79 mjm) to 3',132 inch (2.3 m 'm) (1.5 m/m) to 3/16 inch (4.7 m/m)
before top dead center. before top dead center.
Inlet valve closes with piston !/s inch Inlet valve closes with J:iston 7l 16 inch
(3.1 m/m) to Y.4 inch (6.3 m/m) after ( 11.1 m/m) to Ys ind:~ ( 15.8 m/m)
bottom dead center. after bottom dead center.
The sport model breather valve is made
191 7 TO 1922 "v" TWINS, integral with the secondary gear, therefore
it does not require special timing.
All Standard 61 ". Standard 74". "500".
"A.. and "E" Motors.
Exhaust valve opens with piston 19 132 Miscellaneous
inch ( 15. m/m) to 23,132 inch (14.2
m /m) before bottom dead center. TWIN BERLING MAGNETO
Exhause valve closes with pistons 1I 16 · Lower cam (or shoe) in interrupter
inch ( 1.5 m/m) to 7/64 inch (2.7 mjm) housing times ignition for front cylinder.
after top dead center. Upper cam (or shoe) in interrupter hous~
Inlet valve opens with pistons 5;32 ing times ignition for rear cylinder.
inch (3.9 m;'m) to 19/64 inch (7.5
mjm) before top dead center. TWIN DIXIE MAGNETO
Inlet valve closes with piston ~ inch Cam No. 2 times ignition for front cyl-
(19. m/m) to Ys inch (22.2 m/m) inder. Cam No. 1 tim.~s ignition for rear
after bottom dead center. cylinder.
TWIN BOSCH MAGNETO
SINGLE CYLINDER VALVE TIMING
1912 TO 1918 Interrupter shoe No. 2 times ignition for
front cylinder. Interrupter shoe No. 1
Exhaust valve opens with piston Ys inch times ignition for rear cyiinder.
( 15.8 m/m) to ~ inch ( 19. m lm) be~
fore bottom dead center. ALL "v" TYPE TWIN GENERATORS
Exhaust valve closes with piston 1 /32 Small cam times ignitilln for front cylin~
inch (.79 m/m) to 3j32 inch (2.3 m/m) der. Large cam times ignition for rear cyl-
after top dead center.
inder.
Inlet valve opens with piston 1 /32 inch
(.79 m/m) to Ys inch (3.1 mim) before SPORT MODEL MAGNETO
top dead center. The front interrupter shoe on· the Sport
Inlet valve closes with piston Y4 inch Model magneto times ignition for the front
(6.3 m lm) to Ys inch (9.5 m/m) after cylinder. The front high tension cable
bottom dead center. also goes to the front spark plug.
 To Time Inlet and Exhaust Y alves
Assuming that the explosion of the fuel opening is when the piston is between Y4
has taken place, it can easily be under- inch (19. mlm) and 9116 inch (14.2
stood that there must be an outlet for the mim) before bottom dead center. The
spent gases, at the proper time, in order exhaust valve closes when the piston is
to get the full benefit of the energy ob- 1:;32 inch (.79 mlm) to 3132 inch
tained by the explosion and to prevent (2.3 mlm) past (after) top dead center.
possible injury to the motor. The exhaust The exhaust valve of the Sport Model
valve and its lifting mechanism serves this opens when the piston is between 9 I 16
purpose. The time of valve opening and inch (14.2 m/m) and 7116 inch (II.
closing can best be determined at the point mlm) before bottom dead center. It
when the push rod or lifter pin begins to should close when the piston is I 132 inch
tighten or loosen when operating the valve (.79 m/m) to 3132 inch (2.3 mlm)
stem. This can easily he ascertained by past (after) top dead center.
turning the push rod while the motor is Since the inlet and exhaust cams are
being turned over. mounted on the same timing gear (made
With the "V" type and the single cyl- integral) on all twin motors, the inlet
inder motor, the point of exhaust valve valves do not require independent timing.

Single Cylinder Inlet Timing

All 191 3 and 1918 siJ·gle cylinder mo- valve should close when the piston is from
tors require independent timing of the in- Ys inch (3.1 mlm) to Ys inch (9.5 mlm)
let valves, because the inlet cam is mount-
past (after) bottom dead center. Single
ed on one of the intermediate timing gears.
The single inlet valve should open 3 I 16 cylinder motors prior to 191 3 have auto-
inch (4.7 mlm) before the piston reaches matic inlet valves, therefore require no
top dead center, to top center. The inlet timing.

To Time Mechanical Relief Valve

To assure releasing the exact volume of and oil vapor into the crank case and cyl-
crank case compression ·1t the proper time, inders, thereby lubricating all the moving
all motors are fitted with a relief or breath- parts on the interior of the motor.
er valve. All twin motors beginning with The port in the sleeve of the relief valve
the 1914, but excluding the EH model, ( 1915 to 1922) must be open between
are fitted with a mechanically operated ro- 1/16 inch (1.5 m/m) and 3132 inch
tary relief valve. As the pistons descend (2.3 mlm) when the FRONT piston is
in the cylinders a cert"lin amount of com- on either top dead center. This port opens
pression is formed in the crank case. Some gradually when the motor is turned in the
"\''' Twin motor with <·uta"·ay gear <'0\·er, showing how 19Hi to 1'.122 twin magneto
outlet for this compression must be pro- direction it runs, and closes when the piston
model!'< should he ~et ae<'ording to gpar marlu~ vided for, in order that the motor can func- has reached bottom dead center. All sin-
tion properly. The timmg of the relief gle cylinder motors (except 21 CD), the
IllustJ'ation No. 1 valve controls the lubricating system to a EH motor, and all twin motors prior to
large degree. When the pistons rise in 1914, are fitted with an automatic relief,
the cylinders the relief (breather) valve or breather valve which, of course, re-
closes and causes the piston to create a quires no hmmg. · Single cylinder model
partial vacuum in the crank case and cylin- 21CD, should be timed according to 1915
ders. This partial vacuum draws the oil instructions as outlined above.
 To Time Spark Ignition Timing for Fast "500," "M," "A"
When the fuel chaqe is properly com- plode and expand, forcing the piston down- and "E" Type Motors
pressed, it must be ignited. Ignition of ward and giving energy to the rear wheel
of the motorcycle in the form of power. Ignition timing for special built fast mo- ignition timing alone will not make any mo-
the compressed gases is accomplished by a
Since an interval of tim~ is. required for tors should be set with the piston Ys inch tor fast, it must be built for speed in the
storage battery and generator-ignition
ignition to propagate a Harne thru the (9.5 mjm) to 7/16 inch (II. m 1 m) first place.
unit, or by a high tension magneto. Igni-
gases and cause complete combustion, the before top dead center. Remember that
tion, or the electric spark, occurs at the
time when the generator or magneto cir- timing of the electric sparks occurrence is
cuit breaker points are just separating. At always set before the piston reaches its top
this juncture, a high tension (high voltage) dead center on the compression stroke. The It is common practice to set automobile ignition timing with the circuit
spark is induced to jump ktween the spark following paragraphs will enable one to breaker lever retarded, pistons located at top dead center and the circuit breaker
plug points and ignite the highly com- correctly time the ignition for any Harley- points just opening. This method cannot be practiced on motorcycle motors,
pressed gases, causing the gases to ex- Davidson Motor. because the ignition would occur Ys inch (3.1 m/m) late. This, of course,
would cause the motor to overheat and not develop its fullest efficiency.
Magneto Equipped, Standard Solo "V" Twin
High compression solo motors with mag- on the compression stroke. The circuit
neto ignition are timed to spark when the breaker lever must be fully advanced and
piston is I 7/64 inch ( 6.7 m/m) to 5jl6 the circuit breaker points just breaking Circuit Breaker Adjustments
inch ( 7. 9 m/m) before top dead center when timing all motors for ignition. To insure extreme accuracy in ignition Harley-Davidson
timing, make sure that the circuit breaker Generator .. -.020 inch (.51 m/m)
Magneto Equipped, Sidecar "V" Twin points are set according to the manufactur- Remy model 250
Generator ... -.020 inch (.51 mlm)
To time low compression sidecar motors pression stroke, with the circuit breaker ers specifications. An adjusting wrench
Remy model 235
with magneto ignition, set the piston 13,164 lever fully advanced and the breaker points fitted with a thickness gauge accompanies
Generator ... -.020 mch (.51 m1 m)
inch (5.1 m/m) to 17j64 inch (6.7 just separating. each ignition apparatus. If such a gauge Bosch magneto-. 0 15 inch (.4 m/m)
nt/m) before top dead center on com- is not available, adjust the breaker points Berling magneto-.0 18 inch (.46 mlm)
according to the following data: Dixie magneto-.020 inch (.51 mlm)
Generator Equipped, Standard Solo "V" Twin
High compression solo motors with gen- inch ( 7.1 m/m) before top dead center
erator ignition should be timed when the on the compression stroke. Reasons for Advancing and Retarding the Spark
piston is 15!/64 inch (5.9 m/m) to 9132 Theoretically the proper time for ex- inch (3.1 mlm) past top center on the
ploding the charge is at ~op dead center on power stroke, and considerable energy will
Generator Equipped, Sidecar "V" Twin the compression stroke, when the charge is be lost on account of the lapse of time be-
compressed as much as it can be. How- tween the spark and complete explosion.
Side car motors equipped with generator 13164 inch (5.1 m1im) to 17 64 inch ever, there is a slight lapse of time between Then again, running the motor at slow
ignition should be timed when the piston is (6.7 m/m) before top dead center. the sparking and explosion. When the speed with an open throttle and fully ad-
spark occurs, it first ignites the charge vanced spark will result in injury to the
All Single Cylinder Motors around the spark plug points. This flame motor in time, because complete combus-
then spreads through the rest of the mix- tion of the charge will take place before
Time all single .cylindci motors (except vanced and the breaker points just break- ture, forcing ·the piston downward. The the piston has reached top dead center on
21 CD) when the piston is 3/ 16 inch ing. The 1921 CD, c:>mmercial single time between the spark and complete ex- the compressie>n stroke. The effects of
(4.7 mlm) to y.j inch (6.3 mlm) before should be timed with the piston y.j inch plosion of the mixture is very short, but it this can be more easily noticed in the
top dead center on the compression stroke, (6.3 mlm) to 9132 inch (7.1 m m) can easily be understood that as the speed form of a knock, when driving at low
with the circuit breaker lever fully ad- before top dead center. of the motor is increased, the spark should motor speed with an open throttle on a
be advanced. For this reason, the time of hard pull. Therefore, to get the full effect
Sport Model Ignition Timing ignition is made adjustable with the use of of the explosion, the spark should occur
the left grip. slightly before top center on the compres-
Time all Sport Model motors for igni- center on the compression stroke. On the If the motor is run at high speed with a sion stroke.
tion when the piston is Ys inch (9.5 m/m) magneto models, the front interrupter shoe retarded spark, the spark will occur when The time of sparking is controlled by
to 7 I 16 inch (II. mlm) before top dead times for the front cylinder. the piston is I I 16 inch ( 1.5 mlm) to Ys turning the left grip to the right or to the
 Do not form the impression 1 rnm the
1<11. depending on the 't'rcd of the motor generator gears remain to be set. generator gear, and intermediate worm
and "!tether or not un<h· a h~td """· If above explanation that tt is necessary to Place the generator gear and key on gear line up exactly true. Pay special
the abo1e is understood. ihe !ell grip will carry the spark in retarded position when- the generator shaft, fit the washer and attention to this because if one of these
al11·«ys bP carried in tk proper position. draw up the LEFT HAND clamp nut gears is just one tooth from the proper
ever clriving slowly. D > not do this un-
l~unning the motor accordingly will mean temporarily. Remove the distributor cap position, the point of ignition will be off
added life, because the f xplosion is takmg less the motor is pullin~ hard at a low from the generator. Turn the generator Y4 inch ( 6. 3 mim), which would have
place when the piston i5 ;., the proper posi- motor speed. drive gear backward or to the left until the a decided effect on the running of the
tion. small cam just touches the fibre block on motor. After having the gears lined up
the circuit breaker lever. This is very im- properly, securely tighte'l the generator
portant because the generator drive gear gear clamp nut and fit the split rings and
To Time Model 2 3 5 Generator for the First Time and circuit breaker cam are geared three collars on the gear studs.
to one respectively. Place the intermedi- As a matter of safety, check over the
\Vhen a model 2 35 generator is filled Be careful when selling this cam, not to ate generator gear on the stud so that the timing of the ignition following prevtous
to a motor for the fnst time, gear marks use the wrong cam for the cylinder that is marks on the generator r;ear, intermediate instructions.
cannot be referred lo. to gel the timing being timed. The small cam times the
correct, because the interrupter cam i3 front cylinder while the large cam times
loose on the shaft and must be set for that
the rear cylinder. After the cam has been
particular ;,.,olor. Proceed to time the
generator by fits! placing all the gears with
properly set and securely clamped, check To Time the Harley-Davidson Generator on "V" Type Twins
marks in line in their respective places. An over the timing and if it is 0. K., place
tnspection will prove that the front piston the high tension distributor segment over Owing to the circuit breaker cam and be possible to time the ignition properly by
is near the top center on the compression the end of the shaft in such a position that the timer shaft being made integral, new lifting the timer base from the generator
stroke. Turn the motor, whichever way the driving pin on the cam lines up with timing instructions are obvious. It will not body and meshing the spiral gear on timer
is necessary, to bring the front piston be- the provided hole in the distributor seg-
tween 7 32 inch (5.5 m/m) to 9 32 ment. Later models have a special clip lo
mch ( 7.1 m m) before top center on the support the distributor segment. The bake-
comr•ression stroke. Remove the bakelite lite distributor cap can then be placed over
distributor cap and the high tension dis- the circuit breaker assembly, it being only
lrtbutor segment. Remove the hexagon nut necessary lo line up the stop of this cap
clamping the circuit breaker cam, and with with the slot in the upp~r rear edge of the
the spectal wrench (see illustration No.2) timer head and securing it by means of the
pry the cam loose from the tapered timer springs. When placing the ignition cables
,haft. Advance the cir•cdit breaker as far into the distributor cap, be sure lo place
as it will go by pushing it forward. Move the short cable, which is· for the rear cyl-
the cam on the shaft in the direction it inder, into the extreme felt boss. The long
runs so that the SMALL CAM is just causing front cylinder cable should be placed into
tlw circuit breaker points to break contact. the extreme right boss d the distributor
Then tighten the cam clump nul securely. cap.

ll!n~tration No.
TL\ -1111 r'1·k(' $.2ii

To Time Model 235 Generator According to Gear Marks

Assuming that the pinion, relief, sec- marks as is covered under: To Time
ondary, intermediate, and intermediate Twin Cylinder Motors According to Gear
worm gears have been set according to Marks, only the generatoc intermediate and
lllustration No.
 tained. These timing in,;tructions if prop- be in the same pos1t1oll while timing as
shaft with the worm gc<ll on the armattne ( .4 rn m). Not<': Th~ full opc:ing of when O<'ing driven by d1.: motor. l11sert
th<' circuit hreak<'r points when p1opcrly erly carried out will be <•ccurate to within
,haft. a 6-inch (I SO. m m) steel scale (ruler)
The generator drive gear and the inter- adjusted is between .020 inch (.S I m m) a small margin. Should the motor be out
of the frame, the cylinder plug (found in into the front cylinder and lay some Rat
mediate compound gear are not marked, to .024 inch (.61 m;'m). With the cir-
object across the vertical cylinder Ranges
however, the remainder of the gears; in- cuit breaker points set as specified (open the cylinder head) may be removed with
to facilitate the reading of the scale. Note
termediate worm (oiler) gear, intermedi- . 0 IS inch . 38 m m) and the marked gears a special wrench, and a steel scale (ruler)
the reading of the scale in this position,
ate, secondary (cam), pinion, and relief in perfect line, hold the small generator inserted in the hole and the results may then turn the motor (clockwise) and note
gears rctain their original markings. \Vhen gear firmly with the thumb of the left be checked as follows: how much the scale rises tmtil it reaches its
all of the marked gears are set properly, hand. Insert the compound intermediate
Advance the spark lever. Rotate the highest point. When the ignition is prop-
i.e., all marks in line, the front cylinder pis- gear by turning it and trying to mesh it
motor in a right hand (clock-wise) direc- erly timed the scale should rise between
ton will be approximately 3 I 6 inch with the generator and intermediate oiler
tion until the small or front cylinder cam IS 64 inch (S.9 mjm) and 9/ 32 inch
( 4. 7 m/m) from top center on the com- gears. The. construction of the compound
just begins to separate the breaker points. (7.1 m;m) for standard solo motors, and
pression stroke. Refer to illustration 3 intermediate gear (one gear being smaller
If it should be necessary to turn motor 13j64 inch (S.I mtm) to 17.!64 inch
for proper gear settings. than the other) allows proper meshing of
backward (anti-clockwise) in order to get ( 6. 7 m:;'m) for sidecar motors. Should
Actvance the timer lever (illustration the teeth at several positions. Do not force
the proper setting of breaker points be sure the readings not check according to these
No. 4) by moving it forward to the full the compound gear into meshing with the
to remove back lash in the timer shaft if figures the first time they are checked, do
any, by trying to turn the timer shaft to not change timing until it has been re-
the left with the hand, as the gears should checked several tiines.

To Time Twin Cylinder Motors According to Gear Marks

Assuming that all of the gears have After the compression relief valve has
been removed, but that no new gears are been properly fitted and timed, place the
to be fitted, it is a simple matter to re- secondary gear on the stud in such a man-
time the motor correctly according to the ner that the mark will line up with the mark
following: Place the pinion gear on the on the pinion gear. In order to get this
fly wheel shaft, and fit the key and the result with the 1914 and 191 S motors,
pinion lock screw. (The lock screw has the motor must first be turned until the
a left hand thread). Fit the compression mark on the pinion gear is in an upward
relief valve in the bronze bushing. On pos1t1on. The secondary gears on all
191 4 and 191 S motors, line up the marks 1915. 1916, 1917, 1918, 1919, 1920,
on the compression relief valve gear and 1921 and 1922 motors have two marks.
the pinion gear. Be sure to place the gear on the stud in
On 1916, 1917, 1918, 1919, 1920, such a position that the other mark will be
1921 and 1922 motors, line up the mark toward the intermediate drive gear. See
of the compression relief valve gear with illustration No. I. The exhaust valve tim-
the mark ("A") stamped in the crank ing can now be checked over and must
case. See "A" illustration No. 3. Be- correspond within the limits already men-
fore fitting this gear, be !<ure that the motor tioned. Fit the drive case after being sure
is in such a position that the mark on the that the marks of the pinion and secondary
driving pinion is in perfect alignment with gear are in line. Then place the inter-
the secondary gear stud and lifter arm mediate gear so that its mark will coincide
lllu:;:tration No. 4
stud as shown in the illustration. It is with the mark on the secondary gear. After
always advisable to check over the timing
the intermediate gear has been placed in
after a gear has been set according to
extent of its travel, as indicating by the other two gears-but keep turning it and marks. We therefore urge that the tim- position, the motor should not be turned
arrow. Since ignition for the front cylin- trying different positions. until it slips in ing of the compression relief valve be again. The intermediate worm gear is
der is in order, select the SMALL END of place freely. After properly meshing the then placed on the stud in such a way that
checked over to see whether it corresponds
the timer cam (illustration No.4) and turn gears put the spl;t lock ring in place; this with the timing mentioned previously in one of the marks of this gear and the inter-
it to the right (clockwise) until it has prevents the gear from coming off of the this article. mediate gear line up.
opened the circuit breaker points .0 IS inch stud and losing the correct timing just ob-
 ·1 he magneto or 2)0 model generator gear are not in line. th~ shaft on!" may When disassembling generator from the against the flat side of the timer shaft
he turned, hccau'c gear mark> must be in motor do not remove the generator drive "8," the flat side of the timer shaft
driYe gear (not the 2 3) or Harley-David-
line to have the timing right. Fit the lock gear unless generator must be entirely dis- should be accurately aligned with the filed
son genera lor) is then lined up with the mark "A" on the outer edge of circuit
washer and draw the damp nul tight. assembled. The hole in the rear of gear
nllemrediate worm gear dter the key has After completing these operations the gear case is large enough to permit the passage ~reaker casting or frame. When aligning
been properly placed in :he keyway of the marks will be in line as shown in illustra- llmer shaft with filed mark on casting, be
of the gear while on drive shaft. Inspect
shaft. If the keyway ol the shaft and tion No. I. sure that the flat •ide of the shaft is to
circuit breaker points before siarting to
the right rear of the shaft center. See il-
time motor, for proper gap which should lustration No. 5.
To Time Single Cylinder Motors According to Gear Marks be .020 inch (.51 m/m) and can be de- When timer shaft is in the above de-
termined by thickness gauge or by the steel scribed position and the marks on the
Place the pinion gear on the Ay wheel with the mark on the gear mounted with
shaft. Turn the motor until the mark the secondary gear. Fit the· other inter- gauge on the back of the generator wrench. pinion gear, secondary gear, and inter-
on this gear is upward. Then place the mediate gear and then the magneto gear Remove the generator intermediate gear. mediate gear are properly lined up, the
secondary gear on the stud so that the according lo marks. When the gears are Rotate the motor until pinion gear marks generator intermediate gear will mesh with
marks of this gear and the pinion gear are set according to marks, all marks visible "A" and "B" are directly in line with the intermediate gear and the generator
in line. Replace the drive case. Turn the will be in line. secondary gear and intermediate drive gear. drive gear. Place this gear in position and
motor until the mark on the gear which These instructions, as already mentioned, See illustration No. 7. secure with split locking ring. After gen-
is mounted with the secondary gear will apply to retiming a motor when the origi- It is very essential that these marks are erator is correctly timed be sure that out-
be toward the intermediate cam gear stud nal gears are used. If a new gear is fitted, acccurately aligned. Every circuit break- side terminal of distributor cap leads to
(toward the rear of the motor). Place time the motor according to piston posr- er casting or frame has a filed mark on the the front cylinder. These terminals being
the intermediate or intake cam gear on the tions, as previously exphined under: To outer edge of this casting. Remove dis- the same length makes it possible for them
stud so that the proper mark will line up Time Inlet and Exhaust Valves. tributor segment and holder, and by plac- to become crossed which would, of course,
ing the edge of a 6 inch ( 150. m/m) scale change the timing. See illustration No. 6.

Timing Ignition for the Sport Model Without Removing

the Generator Drive Gear
Timing Sport Model Ignition When the Generator
Drive Gear Has Been Removed
Inspect circuit breaker points before the outer edge of circuit breaker casting
starting to ti·me motor, for proper gap, or frame. See illustration No. 5. When
which should be .020 inch (.51 m/m) aligning timer shaft with filed mark on
and can be determined by a thickness casting be sure thai the flat side of the shaft
gauge, or the steel gauge on the back of is to the rear of shaft center. When timer
the generator wrench. The generator shaft is in the above described position
drive gear has three keyways, which are and the marh on the pinion gear, second-
placed in different positions, permitting the
changing of timing by I j3 of a tooth,
2 '3 of a tooth or by 1 tooth. Rotate the
motor until pinion gear marks are directly
in line with secondary gear and intermedi-
ate gear. See illustration No. 7. It is FRONT CYLINDER
rABl£
very essential that these marks are accurate-
ly aligned. Every circuit breaker casting
or frame has a filed mark on the outer
edge of this casting after the motor has
once been timed at the factory. Remove
distributor segment and holder, and by
placing the edge of a 6 inch ( 150. m/m)
scale against the flat side of the timer
shaft, the flat side of the timer shaft should
Jlllll'>tnttion No. 5 be accurately aligned to •he field mark on IJlustration No. 6
ary gear and intermediate gear are prop- before top dead center, on cmnpre"ion
erly lined up, try the gmcrator dri\'e gear stroke, with interrupter fully advanccd. It
in each of the keyways, until it slips in is necessary to remove the front foot board Summary of All Motor Valve Timing
mesh, without changing the position of support and the front cylinder plug for
timer shaft or without turning the pinion this operation. After generator is correct- 1912 TO 1916 "v" TWINS SPORT MODEL VALVE TIMING
gear. It is advisable to recheck timing by ly timed, be sure that the outside terminal Exhaust valve opens with piston '% Exhaust valve opens with pistons 7 ' 16
inserting a 6 inch (I SO. mi/m) scale in of distributor cap leads Ia the front cylin- inch ( 15.8 m/m) to Y4 inch ( 19. m 'm) inch (I 1.1 m m) to 9 16 inch ( 14.2
front cylinder to determine whether cir- der. These terminals being both the same before bottom dead cente.-. m/m) before bottom dead center.
cuit breaker points are just beginning to length makes it possible for them to become
Exhaust valve closes with piston I '32 Exhaust valve closes with piston I /32
separate when piston is from Ys inch crossed which would entirely change the
inch (.79 m/m) to 3;32 inch (2.3 m m) inch (.79 m m) to 3 1 32 inch (2.3 m/m)
(9.5 m/m) to 7/16 inch (II. m/m) timing. See illustration No. 6.
after top dead Cl'nter. after top de~d center.
Inlet valve opens with piston I 1 32 inch Inlet valve opens with piston I/ 16 inch
(. 79 m/m) to 3/32 inch (2.3 m m) (1.5 m m) to 3/16 inch (4.7 m/m)
before top dead center. before top dead center.
Inlet valve closes with piston 1;8 inch Inlet valve closes with J:iston 7/16 inch
(3.1 m/m) to !:4 inch (6.3 mim) after (11.1 m/m) toYs incJ. (15.8 m/m)
bottom dead center. after bottom dead center.
The sport model breather valve is made
1917 TO 1922 "v" TWINS, integral with the secondary gear, therefore
All Standard 61 ", Standard 7 4", "500", it does not require special timing.
"A" and "E" Motors.
Exhaust valve opens with piston 19/32 Miscellaneous
inch (IS. m/m) to 23,132 inch ( 14.2
m/m) before bottom dead center.
TWIN BERLING MAGNETO
Exhause valve closes with pistons I / 16
inch ( 1.5 m;m) to 7/64 mch (2.7 m/m) Lower cam (or shoe) in interrupter
after top dead center. . housing times igni1ion for front cylinder.
Upper cam (or shoe) in interrupter hous-
Inlet valve opens with pistons S ;'32
ing times ignition for rear cylinder.
inch (3.9 m/m) to 19164 inch (7.5
mjm) before top dead center. TWIN DIXIE MAGNETO
Inlet valve closes with piston Y4 inch Cam No. 2 times ignition for front cyl-
(19. m/m) to U inch (22.2 m/m) inder. Cam No. I tim.~s ignition for rear
after bottom dead center. cylinder.

SINGLE CYLINDER VALVE TIMING TWIN BOSCH MAGNETO

1912 TO 1918 Interrupter shoe No. 2 times ignition for

front cylinder. Interrupter shoe No. I
Exhaust valve opens with piston Ys inch times ignition for rear cylinder.
(15.8 mjm),to Y4 inch (19. mlm) be-
fore bottom dead center.
ALL "v" TYPE TWIN GENERATORS
Exhaust valve closes with piston I /32
inch (.79m/m) to3j32inch (2.3mlm) Small cam times igniti<Jn for front cylin-
after top dead center. der. Large cam times ignition for rear cyl-
inder.
Inlet .valve opens with piston I /32 inch
(.79 m/m) to Vs inch (3.1 m/m) before SPORT MODEL MAGNETO
top dead center.
The front interrupter shoe on the Sport
Inlet valve closes with piston !:4 inch Model magneto times ignition for the front
(6.3 m/m) to Ys inch (9.5 m/m) after cylinder. The front high tension cable
bottom dead center. also goes to the front spa~k plug.
Illustration No. 7
 to cause InJury to the generator and to and not capable of furnishing current. it

Service Dept. Bulletin burn out the lamps. Therefore, even

though the storage battery be exhausted
must be left in its place, connected up 1f
the machine is used.

No. 74.-july 1, 1921 Harley-Davidson Motor Co., Milwaukee Do Not Overload the System
Be careful not to add electncal acces- designed for a definite load. The only
sories of any kind nor to equip the lamps exception to this is the use of a sidecar light
with higher candlepower bulbs than those and .this may not be over 2 candlepower.
regularly furnished, because the system is

Important Instructions
Stop your motor ONLY by turning off Be sure to see that your generator ad-
the ignition switch, which is the lower vance lever advances all the way down. It
;witch in the switch box. Failure to turn is equally important that the circuit breaker
this switch off will cause complete dis- cannot be advanced too far or forced. If
charge of the battery in a short time ( 45 the control rods are adjusted so that they
are too long and too much pressure is ap-
minutes). Turn the switch off, regardless
plied when the circuit breaker is already
of how short the stop is. After switching fully advanced, the circuit breaker will be
off the ignition, be sure to remove the forced out of line and change the gap of
switch key. This will prevent meddlesome the breaker points. When this takes place,
persons from tampering with the switch, the motor will miss with a fully advanced
thereby causing discharge of the battery. spark and sometimes stop entirely.

Illustration No. 1 The Lighting System

General w1nng diagram for electrically equipped models with type 250 Generator.
Note-Soll!e l,~l6 ,g~nerato~3 h;:v,~ tw~ wires leading to th·e terminal. cl~mp The headlight contains two bulbs, the definite number of lamps. Do not add any
connechon 10, dlustrahon 5 while the other one leads to the circuit bright bulb a twenty-one candlepower lamps, with the exception of one for the
breaker. These wires can be connected either to top, bottom nitrogen, and the dimmer bulb a two can- sidecar, and this bulb mnsl not be over
or upper right hand binding post of the ignition switch.
dlepower tungsten. The tail light carries two candlepower.
This bulletin is based upon instructions erators in service, it is suggested that this a two candlepower tungsten bulb also. The If any of the lamp bulbs need renewal,
issued during the past five seasons on the bulletin be filed for ready future reference lighting switch has three positions; all off, be sure to replace with lamps of the same
care and adjustments of the model 250 if it is not needed immediately. The igni- bright headlight and tail light, and dim candlepower. This is ext~emely important;
generator used on 1915, 1916 and 1917 tion and lighting system will require at- headlight and tail light. 6 to 8 volt bulbs should be used. In or-
models. The current instruction book does tention from time to time and the instruc- Never let the machine stand with the dering, specify single point bulbs. The
not cover this type generator and since tions and suggestions herein will frequently bright headlight turned on or the battery sidecar light, or the trouble lamp connec-
there are many thousands of such gen- be found valuable. will be exhausted in a short time. The tion, is made by insertmg the plug into the
generator and battery are designt>d for a terminal box on the battery h--x.
Model 250 Generator
The model 250 generator generates low The generator supplit's current directly Key to Wiring Diagram on Page 3
tension 6 volt direct current for the lights, to the lamps, horn, and for ignition; the
surplus current keeping the storage battery
I , horn switch; 2, high tension post for points; 14, circuit breaker adjusting screw;
signal system, and for charging the bat- front cylinder; 3, primary post and wind- 15, circuit breaker cam (small end times
tery. This current is "stepped up" or properly charged. The latter provision is
ing for front cylinder coil; 4, high tension for front cylinder) ; 16, front field coil;
necessary, for the battery in 'urn supplies
transformed into high tension current for post for rear cylinder; 5, primary post and I 7, coil primary distributor points; 18,
current for the lights wlwn the motor is
ignition by the spark coils on top of the not running, and for ignition when starting winding for rear cylinder coil; 6, positive lighting switch; 19, horn fuse; 20, ignition
or main brush; 7, commutator, cousisting of or manual switch: 21, lights fuse; 22, tail
generator. the motor.
12 segments; 8, third or regulating brush bulb; 23, battery positive post; 24, stor-
Why Battery Must Be Kept in Circuit (non-movable); 9, negative or ground age battery; 25, battery negative post; 26,
brush; I 0, condenser, located in the gen- dim headlight bulb; 27, bright headlight
The battery acts as an accumulator and erator. Without the battery in circuit the bulb;· 28, horn; 29, distributor blade for
erator for convenience; I I , rear field coil;
governor; and keeps the voltage down to 6 voltage raises above 20 voits at 60 miles
12, circuit breaker lever; I 3, contact spark coil primary windings.
volts regardless of the speed of the gen- per hour (96 km) which ic sufficiently high
 When Lights Do Not Burn While Motor is Idle
Failure of the lamps to bura while the break, also look over the cooHteclicJb to sec
motor is not running, generally indicates it any are loose or broken. If the hailrry
that the battery is discharged or that the is discharged, have it recharged immediate-
lighting fuse is burned out du(> to a defect ly (see instructions on rech3rging in bat-
or short circuit in the lamp wi.-.ng. In lhe tery pamphlet) and if the trouhle \vas due
latter case, remedy the defect before re- to a loose or broken connection, or a short
placing the fuse. See that the fme is held circuit in the wiring, remedy before re-
firmly in the holder. Examine the sliding placing. See reasons for di;chargcd bat-
contacts of the lighting switch as shown in tery, pages 6 and 7.
illustration and explained on page 7
After some riders had complal!led that
under inspection of ignition switch in-
their storage batteries had become di~­
structions. The construction of the light- charged, investigation has shown the cause
ing and ignition switches is practically alike. !o be excessive or careless use of the lights.
To ascertain whether th1· hatterv .is dis- If the motor is not running, the use of the
charged, test it with a l,ydromete~. The large headlight will completely exhaust the
subject of battery care is covered in another storage battery in a very short time. A
pamphlet, copy of which will be furni~hed fu•e is mounted in the switch box in the
upon request. If the fuse and battery are lighting circuit between the lights and the
found to he in good concl:t;on, the trouble battery to prevent discharge 'tad possible
lies in the lamps or in the wiring. Inspect ir.jury to the battery should a short circuit
the bulbs and examine the wiring for a occur in the lamp wiring.

When Replacing a Fuse

c In case a fuse burns out, do not use a switches or wiring, and discharge the bat-
0
·.::: piece of wire or any other substitute. tery. This holds true of both the horn and
~.
:1
Locate the cause of the trouble, and re-
place the fuse with a new Harley-Davidson
lighting fuses. In an emergency, if the
fuse in the lighting switch has burned out
= fuse. By using a substitute, the short cir-
cuit that was responsible for the fuse burn-
and the short circuit has been remedied, the
horn fuse can safely be used in the lighting
ing out may cause serious injury to the system.

Faulty Lamps
If all the lamps but one burn, the fault may be due to a burnt out bulb, and the
lies in that particular lamp, or in the wiring test of inserting a good bulb in place of
thereto. It may be that the sliding contact the suspected one immediately suggests
~nr that lamp has been forced and is mak-
itself. If the good bulb fails to burn, the
Ing a poor connection with the binding pole
wiring and connections to the lamp should
head. See ignition switch instructions,
page 7. Failure of a lamp to burn be carefully examined.

If Both Headlights Fail to Burn

If the tail light burns and both head to the lamp body. If it is necessary to
light ou~bs do not, the trouble must lie examine the reflector, use the greatest care
either in .the bulbs. the wiring, the lighting not to touch the reflecting surf ace.
switch, or the double connector in the head- To open the lamp for replacing a bulb,
light. Sometimes t~ouble with the small loosen the screw in the bottom of the front
headlight is caused by failure of the re- bezel and remove both screw and bezel.
flector to make a good connection or ground Front of lamp will then slide off.
 the battery ground wire on the outside of starting, the hallery ground wire must be
Fluctuating Lights the battery box should be disconnected, reconnected at once to put the battery 111
If the lamps burn brightly when the from the battNy to the ignition o~witch. See and the motor turned over as before. After circuit or the generator may be ruined.
motor is running at moderak speed. hut that the lower fuse is O.K., that it IS held
vary and flicker when the motor is running securely. and that the wire connections on
slowly, the cause is a discharged battery the ignition switch binding post; are firmly Caution
or a poor circuit between the ballery and If the ballery needs outside charging, wires other than the spark plug wires, dis-
clamped. Examine the sliding cenlacts of
the lights at one or more of the following or extensive allention be sure to take it to connect the ballery ground wire on the out-
the lighting switch as explained and illus-
points: your dealer or a competent charging station side of the ballery box to prevent burning
Carefully inspect the ground w1re trated on page 7. Under in"pection where intelligent, experienced service is
out. a fuse or short-circuiting the bauery.
clamped on the outside of the battery box of ignition switch instructions. Lxamine obtainable if no dealer is convenient. Do
and leading to the negative pole. In like · the wiring .leading to the lamps and the The ballery ground wire should be recon-
not let anyone work on the ballery who is
manner examine the positive wire leading connections on the inside 0f the la.ops not experienced in this particular line of nected before the motor is started for the
work. Before disconnecting any of the reason already explained.

The Warning Signal

The warning signal or hom ':an only be is replaced. If the horn sounds continually To Test Whether the Generator is Charging the Battery
sounded while the ignition switch is dosed while the ignition switch is turned on, there If the storage hallery is exhausted and chine. If arcing occurs, the circuit is 0.
or turned ON, therefore, onl} when the is a short circuit either in tl1c horn swit-:h it is suspected that the generator is not K. This is an important lest, for if the
motor is running if the rider use·; th~ manual on the handlebar, or in the wire from the charging, make the following tests: Start circuit between the generator and battery
ignition switch as he should. This feature horn switch to the horn. the motor in the regular way; then disc~n­ is not closed, the excess current produced
discourages meddling and prevents dis- necl the ground connection. If the motor by the generator cannot keep the battery
If the horn cannot be wunckd while
charge of the battery through unnecessary continues to run, the generator is furnishing charged and the high voltage may cause
the ignition switch is on, remo'e the horn
use of the horn. current. If the m.otor slops, the generator injury to the generator.
cover and make sure that the vibrator con-
It is well to get into the habit of is faulty. During this test the motor must
tacts are not pitted or stuck together. and If no sparking occurs at the ground wire
attempting to sound the horn after not be run at a speed exceeding 2() miles
that there is a clearance of about ! {; 1 inch according to the above test, the circuit be-.
stopping the motor to make sure per hour (32 km) for the reasons ex-
(.4 m/m) at the points when the armature tween the generator and batt~ry is not
that the ignition switch has been is pressed against the diaphragm stem. If plained under the heading Why Ballery
closed. In that case examine the battery
turned to the OFF position. the points are not at fault, see that the wir- Must Be Kept in Circuit. ground wire, likewise the positive wire
ing from the switch box to the horn and After determining whether or not the leading from the battery to the ignition
A fuse is placed in the horn circuit so
generator is charging, it is easy to ascertain switch. Be sure that this wire is firmly
that if a short circuit should occur in the from the horn switch to the horn is not
whether the circuit between the generator clamped to the switch binding post.
horn or in the wiring thereto, from any damaged, that the fuse is 0. K. and not
and battery is ·closed by rubbing the ground
cause, the ballery will not be discharged. blown out or held loosely in the ruse holder. The best way to determine the exact
wire against some metallic part of the rna-
This fuse will burn out in the case of a charging condition of the generator is to
short circuit and, of course, with a burnt Do not use any electric horn except that
install a suitable ammeter in the circuit.
out fuse, the horn cannot. be sounded. The supplied regularly with this model. since The ammeter shown in the illustration was
cause of any such short circuit must be some horns consume an excessive amount designed for motorcycle duty and is a
found and remedied at once before the fuse of current. thoroughly reliable instrument. The wiring
and special mounting make it easily
adapted to the machine.
To Run With a Discharged Storage Battery
The motorcycle may be run with a dis- turn over the motor rapidly. It may tak.· To connect an ammeter in the circuit, re-
charged or disabled battery, but it is very move the battery negative or ground wire
several strokes of the starter to start the
important to have the battery recharged or motor under these conditions because the from the battery box and connect the posi-
repaired immediately, because if the hallery spark is being taken directly from tlw gen- tive ( I ) post of the ammeter to the bat-
is left in a discharged or disabled condition erator. tery wire. Then ground the negative
for any length of time, it will be ruined. If after three or four attempts it JS found ( --) post of the ammeter on the battery
box, under the cover screw.
If the storage battery is disabled, turn that the motor will not start by means of
off all lights before attempting to start the the starter, it is a good plan to put the gear When the generator is working properly
motor. Prime the motor, as per manual in- shifting lever in second or low geM, engage the ammeter should show a charge of from
structions given for starting the motor in the clutch, raise the exhaust valves, push I he 3 to 4 Yz amperes. If it does not show this
cold weather. See that the spark plug machine at a good pace, nm alongside. Illustration No. 3 output, refer to instructions under, "To
points are clean, and adjusted to .025 inch drop the valves, and jump on as soon as I he JK 123-Ammeter Complete with Clean and Reseal Brushes and Commu-
(.64 mjm). Switch on the ignition and motor starts. If the machine will not start, mounting and wiring. $5.50 tator."
 If the ignition switch hi\s hcl"n forced is turned to the ON po,ition. In that case dealer or Exide battery service station. If and should be referred to the nearest Exide
by applying too much pressure on the key, remove the switch and mak<' the inspt'ction it is not convenient to do this, the battery l>altery service station for inspection and
the sliding contacts may have been Lent of the sliding contacts as shown in the ac- can easily be tested as follows: Have the repaus.
and the circuit is not closed when the switch companying illustrar_ion. battery charged. After charging tape the If the above tests prove that the gen-
ends of the wires. Take a hydrometer
erator is charging, that the circuit bet ween
To Inspect and Correct a Forced Ignition Switch reading and make note of the specific
the generator and battery is closed, that
gravity of each cell. Set the battery in a
Be sure that the sliding contacts bear blackened post heads are a sure indication there is no short circuit, and that the bat-
cool, clean, and dry place for twenty-four
with sufficient pressure a~ainst the post of a poor circuit in the ignition switch. tery is not at fault, the output of the gen-
hours; then take a second hydrometer
h.. ads to insure a closed circuit. Pitted or To correct a forced ig~ition switch •e- reading of each cell. If the battery is 0. erator most likely is not normal due to a
move the pitted binding post; thcu turn K., the readings will practically check up dirty commutator and brushes. In that
the sliding . contact over the countersunk with the previous readings. If there is a case, clean and reseal the commutator and
hole into which the binding post heaJ fits, decided difference, the battery is at fault, brushes as explained under that heading.
and force the sliding contact into the hole.
This will increase the tension to in~ure a
closed circuit. Replace the binding post Circuit Breaker and Distributor
and make another inspection to see that Inspect the circuit breaker points at
the sliding lingers make proper contact and "I 3," see accompanying illustration, every
cannot slide beyond their respective binding 1500 miles (2400 km) to see that they
pole heads. If these tests prove tl,ai the are in good condition ;1nd not pitted or
generator is charging and that the circuit
between the generator and battery is closed,
0 burned. At the same time examine the
distributor terminals "6" as well as the
and if any existing fault has heen corrected, two points on the distributor blade "4."
the discharged condition of the battery is
most likely due to excessive use of the
lllusttation No. 4 lamps or failure to turn olf the ignition Key to Illustration No. 5
How to Inspect Ignition Switch Contacts switch. The remedies are apparent.
I. spark coil; 2, coil primary terminal;
To Recharge a Dead Battery 3, positive brush; 4, distributor blade; 5.
A discharged battery, if otherwise in outside source. After riding a rea- circuit breaker ring; 6, distributor blade
good condition, can be recharged by suf- sonable distance see that the battery 18 points; 7, rear cylinder contact blade; 8.
ficienl daylight riding at a reasonable is really charging, by turning on the lights front cylinder contact blade; 9, conduit
speed. The output of the generator is while the motor is not running. If they do and terminal assembly; I 0. main circuit
greatest at a speed of 25 to .30 miles per not burn, the battery is charging very knife connection (this must be connected
hour ( 40 to 48 km). Below I 0 miles slowly or not at all. In such event there securely) ; I I, top sliding switch blade;
per hour ( 16 km) the battery furnishes the is a leakage of current, the generator out-
12, circuit breaker adjustiug screw; 13,
igmllon current. However, the best way put is low, or the ignition switch is not
circuit breaker points; 14, sliding switch
to charge an exhausted battery is from an making good contact.
contact assembly; 15. circuit breaker cam
If Battery Discharges Without Apparent Cause 16 (small end times for front cylinder) ; 16.
If the battery discharges with normal liners. Be sure that the insulation of the circuit breaker lever; I 7, distributor blade
use of the lamps and correct use of the positive wire is not damaged. Test for spring; 18, ground or negative brush; 19,
igniticn switch, and provided the generator a short circuit between the generator and third or regulating brush.
is charging according to the previous test, battery as follows: Have both the ignition
one of the following conditions applies: and lighting switches turned to the OFF
Lubricating the Generator
There may be a partial short circuit be· pos1llon. Disconnect the ground wire on
tween the battery and the ignition switch. the outside of the battery box and rub it Never use thin oil on any part of the
This short circuit may be due to a satu- against some metallic pari of the machine. Remy Generator. Once a year put a
rated battery and box. If so, clean both If sparking occurs, there is a short circuit
thorou3hly with household ammonia, or and the just mentioned suggestions should little vaseline about half the size of a pea
baking soda, and fit a new ~el of wood be applied. on the lop of the fibre block of the circuit
breaker lever and insert a limited
How to Test a Suspected Battery quantity of vaseline in the ball bearing at
If this lest and the above explained con- be at fauh. In that case it is best to gel Illustration No. 5 the left end of the armature shaft.
ditions do not apply, the battery its..Jf may in touch with the nearest Harley-Davidson
 covNed with grease or dirt. Clean the ful not to get a finger caught in the drive
To Clcan·:circuit l3rcaker Points commutator with a piece of clean soft cloth chain. When cleaning the commut<Jtor
To clean the circuit breaker points, it fell gasket before replacing the circuit by holding the cloth on the commutator see that the brushes have a good and clean
will. of course, be necessary to remove the breaker cover. while the motor is running slowly. Be care- bearing surface against the commutator.
chain guard and the breaker cover on the If the circuit breaker points at "I 3"
generator to expose the circuit breaker are slightly pilled or burned, they should Causes of Commutator Wear
be cleaned with fine s<Jndpaper (never use Commutator wear can generally be the commutator if the machine is used in
parts.
emery cloth). traced to one or more of the following very sandy or dusty country, especially if
When removing the spider, hold a screw When cleaning the circuit breaker points three causes: Hard carbon brushes, sand and dust can get under the circuit
dri\·er against the circuit lm·akcr plate near or making any adjustments on the gen- brushes bearing with too much pressure breaker cover.
the lop so as not to damage the sliding erator, extreme care should be exercised so against the commutator, or failure lo clean
m·itch contacts. Be sure to replace the as not to bend any of the sliding contacts.
Hard Carbon Brushes
To Adjust the Circuit Breaker If a commutator is found grooved and brush cannot be seen with the eye. There-
inspection of the brush tension, as described fore, when a faulty brush is suspected, all
ll1e fibre -block on the circuit breaker slowly by means of the rear wheel. (trans-
hereinafter, prooves that the springs are three brushes and brush holders should be
arm is subject to a certain amount of wear mission must be in high gear and the clutch
properly adjusted and the mechanism on replaced. Never replace a brush without
in service and after several thousand miles engaged), until the steel cam hits the fibre
the inside of the circuit breaker cover is replacing the holder because it is very
it will be necessary to readjust the contact block and separates the contact points
clean, hard brushes are the cause of the important to have a perfect circuit between
points to make up for this wear. As a mat- "I 3" and as far as they will go. The lock commutator wear. the two, and to obtain this circuit very
ter of precaution, an inspection and ad- nul should then be loosened with the gen- carefully soldering and tinning are re-
justment, if necessary, should be made, say erator wrench, and the point "12" screwed The reference to hard brushes does not
quired. The cost of a brush holder is less
every 1500 miles (2400 km). mean that the brushes are as hard as a
out by turning the hexagon head until it is than the cost of the labor required to solder
It is necessary when adjusting these piece of steel, but rather that the composi-
just possible to insert the flat steel gauge and tin a new brush lo an old holder. Usc
points that the fibre block is resting tion of the material in the brush lacks
on the wrench between the points <'I "I 3." onlJ; the genuine product when renewing
on the center of the steel cam "15" so
After the points are correctly adjusted, graphite. The amount of graphite in a brushes.
that the points at "13" are separated as
far as they will go. If the steel cam "I 5" carefully tighten the lock nut and measure
is not in contact with the fibre block, it the clearance again to be sure that the ad-
To Fit and Adjust New Carbon Brushes
will be necessary lo turn over the generator justment is correct. Trim the new brushes lo conform with brush with the coarse side towards the
the radius of the commutator. Place the brush.
brush holders on the studs. Cut some 00
Care of the Distributor Points sandpaper (never use emery) into strips
After the sandpaper has been properly
placed, bear down lightly on the brush
The distributor blade "4" works both In rare cases, the points "6" and both Ys inch wide (9.5 mim). Place this holders and pull out the sandpaper.
ways between the points "6." The dis- points on the blade "4" may require clean- sandpaper between the commutator and
tance between the points on the distributor ing by drawing a piece of fine sandpaper Be careful when pulling out the sand-
between them, taking care to see that thP paper not to damage the near edge of the
blade and the points should be twice the
contacts are not bent or sprung during t!vo brush. Follow the radius of the commu-
thickness of the gauge on the generator
process. The blade "4" should be;,r with tator with the sandpaper <>s much as possi-
wrench. ble. Refer to illustration. To obtain a
equal pressure on points "6."
good bearing of the brush against the com-
Care of the Commutator mutator may require ·pulling the strip of.
sandpaper through several times, but the
A commutator which is grooved. show- in time render the commutator useless. A
operation should be repeated only as often
Ing that the brushes are gradually cutting careful periodic inspection for wear, and
as necessary.
into it, should not be neglected. Inspection the application of the proper remedy when
of the commutator is recommended when- wear is found will make renewal of the When trimming the forward brush, be
ever the circuit breaker or distributor points commutator unnecessary during the life of sure to pass the sandpaper bei ween the
are inspected and adjusted. Neglect will the machine. lower bearing housing support and the com-
mutator if the strip is long enough, and
To Clean and Reseat Brushes and Commutator pull upward and backward so that the
edges of the brushes will not be trimmed
Inspect the commutator l'nd brushes every dark brown or copper colored, and if found Illustration No.4 off. When trimming the two rear brushes,
month or every 1500 miles (2400 km). If in that condition should not be touched. How to clean and seat brushes. Have pass the strip of sandpaper under the upper
the commutator is found blackened, it Carbon from the brushes will blacken the the sandpaper follow the radius of
the <Commutator as much as possible housing support, then under the upper and
should be cleaned by burnishing with 00 commutator, therefore do not clean the lower brushes, and draw the sandpaper
to prevent trimming off the edges of
sandpaper. Normally, the commutal0r is commutator because it is black unless it is the brush. towards the front.
 J\ftrr the brushes !rave been properly instructions on adjmtinr- the hruslr springs
seated. remo\ c ail I races of grit by wiping
Poorly Fitting Circuit Breaker Cover
refer to instructions under Proper Pressure
the commulalor with a gasoline soaked rag If grit and dirt are found on the circuit entrance of dirt or grit. If dirt can enter,
of Brushes against Commutator and To breaker and distributor mechanism when-
and then drawing plain writing paper he- it will wear the brushes and commutator
1\djust Tension of Brush Springs. ever the circuit breaker cover is removed,
tween the brushes and commutator. For unnecessarily and may get on the breaker
examine the felt washers and note whether and distributor mechanism, causmg Irregu-
Proper Pressure of Brushes Against Commutator the cover is bent. The cover must fit well lar running of the motor.
enough against the generator to prevent the
The proper brush pressure against the is balancing. Never let a brush hear with
commutator is six ounces. Determine the greater pressure, nor have it considerably
proper pressure with a small spring scale or less. T 00 much pressure will cause quick
To Secure Drive End Bearing Housing
hook the end of the brush holder with a
wear of both the commutator and brushes,
piece of wire to a scale graduated to
ounces. Th e exact brush pressure is de- while too little tHessure will aflect the con-
termined at the point when the brush is ductivity of the brush and interfere with
just leaving the commutator and the scale the current output of the generator.

To Adjust the Tension of the Brush Springs

\\'hen inspection proves that the brush or if the pressure is too little, give the coil
spnngs are Improperly adjusted, the fol- spring another half turn.
lowing instructions should be applied: The
colter pins holding the brush holders on If it is impossible to obtain the proper
their studs should he withdrawn, so that pressure by turning the spring one-half turn
the holders and springs can be removed one way or the other, proceed as follows:
from the studs far enough to release the Release the spring entirely by withdrawing
springs from the slvts in the studs. A pis- the brush holder part way from the stud;
ton pin lock pin, or something similar to it, then replace the brush holder and spring
should then be placed through the outside on the stud without having any pressure on
opening of the brush holder and over the the brush. With a pair of narrow-jawed
straight end of the spring. Wind up the pliers take hold of the end of the spring
spring to the proper tension by turning the which bears against, or is hooked onto, the
piston pin lock pin and pushing the brush brush holder. Pull this end of the spring
out until the proper tension has been ob- I<-- WIDTH OF OLD PLATE~
holder back over the stud. When this is
done, the spring will have to follow and tained and cut off the spring, leaving just It sometimes happens that the drive end take off and discard the bottom plate.
no trouble will be experienced if the slot enough of the spring to overcome ali danger bearing housing (right end plate), of a Loosen the drive end bearing housing clamp
of the lock pin lines up with the slot in the of it slipping of! the brush holder. Be sure model I 5 or 250 Remy generator works screws, pull the housing upward as far as
brush holder stud. to try the pressure of the brush from time loose regardless of how securely the screws possible, and while holding it in this posi-
Again test the tension of the brush to time while pulling out the spring so that are drawn up. To prevent this, we fur- tion, again tighten the clamp screws. With
against the commutator. If the brush no more is pulled out than is necessary. nish a steel plate to fit under the generator a file carefully trim off the bottom of both
seems to be bearing with too much pres- After the spring has bePn properly ad- that serves as a support to both end plates end plates until they are flush with the bot-
sure, release the coil spring one-half turn, justed, replace the cotter pm. and pole piece assembly. This plate holds tom of the pole piece assembly, (body of
the drive end bearing housing secure. The the generator). The steel bottom plate is
To Repair a Grooved Commutator plate is listed under factory No. H.K-122 then secured with the two screws that se-
A grooved commutator can be repaired down, remove all copper chips from be- and sells for I 0 cents list. When you cured the original bottom plate. Draw
if the groove is not more than ~';.:inch ( 1.5 tween the segments and reassemble the in- have occasion to remove a generator, fit one all screws tight. Make sure the drive end
m m) deep. Place the complete armature struments. Careful inspection will show of these plates. Instructions for fitting the bearing screws are tight by drawing up on
in a lathe, holding it between centers, and that the brushes have only a little bearing plate are as follows: them with a screw driver every week or
turn down the face of the commutator. surface on the commutator, necessitating Remove the generator from the motor, two.
When turning the commutator down, be retrimming of the brushes as already ex-
sure to take off light cuts at a time, and plained. If a commutator, necessitating When New Parts Are Needed
under no circumstances turn o fl any of the retrimming of the brushes as already ex- Genuine parts for Remy generators used If you are a dealer and have a generator
shoulder of the commutator which is plained. If a commutator is cut too deep on Harley-Davidson motorcycles are sold needing extensive repairs that you are not
toward the armature end of the commuta- to be refaced, the generator should be re- exclusively by the Harley-Davidson Motor prepared to take care of, refer it to the
tor and is about Vs inch (3. m/m) wide. ferred to the Harley-Davidson Motor Co., Co., and its dealer organization. If you
After the commutator has been turned Harley-Davidson Motor Co.
to be repaired. are a rider do not take a generator apart:
 make starting more difficult. After prim- spark three-fourths and with the throttle
ing the cylinders and closing the carburetor closed, start the motor in the usual manner.

Service Dept. Bulletin air valve, open the throttle, raise the valves
and turn the motor over several times with
the starter. This will charge the cylinders
with a vaporous mixture. Advance the
If the weather is not cold enough to war-
rant priming, a cold rnotor may be started
by closing the carburetor air valve and
charging the cylinders as outlined above.
No. 93.---Dec. 10, 1921 Harley-Davidson Motor Co., Milwaukee
To Start a Warm or Hot Motor
After the cylinders and manifold have with the throttle slightly open, use the
Ignition Tests With Special Reference to become warm, it should not be necessary to starter in the usual manner.
introduce a heavy gas mixture into the mo- When starting a hot motor, completely
Easy Starting tor for starting. An extremely rich mix- close the throttle and slightly retard the
In presenting this bulletin we realize that gasoline while attempting to start. This ture used when starting a warm motor may spark. The air valve button should be in
because the facts stated are simple and will illustrate the necessity of a careful be difficult to ignite and interfere with its normal position.
fundamental, they are likely to be discount- study of this bulletin by every dealer and easy starting. This applies especially to When starting a hot 74" motor, make
ed in some cases or even ignored. repairman whether he sells or repairs one starting warm or hot 74" motors. sure that the throttle is not unconsciouslv
A factory Service Man found, on a machine a year or one hundred. The correct method of starting a warm opened at the same time the starter is used.
recent trip among a considerable number motor is as follows: Pull out the air valve To do so will load the cylinders with gas
of dealers, that hard starting was blamed The coming of cold weather always in- button, advance the spark three-fourths and and prevent easy starting.
to spark coils when, as a matter of fact, creases interest in the question of easy start-
fouled spark plugs or improperly adjusted ing. Hard starting is usually due to a Use Winter Oil
cut-out switches were at fault. In several well defined cause and can be readily lo- oiler, bearings, cylinders and pistons before
He.avy oil will make a motor hard start-
cases hard starting was found due to noth- cated and easily corrected if gone after in- the oil becomes distributed. Use winter
ing more than loading the motor with raw telligently. ing. Its use is moreover accompanied by oil for temperatures below 40° F. ( 4°
the danger of damaging the mechanical Centigrade).
How to Clean and Adjust Mica Spark Plugs
Mica core spark plugs can be used to liberal oil supply, and that the spark plugs How to Test Spark Coils and Diagnose Ignition Troubles
better advantage in an air cooled motor- should be the first item tested when ignition From time to time it becomes necessary
cycle motor, than most porcelain core difficulty is suspected. to test the spark coil or some other part
Remove an oil soaked or carbonized of the ignition unit. The test should be
plugs. The one difficulty arising in mica mica core and after thoroughly cleaning it, quick and sufficiently accurate to insure
core plugs is that the cores may absorb oil, burn it in an open flame until all traces a logical decision. The rider's future con-
gas and carbon easily and in consequence, of oil and gasoline have disappeared. Plug fidence and satisfaction as well as the re-
foul at low speeds. It should Le realized cores treated after this fashion will work pairman's reputation are at stake; there-
at the outset, therefore, that fouled plugs more satisfactorily. Fouling and prema· fore one cannot afford to fumble when
may be the cause of hard starting, es- ture ignition at high speed will be mini- testing.
pecially in a new motor adjusted for a mized. Very often when a motor is hard to
start the spark coil is condemned, whereas
Correct Method for Starting Motor the trouble is due to fouled spark plugs,
lH-4 H/i~£~r;...-t.fv.t.D BL ~rrr~ ,..., ~~ ~""~~' .1'-'f..::ui. .2!..£
Comparatively few motorcyclists under- tion of this mixture may vary with each improper carburetion, a poor electrical ~"f~"~.::'!:.f:!.n:-.#" T3'....L-:..-r~~ AA~...-t'!'"cr~:z.i!£.'?!.a''
stand the function of the carburetor. The motor's characteristics, in other words, some connection or a poorly adjusted cut-out .__0!._0~ !,7.r.:-l'l.("'~~ ..:fJ~~·~4J.Y .-~<f~ll~Nr~-r~

importance of proper carburetion when motors may require an open throttle to switch. Illustration No. I
starting the motor is, therefore, likely to start, while others require a closed throttle. Coil tests are often faulty and lead to
be overlooked. To start a motorcycle These individual characteristics must be incorrect deductions or conclusions. The of spark it should give in dry open air, and
motor requires that a charge of gas of learned by the rider. In case of a new repairman should, therefore, be able to the volume of the spark; next, the method
proper consistency be drawn into the rider, it is up to the dealer to teach him make a prompt and reliable test. of testing should be selected, depending
cylinders to be ignited on the completion the best method of starting his particular The first thing is to determine just what upon whether the coil is mounted on the
of the compression stroke. The propor· motor. is expected of the spark coil,-what length generator or not.
To Start a Cold Motor Testing a Spark Coil While on the Generator
With low temperature may come the never use more than one-third priming gun The best way to test a spark coil is connected and the test is likely to be ac-
necessity for cylinder priming, in order of gasoline for each cylinder; to use more under actt1al working ~onditions on the curate. Testing a coil removed from a
to start the motor. If priming is necessary, gas for priming, may flood the motor and motorcycle, because the coil is properly machine may lead to false conclusions
becauoe the test is inaccurate or incorrect ,.<'f'L'r:~,..;:;~,.,ry
a piece of wire, make and break a circuit condition, and these in;tructions are care-
J'"-N'Do./t
due to improper connections. between the front primary terminal post fully followed. Refer to illustration No.
Before testing a coil be sure that a and the coil base. A spark will jump the 3 for graphic explanations of the above
ground wire JR 148A, is permanently provided gap if the coil is in good working coil test.
fitted, one end of it to one of the
circuit breaker control lever studs and the
other end to one of the coil mountin_g If a Coil Tests Satisfactorily and the Motor IS Difficult to Start
screws. Make sure that all connections are It must be remembered that the ignition used; when they are, higher speed is neces-
clean when fitting the ground wire; this is unit and the generator unit are two entirely sary for the generator to carry ignition.
to insure a perfect "ground" between the different elements and their functions are It may be seen from the foregoing that
circuit breaker assembly and the coil base. for different purposes. The system is de- the efficiency of the ignition system de-
Refer to illustration No. I. signed for battery ignition and therefore a pends upon the action of the centrifugal
Clean the circuit breaker points and re- storage battery and direct current generator .cut-out switch. This switch must be ac-
move and clean the circuit breaker lever curately adjusted and not tampered with
Itlustration No. 2 are the main sources of current supply.
stud. Th.is stud may be rusty in its socket by the novice, Only too frequently riders
The ignition unit receives its current from tamper with the sensitive adjustment of the
and prevent the primary current from pass-
ing freely to the ground. either the battery or generator, depending cut-out switch and then register the com-
terminal post. Hold one of the spark plug upon the speed of the motorcycle. When
The storage battery should be at least cables i'..'' (5 m m) from the cylinder, plaint that their motors are hard to start.
one half charged. the motor is first started, the down stroke Illustration No. 4 shows the factory setting
and give the starter several strokes. If a
Make a jumper wire about 12 inches of the starter closes the centrifugal cut-out of the cut-out switch blades and points.
spark jumps the ·iV' (5 m m) gap, it is
long, using testing clips for each end. The switch and causes battery current to enter On rare occasions the cut-out weights
proof enough that the spark coil is func-
testing clips will be found most convenient the generator and ignition units. After the may be found magnetized, thus sticking to
tioning satisfactorily. This is the simplest
when making quick temporary connections. motor has reached approximately 12 miles the base proper and causing sluggish action
test that can be applied to the spark coil,
Thru the jumper test wire, connect the bat- per hour, the generator voltage is in ex- of the switch. Magnetized weights shoulcl
yet it is sufficiently accurate to be reliable.
tery direct to the rear spark coil primary cess of the battery voltage and the ignition be replaced with weights free from mag-
current is furnished by the generator. This, netism. They may be tested for magnetism
Testing a Spark Coil While Removed from the Generator Body of course, holds good only as long as the by- trying to lift small particles or chips of
Before testing a coil removed from the head lights or warning signal are not being iron or steel.
generator, the internal construction of the
coil, and the condenser connections should
be thoroughly understood. \Vithin the coil How to· Adjust the Centrifugal Cut-Out Switch
housing is contained a simple, induction, Blacdes and Contacts
or transformer coil consisting of an iron
core and a primary and secondary wind- Referring to Illustration No. 4, adjust
ing. A condenser for protecting the cir- the upper blade so that the Bakelite but-
cuit breaker points and increasing the effi- ton "B", is .004" (,I 0 m m) from the
ciency of the spark is secured in the bottom plane of the switch cover "C". A simple #Pl.~ /AI' CJV~,e'

of the coil housing. way to gauge this adjustment is to set the tfvrTDIV A-?<Nr/\{.-
ENr£=C l7.'"1J ,4'D~.i-
One condenser lead is connected to the blade so that a piece of average writing
front primary terminal post and the other is I
paper may be slipped between the switch
grounded with the coil mounting base. The I
I coYer and the button. Never adjust the
primary winding is connected to the front d~m<~ upper blade to cause the bal(elite button to
~nd rear primary terminal posts. One end be "within" the switch cover hole. Next
c,f the secondary winding is grounded with adjust the lower blade to give the contact
the coil molinting base and the other end Illustration No.3 points "D", a distance of I ,132" (.79 m
i.s connected to the high tension terminal m) to 3 64" ( 1.19 m m). The clear-
post, mou:;ted on top of the housing. The In e~ergency, 4 good dry cells may be ance between the points should never ex-
complete assembly is then filled with an used. Connect one battery lead to the ceed3,!64" (1.19mm).
insulating and weatherproofing compound. rear primary coil terminal post and con- Aftec adjusting the blades as outlined Illustration No. 4
Illustration No. 2 plainly shows the in- nect the other battery lead to the coil above and dressing the points so that they
ter n1l connections of all Harley-Davidson mounting base proper. Arrange a spark make a clean square contact, the switch the ball. To do so would only cause the
and Remy 235 coils. gap between the high tension terminal and will function properly. oil to find its way to the points and cause
To It'S! a coil, use a 6-8 volt storage tire coil mounting base. This gap should Never apply oil to the switch weights or difficult starting.
L,:tlery wlrirh is at least one lra!f clrargcd. be between ,",;''and !;.4" (5 m m). With
 Ready Reference Charts for Locating Ignition Troubles Ready Reference Chart for Locating Ignition Troubles
(Continued)
r Discharged storage battery.
Oil soaked or fouled spark plugs.
A poor electrical connection. rPoints too far apart.
Fouled-oil soaked or sooted mica.
Circuit breaker points dirty. Spark p Iugs J, p I . k d d f .
Circuit breaker points not opening. / orce ~m crac e ~r ..e echve,
~AlLURE To START l causmg premature Igmlion.
Circuit breaker lever stud rusty.
Broken primary wire or fibre insulating bushing. Circuit breaker points not properly adjusted.
I No short circuit wire, IR 148A on circuit breaker housing.
Cut-out switch not closing. (Try horn button.)
Circuit breaker points dirty or crystallized.
Circuit breaker lever spring weak. (Should have 16 oz.
l Make spark coil test to ascertain condition of coil. compression.)
Circuit breaker housing loose-no IR 148A ground wire.
MISSING AT HiGH Primary wire broken or has loose connections.
SPEED. Primary wire stud fibre bushing cracked.
Circuit breaker screw stud loose in plate.
Tungsten contact points beaten off lever or screw.
Battery out of generator circuit.
rS k I {Points too close. Water soaked distributor cap or cap is sweating. (Thorough-
par pugs Fouled-oil soaked or sooted mica. ly clean and dry.)

l Circuit breaker points set too close.

Circuit breaker points set too far apart.
Dirty circuit breaker points.
Using distributor segment made for automobile ignition.
This holds good only on Remy 235 generators. Test
for short circuited generator two wire cable. (May
Improperly adjusted cut-out switch. occur where cable enters generator body.)
Circuit breaker head loose-no IR 148A ground wire. l Defective spark coil.
Primary wire broken or has loose connections.
MtsstNG AT Low Primary wire stud fibre washer cracked.
SPEED. Circuit breaker screw stud loose in plate.
Tungsten points beaten off lever and point.
Circuit breaker lever rusty in stud socket.
Crystallized points.
Battery out of circuit, generator not running fast enough
to charge.
Battery discharged, generator not running fast enough to (If the motor misses or cuts out entirely after becoming
MoTOR MissEs OR
charge.
Wale~ soaked distributor cap.
l Sweating inside distributor cap.
CuTs OuT AFTER
BECOMING WARM. { warm, the primary or secondary coil winding may
be broken down. Coils thus affected may function
again after being allowed to cool.
 The Buzzl'r ('oil: The huzzl'r coil No. (j (illustration No. 2) ha'' onf' winding
only, which is con11celcd to the Yihr:•lor hlad<' No. il (illu~l•·alion No. 2) and the

Service Dept. Bulletin manual switch contact '•lade No. X (illustrati<~n No. 1 ). It is connceted in ~uch a
way as to work unly 1\ hen thC" manual switch h turned on an. I lhl' rC'Iay coil ,-ihralor
blade held down by either battery or g-enerator current. The buzzer proper is quite
simple, being simpler (less complicated) than a common e!eclric _door hell.
No. 94.---June 15, 1922 Harley-Davidson Motor Co., Milwaukee To Adjust the Vibrator Blade Points: To ascertain the adjustment of the
vibrator contact point·;, hold the blades l'io. 1 nnd No. 2 (illustration No. 2) firmly
against the lower brass ,-tops No. :l and No. 7, and observe the g-ap between the
points. The correct gap is 1 ;32 inch, (.7 m .•m). When neces~ary this adjustment
The New Manual Switch and Buzzer can easily he obtained hy Lending the vibrntor blades according-ly. When the
vibrator blades arl" released, thl"ir ends should hP.ar lightly against the upper part
of the brass stops No. a and No. 7 (illustration No. 2). If the Yibrator blade ends
For some time all hiJ; twins have been equipped with a manual ~witch and do not lightly touch thl" upper brass stops, bend the blad(' supports No. 10 (illustra-
buzzer instead of the centrifug-al switch. Opr>ruting-. instructions aecompany each tion No. 1) either up or down, as may I"' nl"cessary to obtain the proper adjust-
machine. ment. If necessary, the contact points may be cleaned with No. 00 sandpaper.
In the following thl" switch and buzzer principle and constnwlion, as well as As long as the buzzer is functioning prope.-Iy and sound" when thl" switch is
the metho<l of fitting the switch to e:n·licr machinPs in place of t.hf' c<>ntrifug·al pushed in or turned on, do n')t tamper with it.
switch, are explainl"d in detail for tlw dealer and repairman.
Important Instructions for Making Amnwter Conn<'elions: When an ammeter
The manual switch and buzzer are of simple, sturdy construction hut inasmuch is used in the electrical system, it must ue of the two wire type and connectl"d as
as thl"y are t\ew to Harley-Davidson de,ig-n. the dealer and r<'ntdrman should undct- follows: Connect the metl"r positive tl"rminal wire to thl" battery nl"gative wire and
stand their construction and lhe functions of the var:ous members in or<IPr to he thoroughly insulate the joint with tape and shellac. Then ground the meter nl"ga-
able to render proper service. tive terminal wire on the battery ground lock washer No. 2 (illustration No. 3) or
some other clean metallic part of the frame.
The complete functions of the manual switch, relay coil and buzzer are as Do not depend on tool boxes for g-ood grounds b~cause enaml"l, parkerization
follows: and rust in many cases practically insulate them from the frame. Hencl", if a one
wire ammeter is used, an actditional "ire must be connected to the meter negative
Thl" l\fanual Switch: The manual switch controls the battery, genera lor and terminal post and then securely grounded on the battery ground lock washer.
i~nition circuits; that is, upon closilw tlte switch, disc No. !J (illu~l.-alion No. 1)
makes contact with generator switch blade No. 2, battery switch blade No. :1 and Battery Ground Lock Washl'r-10\-381-P: It i3 imperativ(' that the battery,
ignition switch bladf' No. 8, thu~ conne•:ting these three circuits in unit to mn.ke or ammeter, negative wirl" be sl"curely grounded in order to keep thl" l"lectrical
ready for starting the motor. Upon turning the manual switch OFF, the threl" mam, system balanced at all times and prl"vent the generator voltagl" from dangerously
or generator, battery and ignition circuits are opened. A close examination of the increasing with the higher motorcycle speeds.
manual switch proper will reveal unique simplicity of design and n~ggl"dness o( A simple yet positive ground for the battery has been made in the form of a
construction, thus assuring positive action nt all times. lock washer which tits under the .seat post clamp bolt nut. This special washl"r is
provided with a screw and lock washer to clamp the battl"ry, or ammeter, negative
When the switch stem is released, the proper distance between the contaet disc terminal. For a likeness of this new ground tl"rminal refer to No. 2, (illustration)
and the three switch blades is 3,'32 inch (2.:l m/m). Whl"n necessary, this adjust· No.3.
ment can be obtained by bending the blades accordingly. The coil spring No. 7 Instructions for Operating the Manual Switch: To start the motor turn the
(illustration No. 1) opens the switch when the stem is turnl"d to thl" proper posi- switch ON by pushing thl" key and stem all the way in and then turning the key
tion. As this spring carries no electric current it should never require attention. one quarter turn in either direction. Start the motor in the regular way as quickly
as possible after closing the switch, to prevent excessive discharge of the battery.
Relay Coil: The relay coil No. 4 (illustration No. 2) consists of a soft iron cor!' In cold 'weather particularly, the switch should not be turned ON until the
an<l two (series and shunt) windings. The outside or heavy winding- is the ""·ies motor has been made rl"acly for starting according to the directions in the instruc-
coi-l, which is connected in series with the battl"ry and g-l"nerator; while directly ovP.r tion book. This will prevl"nt the battery from being <'ischarged unnecessarily.
the core and under this winding, are wound many turns of fine wire to form thl"
shunt coil. One end of thl" shunt winding is grounded and the other end i~ con- To facilitatl" starting a 74" (1Z08 cc.) motor, thl" spark control should be re-
nl"cted with one end of the hl"avy or serie~ winding. tarded slightly. This will permit the tiy wheels to carry thl" piston ov('r top dead
center on the compression stroke and thus prevent backfiring.
The hl"avy outside or series winding and the fine inside or shunt winding are To stop the motor turn the switch OFF by turning the key in eithl"r direction
wound over the core in opposite directions. This is <lone to cau~e the relay core to to .original position and allowing the switch stem to project out of the covl"r. The
bl"come magnl"tized when currPnt comes from the battery, and to he neutral (not buzzer will stop sounding when the switch is turned OFF.
magnl"tized} when the generutor f;,rni~hes the current. This theory holds g-ood If the switch is left turned ON with the motor not rnnning, a fully charged bat-
only whl"n the battery and generator are in thl" circuit. tery will be discharg<'d within one hour; hence the importance of using the switch
correctly.
When the switch is tumed on, current from the battery pass<'s throug-h the
relay series and shunt windingi< in the same g·eneral direction and causes tiH' The horn is connected with the ignition circuit as on former l"lectrically l"quip-
vibrator blade No. 1 (illustration No. 2) lo be drawn down and make contact with pe<l modl"ls and will soun•l only when the manual switch is turn('d ON.
the buzzer coil vibrator blade No. 8 (illustration No. 2). Thus thl" lmzz..r coil is THE BATTERY 1\IUST Bl'~ 1\EPT IN CIRCUIT
put into the circuit and its ,-ibrat.ing bladp se•·ves as a warning- sig·nal that the hat-
tPry is being discharged and that the motor should be started immediately. or the If the motor is run with the battery out of thl" circuit, the relay coil will func-
switch be turned OFF. tion because of the excessively high generator voltage. The switch buzzl"r points
(vibrator blade contact points) will be damaged by such high voltage and there is
When the motor is started, tlw generator charging cunent passes throug-h tlw also danger of damaging the armaturP and coil, making apparent thl" nel"d of keep-
relay series and shunt winding.s in opposite dircctio11,, causing- them to neutralize in!!' the battery in circuit while the motor is running. It is, therefore, necessary
(demagnetize) the core and open the vibrabt· blade poi11ts and slop the ltuzzP.r Bhould the buzzer points become burnl"d, to examine all connections carefully and
action. make them secure if necessary.
 The motorcycle ca11 he operat<'d ('\'ell thoug·h the h!l7.7.<'r i~ <>tl( of onl<'r (poi11f~
hunwd ~o that, the buzz<'!' will not "H111d); all that is IIC~<'~~ary in such a ca~c i~ to Instructions for Fitting the
~epa rat<' the huzze1· pni11!s or ill~!! late i ll!'lll <o that th<'y cannot ntak<' contact with
each other. It is well to pass this information on to the rider so that he can help
himself in an eme1·genc~·. ]\;atumlly a buzzer thus humed should he replaced as
Harley-Davidson Manual Ignition
soon as possible to keep the elect rica! system pnip~rly balanced.
Switch to 1920, 1921 and
1922 Models
To fit the manual switch, the centrifugal switch parts, the origittal fuse box
bracket and the generator two wire cable must be removed. The front field coil
wire which connects the positive (front) brush with the upper centrifugal switch
blade should be cut so that it connects the field coil and brush only. :Wire No. 14
(see illustration No. :3) should be passed up through the bushing in the bottom of
the generator and connected together with the field wire to the positive (front)
brush holder. The terminals ~hould be arranged so that there will be no possible
chances of grounding with the generator frame.
The commutator end bearing cover 8hould be replaced with the plain cover
furnished with the manual switch. The new cover is provided to close the bearing
end in order to keep out the dust and grit as much as possible. This is the only
work necessary to convert the generator.

Using Manual Switch Assembly, KK 344P, with

Original Fuse Box Parts
Transfer the original fuse base to tre m:mual switch bracket. Also transfer
the tail and sidecar light terminal No. 6 '(illustration No. 3) to the new bracket,
making sure that it is properly insulated. The fuse box should have its upper edge
filed or cut away to fit the new bracket.
Illustration No. 1 Illustration No. 2 If the complete manual switch and fuse box assembly KK344AP• is used, the
above mentioned changes are not necessary.

Fitting Manual Switch Bracket to Frame

Spare Parts: It will be noticed that f he various components of the switch an< I Fit the manual switch bracket to the frame tube, making sure that it is in
buzzer units are securely riveted together. If any part of the assembly develops good contact with the frame. The switch bracket clamp must be grounded to com-
trouble, it cannot be rebuilt by the rider or dealer and must, be referred to the plete the buzzer circuit. The top edge of the bracket clamp shoul<i be 1 inch (25.
factory for repairs or exchange. The parts that can be obtained are listed below. m/m) from the frame seat post cluster. Turn the switch bracket on the frame
KK-344P -Manual switch complete less fuse box parts ..................... $4.95 tube so that there is approximately 'l8 inch (9.5 m;m) clearance between the bat-
KK-344AP-Manual switch anci fuse box complete ........................... 6.25 tery box and the switch cover. The cover is recessed to permit the battery positive
wire to pass without being pinched. The switch and fuses are now ready for final
(Either of these assemblies can be used lo replace a cenlrifugal connections.
switch. Jnstructlcns for fiti.ing are included with each set of
parts.)
KK-385 -Manual switch only ........................................... . 4.00 Instructions for Making All Electrical Connections for
KK-342 -Mounting plate assembly ..................................... . .45 1920, 1921 and 1922 Models
KK-339 -Switch cover ................................................ . .20
B0-13W -Switch mounting screws (3) each ............................. . .01 Refer to illustration No. :3 when making the following conrle<•tions:
G0-13W -Switch mounting screw wvshers .............................. . .01 Connect eyelet of wire No. 3 to eyelet of wire No. 14 and thoroughiy tape the
KK-381P -Battery ground lock washer complete ......................... . .05 connection. No. 13 shows this connection. Tape the joint to the frame tube just
KR-15 -Generator left bearing co\'er plate ............................. . .08 below the gear shifter bracket and shellac it.
DK-321 -Switch key .................................................. . . 15 Connect the central eyelet of wire No. 7 to the rear spark coil terminal. No .
8. Have this wire in a vertical position to prevent grounding on the metal coil end
and loop back to horn fuse terminal No. 10.
Connect the central eyelet of wire No. 1 to the battery box bakelite terminal
block. The end of this wire must be connected to light fuse terminal No. 11.
Make sure that the battery negative wire is securely grounded to the batter!'
ground lock washer, see No. 2, which fits under the seat post pinch bolt or the frame
brace eye bolt nut. This battery ground lock washer is furnished with the switch.
The battery negative wire must be positively grounded to prevent the manual
switch vibrator points from burning.
The manual switch is now in circuit with the battery and generator.
 The following instructions arc f'or fitting· the Harley-Davidson manual ig-nition
s"(itc~ to .1918 ~nd 1919 clectric'llly equipped models using the original headlig-ht
and hghtmg switch.
Connecting Horn and Light Cable Wires to Fuse Box M_ake all changes in the generator according- to directions under Instructions
Connect the eyelet of the RED cable wire to light fuse terminal No. 12. Connect for Fitting the Harley-Davidson Manual Ignition Switch. Then assemble the
the eyelet of the (;HEI~N cahle wire to horn fu~e terminal No. 9. Connect the lighting switch and manual ignition switch as follows:
large eyelet of the BLACK cable wire to the insulated terminal No. 6. Also con- Remove the light switch and bracket from the frame. Remove the light switch
nect the tail light wire eyelet to this terminal. The hole in terminal No. 6, is for cover together with the fuses and wiring and observe two rivets which secure the
plugging in a side car light or trouble Ji~ht conne>ction. base plate to the bracket. With a 'A inch (6.3 mjm) drill, counterbore the peaned
All wiring and connections are now complete. ends of the rivets in order to remove them. Separate the base plate from the
frame bracket.
The short tail light wire should remain, with the insulating bushing, in the
base plate.
Mount the light switch base plate on tl1e fuse block extension of the manual
switch bracket in the following manner.
Temporarily place the light switch base over the bracket extension (have the
base slightly forward with the cable outlet at the bottom) and mark the plate,
from the rear, through the three threaded holes in the bracket extension.
\::>I • Strike. these marks ~ith a center punch and drill .the three holes in the plate
i With a % mch or 5;32 mch (3 m;m or 3.il m/m) dnll. Secure the plate to the
bracket extension with three 6-32 screws ',i inch (6.3 mjm) long.
\\ 6 Transfer the tail and sidecar light insulated terminal No. 6 (illustration No. 4)
to the manual switch bracket.
\
-\
Follow instructions under Fitting Manual Switch Bracket to Frame to fit the
assembly to the motorcycle.

Making All Electrical Connections for 1918 and

1919 Models Only
Refer to illustration No. 4 when making the following connections:
\
Connect eyelet of wire No. 3 to eyelet of wire No. 17 and thoroughly tape the
connections. No. 16 shows this connection.
\
Tape the joint to the frame tube just below the gear shifter shaft bracket
/ '' and shellac it.

® ~ (.~
(/) 7
/ -\

~!;\\
4
@ I \
Illustration No. 3
Key to Above Diagram for Fitting the Harley-Davidson Manual
Ignition Switch to 1920, 1921 and 1922 Models I'
1-Battery positive wire connected with E-yelet of wire No. 4 at tenninal block; I
2-Battery negative wire grounded to hatterr ground lock washer; 3-Switch-
Generator wire, connects with generator feed wire at terminal No. 13; 4-Switch-
Battery wire connects with light fuse terminal; 5-Switch key shaft, used when
~tarting and stopping the motor; 6-Tail and sidecar light terminal, black wire of
three wire lighting cable connects here; 7-Switch-Ignition wire, connects with rear
spark coil terminal No.8 and horn fuse terminal No. 10; 8-Rear spark coil terminal;
9·-Horn fuse terminal, green wire of three wire lighting cable connects here;
10-Horn fuse terminal, fed from wire No. 7; 11-Light fuse terminal, fed from
wire No. 4; 12-Light fuse terminal, red wire of three wire lighting cahle connects
here; 13-Bolted connection of switch wire No. 3 and generator wire No. 14; I
14-Generator feed wire, connects with field coil wire to generator positive brush
holder, and with ~witch wire No. 3 at terminal No. 13. I
I
Instructions for Fitting the Manual Switch
to 1918 and 1919 Models
To fit the manual switch to 1918 and 1919 models using the new style head Illustration No. 4
light (the head light with the switch mounted on it) and lighting cable, follow
directions under Instructions for Fitting the Harley-Davidson Manual Ignition
Switch.
spring "4" lo lhe high tension lcrminals al "2"; 6 Sloi in limn hc<td casting lines during the daytime and are not used at night; and for machines which are driYcn con-
up wilh lug "I" when the distributor cap "3" is properly frtlcd; 7 -Circuit breahr siderably with the lights burning and very little without, as in the winter time due to
lever; 8---Circuit breaker cam; 9-Circuil breaker points; I 0--Adjusting screw with the short days. If additional lights are used, the output of the generator should be·
which the gap at the circuit breaker points "9" is adjust.,d: II- -Adjusting screw lock increased to take care of them. Care should be taken, however, not to overload the
nut, prevents adjusting screw "I 0" from lurning automatically. The lock nut must system. The battery also requires a higher charge in winter to keep it up.
be loosened before an adjustment is made, ;:nd must be securely tightened after adjust- A dirty commutator or improperly seating brushes will affect the output of the
ing; 12--Primary wire connects primary winding of coil "16" to ground through generator; therefore, before changing the position of the regulating brush be sure that
circuit breaker points at "9"; I 3---Distributor cap spring (two used) holds the dis- the commutator is clean and the brushes are seating properly. Use No. 00 sand paper
tributor cap "3" securely in position: 14--High tension carbon contact insert which to clean the commutator and seat the brushes. NEVER USE EMERY CLOTH.
carries the ignition current from wire "I 5" to distributor segment contact spring "4"; After cleaning the commutator and seating the brushes, remove all traces of sand and
IS-High tension wire which carries the i·~nition current from the secondary winding carbon.
of the coil to the carbon contact insert "14" in the distributor cap; 16-Coil, one only If the charging rate of a generator is sufficiently high to overcharge a battery, it
used. should be reduced. Whether or not a battery is receiving an overcharge can best be
determined by the state of charge of the battery, and the amount of water consumed.
To Adjust the Circuit Breaker Points If water is added weekly, and there is not enough solution above the plates to obtain
a hydrometer reading with the standard hydrometer, and provided the jar does not
The nbre block on the circuit breaker arm is subjected to a certain amount of
leak, the battery is receiving an overcharge.
wear in service, and after several thousand miles it will be necessary to readjust the
contact points to make up for this wear. As a matter of precaution, an inspection and How to Determine the Proper Generator Charging Rate
adjustment if necessary, should be made, say, every I ,500 miles. If the high side of
one of the steel cams is not in contact with the fibre block, it will be necessary to turn The output of a generator may be regulated with the generator either on or off
over the generator slowly by means of the rear wheel (transmission must be in high gear the motorcycle.
and the clutch engaged), until the steel cam hits the fibre block and separates the The generator output can be tested by connecting a reliable direct current am-
contact points as far as they will go. The lock nut "I I" should then be loosened meter, having a 0 (zero) to I 0 ampere scale,' in the circuit between the generator and
with the generator wrench, and the adjusting screw "I 0" should be turned in or out battery and running the motor. If the condition of the ammeter mounted on the ma-
by turning the hexagon head until it is just possible to insert the flat steel gauge on the chine is questionable; then use a meter of known quality.
wrench between the points at "9". After the points are correctly adjusted, tighten To cut in an ammeter to test the output of a generator on a machine, disco.mect
the lock nut care fully and measure the clearance again to be sure that the adjustment the ammeter on the machine, and connect !he positive post of the test ammeter to the
is correct. negative post of the battery; then ground the negative post of the ammeter to the machine.
All Remy model 235 generators when adjusted for ordinary service generate from
Lubricating the Generator 3 Yz amperes to 4 amperes; Harley-Davidson generators are adjusted to give a maxi-
(All Models Between 1918 and 1920) mum of 4 amperes. This rate will be found to be too much if the machine is never
driven at night, and the position of the regulating brush should be changed so that the
Never use thin oil on any part of the generator. Once a year put a little vaseline highest charging rate is from 2 Yz amperes to 3 amperes.
about half the size of a pea on the top of the fibre block of the interrupter lever and Run the machine either on the stand or on the road at approximately 20. 30 and
keep the cup on the right side of the generator filled wilh good vaseline if the cup is 45 miles per hour to check the charging output of the generator.
provided with a wick. This cup will require filling about every 1,000 miles. If the The current rate at 20 miles an hour should be approximately 2 amperes; at 30
generator has a regular grease cup here instead of a Vaseline cup, give this one"hal f miles an hour, 3 or 3 Yz amperes and at 40 miles an hour, 3 Yz or 4 amperes.
turn every 500 miles and keep it filled with a good grade of cup grease. If the generator has been removed from the motor for testing it should be mounted
on a bench and driven by a variable speed motor or line shaft at speeds approximating
When New Parts are Needed 20, 30, 40 and 50 miles an hour (sidecar gearing).
Order new parts through your dealer or from the Harley-Davidson Motor Co. The armature revolutions at the suggested speeds are respectively-1750, 2630,
direct, if you are not ncar to a dealer. Specify whether your generator is a Remy or 3500 and 4375.
Harley-Davidson and mention its serial number and model.
Making Connections for Testing Generators on Bench
To Regulate the Charging Rate [Output] of the Harley- Connect the RED wire of the double cable leading from the bottom of the gen-
Davidson and Model 235 Remy Generators erator to the positive wire of a motorcycle battery that is at least one-half charged
(1918 to 1923 Models) (gravity reading 1200 or more). The battery negative wire must be connected to
the positive terminal of a reliable ammeter. The. remaining ammeter terminal can now
The output of a generator should r.ot be changed if the machine is used for be grounded to the generator frame.
ordinary service when the lights are used r-easonably, because each inst~ument is accur- Make some provision for testing the spark; a pair of spark plugs grounded to the
ately adjusted at the factory to meet the requirements of such service and danger of generator frame will suffice.
overcharging will never occur. A change in adjustment is recommended only for ma- Remove the generator commutator end cover and the generator is then ready for
chines, either in commercial, or in private service, which are driven considerable distances testing.
 Adjustment of the Brushes
When the generator has not been
taken entirely 2part it is only necessary to
change the position of the regulating (up-
per right hand) brush "3" (Illustration
No. 3) on the commutator. To reduce the
output, loosen the third brush plate clamp
screw "I" (Illustration No. 4) a few
turns with a special wrench, LK881 , and \0\... .... ~~c.. "'~~, \...\G..~'T -
REO WIRE.
move the regulating brush "3" and brush
plate assembly "4" away from the nega-
tive brush "5" about I I 16". To in- 4
\o 51'"\P.\.\. 1-\EAI)\.\~"T
crease the output, move the regulating
1!>\.AC"I-< \11\ I". E.
brush "3" and brush plate assembly "4" 5
towrurd the negative brush "5" about
I I 16". After moving the regulating
brush "3", make sure that it bears squarely
against the commutator and again tighten
the third brush plate clamp screw "I ".
Test the output of the generator and
see whether or not there is considerable
arcing (sparking) between the regulating
brush and commutator. If the arcs To Sw lTC>\ n'f\'Aci<E.··n·E.'Rt'\1 N,~>,\...
(sparks) appear to jump from either edge
3
\.'AI\.- ........ 1> OIPE c,...., \.la.,>{T")
of the brush, the brush is not bearing Illustration No.

squarely against the commutator. To squa:·e up the brush, insert a strip of No. 00
Switch Wiring Diagra-m of 1918 Models
sandpaper between the brush and the commutator, the sanded side against the brush.
Press lightly on the brush and withdraw the strip. The curvature of the commutator
and abrasive will cut the brush face clean. After seating brushes, clean brushes and
commutator, and remove all traces of sand
and carbon. NEVER USE EMERY
CLOTH.
Test the generator again to see
whether or not the resealing of the brush
on the commutator affected the output RltD V"\\

to such an extent that the regulating brush

plate must be moved once more. It may '0 81'.""1"\'E~Y
8\.J<CV.'r\IRE;
be necessary to change the position of the
regulating brush several times before the ' 0 ~MA\.\. 1-\EJ<D\.IG\\T
desired results are obtained. 'B\.AC."6 Y"\ \ ft£

To Reseat All Brushes

(Remy Generators Only)
If a generator has been completely
stripped and the main brush plate has
2 been removed, the proper (neutral) posi-
tion of the brushes is determined by watch- TO ~'MITCH BR,.Cli.'ET ""I"ERI"'\IM"\.
ing the arcing between the positive and "TAl\. § SlOE CAR \.14\\T
ground brushes, and the commutator. Most
arcing will appear between the positive
brush "2" (Illustration No. 4) and the Switch Wiring Diagratn of 1919-and early 1920 Models
commutator. No attention should be paid Illustration No.5
Illustration No.4 to the regulating brush during this test.
 The grncrator should be run approximately 30 milt>s an hour and the brush plate This wire can be obtained from your dealer or tht> factory at sm~ll rosl. Makr wre
moved back and forth until a plan· is found whNc the least arcing (sparking) will that all connections are clean when filling the ground wirt>; this is to insur<' a perf eel
occur; then tighten the main brush platr clamp screw "6". When making this adjust- "ground" between the circuit breaker assembly and the coil base. Hefer to illustration
ment on the machine, b.. careful not to get your hand caught in the drive drain. The No.6.
best mt'lhod is to stop the motor, shift the brush plate, then restart the motor-doing Clean the circuit breaker points and remove and cl .. an th .. circuit hrt>aker levt>r
this until the desired results havt' bren accomplished. stud. This stud may be rusty in its soc~ct and prevent the prim~ry curr<'nt from pa,s-
The output of the generator is then adjusted by moving the regulating brush plate ing freely to the ground.
"4" to the proper position as explained previously. The storage battery should be at least one-hal£ charged when making this as well
as all electrical tests.
Make a jumper wire about I 2 inches long, using, if possible, testing clips for <>ach
Notice end. The testing cli'Ps will be found most convenient when making quick temporary
connections. Thru the jumper test wire, connect the ballery direct to the rear spark
The armature and brush plate of the Harlt>y~Davidson generator are coil primary terminal post. That is, connect one end of the wire to the battery positive
so constructed that it is not necessary to locate the neutral brush plane; terminal and the other end to the rear spark coil terminal post.
therefore, the main brush plate is rigidly secured to the generator body and Hold one of the spark plug cables about 3/ 16" from the cylinder to make a
requires no adjustment. spark gap, and if a good snappy spark otcurs after using the starter several times, it is
proof enough that the spark coil is functioning satisfactorily. This is the simplest test
that can be applied to the spark coil, yet it j, sufficiently accurate to be reliable.
When assembling the centrifugal swit<:h, take special care to tighten the cutout
switch base screw as tight as possible. Examine the hard rubber insulators of the Testing a Spark Coil Removed from the Generator Body
terminal screws (switch blade clamp screws) for cracks. These bushings must be in Before testing a coil removed from
good condition, and the fibre terminal washers must be properly placed, or a short the generator, the internal construction of
circuit will result which may cause serious trouble. the coil, and the condenser connections
How to Test Spark Coils and Diagnose Ignition Troubles should be understood thoroughly. With-
in the coil housing is contained a simple.
(All Models between 1918 and 1922) induction, or transformer coil consisting
It may become necessary to lest the spark coil or some other part of the ignition of an iron core and a primary and second-
unit and the test, therefore, should be quick and sufficiently accurate to insure a logical ary winding. A condenser for protecting
decision. the circuit breaker points and increasing
Very often when a motor is hard to start the spark coil is condemned, whereas the the efficiency of the spark is secured in a
trouble is due to fouled spark plugs, improper carburetion, a poor electrical connection metal case in the bottom of the coil hous-
or a poorly adjusted cut-out switch. mg.
Coil tests are often faulty and lead to incorrect deductions or conclusions. The
rider or repairman should, the~efore, be able to make a prompt and reliable test. One condemer lead is connected to
The first thing is to determine just what is expected of the spark coil.- what length the front primary terminal post and the
+ C=0 other is grounded with the coil mounting
of spark it should give in dry, open air, and the volume of the spark; next, the method ooo
8
~
of testing should be selected, depending upon whether the coil is mounted on the gen- base. The primary winding is connected
C=8 G:> --- to the front and rear primary terminal
erator or not.
posts. One end of the secondary winding
Testing a Spark Coil while on the Generator Illustration No. 7 is grounded with the coil mounting base
and the other end is connected to the high tension terminal post, located on top of the
The best way to test a spark coil is
housing. The complete assembly is then filled with an insulating and weatherproofing
under actual working conditions on the compound.
motorcycle, because the coil is properly
Illustration No. 7 shows quite clearly the internal connections of all Harley-David-
connected and the test is more likely to be son and Remy 235 model coils.
accurate. Testing a coil removed from a
To test a coil, use a 6 to 8 volt storage ballery which is at least one-half charged.
machine may lead to raise conclusions be- In emergency four good dry cells connected in series may be used. Connect one bat-
cause the lest is inaccurate or incorrect due tery lead to the rear primary coil terminal post and connect the other ballery lead to the
to improper connections and the method coil mounting base proper. With a piece of stiff wire arrange a spark gap between the
used. high tension terminal and the coil mounting base. This gap should be between 3}16"
Before testing a coil; be sure that a and \l.f ". With another piece of wire, or a screw driver, make and break a circuit
ground wire JR 148A, is permanently between the front primary terminal post and the coil base. If these instructions are
fitted, one end of it to one of the circuit followed carefully a spark will jump the provided gap if the coil is in good working
r;.-..s MA"r Jltl'#vl.# & l"inYII ,.-. £vllr'!'#D ,,..;~~ t'PprL n.;
8'1'"fttf.l'N£~Antf' ".h'Jvg J~A.f-JII"4er G.PvNp lfrrwru breaker control lever studs and the other condition. Refer to the illustration No. 7 for graphic explanations of the above coil
T"lr'l Ci<rCVIT Q,f'rAK.l'~ 1/J~Pf#L'(,.,tft-I:(A,-,#~
end to one of the coil mounting screws. test.
111uetratlon No. 6
 f J.=>oints too close
If a Coil Tests Satisfactorily and the Motor is Difficult to Start Spark plugs ~ Fouled (oil soaked) or sooted mica
( 1918 to 1922 models) Circuit breaker points set too close
Circuit breaker :•oints set too far apart
It must be remembered that the ignition unit and the generator unit are two separ- Dirty circuit breaker points
ate and entirely different elements and their functions are for different purposes. The Improperly adjmted cut-out switch
Harley-Davidson electrical system is designee! for battery ignition and therefore a storage Circuit breaker head loose--no JR I 48A ground wne
batlery and direct current generator are the main sources of current supply. Primary wire broken or has loose connections
The ignition unit receives its current from either the battery or generator. depending Primary wire stud fibre washer crad..d
upon the speed of the motorcycle. When the motor is first started, the down stroke of MrssiNG AT Low Circuit breaker so:rew stud loose in plate
the starter closes the centrifugal cut-out switch and causes "battery current" to enter SPEED IF DuE TO Tungsten points beaten off lever and point screw
the generator and ignition units. After the motor has reached approximately I 2 miles IGNITION Circuit breaker lever rusted in stud socket
per hour, the generator voltage is in excess of the battery voltage and the ignition cur- Crystallized points
rent is furnished by the "generator". This, of course, holds good only as long as the Battery out of circuit, generator not running fast enough to
head lights or warning signal are not being used; when they are brought into use, · produce current
higher speed is necessary for the generator to carry ignition. , Battery discharged, generator not running fast enough to
Ammeter readings at various speeds and under variable conditions indicate the produce current
movement of current in the system as follows: Water soaked distributor cap
When driving during daylight and the ammeter needle shows, say 3 amperes, it Sweating inside distributor cap
means that 3 amperes current are passing into the battery. Short circuited distributor cap. (Usually fires on one
If the meter shows a 0 (zero) reading, the system is more or less balanced, that cylinder only.)
is, current is coming from both battery and generator for ignition.
If the meter needle shows a discharge of, say, I or 2 amperes when driving with or
without the lights turned on, it indicates that the current is coming from the battery.
Points too far apart
This can be caused by the generator not furnishing sufficient current to offset the current
used by the lights, if the lights are turned on, or else the generator is not charging at Spark plugs
Jl. Porcelain
Fouled (oil soaked) or sooted mica
cracked or defective, causing
all if the lights are turned off. premature ignrhon
It may be seen from the foregoing that the efficiency of the ignition system depends
upon the action of the centrifugal cut-out switch. This switch must be accurately ad~ Circuit breaker points not adjusted properly
justed and not tampered with unless absolutely necessary. Only too frequently riders Circuit breaker points dirty or crystallized
tamper with the sensitive adjustment of the cut-out switch and then register the complaint Circuit breaker lever spring weak. (Should have I 6 oz.
that their motors are hard to start. Illustration No. I shows the factory selling of the compression or tension)
cut~ut switch blades and points, Circuit breaker housing loose -no JR I 48A ground wire
MISSING AT HIGH Primary wire broken or has loose connections
SPEED IF DuE TO Primary wire stud fibre bushing cracked
Ready Reference Charts for Locating Ignition Troubles . IGNITION Circuit breaker screw stud loose in plate
NoTE: Before condeming the ignition system, make sure gasoline i~ actually reaching Tungsten contact points beaten off lever or screw
the carburetor and that there is sufficient compression in the cylinders to cause Battery out of generator circuit
combustion after the gases are ignited. Water soaked distributor cap or cap is sweating. (Clean
and dry thoroughly)
Discharged storag•! ballery Using distribut?r segment made for automobile ignition.
Oil soaked or fouled spark plugs lltis hold good only on Remy 235 generators
A poor electrical connection Test for short r:ircuited generator cable. (May occur
Circuit breaker points dirty where cab!~ enters generator body.)
FAILURE TO START Circuit Breaker points not opening Defective spark coil
IF DuE TO IGNITION Circuit Breaker lever stud rusty
Broken primary wire or fibre insulating bushing MoToR MisSES oRJ If the motor mis•es or cuts out entirely after becoming warm,
No short circuit wire, JR I 48A on circuit breaker housing CuTS OuT AFTER the primary or secondary coil winding may he broken
Cut-out switch not closing. (Try horn button ) BECOMING WARM IFl down. C•·ils thu5 affected may function again after
Make spark, coil test to ascertain conditions of coil DuE To IGNITION being allowed to cool
Mechanics' Bulletin
No. 100 April 1, 1924 Harley-Davidson Motor Co., Milwaukee

Complete Timing Instructions for Harley-

Davidson Motors
Working Principles of the Harlev-David_son Motor
The Harley-Davidson motor is of the Each 180 degrees of fly-wheel travel
conventional four-stroke-cycle principle. is one event or stroke. The flywheel must,
Each complete power cycle is made up of therefore, make two revolutions to com-
plete one power cycle of the motor. The
four events, or strokes; hence the term four-stroke-cycle principle is briefly: 1---
"four-stroke-cycle". This type of motor lntake or admission stroke; 2-Compres-
is commonly referred as a "four-cycle" sion stroke; 3-lgnition and power stroke;
motor. 4-Exhaust or scavenging ~troke.

ILLUSTRATION NO. I
The Accompanying Illustration Graphically Explains the Four-Stroke-Cycle Principle' ILLUSTRATION NO. 2

"V" Twin Motor with Cutaway Gear Cover, showing how 1915 to 1924 Twin Magneto
General Models should be set according to Gear Marks. Valve Timing on all motors
since 1915 should have Gear Marks Aligned as_ shown in this Illustration
To insure the most accurate results piston head so as to locate it properly in
when timing valves and ignition, the motor the cylinder for setting valves and timing
should be taken out of the frame and the ignition.
front cylinder plug removed. After the Piston positions in motor timing are de-
cylinder plug is removed, a 6" scale can termined from either top (upper) or bot-
be passed through the opening to reach the tom (lower) dead centers. Dead center
is the point at the extr~me top or bollom instructions must. therefore, h.- studi~d and
applied carefully to o:,tain the original fac ·
5 i 16" before top dead center. This means from the lop end of its travel, lhc cam
·end of piston travel--the point whne the
that the piston is on an upward stroke and gear has turned so th.- inlet valve starts
piston is "dead". tory timing.
when it is between 3, 16" and 5 · 16" to open.
The close relation between piston travel Complete valve and ignition timing for
and valve operation requires close measure- Nch type of motor will be found und~r a
ments when timing a motor. The following heading covering that type of motor. Inlet Valve Timing Specifications
The ink! valve should open when the 1be inlet valve should close when the
To Convert Inches Into Millimeters piston is between 3 16" and 5jl6" before piston is between 3,14" and 7 8" after
lop dead center (piston is coming up on bottom dead center (piston Is commg up
First of all convert the fraction into The decimal or fraction can now be
converted into millimeters by multiplying it exhaust stroke). on compression stroke).
decimals as follows: Add c i p h e r s
(naughts) to the numerator and divide by 25.4
this by the denominator. Place the deci- Example: 7 8 inch-=.875=22.22
Exhaust Valve Timing Specifications
mal point so as to make as many decimal millimeters. The exhaust valve should open when The exhaust valve should close when
places in the result as there were ciphers Process .875 the piston is between 5 /8'' and 3;'4" the piston is between I I 16" and I /8"
(naughtl>) added. 25.4 before bottom dead center (piston is going after top dead center (piston is going down
Example: 7,'8 inch fraction equals down on power stroke). on intake stroke).
.875 inch (decimal). 3500
4375
Process 817.000 1750
Breather Valve Specifications
The port in the sleeve of the relief on either top dead center. The breathe~
0.875 22.2250 valve must be open between I I 16" and valve port opens as the shaft is turned in
3 132" when the front cylinder piston is a left handed direction.
Twin Cylinder "V" Type Motors
To Timer Breather Valve or Mechanical Relief Valve
To Time Valves on "V" Twins (1914 and Later "V" Twins)
All twin motors, since 1915, have the the pistons and cams will be in proper re-
The relief valve is provided to allow the When the pinion gear and cam gear
pinion and .cam gears marked which, of lation; however, the valves will not open
course, makes valve timing on these models and close properly until the valve tappets crank case compression to be expelled when marks are aligned the breather valve gear
a very simple matter. By merely lining up and push rods are adjusted according to the pistons descend. can be meshe~ with the pinion gear so the
these marks as shown in illustration No. 2, the following specifications. Besides relieving the crank case com- marked tooth is within the "V" stamped
pression, the breather valve controls the in the crank case. Refer to Illustration
Valve Tappet Adjustment lubricating system to a large degree. The No. 2 showing correct valve and breather
( 1915 and Later Models) importance of correct timing for this valve valve timing according to gear marks.
When making adjustments to valve tap- .0 I 0" between their heads and the valve is therefore obvious.
pets, the motor must be cold in order to stems.
obtain accurate results. The inlet valves must hav'! a clearance
The exhaust valve tappets must be ad- of .004" between their stems and Ieven;. Ignition Timing for "V" Twin Motors
justed to have a clearance of .008" to
Circuit Breaker Contact Point Specifications
Valve Timing Specifications for "V" Twin Motors To insure extreme accuracy in igni- Harley- Davidson
(The Following Covers Valve Timing Regardless of Gear Marks) tion timing, make sure that the circuit Generator .... -.020 inch
The following are piston locations m breaker points are set according to the Remy Model 250
The exact time of valve opening and
closing can be determined easily by turning fractions of an inch, from either top or manufacturer's specification&. An adjust- Generator .... -.020 inch
the push rod or lifter pin while the motor bottom dead centeTs, when the valves are ing wrench fitted with a thickness gauge Remy Model 235
is being turned over. When the push rod opening and closing. accompanies each ignition apparatus. If Generator .... -.020 inch
or lifter pin be&ins to tighten or loosen, as For an example: With the gears such a gauge is not available, adjust the Bosch magneto ... - . 016 inch
the motor is being turned over, the valve is meshed properly the inlet valve opens breaker points according to the following Berling magneto .. - . 0 18 inch
beginning to open or close. when the piston is between 3 I I 6" and
data: Dixie magneto .. -.020 inch
Mechanics' Bulletin
No. 100 April 1, 1924 Harley~Davidson Motor Co., Milwaukee

Complete Timing Instructions for Harley-

Davidson Motors
Working Principles of the Har}ey~Davidson Motor
The Harley~Davidson motor is of the Each 180 degrees of fly-wheel travel
conventional four-stroke-cycle principle. is one event or stroke. The flywheel must,
Each complete power cycle is made up of therefore, make two revolutions to com-
plete one power cycle of the motor. The
four events. or strokes: hence the term four-stroke-cycle principle is briefly: 1-
"'four~stroke-cycle". This type of motor lnta.ke or admission stroke; 2-Compres-
is commonly referred as a "four-cycle" sion stroke; 3-lgnition and power stroke;
motor. 4-Exhaust or scavenging stroke.

,.;,
1 z (,rp;r;-}
Ppw.lt"A!"Sr,..,Jt'll!

ILLUSTRATION NO. 1
The Accompanying Illustration Graphically Explains the Four-Stroke-Cycle Principle

General
To insure the most accurate results piston head so as to locate it properly in
when timing valves and ignition, the motor the cylinder for setting valves and timing
should be taken out of the frame and the ignition.
front cylinder plug removed. After the Piston positions in motor timing are de~
cylinder plug is removed, a 6" scale can termined from either top (upper) or bot-
be passed through the opening to reach the tom (lower) dead centers. Dead center
 ILLUSTRATION NO. 2
"V" Twin Motor with Cutaway Gear Cover, showing how 1915 to 1924 Twin Magneto
Models should be set according to Gear Marks. Valve Timing on all motors
since 1915 should have Gear Marks Aligned as shown in this lllustration
is the point at the extreme top or bottom instructions must, therefore, be' studied and
end of piston travel-the point where the applied carefully to obtain the original fac-
piston is ··dead''. tory timing.
The dose relation between piston travel Complete valve and ignition timing for
and valve operation requires close measure- each type of motor will be found und-er a
ments when timing a motor. The following heading covering that type of motor.

To Convert Inches Into Millimeters

First of all convert the fraction into The decimal or fraction can now be
decimals as follows: Add c i p h e r s converted into millimeters by multiplying it
(naughts) to the numerator and divide by 25.4
this by the denominator. Place the deci- Example: 7/8 inch=.875=22.22
mal point so as to make as many decimal millimeters.
places in the result as there were ciphers Process .875
(naughts) added. 25.4
Example: 7j8 inch fraction equals
.875 inch (decimal). 3500
4375
Process 8/7.000 1750

0.875 22.2250

Twin Cylinder "V" Type Motors

To Time Valves on "V" Twins
All twin motors, since 19 J 5, have the the pistons and cams will be in proper re-
pinion and cam gears marked which, of lation; however, the valves will not open
course, makes valve timing on these models and close properly until the valve tappets
.a very simple matter. By merely lining up and push rods are adjusted according to
these marks as shown in illustration No. 2, the following specifications.

Valve Tappet Adjustment

( 191 5 and Later Models)
When making adjustments to valve tap- .01 0" between their heads and the valve
pets, the motor must be cold in order to stems.
obtain accurate results. The inlet valves must have a clearance
The exhaust valve tappets must be ad- of .004" between their stems and levers.
justed to have a clearance of .008" to

Valve Timing Specifications for "V.. Twin Motors

(The Foil owing Covers Valve Timing Regardless of Gear Marks)
The exact time of valve opening and The following are piston locations in
closing can be determined easily by turning fractions of an inch. from either top or
the push rod or lifter pin while the motor bottom dead centers, when the valves are
is being turned over. When the push rod opening and closing.
or lifter pin begins to tighten or loosen, as For an example: With the gears
the motor is being turned over, the valve is meshed properly the inlet valve opens
beginning to open or close. when the piston is between 3/16" and
5I 16" before top dead center. This means from the top end of its travel, the cam
that the piston is on an upward stroke and gear has turned so the inlet valve starts
when it is between 3 I 16" and 5/ 16" to open.

Inlet Valve Timing Specifications

The inlet valve should open when the The inlet valve should close when the
piston is between 3jl6" and 5/16" before piston is between 3 j4'' and 7j8" after
top dead center (piston is coming up on bottom dead center (piston is coming up
exhaust stroke) . on compression stroke).

Exhaust Valve Timing Specifications

The exhaust valve should open when The exhaust valve should close when
the piston is between 5 j8" and 3/4" the piston is between 1/I 6" and 118"
before bottom dead center (piston is going after top dead center (piston is going down
down on power stroke). on intake stroke) .

Breather Valve Specifications

The port in the sleeve of the relief on either top dead center. The breather
valve must be open between I /16" and valve port opens as the shaft is turned in
3132'' when the front cylinder piston is a left handed direction.

To Timer Breather Valve or Mechanical Relief Valve

( 1914 and Later "V" Twins)
The relief valve is provided to allow the When the pinion gear and cam gear
crank case compression to be expelled when marks are aligned the breather valve gear
the pistons descend. can be meshed with the pinion gear so the
Besides relieving the crank case com- marked tooth is within the "V" stamped
pression, the breather valve controls the in the crank case. Refer to Illustration
lubricating system to a large degree. The No. 2 showing correct valve and breather
importance of correct timing for this valve valve timing according to gear marks.
is therefore obvious.

Ignition Timing for "V" Twin Motors

Circuit Breaker Contact Point Specifications
To insure extreme accuracy in igni- Harley-Davidson
tion timing, make sure that the circuit Generator .... -.020 inch
breaker points are set according to the Remy Model 250
manufacturer's specifications. An adjust- Generator .... -.020 inch
ing wrench fitted with a thickness gauge Remy Model 235
accompanies each ignition apparatus. If Generator .... -.020 inch
such a gauge is not available, adjust the Bosch magneto ... - . 0 16 inch
breaker points according to the following Berling magneto .. - . 0 18 inch
data: Dixie magneto .. -.020 inch
 Ignition. or the electric spark occurs at gasses and hence cause complete combus-
the time when the generator or magneto tion, the timing of the spark's occurence is
·circuit breaker points are just separating. always set before the piston reaches top
Since an interval of time is required for ig~ dead center on the compression stroke.
nition to propagate a flame through the

How to Locate Compression Stroke of Piston for Ignition Timing

(All Motors)
As the inlet valve opens, the piston de~ haust valves on the same cylinder will be
scends. taking in a charge of fuel. The dosed when the piston is coming up on the
next up stroke of the piston will be the compression stroke.
compression stroke. Both the inlet and ex~

Setting the Piston for Ignition Timing {All Motors)

After locating the compression stroke, your motor) from the top of the stroke.
move the piston to top dead center ; then By reading the graduations on the scale.
back it down (tum motor backward) the the distance between the piston head and
required distance (see specifications for top center can be determind easily.

Ignition Timing Specifications for "V" Twin Motors

The following specifications give the piston can be set and the circuit breaker
correct piston positions before top dead cen- points timed on the proper cam. to just
ter for solo and sidecar motor ignition tim- separate with the spark lever advanced
ing. The measurements are given so the fully.

7 4" Sidecar or Low Compression DCA Motors

(Generator or Magneto Equipped)
Pistons must be set between 7 j32" and 1 j4" before top dead center.

7 4" Solo or High Compression DCA Motors

(Generator or Magneto Equipped)
Pistons must be set between 1 3 j32" and 7j16" before top dead center.

7 4" Sidecar or Low Compression Motors Using Standard Cast Iron

Pistons
(Generator or Magneto Equipped)
Pistons must be set between 7 j32" and I /4" before top dead center.

7 4" Solo or High Compression Motors Using Standard Cast Iron

Pistons
(Generator or Magneto Equipped)
Pistons must be set between 9/32" and 5jl6" before top dead center.
61" Sidecar or Low Compression Motors Using Standard Cast Iron
Pistons
(Generator or Magneto Equipped)
Pistons must be set between 7 j32" and I j4" before top dead center.

61" Solo or High Compression Motors Using Standard Cast Iron

Pistons·
(Generator or l\1agneto Equipped)
Pistons must be set between 9 j32" and 5 /16'; before top dead center.

61" Sidecar or Low Compression Motors Using Aluminium Pistons

{Generator or Magneto Equipped)
Pistons must be set between 7j32~ and 1 j4" before top dead center.

61" Solo or High Compression Motors Using Aluminum Pistons

{Generator or Magneto Equipped)
Pistons must be set between 11 j32" and 3 j8~' before top dead center.

ILLUSTRATION NO. 3
 61" Special Fast Stock 500, M, A and E Type Motors
(Generator or Magneto Equipped)
Pistons must be set between 3j8" and 7/16'' before top dead center.

To Time Generator for Ignition on .. V .. Type Twins

Before attempting to time the generator, mediate gear may not mesh with the
remove the gear case cover and compound generator and large intermediate gears on
intermediate gear. Refer to illustration the first attempt. However, by turning the
No.3. compound gear a tooth at a time, a place
The timer cam for '"V.. Twins is will be found where it will slide into mesh
shaped to have a large and a small end, the easily.
small end being used for timing the front It is a good policy to check the timing
cylinder. Looking at the circuit break,er after the piston has been located, the points
housing from above, the cam turns in a set and the gears meshed. This can be done
clockwise (right hand) direction. by turning the motor until the points are
The timer advance and retard lever just separated; then pass a scale
must be all the way advanced (forward) through the cylinder plug hole to the
when timing ignition. With the front cyl- top of the piston, finally turning the motor
inder piston set according to specifications forward until the piston reaches top dead
for the particular model of motor, turn the center. Note the piston's upward travel
timer cam clockwise, by means of the gen- in fractions of an inch and if it does not
erator gear until the small cam is just check with the specifications, retime th~
starting to separate the circuit breaker or motor as may be necessary.
contact points. Now that the piston and When timing ignition, the backlash of
timer cam are set, hold the generator gear the gears and timer cam must be taken
with the thumb of the left hand to keep into consideration. Otherwise, the piston
it from turning; then mesh the compound location and bre~ker points will not check
intermediate gear. The compound inter~ according to the specifications.

Magneto Ignition Timing for "V.. Twin Motors

(Roadside or Temporary Timing)
The magneto can be timed by lining up however, it must not be taken as a factory
all motor gear marks ; then fitting the mag- standard. The best method is, of course.
neto gear to the armature shaft. The to remove the front cylinder plug. locate
magneto drive key must. of course. be in piston and set the interrupter according
place. This method of timing will be close to the following instructions. Refer to
enough for emergency or quick timing. illustration No. 2.

Factory Method for Timing Magneto Ignition

The magneto drive key used between Locate the piston in the front cylinder
the gear and shaft should be filed thin so according to specifications for solo or side-
as to allow movement of the gear on the car service. Loosen the magneto drive
shaft if necessary, to obtain the correct in- gear nut (do not remove the nut) and
terrupter and piston setting. loosen the drive gear on the shaft. The
gear should be loosened with gear puller then force the drive gear on the shaft.
FK831, or, if this tool is not at hand, by tightening the lock nut to hold the gear in
tapping it sharply with a small hammer, place.
preferably a brass hammer. Check the timing by observing the open-
Advance the magneto timer by shifting ing of the interrupter points and measuring
it downward. Turn the interrupter in an the distance of the piston's upward travel
anti~clockwise (lefthand) direction, until before it reaches top dead center. If nee~
the lever fibre block· is just touching the essary. retime the motor until it does check
rear housing interrupter shoe. Hold the with the specifications for that particular
interrupter in this position so it cannot tum, type of motor.

Ignition Timing for Model 250 Remy Generator

The 250 model generator timing is the cam turned clockwise until the circuit
similar to that of the magneto. The timer breaker points are just ready to separate.
cam has a small and a large end. The After the proper piston position has been
small end is used to time the front cylin~ obtained, the generator gear can be fitted
der. to the shaft and secured in place with the
The circuit breaker ring assembly is lock nut. As in the case of the magneto,
advanced when turned to the right or the drive key should be filed thin in order
clockwise. to allow the gear to be shifted on the shaft
The timer should be advanced fully and if necessary.

Valve Timing for 191 3 & 1914 "V'' Twin Motors

Since the cam gear used in these motors The roller arm roller for the front cylinder
is not marked. it will be necessary to lo~ will be just riding off the first or exhaust
cate the pistons in the proper places in the valve cam. Looking at the gears from th!:!
cylinders and then set the cam to operate right side of the motor, the small pinion
the \•alves accordingly. gear turns in a righthanded direction and
It is probably easier to set the exhaust the cam gear turns in a left handed direc-
valve on its chfing period because this tion. When timing valves according to this
takes place when ·the piston is just over top method, the exhaust valve tappets must, of
dead center. That is. the piston has reached. course, be adjusted to have between .008"
top dead center and has just started on and . 01 0" clearance.
the next downward stroke. Since the exhaust and inlet valve cams
Locate the front cylinder piston between are mounted on the same timing gear
I j16" and 3 jB" after top idead center. (made integral) the inlet valves do not
then mesh the cam gear with the pinion require independent timing.
gear so the exhaust valve is just closing.

Valve Tappet Clearance for 191 3 and 191 4 "V" Twin Motors
On all Twin cylinder motors, prior to made in various thicknesses and if neces-
1915. allow .004" clearance between the sary, can be ground until the correct clear-
exhaust lifter pins and the valve stems or ance is obtained.
caps. The caps used on the end of the The inlet levers and valve stems should
exhaust valve stems on ~ese motors are be adjusted to have . 004" clearance.
 Single Cylinder Motors
Single Cylinder Valve Timing {All Models)
The exhaust valve timing in all single On most single cylinder models the pin-
cylinder motors should be such as to ion and cam timing gears are marked, thus
cause the valve to open when the piston making exhaust valve timing a simple mat-
is between 3 j4" and 9/16" before bot- ter. All that is necessary in this case is
tom dead center and close when the piston to line up the pinion and cam gear marks
is between 1 j 16" and 1/8" after top and the valve is rimed.
dead center.

Exhaust Valve Tappet Clearance for All Single Cylinder Motors

Except Model 21 CD
Adjust the exhaust tappet to allow end of the valve stems. These caps are
.004" clearance for all single motors ex- furnished in various thicknesses, and can, .
cept model 21 CD. On early model therefore, be ground to give the correct
motors steel caps were placed over the clearance.

Single Cylinder Motor Inlet Valve Timing

All 191 3 to 1918 single cylinder between 1 /8" and 3 /8" after bottom
motors require independent timing of the dead center. Allow .004" clearance be-
inlet valves, because the inlet cam is on tween inlet lever and valve stem when
one of the intermediate timing gears. The motor is cold.
inlet valve should be timed to open when Single cylinder motors made prior to
the piston is 3/ 16" before top dead center. 191 3 have automatic inlet valves, which
The inlet valve should be timed to close therefore, do not require timing.

19 21 CD Single Motor Inlet Valve Timing

The inlet valve in this motor is operated not, therefore require independent timing.
by the secondary or cam gear and does

Valve Tappet Clearance for 21 CD Single Motor

When motor is cold, allow .004" 'clear- between .008" and .01 0" for the ex-
ance for the inlet valve stem and lever, and haust valve stem and tappet.

Breather Valve Timing for Single Cylinder Motors

All single motors except model 21 CD gear so its marked tooth checks with the
have automatic relief or breather valves. A stamped in the crank case. Refer to
which, of course, requires no timing. illustration No. 2 showing the proper set·
To time the breather valve on model ting for valves and breather according to
21 CD single motors. align the pinion and marks.
cam gear marks. then mesh the breather

Single Cylinder Motor Ignition Timing

(All models except 21 CD)
All single cylinder motors should be ton set between 3 j 16" and 1 j4" before
timed for the spark to occur with the pis~ top dead center on compression stroke. The
interrupter housing must be advanced fully lever set just ready to break the points with
(shifted downward) and the interrupter the piston located as mentioned above.

Model 21 CD Single Ignition Timing

The 1921 CD model commercial sin~ 1 /4" to 9/32" before top dead center.
gle should be timed with the piston set

Timing Single Cylinder Motor Ignition According to Gear Marks

With the pinion gear and cam gear and gear, then fit the intermediate gears
marks aligned, fit the magneto drive key so all marks are aligned.

ILLUSTRATION NO. 4
 Connect the central eyPiet of wire No. 7 to the rear spark coil terminal (have
this wire in a ,·ertic:tl ji<'Sition to pre,·e,,t grounding on the n1etnl t·oil !'nd) and
loop back to horn terminal No. H.
Connect the central eyelet of wire No. 4 to the battery box bakelite terminal
block with the positive battery wire. The end of this wire must be connected to
light fuse terminal No. 15.
Make sure that the battery negative wire is securely grounded to the battery
lock washer, see No. 2, which fits under the seat post pinch bolt or the frame brace
eye bolt nut. This battery ground lock washer is furnished with the switch. The
battery negative wire must be positively grounded to prevent the manual switch
vibrator points from burning.
The manual switch is now in circuit with the battery and generator. Make the
light and warning signal connection3 as follows:
Connect the eyelet of the RED cahle wire to terminal No. 9. Connect the eyelet
of the BLACK cable wire to terminal No. 11. Connect the eyelet of the Gin:EN
cable wire to terminal No. 12.
Note:-Terminal No. 10 on 1918 lighting ~witches becomes void when fitting
the manuat switch.
The short wire which passes through the hushing in the light switch base must
be connected to Terminal No. 13 and with the large eyelet of the tail light wire to
.terminal No. 6. Make sure that this terminal is properly insulated from the manual
switch bracket.
All wiring and connections are now complete and the manual and lighting
switches are ready for use.
The lighting switch is used in the regular manner. The manual Ignition switch
must be operated according to directions under Instructions for Operating the
Manual Switch.
For adjustment. to any part of the manual switch, refer to directions under
To Adjust the Vibrator Blade Points.

HARLEY-DAVIDSON MOTOR CO.

MILWAUKEE, U. S. A.
 ~

·--~

Service Dept. Bulletin

No. Part No. Name of Pnrt No. Part No. Nnme of Part

1
2
3
AG
AG
AG 8
Releasing disc
Friction disc
Drive disc
16
17
HG 122

HO 389
Actuoting cam drum
sembly
SPACER WASHER
...
4 CQ 351 Driving hub 18 HG 127 Left cone
5 AG 13 Drivina: hub nut 19 HG 129 Axle bu!!hing
No. 83 B April 1st. 1922 Harley-Davidscn Motor Co., Milwaukee 6 AQ 14 Driving hub lock nut 20 CG 265 Lock washer
7 AG 15 Drivlna disc lock nut 21 WHA534 Drum stationary cam
8 AG 6 Friction disc assembly 22 BO 43 Actuating collar clamp screw
9 AG 19 Actuating collar 23 1;10 453 !-'"ball
10 CG 20 Actuating plate 24 HO 768 Lock nut
II AG 22 Clutch apnng screw 25 HG 128 Outer cam bearing
12 AG 23 Sprina nut sector 26 DG 85 Hub shell assembly (1915-16
13 BQ :u Clutch spring 17·18)
14 AG 33 Ball retainer assembly
Instructions for Fitting and Making Necessary 15 CG 85 Hub shell asse~_bly (1914) _
~--~--
-~~---

Adjustments on Set HG -I 3 3
Cam Action Set HG-133 for HARLEY-DAVIDSON
REAR HUB CLUTCHES USED WITH
SINGLE SPEED MODELS
The left cone that is supplied with the As the friction discs of the clutch wear,
new cam action set replaces the original additional washers (No. I 7) will have to
actuating worm cone. This new cone be ADDED to compensate for this wear,
should be screwed on the axle just far otherwise the clutch cannot be released
enough to permit a very slight shake at the provided it is adjusted so that it will
rim ; this insures the wheel bearings against hold.
being cramped. If the space between the axle bushing
The actuating cam drum assembly is and the outer cam bearing is entirely filled
then placed over the left cone after the with spacer washers, the clutch will not
actuating plate has been fitted, and is fol- hold, because the discs cannot come to-
lowed by the drum stationary cam, outer gether. This explains the importance of
cam bearing, axle bushing, spacer wash- the correct adjustment that is obtainable
ers, axle lock washer, and the lock nut. with these washers.
The plain washers are spacer washers The clutch adjustment is effected in
(See No. 17) which, when not properly the same way as it was heretofore, i. e.,
fitted, interfere with the control of the changing the position of the actuating col-
clutch. For that reason care must be tak- lar on the actuating cam drum assembly,
en to place the proper number of washers (formerly the actuating nut), and turning
in the outer cam bearing. The proper the six clutch spring adjusting screws. If
number of washers are in position when the adjustments explained in this para-
there is a distance of I 132" or less be- graph will not give the desired resul!s, the
tween the top spacer washer and the outer number of washers must be increased
edge of the hole in the outer cam bearing. or decreased, whichever the case may be.

Cr<tM Section of Cam Actlcm Set HG.J33 •nd

Harle7•DaYid.oa Rear Hub Clutch Used
with Sinal• Speed Model&
 the clamp ring may bt" squeezed together must not I)(' assumed thai the glass anrl

Service Dept. Bulletin in a vise so as to make the inside dimension

about I 32" (.79 mm) less than
standard.
When filling the head lamp ring, it
ring a1r ti~ht by merely tightening up the
retaining scrrw. The best mrthod is to
lap the ring lightly around its circum-
ference and then lighten the screw again.
No. 95. October I, 1922. Harley-Davidson Motor Co., Milwaukee
Satisfactory Method for Repairing Model 23 5
Miscellaneous Bulletin
Most of the contents of this miscd- docs not often retain copies of the News
Generator Right End Plates
lanl"ous bulletin have appeared from tine Bullet'n, we are, therefore, publishing this IftHe right end plate on a model 235 edges inward with a hammer to reduce
to time in the Weekly News Bulletin. Service Bulletin for the repairman's ref- generator becomes loose and· the generator the diameter to give a press lit on tlte right
Owing to the fact that the repair shop erence. is used for any length of time with it in end plate. The peening process should he
this condition, serious damage may result done on the lower half of the hody's open
Important Instructions to the· armature. end, striking the hammer against the outer
The clearance between the armature edge at a 45'' angle. The peening process
for Machines Equipped with Ammeters should be continued until the body has
core and pole pieces is approximately
We ha\e traced many cases of so-call~d sulate the joint with tape and shellac. .007" (.17 mm). Should the end bear- shrunk so that it will be necessary to force
ball<'IY and generator trouble directly to Then ground the rnett'r ne~aliH· ternnnal ing plate work loose and wear the gener- the right end plate in place. Note: Be-
the ammeter installation. Very few rid.,rs wire on the ballery ground lock washer, ator body excessively, the armature core fore attempting to peen a generator body,
realize that the ammeter is in .direct series KK-381-P, or some other clean metallic will rub against the pole pieces and in make sure that it is malleable and not cast
with the battery and generator and if it part of the frame. consequence will become damaged - iron. Bodies have been made from both
should cea<e lo function, that these units Do not depend on tool hoxes for good perhaps beyond repair. It is, therefore, of these metals. Cast iron would chip
may possibly be damaged. It is, the•e- grounds because enamel, parkerizalion important that the repairman be on the and break if peened as above descrihed,
fore, imperative that the ammeter be hpt and rust in many cases pr~ctically in- lookout for difficulties of this nature and while malleable iron is Iough and will give
in circuit at all times. sulate them from the frame. Hence, if effect a remedy before they become serious. under hammer blows. Hence, there is
When an ammfler is used in the el•·c- a one-wire ammeter is used an additional no apparent remedy for repairing a worn
trical system it mu'l be of the two-wire wire must be connectPd to the mekr A worn generator body register can b~ cast iron body - except replacing it with
type and connected as follows: Conn•'cl negative l<'rminal post and then securely usually repaired by peening its outside a new one.
the meier positive terminal wire to the grounded on the baltery ground lock
batlery negative wire and thoroughly in- washer or elsewhere. Instructions for Fitting
Importance of Generator Brush Inspection New Circuit Breaker Lever Ground Spring
The generator voltage is controlled by This arrangement makes periodical in- Good, clean metallic connections at all
the 6-voh storage battery be.ng in the spection of the brushes absolutely nrcrs- primary circuit joints are absolutely essen-
circuit and should the battery be remov.,d, sary because serious damag<' may result tial for easy starting and efficient operation
purposely or by an accidental open circuit, to the armature if the brushes wear until of the motor. Although the circuit breaker
the generator current and voltage will be they are held away from the commutator. lever stud is bearing in a bronze bushing
exlremel¥ high when high speeds are at- Should the negative brush wear until and is held tight by a strong spring,
tained. Such high current and voltage rr.ay the holder strikes the slop, thus holding chances still remain for oxidation which
prove disastrous to the generator a 1d the brush away from the cummutalor, the would partially insulate the lever elec-
ignition units. Hence the importance of battery will be ~ut of the circuit and in trically.
the following is obvious. To .overcome the possibilities of bad
On all model 235 and Harley-Dav;d-
wn generators, a stop is provided for ench
consequence a high voltage will be grner-
ated in the :umature. This high cqrrenl
and voltage will heat the armature exces-
connections at this point, we have allached
a bronz.e spring to the circuit breaker ___
-- --.-
.......t_
brush holder to prevent the brushes fnm · sively and cause the mldered connections lever, which .should be grounded to the
wearing until the holders bear on !he to loosen which in turn may damage the circuit breaker base.
commutator. armature beyond repair. To. ground the lever spring requires
that the base be drilled with a. No. 35
Method for Retaining Head Lamp Glasses (.110" or 2.79 mm) drill at the location 3
Head lamp glasses vary considera'>ly without additional gaskets. specified in the illustration, and then ter vertical line, and No. I is Y4" ( 6. 3
in thickness, sometimes as much as I -'32" If a glass is too thin it can usually be lapped with a 6-32 machine screw tap. mm) from the line upon which the base
(.79 mm) which, of course, would make used by using a cardboard gasket. If The- hole No. 3 is located as follows: stud and primary terminal holes are drilled.
it impossible to keep a thin glass light this method does not work satisfactorily, No.2 is 5/16" (7.9 mm) from the cen- The illustration is self-explanatory.
 Turning Commutators Use reamer No. 2 for 61" (988 cm 3 ) or oversize throttle shaft, it is beyond
carburetors, and No. 5 for 74" ( 1208 economical repair.
Oflcntimes the repairman is called upon to the tool holder and after selling it
cm·1 ) carburetors. The hushing can now Parts and tools for making above re-
to turn down or dress a commutator and slightly below the center of the work, set
be inse.rted. Start the tapered end of the pairs:
he should. therefore, have a knowledge of the feed to cut as line as possible. The
bushing in the rt·amed hole and drift it in Monel body bushings for 61" and 74"
such work. Whenever possible, a lathe work should he turned approximately 300 place with the special drift. Use drift
should be used for this kind of work r.p.m. for best results. (988 and 1208 cm 3 ) carburetors·-
No. 3 for 61" (988 cm 3 ) carburetors KX-1744.
l>ecause accuracy is absolutely essential. After dressing the commutator as just and No. 6 for 74" (1208 cm 3 ) car-
When selling up a commutator job in outlined, smooth it with a line cut mill file buretors. Monel bushed throttle shaft for 61"
the lathe, nt·ver use the shaft centers he- and finally with No. 00 sandpaper. If the throllle shaft binds in the monel (988 cm 3 ) carburetors - KX-1 712.
<:ause in many cases they are not the true Remove all traces of copper and carbon metal bushing, the lit can be improved by ' Monel bushed throttle shaft for 7 4"
ualer and in consequence the commutator from the grooves between the segments dressing the shaft bushing carefully. ( 1208 cm 3 ) carburetors- KX-17120.
"ould be turned untrue. Chuck the shaft and if necessary undercut the mica as fol- Note: If a carburetor body casting Complete set of six tools for fitting
dnvP end and hold the commutator end lows: With a knife or tool made from a has once been fitted with a Y4" (6. 3 mm) monel bushings- KX-480.
l>e<Hing m the lathe center or steady rest. hack saw blade, remove the mica insulation
This method will, of course, require more to a depth of I /32" (. 7 mm) for the full Lubrication of Rear Mud Guard Hinge on 1923 Models
time and care in selling up the job. How- width of the groove. Owing to the fact that the new style it is, therefore, advisable to lubricate it
ever, the results obtained will more than If the armature leads require soldering, mud guard hinge is exposed to the weather, from time to time with motor oil.
ollsel these differences. it is best to ~older them before turning the
;\Iter chucking and centering the commutator as the surplus solder can then Starter Crank Bushing Assembly HG~591 ~P
ar111ature, lit a diamond point culling tool be removed by. the lathe tool. A much better job can .be made when A set of oversize rivets will be in-
fitting a new starter crank bushing if cluded with each starter crank bushing
Repairing Worn Carburetors by Fitting Monell slightly oversize rivets are used. . These shipped. To fit them, it is necessary to
oversize rivets take care of any wear that drill out the holes in the starter cover with
Metal Bushings may occur in the rivet holes in the starter a 9. 32" (7.1 mm) drill, using the new
cover and will make a tight lit. bushing as a temple!.

Sidecar Support Rod Bolts and Nuts

The sidecar support rod bolts and nuts Small repairs like these will in many
should be examined from time to time to cases prevent a large repair and, inciden-
prevent the body from working loo~e and tally, will help to keep a customer satisfied.
damaging the metal bottom of the car.
Rear Frame Sidecar Bracket Alignment
When fitting the rear frame bracket, carrier, the frame bracket will align per-
DQ-54-Z, for attaching a sidecar, the fectly without the use of the spacing
following instructions should be carefully washer. However, if no luggage carrier
observed. is used, the thick spacing washer, furnished
6 with the motorcycle, should be fitted to
It is absolutely essential that the frame
tlte stud before attaching the bracket. This
lleretofore when a Scheheler Carburetor not furnished separately. The bushed bracket be fitted to the frame studs in
washer acts as a distance piece, thus re-
body became worn at the throttle shaft, it throttle shaft operates in another monel such a way as to be vertical and with no
lieving any strains on the bracket studs
was necessary to frt an oversize shaft. The bushing which is fitted to the body casting. twisting strains on the studs proper.
which might be caused when tightly clamp-
manufacturers have recently developed Carburetor body monel bushing is fitted If the motorcycle is fitted with a luggage ing the stud nuts.
nlimel metal bushings for the carburet"r as follows:
l.ody and throttle shaft to be fitted to worn After removing the throttle disc and New Style Solid Fly Wheels
carhurelors, instead of using oversize shaft, enlarge the body casting bearing A few 1921 and all 1922 and 1923 wheel on parts orders. Bear this in mind
shafts. Monel is a non-corrosive long- with the boring tool. Use tool No. I for 61 cu. in. (988 cm·1 ) motors are fitted if you are called upon to replace an old
wearing metal, and these bushings, there- 61 ·• ( 988 cm 3 ) carburetor, and No. 4 with new style solid fly wheels. These style ":heel· becau.s~ it will be impossible .
fore, make a mud1 more satisfactory re- for 74" ( 1208 cm 3 ) carburetors. Note: wheels art: somewhat heavier than the old to duplrcate the ongmal.
pair than oversite shafts. The boring tool should be used in a drill style webbed or spoked wheels. However, All 74 cu. in. ( 1208 cm 3 ) motors use
l"lre throttle shaft proper is bushed pre;s to prev<'nl possible breakage. the new solid flywheel is interchangeable solid type flywheels. Therefore, it will
11 1!lr a numcl lntslriug. This l>!!slring is Next, enlarge the hole with the reamer. with the old style either singly or in pairs. be impossible to become confused when rc-
We, therefore, supply o11ly the solid type placing flywheels in these motors.
 be fitted with long rollers he referred to us long rollers hecau'c of the width of the
Good Exhaust Valve Seats Are Important for rebushing and regrinding. This will bushing. The bushing would he hell-
After combu:;tion takes place, the and abnormal cylinder valve seat. insure a perfectly paralleled bearing sur- shaped and cause the long rollers to bind
burned gases remain to be scavenged by Lowered valve seats will, therefore, face for the long roller bearings. in the center, which may cause breakage.
prevent. perfect scavenging and hence will NOTF.: If tlwh<'nt·inJ.~ h:ts :tlrPndy u~nl lall~
the next upstroke of the piston. The only rollt·r~. it c:mt!H•n 11(1 lapp<'d for use with m.·w
cause the motor to overheat excessively. This connectin;; rod bushing cannot be
means of exit for these excessively hot lon~-r rollt•rs.
llow(•\'f'r, this cloPS nut hold J.{t>od
lapped with the lapping arbor when fitting for bearings fiit('d vreviously with short roJIPI'l',

V.ALV£ 0!"'&1'1 V/1~VE OPEN

!VorE /low.5HovLvEg Instructions for Using Reamer KK-84 7
o~ni1L c~&/11('/?NC&
I)ECREI?CE.S CI..E/1-f'/11'/CE This reamer is designed to ream gear through the bushing until its end projects
shaft bushing DA-51-P for both standard I%" ( 44 mm) beyond the end of the
and .002" (.05 mm) oversize gear shafts. bushing.
To accomplish this, the cutting edges of Should the reamer become dull, it can
the reamer are slightly tapered throughout be sharpened as follows: Rub the cutting
their length. face of one blade with a hardened steel
When reaming new bushings for stand- tool. Such a tool can be made by grind-
ard shafts, pass the reamer through the ing off the teeth of a broken file. This
bushing until its end projects Ya" ( 3. method of sharpening will "turn up" the
mm) beyond the end of the bushing. This cutting edge and renew the usefulness of
will give the standard factory clearance the reamer. It is best to mark one cutting
for the shaft and in addition a slightly blade and sharpen it only, from time to
tapered bushing hole which is ideal for iime as rna y be necessary.
this particular bearing. When not in use, keep the cutting
gases is through the exhaust port after The direct result of an overlwating motor To ream a· worn bushing for a .002" edges of the reamer well oiled and away
the exhaust valve is opened. This port is is loss of power, speed and improper (.05 mm) oversize shaft, pass the reamer from hardened steel objects.
open for only a brief interval and its lubrication. In addition to these, the ex-
greatest area is a trifle over one square haust valves may be warped and· burned. Compression of 74 cu. in. ( 1208cm3) Motors
inch (six and four tenths square centi- All cylinders having lowered exhaust The 1922 model JD (74" solo) compression. On the other hand, if a
meters). It is, therefore, obvious that valve seats should. therefore, be machined motor is fitted with I/ 16" ( 1.5 mm) motor has been running satisfactorily it is
the valve, valve seat and lifting mechanism with the special clearance cutter JK-845- compression plates. The 19 22 model riot necessary to change the compression.
be in good condition and adjusted prop- A. This cutter is made to fit the standard JDS (74" sidecar) motor is fitted with a Note: All 1922 74" (120S cm: 1) molo1·s above
erly. valve seat reamer handle. The cutting set of Ya" and 1,/16" (3.1 and 1.5 mm) 22JfJ664V are fitted with 1',:" (1.5 mm) 1ong-f'r
erlindcrs. The1·efore it. should n<'\'(-'1' h£> n<'c:"'<'~
Constant beating of the exhaust valve edges are ground to a 3" angle to give the compression plates. The compression of ~ary to lowPr the compt'e!'>sion of these motors
proper clearance for the valve. This cutter these motors is 1. 16" ( 1.5 mm) lower for ordinary !>ervice.
head against the cylinder seat will even- For solo st>rvicP, these mo(ors use no compre~­
tually wear the seat, that is lower its will work in all cylinders since 191 5. than the 1921 motors. It is well to bear sion plntcs. For l".idecar serviee ~f.!·" !!l.l mm)
C•.lmpression piRtes only are used.
position. Lowered valve seats leave a When using the clearance culler, do this· in mind when overhauling the 1921 All cylinden;. that are 1\ ; " ( l.fi mm) lonJ!f'l'
shoulder that partially envelops the valve not remove any more metal than is neces- motors. If a motor is inclined to overheat than }lrC'dou:-; ~tnndard cylinrler~ will 1x> markt:d
with nn al"!'o\V on the rig-ht ~ide of th£" hn-.e
head and consequently prevents a full port sary from the bottom of the valve chamber. or "knock," it may be well to lower the flnn~t·.

opening even with the vaive in an open The proper method is to remove just
position. Refer to the two illustrations enough metal to remove the shoulder from
for a graphical explanation of a normal the valve seat.
HARLEY-DAVIDSON MOTOR CO.,
Long Connecting Rod Roller Bearing KA-8 0 7 Milwaukee, Wi~., U. S. P. ..
This roller bearing has been used in will give unusually long service with
the rear connecting rod of all 1922 motors minimum of wear.
numbered above 22-JD-8385, thus dis- Owing to· the necessity of a perfectly
placing the twenty-four short rollers true bearing surf ace in order to use long
formerly used in this bearing. The spacN rollers satisfactorily, a repair job .cannot
washer, DA-746, will be used at one successfully be made without first referring
side of the assembly in order to maintain the rods to the factory for regrinding. We,
the same length. The new long rollers therefore, suggest that all rods that are to
 No. Part No. Nam~ of Part
--- --- -------~

Service Dept. Bulletin

1 HO 122 Actuating cam drum a5semb1y
2 HO 389 Spacer washer
3 HG 128 Outer cam bearing
4 HO 130 Inner cam bearing
5 HG 131 Axle bushing
6 co 265 Lock washer
1 WHA 534 Drum stationary cam
No. 83A. November 1, 1922 Harley-Davidson Motor Co., Milwaukee 8 co 85 Hub shell asoembly (1914)
9 DO 85 Hub shell assembly (1915·16·17-18)
10 HO 768 Lock nut
II HO 390 Large Spacin~._.,w,.,• ..._•h~e:-_r_ _ _ _ _ __

Instructions for Fitting and Making Necessary

Adjustments on Set HG-1 34 for
TWO-SPEED HUBS
In the following instructions, the num- is a distance of I j32" or less between the
bers mentioned will correspond to the lop spacer washer and the outer edge of
enumerated parts in the sectional illustra- the hole in cam bearing 3.
tion. The- assembly should. therefore, be As the friction discs of the clutch
made without difficulty providing these in- wear, additional spacer washers 2 will
structions are followed closely. have to be added to compensate for this
The inner cone bearing 4 which re- wear, otherwise the clutch cannot be re-
leased provided it is adjusted so that it
places the actuating worm cone must be will hold when fully engaged.
screwed onto the axle just far enough to
permit a slight shake at the wheel rim. If the space between the axle ~hing
This insures the wheel bearings against 5 and the outer edge of the cam bearing
being cramped. 3 is entirely filled with spacer washers 2,
the clutch will not hold, because the clutch
After the actuating plate (triangular discs cannot come together. This ex-
plate with three legs) and ball thrust plains the importance of the correct ad-
bearing have been fitted, the remaining justment that is obtainable with these
parts are put in place in the following washers.
order:
To compensate for the wear of the
!-Actuating cam drum assembly ; 7 actuating cams, additional spacing wash-
---drum stationary cam ; 5-axle bushing ers I I , can be added to give the proper
with counterbored end inward ; I I --outer adjustment.
cam bearing spacer washers (large); 3 -
the outer cam bearing; 2-spacer washers The clutch adjustment i; made in the
(small); 6-axle lock washer, and left same way as it was heretofore; that is,
cone lock nut I 0. changing the position of the actuating col-
lar on the cam drum assembly, (formerly
The small spacer washers 2. when not the actuating nut), and turning the six
prcperly fitted, interfere with the control clutch spring adjusting screws. If the
of the clutch, and for that reason care adjustments explained in this paragraph
must be taken to place the proper number will not give the desired results, the num-
of these washers between the axle bushing ber of spacing washers 2, have to be in-
5, and the lock washer 6. The proper creased or decreased, whichever the case
number of washers is in position when there may be.

Cross Section of Cam Action Set HG-134 and Clutch Uaed with all Two-Speed Mod.le
Service Dept. Bulletin Reseat Brushes after Turning Commutator
After turning and dressing a commu-
tator, make sure the brushes are in good
Use No. 00 or the finest grade of
"sand paper" obtainable for resealing car-
No. 98. Oct. 10, 1923. Harley-Davidson Motor Co., Milwaukee condition and that the brush springs, on bon brushes. Cut the sand paper in
models up to 1924, have a· tension be- strips 3/8 inch (9.5 mm) wide for con-
tween 8 and 9 ounces, (.22 or .25 KG). vemence. Lift one of the brushes and
The 1924 model generator brushes should
How to True Commutators Using Collar have a spring tension between 8-1 /2 to
place a strip of sand paper between it and
9-l/2 ounces, (.23 to .26KG). the commutator, sand side next to the
M-K-883 for Bearing Center On earlier than 1924 models it is a
brush. Press lightly on the brush and
When armatures are finished in the fac- Clamp the drive end of the armature good policy to fit new brush springs every withdraw the sand strip. Repeat this
tory, that is, when final turning and grind- shaft in the lathe chuck close up to the time the motor is down for carbon re- operation until the brush face conforms
ing is done, the shaft centers are not used. armature windings. Center the commu- moval. If the generator is not already to the curvature of the commutator.
All commutators are turned from bearing tator end and oil the tail stock and collar fitted with new style brushes, IR 160A Reseal all three brushes accordingly.
centers because the armature must revo!Ye centers. and IR 163A, by all means lit these
in ball bearings and be true to within .001 Use a diamond culling tool, set at the brushes as they are much larger and con- Set the regulating brush to give a cur-
inch (.025mm) of accuracy. proper angle, and turn the armature about sequently longer lived. rent output of not more than 3 I /2 or 4
Therefore, when redressing or turning 300 R. P. M. for· best results. Take The commutator will be slightly smaller amperes. This current rate will be found
commutators use bearing and not shaft off very fine cuts. Finish the commutator after turning, therefore making it neces- ~uflicient for all general conditions of serv-
centers. with a fine tooth file and the finest grade sary to reseal the brushes. Ice.
of sandpaper obtainable, preferably No.
Refer to the illustration, showing how 00.
the special collar, MK883, is used to re-
place the ball bearing when turning com- Clean out the grooves between the com-
mutators. This collar makes a true shaft mutator bars with a knife or specially
bearing center for the turning job. made tool. The grooves should be be-
tween I j64 and I /32 inch (.39 and The following are the factory charges for making commutator
The lathe tail stock center point must .79 mm) deep and the full width of the
be ground off about 3/8 inch (9.5mm) slot to prevent the mica from striking the and armature repairs:
to prevent the point of the center from brushes and cause arcing. Soldering a,nd turning Harley-Davidson and Remy 235-type
touching the armature shaft. commutator on Harley~
If the armature leads are to be soldered, armatures are not rewound.
Remove the armature shaft bearings it is best to do this before turning the com- Davidson and Remy ar-
and worm gear and lit the collar to the mutator. Use powdered rosin and al- matures . . . . . . . . . . . . $1.25 net Wiih the collar above described, it
commutator end, securing it in place by cohol as a flux and half-and-half solder becomes easy to reface commutators prop-
Fitting commutator to erly. If, however, you cannot do the job
the set screw. The side with the beveled for the best results. Thoroughly heat the Remy 235 type arma- or have it done locally, we advise sending
center hole should face outward to serve commutator bars so the solder will flow ture, GXI067 or armatures with commutators that need
as a center for the tail stock point. into the wire slots. GX I 067C . . . . . . . . . 6.25 net refacing directly to us, because unless
The price of a new Harley-Davidson such commutators are refaced, the gen-
armature is such that it does not pay to erators will not perform satisfactorily,
replace commutators on old armatures. even though new bru5hes are installed.
Remy- 250-type commutators cannot be
I~ someone is refacing commutators
replaced without rewinding armatures.
for you, see that he uses an MK883 col-
Rewinding 250-t y p e lar and is not turning the armatures on
armature including new the shaft centers.
commutator ......... $12.00 list

CA'PCK .5#-9/r PP a.,_.

}f;J,,#"//t!CD/I'Vfl.S.
 Motor Repairs
Pistons are always lapped in when cylinders are reground.

Standard Factory Repair Prices Regrinding 61 " cylinders and fitting oversize cast-iron pistons,
nngs, new pins and lock pins .................... per set
Mat') $ 6.26 list
Labor 5.63 net
Mat') 6.68 list
Regrinding 74" cylinders and fitting oversize castJiron pistons,
Nov. 1st 1923. Thisr<PI•mS.muD<pt.Bufl"inNo.96. Harley-Davidson Motor Co., Milwaukee nngs, new pins and lock pins .................... per set Labor 5.63 net
When cast-iron piston motors are fitted with aluminum pistons, the
fly-wheels must be rebalanced and the connecting rods drilled. See
prices below. Instructions for this purpose are furnished upon request.
~IS lis.t is intend~d ~o enable the dealer to quote his customers on repair
T Jobs wh1ch are ordmanly sent to the .factory for attention. The advantages of
such a price list are these:
Regrinding 61"
size aluminum
cylinders, any model,
pistons, rings, new pins
and
and
fitting 1923 over Mat' I 13.62 list
lock rings .. per set Labor 7.25 net
Regrinding 61 " cylinders, any model, and fitting 1924 over- Mat') 12.72 list
I. Th~ dealer can ~xchange a damaged frame or other piece of size aluminum pistons, rings, new pins and lock rings .. per set Labor 7.25 net
eq~upment for a nder from his stock of repaired parts at a price
Regrinding 74" cylinders, imy model, and fitting 1923 over- Mat'l 12.72 list
fan to both, the rider getting immediate service at a fair cost. 7.25 net
size aluminum pistons, rings, new pins and lock rings .. per set Labor
i. If a rider is supplied witha new part from stock the dealer can Regrinding 7 4" cylinders, any model, and fitting 1924 over- Mat') 12.82 list
easily figure the allowance to be made for the damaged part. SIZe aluminum pistons, rings, new pins and lock rings .. per set Labor 7.25 net
When having cast-iron piston cylinders fitted with aluminum pis-
3. Prices for factory repair work become standardized. The tons, specify whether 1923 or 1924 parts are wanted. To fit 1924 alumi-
cha11ce of under-or over-charging the rider is eliminated. num pistons to an earlier than 1924 or 24 JD or FD motor requires the
fitting of 1924 connecting rods because of the larger piston pins.
In estimating the cost of repairs on frames and forks it should be remembered
that the ch~rges given in .the first part of this bulletin are for labor only. To arrive Reaming 61" cylinders for 74" exhaust valves ........ each Labor $1.00 net
111 the repaJT cost, the pnce of the parts needing replacement must be added to the Sandblasting and rewhitening cylinders .....•....... per set Labor 1.50 net
labor charg':. . Frame and for~ fittings are listed in this bulletin. As an example, the Cylinders are rewhitened only when specified.
c.ost of repamng a frame needmg a new rear stay and two casing clamps will be es- Fitting oversize inlet housing clamp nut ................. . Mat' I .50 list
timated as follows: Labor 1.25 net
Rebushing one set 61" or 74" connecting rods at both ends and Mat') 2.16 list
Labor charge (3 parts replaced) ................ $10.00 net
lapping steel bushings ...•.•.............•........•• Labor 1.56 net
I-EE85 R rear stay. . . . . . . . . . . . . . . . . . . . . . . . .90 list
2-DE2 casing clamps @ .20. . . . . . . . . . . . . . . . .40 Rebushing one set 61" or 74" connecting rods at both ends and Mat'l 5.56 list
fitting rollers, retainers and crank pin ..........•.. per set Labor 2.19 net
$11.30 Drilling one set of 61 " or 7 4" connecting rods .........••. Labor 1.25 net
Rebalancing 61 " flywheels for use with aluminum pistons. per set Labor 1.88 net
Any part on which the dealer quotes a repair or exchange price should be in- Rebalancing 74" flywheels for use with aluminum pistons.per set Labor 2.50 net
~pecte~ very carefully. It may be found, for example, that a frame which on first
Tlle86 price8 appi1J onl11 when fltltlllletfl• without 811atta are aent fn.
mspect1on seems to be out of line, has one or more cracked parts such as cylinder or casing Mat') 1.00 list
clamps, or even more expensive fittings. Rebusbing one set of inlet lifter arms and fitting rollers and pins { Labor .63 net
Rebushing one set of exhaust lifter anns and fitting roller and pins Mat') 1.04 list
All ~rices on part~, except whe~e otherwise noted, are list. Where list prices Labor .63 net
are not subJect to usual d1scount, net pnces are shown. All labor prices are net.
Refacing exhaust valve ...........................• each Labor .31 net
All quotations are subject to change without notice. Fitting 1915 to 1922 type mechanical oiler with operating shaft Mat') 1.35 list
and bushing ................................•.... Labor 1.25 net
QUOTATIONS COVER ONLY SPECIFIED OPERATIONS Fitting 1923 and 1924 type mechanical oiler with operating shaft Mat'! .95 list
Labor .88 net
We suggest that the dealer go over the liat carefully and set a .40 list
Rebushing transmission main shah ..•................... Mat'l
definite schedule of retail prices. ' Labor 1.25 net
 SPORT MODEL FRAME PARTS
Part No. Name Models Price
WGE31 Front Bar Only .................... All Sport Models $ .95
WIE41 Rear Bar Only ..................... All Sport Models 1.05
AWGE20 Upper Bar ........................ All Sport Models 2.30
AWGEII Lower Bar ......................... All Sport Models 1.05
WGE70R Rear Fork (Upper) .................. All Sport Models .75
WGE71R Rear Fork (Lower) .................. All Sport Models .85
WGE7 Frame Head ....................... All Sport Models 3.00
WGE32 Front Motor Bracket ............ ." ..... All Sport Models 3. 70
WGE42 Rear Motor Bracket .................. All Sport Models 3.60
WGE9 Front Connection for Lower Bar ........ All Sport Models .95
WIEIOA Rear Connection for Lower Bar ......... All Sport Models 1.00
WGE8 Seat Post Cluster .................... All Sport Models 230
WGE23 Seat Bar Bracket .................... All Sport Models .45
WGE85 Rear Mudguard Support .............. All Sport Models .90
WGE62- Left Rear Axle Clip ................ All Sport Models 2.20
WGE52 Right Rear Axle Clip ................ All Sport Models 2.20
SWIWAU FRAME PARTS-SINGI.E PASSENGER----11)15 TO 1924
DQ33 Main Bar (Next to Motorcycle) ......... 1915 1to 191 7 $2.40
GQ33 Main Bar (Next to Motorcycle) .......... 191·8 to 1923 3.50
MQ33 Main Bar (Next to Motorcycle) .......... 1924 5.20
DQ6P Axle Tube (Rear Bar Assembled) ........ 1915 to 1923 3.00
MQ6A Axle Tube (Rear Bar Assembled) ........ 1924 3.55
EQ37 Side Bar (Away from Motorcycle) ........ 1915 to 1924 1.00
EQ36 Front Bar ............................ 1915 to 1916 I .00
EQ36A Front Barr ............................ 1917 1.65
GQ36A Front Bar ............................ 1918 to 1923 1.35
MQ36A Front Bar ............................ 1924 1.55
DQ7 Truss Bar (Diagonal) .................. 1915 3.80
EQ7 Truss Bar (Diagonal) .......•.......... 1916 to 1917 2.1 0
JQI21R Truss Bar Front (Diagonal) ............ 1918 to 1923 1.90
MQI21R Truss BaT 'Front (Diagonal) ............ 1924 ·2.15
JQ7R Truss Bar ReaJr (Diagonal) ............. 1918 to 1923 1.60
MQ7R Truss Bar Rear (Diagunal) ............. 1924 1.65
DQ9 Connection for Main Bar & Axle Tube ....... 1915 to 1924 .75
EQ76 Connection for Side Bar & Axle Tube ....... 1916 to 1924 I. 90
DQ8 Connection for Main Bar (Center & Front) (2) . 1915 to 1924 . 70
DQI5 Truss Bar Center Connection ............. 1915 .35
EQJ5 Truss Bar Center Connection ............. 1916 to 1917 .20
GQ15 Truss Bar Center Connection ............. 1918to 1924 1.65
DQ16 Truss Bar & Main Bar Connection ........ 1915 .40
EQ16 Truss Bar & Main Bar Connection ........ 1916to 1917 .25
IQI6 Truss Bar & Main Bar Connection ........ 1918 to 1924 .45
EQ38 Connection for Side & Front Bar .......... 1915 to 1916 1.00
FQ38R Connection for Side & Front Bar ......... 1917 .80
GQ38P Connection for Side & Front Bav- ......... 1918to 1924 1.15
DQIOA Frame 'Brace Bracketi .................. 1915 to 1917 1.1 0
GQIO Frame Brace Bracket ................... 1918 to 1924 .80
DQI3 Mudguard Support Rod Bracket ... , ...... 1915 to 1917 .60
EQ48A Mudgu3lld Support Rod Bracket on Truss
Bar .............................. 1915 to 191 7 .30
 NOTE: Be aure and read the following instruction before fitting any of theae ring•
to DCA motor piatons.

Mechanics' Bulletin
Factory Description Where Used Tax Price
number Statui Each
Used m the two TOP
LAIIDK Standard plain ring grooves- NT 20c
DCA Moton
No. 99. Nov. 1, 1923. Harley-Davidson Motor Co., Milwaukee
Uaed in the two LOWER
MAllO Standard bevel edge ring grooves- NT 25c
DCA Moton
The Service Department will from time have live material, thereby keeping th<! re-
Overoize thiclmeoa ring Uoed in THIRD ring
to time issue bulletins to be mailed with the pairmen informed with ll'j>-to-the-minute MAIIDA (.001"+) with beveled groove (first above pin) to NT 25c
edge. Marked in RED take up wear-
Weekly News Bulletins. covering me- shop news. If the Weekly News Bulletin DCA Moton
chanical suggestions and ideas of interest does not reach the shop, be sure to follow
Ovenize thicltneos ring Used in BOTTOM ring
to the shop. These bulletins will cover up the office from time to time and ask MAIIDB (.0025" +) with beveled groove to take up wear NT 25c
the same ground as the Service bulletins them if any mechanics' bulletins have been edge. Marked in YELLOW DCA Moton
issued in the past, excepting that they will received.
Standard size asoorted up- Uaed in new motors and on
be issued m9re frequently, or whenever we MAIIDD per and lower new standard piatons- NT Ea. 2Jc
DCA Moton

A11orted ovenize thiclmeoa

MAIIDE rings for third and bottom Uoed in THIRD and
grooveo. Marked in RED BOTTOM grooveo-- NT Ea. 25c
DCA Moton
Adjustment and Repair of DCA and E Motors and YELLOW

Fitting Piston Rings in DCA 7 4 cu. in. Motors Fitting Rings to Piston Grooves
Because Harley-Davidson Aluminum When the piston rings are worn to such
extent that the pistons are noisy, replace Try each ring in the piston groove, roll- slightly over very line emery cloth, pref-
pistons are specially designed for use with
ing it around the piston to ascertain the erably number 00, laid on a planed sur-
four rings, they are longer lived than cast the two bottom rings with oversize thick- lit. If the ring does not lit just free in face.
iron pistons. The two lower rings act as ness rings (as explained below.) Do not the groove, its flat side should be rubbed
a cushion between the piston and cylinder confuse oversize thickness rings with rings
walls. A motor fitted with these pistons oversize in outside diameter. It is not Fitting Rings LA 1 1DK
can therefore be kept in practically its necessary to replace the two top rings
original condition by fitting new rings unless they are worn considerably, olr The two top rings have flat or plain more than .002" (.05 m/m), new stand-
burned due to lack of oil.
faces, that is, their edges are not beveled. ard rings should be fitted. This can be
when necessary. determined with a feeler gauge.
The two top rings act as compression These rings, being compression rings
Notice: Step joint rings, such as used only, can be retained as long as they show Never under any circumstances lit over-
rings and hence are used for gas tightness no appreciable wear, side shake in the pis- size thickness rings in the two top ring
on cast iron pistons, are not designed for
only. The third ring (first ring above ton grooves, or discoloration due to lack grooves unless the cylinders have worn at
use with aluminum pistons. To use or-
the piston pin) acts as a compression as of oil. If the clearance between the two least .004" or .005" (.10 or .12 m/m).
dinary piston rings or step joint rings on
well as a bearing ring. top rings and the piston ring grooves is
aluminum pistons will cause the motor to
The fourth or bottom ring acts as a stick or "seize" and in consequence dam-
combination bearing, oil, and tension ring.
Fitting Rings MA 1 1D
age the cylinders and pistons.
The third ring, or first ring above the tors and on new standard pistons.
Piston Rings for DCA Motors piston pin, should have one edge beveled
The fourth or bottom ring groove
and be fitted in the groove with the bev- should also be fitted with an MA II D
On the next page is a list of DCA pis- until such time as we issue a new sheet for eled edge down. The standard thickness beveled edge ring, (beveled edge down),
ton rings. Some of these are new rings. your parts book. bevel edge ring is MA I I D and is used in except when the motor has developed a
Insert the part numbers in your parts book the 3rd and 4th ring grooves in new mo- rattle at medium high speeds.
 allowed at the bottom end of the cylinder taper of .007" (.17 mjm) ; multiply this
Fitting Oversize Thickness Rings MA I IDA and MA I I DB
can be reduced accordingly. If the taper by 3, then add .008" (.2 mjm) for
These rings are furnished only on Standard or oversize thickness rings taper in the cylinder is multiplied by 3 and the proper gap. The result will be .029",
Parts Orders. They are not included must always be lapped in to insure per· .008" is added to the product we will (.73 m/m), or the proper gap for the
with standard rings but can either be or- feet lubrication for the first few hundred have the correct gap for the ring when it ring when located in the lower end of the
dered under the above part numbers or miles, or during the "running in" period. is in the bottom end of the cylinder. As cylinder.
under assortment number MA II DE. These oversize thickness rings should an example: We have a cylinder with a

Fit oversize thickness ring MA II DA take care of motors having from 5,000 to
in the third groove, or groove just above 7,000 miles of service as well as motors
the pin. This ring will be marked in that are noisy at medium high speeds. Lapping Piston Rings in DCA and E Motors
RED and should be fitted in this groove AFTER FITTING STANDARD Lapping is especially recommended Apply a coating of lapping compound,
only. The beveled edge must be fitted OR OVERSIZE THICKNESS
downward for proper lubrication.
when oversize thickness rings are fitted. grade I ~A Clover Leaf grinding com-
RINGS DO NOT FORCE THE
MOTOR OR DRIVE FASTER For the very best results it is advisable pound is recommended, and enter the pis-
_ Fit oversize thickness ring MA II DB ton and rings into the cylinder. Give the
THAN 25 MILES PER HOUR FOR to lap the piston rings in the cylinders
in the fourth or bottom groove with the THE FIRST THREE OR FOUR until they bear perfectly at all points piston with rings a to and fro motion, at
beveled edge down. This ring will be HUNDRED MILES. THIS IS IM- against the cylinder walls. When rings the same time turning it from side to side.
marked in YELLOW and should be PORTANT. are to be lapped in, do not allow as large Lap the rings until they show effects of
fitted in this groove only.
a gap in the ends, because the lapping the abrasive over their entire surface.
Fitting Rings to E Motor Pistons process will enlarge the gap from . 005"
Tlu· rmgs on the E motor aluminum pistons function W~en the pisto~ rings are worn to such. exte~t ~hat to .008" (.12 to .2 m/m), depending on When a cylinder is exceedingly rough,
lht· sumt· d& those un DC/\ pistons, thdt is, the two top the pistons are no1sy, replace the bottom nng With an
hQw long the lapping is continued and the it is advisable to lap the rings on an old pis-
rong• "'" used for 'om pression purr>oscs. the third ring MdA Ill B ..00d25'~ (63 mfi/m) thickebr thanh standard hring·
C11 1 1 · ) 15
· J f · d an lte thtr nng or rst nng a ove I e pm, Wtl a kind of lapping abrasive used. ton, using either grade A or B compound
( ~~ rmg il lOVe t lc pm use . or_ compression an_ standard beveled e'dge ring MAll. It is not necessary
Lcarmg purposes _and the bottom ~mg IS. used for lubn- to replace the two top rings unless they are worn and finishing up on the piston to be used
L..tllon auJ bc<tring purposes. 1 he lhnd and bottom considerably, or burned due to lack of oil. When Oil the piston ring grooves and put the
with grade 1-A compound.
nngs h..tve hcvelt:J edges and are fitted with the beveled replacement is necessary, use standard size plain face four piston rings in their proper places.
t_·dges downwan,J. rings EA11KI3. Fit a slightly loose piston pin to the piston After lapping the rings sufficiently, re·
E Motor Piston Rings and use an old connecting rod with a piece move all traces of the abrasive thoroughly
F adory Tax Price of wood through the lower bearing to serve
Description Where Used with gasoline before assembling the motor.
number Status Each
as a handle.
L\IIKB Siandard plain rmg
Used in the two TOP
j:~ronves~E. motors
NT .20
------- - u,;,r~ ihe !w~TOWER- - - - - - - - - - - - - - -
MJ\tl s, .. nda J hevel edge ring NT .25 Valve Grinding on DCA and E Motors
-~~.?~~==----=-:~ ~~!~! __
()ve~size thickness ring Used in bottom ring
MJ\1111 (.0025" +) with beveled NT .25
groove lo take up wear-E Valve grinding and the proper fitting power, burn spark plugs and picvent
edge. Marked in YELLOW motors
of valves on DCA motors are most im- proper lubrication.
Be Sure to Obtain Proper Ring Gaps portant operations if extreme high speed It is, therefore, important that the
is to be maintained over long distances. valves be ground carefully and adjusted
The beveled joint rings used in both 61 A very good way to get the correct gap These large motors generate more heat properly after scraping carbon and clean-
and 74 cu. in. aluminum piston motors of piston rings in the cylinder is to allow than the 61 cu. in. type motors and con- ing out the motor. Do not simply clean
must have from ,008" to .012" (.2 to about .029" (.73 m/m) gap when the sequently the valves are subjected to more off the valve faces and seats and call it a
. 3 m/m) gap at the ring ends when ring is at the bottom end of the cylinder . abuse. If carbon deposits accumulate be- good job, but lap the valves in on the
located in the TOP END of the cylinder. As the rings are, moved upward the gap tween the valve faces and cylinder seats, seats with a good grade of grinding com-
'The bottom or fourth ring, however, may will automatically close, because the cyl- burning gases will blow by and cause the p~und and test the results as follows:
he filled with a gap up to 3, '64" inders are tapered. After lhe cylinders motor to become excessively ,hoi. This After grinding the valves in, clean the
( 1.1 m/m) without causing serious ellecl. wear, that is, the taper reduced, the gap additional heat will reduce speed and faces with gasoline and mark lhe valve
face with a soft pencil, placing the marks marks, noting whether or not they are High Speed Lubrication of Aluminum Piston Motors
vertically, every % inch (6.3 mjm) erased equally about the face. If the
The fact that DCA and E type motors oiler adjusting screw. Above 45 miles
around the face. Replace the valves and pencil marks do not show the valve to be are fitted with aluminum pistons does not per hour, the hand pump should be
with a screw driver press firmly on the true, continue grinding until the valve and make motor lubrication more difficult. The brought into service as follows:
valve and give it several to and fro turns. seat faces are true. design of these motors allows for sufficient
At 45 to 55 miles per hour, give motor
Remove the valve and examine the pencil cylinder and piston clearance so that they
I /3 pumpful of oil every 4 miles.
will withstand high temperatures without
excessive oil consumption. At 55 to 65 miles per hour, give mo-
Adjusting the Carburetor Air Valve on 74 cu. in. DCA Motors tor 0 pumpful of oil every I mile.
The mechanical oil pump is adjusted,
In some localities and under certain 20, 1923, h~ve 3-i" (3.1 m/m) shorter upon leaving the factory, to provide cor~ At 65 to 75 miles per hour, give m~
conditions a long air valve spring such as air valve adjusting screws. rect lubrication in ordinary service up to tor I pumpful of oil every ~ to I mile.
fitted on some 1924 motors may cause an 40 or 45 miles per hour. This adjust- Above 75 · miles per hour, give mo-
After changing the air valve spring ad- ment is obtained by using one thick and
unsatisfactory fuel mixture between speeds tor I pumpful of oil every 0 mile.
justment it will of course be necessary to two thin washers under the head of the
of 30 and 40 miles per hour. This is a
readjust the needle valve and possibly the
condition that can be remedied very easily
high speed cam as follows: Screw the
and without expense to the rider. Gear Ratios-All 7 4 cu. in. Motors
needle valve inward or down until the
If the motor does not respond to me- proper mixture is obtained. Turn the The following sprocket combinations are now used on machines shipped from the factory.
dium high speeds, or popping occurs at high speed cam indicator to position 3.
the carburetor, it is safe to assume that The carburetor will then be adjusted prop- Sidecar Machines
the air valv·e spring is too weak and erly for all general service up to extremely
should be tightened accordingly. Un- high speed, when it may be necessary to FDS, ]DS, FDCAS and JDCAS sprockets. Gear ratio 4. 91 to I. Previ-
screw the air valve stem bushing three open the shutter on the side of the car- models are iitted with 15 tooth engine ous gear ratio was 4.61 to I.
turns, or 3j32" (2.3 mjm). This will buretor to furnish additional air for high sprockets instead of 16 tooth engine
give just enough clearance for the choke speed purposes.
pin to clear the bushing when in the out~
ward position.
Where high speed is more important Solo Machines
than low or medium speed adjustments,
A still better plan would be to cut Ys" we recommend that a long air valve spring FD and JD models are fitted with 17 rear wheel sprocket is retained. Gear
(3.1 mjm) off the threaded end of the be used, or if the shorter type spring is tooth engine sprockets instead of 18 tooth ratio 4.22 to I. Previous gear ratio was
air valve adjusting screw. All machines engine sprockets. Gear ratio 4.34 to I. 3.97 to I.
used, that a ported air sleeve be fitted to
Previous gear. ratio was 4 .I 0 to I.
shipped from the factory after September the carburetor. It is suggested that any 74 cu. in. m~
FDCA and ]DCA models are fitted tor not performing satisfactorily on hills
with 16 tooth engine sprockets instead of or long runs be geared as above outlined.
Care of Mica Core Spark Plugs I 7 tooth engine sprockets. The 44 tooth

The mica core spark plug may after loose flakes from the core. The plugs
hard service show the effects of heat and should after being reassembled, render
in consequence cause premature ignition. much better service. Compression of DCA Solo and Sidecar Motors
If a large motor, such as the 74 cu. in., is
Ordinarily mica core spark plugs will The compression on both solo and side- plate, under each cylinder.
held wide open for a distance of several
render excellent service and cause very car DCA motors is now as follows:
miles at a stretch, the spark plug cores
little difficulty; however, when pushed at If DCA solo or sidecar motor does
may suffer greatly, in fact they may flake
top motor speeds for long stretches, they DCA solo machines have a I/ 16" not seem to give the desired results on
or crack to such extent that the motor is
are functioning under conditions similar to ( 1.5 m/m) compression plate under each hills or long high speed runs, or has a
caused to slow down to 20 or 30 miles
plugs in racing service and will therefore cylinder, and sidecar motors have the cus-
per hour. If spark plugs cause such dif- tendency to knock, we suggest that com-
break down quicker than when used under tomary 3-i" (3.1 m/m) plate, in addi-
ficulties, remove them and after taking pression plates be fitted according to the
ordinary conditions of service.
them apart scrape and sandpaper all the tion to an extra I /16" ( 1.5 m/m) above.
 Generator Repairs Motorcycle and Sidecar Frames, Forks and Tanks
Soldt!ring and turning commutator . . . . . . . . . . . . . . . . . . . . . . . . Labor $1.25
Inspect Very Carefully Before Giving Estimate To Customer.
List Net These Prices Include Re-Enameling. But No Material.
Fitting commutator to Remy 235 type aJrmature GX I 067 or
GX I 067C ........................................ $8.25 6.25 MOTORCYCLE .FRAMJ<JS

REMY 250 TYPE COMMUTATOR CANNOT BE REPLACED WITH- When luggage carrier studs are needed. add $1.00 net to the quoted labor charges.
OUT REWINDING ARMATURE. . Net
Labor for rep~r!ng slightly bent frame-no new brazed fittings furnished. . $ 7.00
Rewinding Remy 250 type armature including new commutator. . . 12.00 Labor for repamng frame needing one or two cylinder or crank case clamps 8.00
Labor for repairing frame needing three or four cylinder or crank case
clamps ...................•.............•••............. 9.00
Labm for 'repairing badly bent frame--no new brazed fittings furnished .. 9.00
Labor for repairing frame needing one, two or three brazed fittings, one or
NOTE two of which are crank case or cylinder clamps. . . . . . . . . . . . . . . . . . . . 10. 00
Harley-Davidson and Remy 235 type armatures are not rewound and Labor fo! repairing a frame needing four brazed fittings, three of which
Harley-Davidson armatures are not fitted with new commutators because are cyhnder and crank case clamps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I 0.50
the repair cost would exceed the price of new armatures. Spark coils with Labor for repairing frame needing four brazed fittings, two of which are
broken down windings or condensers, damaged cases or terminals, cannot cylinder or crank case clamps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.50
be repaired. Labor for repairing frame needing live brazed fittings, three of which are
cylinder and crank case clamps. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.50
Labor for repairing frame needing six, seven or eight brazed fittings, three
ol which are cylinder and crank case damps . . . . . . . . . . . . . . . . . . . . . . . 14.00
When a lower bar or loop tube ~ furnished the cost includes c;vlinder bracl{ets
List Net or cran~ case clamps.
Repairing manual switch KK385 or MK385 . . . . . . . . . . . . . . . . . $1.40
Labor for overhauling generator or magneto ......•.......... RIGID AND St'RING FORKS
$5.00
to Always add. lower head cone EE66P-32 cents list, to the rigid fork repair prices.
7.50 Net
It is impossible to estimate the material required to repair a generator Labor for repairing rigid fork-no new fittings furnished ....... $2.50 to $3.00
or magneto because of the wide difference between the condition Labor for repairing rigid fork with one broken side, center stem or
of different units. crown plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4.25
It does not pa:v to repair a rigid j(){fr having more than one broken
jilting.
Carburetor Exchange Prices Labor for repairing spring fork-no new fittings furnished. . . . . . 1.75 to 2.50
Labor for repairing spring fork with one broken side, mudguard
NOTE: Missing parts are charged for in addition to the exchange bracket or tip. • . . . . . . . . . . . . . . . . . . . • . . . • . . . . . . . . . . . . 3.50
pnce. Carburetors with oversize throttle shafts, damaged bowls, It does not pey to repair a spring j(){fr having more than one brofren
fitting.
or broken bodies are exchanged for new carburetors at quoted
prices. TANKS
Net
List Net Labor for repairing damaged tank, depending upon extent of damage.$3.00 to $5.00
Exchanging worn 74", 61" or Sport Model carburetor for rebuilt
carburetor ................. · .. · · · · · · ............... $5.75 $4.00
It does not Pa.lJ to repair a badlu damaS!ed 1917 to 1920 tanq.
Exchanging worn 7 4", 61 " or Sport Model carburetor with oversize SIDEJOAR FRAMES
throttle shaft, damaged bowl or broken body for a new carburetor 9.00 6.50 Net
Labor for repairing sidecar frame-no new fittings furnished ...•......... $ 9.50
Exchanging worn 1921 small bowl style 74" carburetor for large Labor for repairing sidecar frame needing one fitting . . . . . . . . . . . . . . . . . . 10.50
bowl style carburetor .... · · . · · · · · · · · · · · .. · · · · · . . . . . . 9.00 6.00 Labor for repamng sidecar frame needing two fittings . . . . . . . . . . . . . . 12.00
Labor for repairing sidecar frame needing three fittings • . . . . . . . . . . . . l3.00
Re-enameling Motorcycle and Sidecar Parts in Olive Green, Part No. Name Models Price
AC2C Rigid Fork Stem ................ 1915 to 1924 ...... $1.00
Brewster Green, or Harley-Davidson Gray BCIB Upper Crown Plate (I ) .......... 1915 . . . . . . . . . . . . . .22
BCIA Lower Crown Pilate (2) ......... 1915 ........ ; . . . . .20
These prices include no labor for stripping, assembling and repairing. Always HCI Crown Plate Upper (2) ......... 1916 to 23-61". . . .16
tell us in your instructions whether to re-enamel only or to re-enamel and repair. Add HCIA Crown Plate Lower (I) .......... 1916 to 23-61 ". . . .16
about 20% to theae prices to cover our labor for tagging, cleaning and getting parts ready HC27 Crown Plate Assembly ........... 1916 to 23-61". . . .80
for enameling. KCID Crown Plate (3) ............... 1922 & 23-74" all 24 .20
Net KC27D Crown Plate Assembly ........... 1922 & 23-74" all 24 .90
Frame, motorcycle or sidecar .........................•........... $ 1.50 H0388 Crown Plate Spacer (4) ......... 1915 to 1924 . . . . . . .04
Set of forks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . I .50 DCI5 Spring Fork Bracket ............. 1915 ............. 1.30
Single fork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • . . . . . . . . . . • .75 ECI5 Spring Fork Bracket ............. 1916 to 23-61 " . . . 1.60
Sport Model fork. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.20 KCI5D Spring Fork Bracket ............. 1922 & 23-74" all24 2.00
Set of tanks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.25 DC32 Rigid Fork Side Upper End ...... 1915 to 1924 . . . . . . .35
Sport Model tank. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . J.50 EC23 Upper End Splice (inner) ........ 1915 to 1924 . . . . . . .I 0
Mudguards, motorcycle or sidecar .............................. each .75 KC23 Upper End Splice (outer) ........ 1915 to 1924 . . . . . . .10
Sidecar body two passenger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7.05 FU.A~II<1 PAUfl'8-TIDtEE-SPJmn l<'RAMES
Sidecar body one passenger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.00 FE607 Loop Tube (Head to Three-Speed Bracket) .. 1915 to 1924 $2.70
Tool box................................................... .75 FE171 Front Loop (Head to Casing Clamp) ...... 1915 to 1924 1.20
Handlebars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 FQ86 Front Loop Bar Reinforcement (2) for Splic-
Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 ing EE 171 to Frame . . . . . . . . . . . . . . . . . . . . . . . . . . .08
Magneto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .75 FE608 Rear Loop Tube ...................... 1915 to 1924 .75
Set of Chainguards . . . . . . . . . . . . . • . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.13 EE606A Top .Bar with Seat Bar Bracket .......... 1915 to 1924 2.10
Stand..................................................... .30 AE605 Lower Bar Only ...................... 1915 to 1924 1.10
Battery box •.••••...•..•••••.•••.•••........•.......•...... · .75 FE609 Lower Bar with Motor Brackets .......... 1915 to 1924 2.00
Wheels, motorcycle or sidecar ................................ each .75 EEI9R Rear Fork Only (Upper) ............... 1915 to 1924 .60
Re-enameling all parts of a motorcycle after it is completely stripped and aU DE85R Rear Stay Only (Lower) ............... 1915 to 1916 .90
fittings. have been removed from parts. . . . . . . . . . . . • . . . . . . . . . . . . . . . 12.00 EE85R Rear Stay Only (Lower) ................ 1917 to 1924 1.10
IE72P Frame Head ......................... 1915tol924 3.75
DE93 Tank Strip Front ...................... 1915 to 1916 .12
List of Spare Parts to be Used in Estimating Repair Costs JE93 Tank Strip Front ...................... 1917to 1924 .10
This list is made up for estimating repair costs only. DE75 Tank Strip Rear ...................... I 9 I 5 to I 9 I 6 .I0
JE75 Tank Strip Rear ...................... 1917 to 1924 .05
SPRING FORU: PARTB-19151 '.rO 1924
DE2 Crank Case Clamp ..................... 19 I 5 to I 924 .20
CE24P Foot Board Bracket .................... 1915 to 1924 .45
Part No. Name Models Price IE505 Handle Bar Control Bracket .............. 1915 to I 924 .I 0
BC19 Spring Fork Side ................ 1915 ............. $1.50 AE504A Rront Cylinder Clamp ................... 1915 to 1924 .30
ECI9R Spring Fork Side ................ 1916 to 1919 ....... 1.15 FE706 Rear Cylinder Clamp ................... 1915 to 1924 .I6
ICf9R Spring Fark Side ............... 1920 to 23--61" ... 1.15 FE735 Gear Box Bracket ..................... 1915 to 1923 5.10
KCI9DR Spring Fork Side ................ 1922 &23-74"all24 1.15 ME735 Gear Box Bracket ..................... I 924 5.1 0
ACI3 Spring Fark End ................ 1915 to 24 . . . . . . . .50 DE36P Seat Bar Bracket & Bushing .............. I 915 to I 924 . 75
DC20 Front Mudguard Support .......... 1915 ............. · .70 EEl Seat Post Cluster ...................... 1915 to 1916 1.55
EC20 Front Mudguard Support .......... 1916 to 22-61 " ... LOO FEI Seat Post Cluster ...................... 1917 to 1924 3.00
LC20 Front Mudguard Support .......... 1923 -61" ....... 1.00 AE5 Rear Mudguard Support ................ 1915 to 1916 .55
KC20D Front Mudguard Support .......... 1922 & 23-74" all24 1.45 FE5 Rear Mudguard Support ................ 19 I 7 to 1924 I. 00
DE7 Left Rear Axle Clip ................... 1915 2.00
EE7 Left Rear Axle Clip ................... 1916 2.00
ltiGID FORK l'ART8-lD15 TO 1024 FE7 Left Rear Axle Clip ................... 19 I 7 to 1924 2.1 0
Rigid Fork Side ................ 1'915 ............. $1.95 EE6 Right Rear Axle Clip .................. 1915 to 1916 2.00
BCJOOP FE6 Right Reali' Axle Clip .................. 1917to 1924 2.10
ECIOOPR Rigid Fork Side ................ 1916 to 1923-61 " . 3.25 Right Luggage Carrier Stud ............ , . 1915 to 1924 . I2
Rigid Fork Side ................ 1922 & 23-74" all24 3.65 DE42
KCIOODP DE41L Left Luggage Carrier Stud ............... 1915 to 1924 . I2
Service Dept. Bulletin When bPnding the long blade sup-
port, care must be taken to bend it w that
the slf'f'l insert in the thrust button is in
fine with the thrust ball in the switch hoiiS·
No.'97. Revised Nov. 20, 1923. Harley-Davidson Motor Co., Milwaukee
ing. This is very important, because. if
the ball comes in contact with the bakelite
This bulletin replaces Service Department Bulletins No. 67, 78 and 93 of the bullon, it will wear a pit into the
and covers the care of the electrical equipment on 1918 to 1920 models be- button in a short time. /\her the large
sides ~eneral electrical instructions that apply to all models. Special allen- blade is in the proper position, obtain the
lion is directed to the "Ignition Trouble Shooting Chart" on the last pages clearance at the contact points by bending
of the Bulletin because this information is invaluable when hunting down A the lower or short blade support. /\ ddi-
ignition troubles. nite clearance for these points cannot be
B given because of the variation in the stiff-
To Inspect and Correct a Faulty Lighting Switch c ness in some of the blades. However, it
(These Switches were used l>etween 1918 and 1920) is safe to assume, that I /32" clearance is
D about right. Bend this blade support ac-
Remove the two hexagon nuts which damp the entire switch box assembly to the cordingly, being careful that the points
studs of the switch base. Take hold of th·~ black switch box cover and remove the line up, and make a good square contact.
entire assembly from the switch base. If the cover sticks it can easily be forced off
by placing a sctew driver against the edge of the cover from the left side of the machine The switch should Le tcstrd as fol-
and then striking the screw driver with the palm of the hand. Remove the two round lows to see whether or not the adjustment
head screws which clamp the black swilch box· cover to the switch assembly and remove is correct. Replace the short chain and
the cover. If an inspection proves that the wires are firmly and properly connected as baltery ground wire, raise the valves, prrss
per illustration No. 5 showing switch wirintl diagram, the fibre switch base to which firmly on the handlebar horn bullnn and
the wires are allached should be removed fr(lm the cover and spider assembly. These Illustration No. I give the starter crank a vigorous stroke. If
two assemblies can be taken apart after the three screws which pass through the side of the centrifugal switch. blades are properly adjusted, and the circuit between the gen-
the spider cover have been removed. erator and baltery, and the battery itself is 0. K. the horn will sound for just a fraction
Inspect the four spider contacts inside of this cover. Make sure that they bear of a second.
against the contact inserts in the fibre base with sufficient pressure to insure a closed On rare occasions the cut-out weights may be founcf magnetized, thus sticking
c~rcuit, and that they cannot slide beyond the insert contacts. To see whether the to the base proper and causing sluggish action of the switch. Magnetized weights
spider contacts slide beyond the insert contacts, turn them to the various positions and should be replaced with weights free from magnetism. They may be tested for mag-
with a pencil, mark the exact location of the rontacts on the metal cover of this assembly. netism by trying to lift small particles or chips of iron or steel.
Then put the fibre switch base assembly into :he switch cover assembly and note whether Watch the action of the centrifugal switch blades. See if they make contact.
each mark lines up with its respective clamr screw. If they do not line up properly, Then if the horn does not sound while pressing the horn button, check for the follow-
bend the spider contacts as necessary. ing possible troubles:
I.-Battery is discharged. 2.-Fauhy manual switch. 3.-Loose wire con-
To Adjust the Centrifugal Switch nections. 4.--F auhy horn or the wire itself is broken at one or more places.
(Used on 1918 tt) 1922 Models) It is well to get into the habit of attempting to sound the horn after stopping the
motor, to determine whether the centrifugal switch is functioning properly.
To get at the centrifugal switch it will. of course, be necessary to remove the left A centrifugal switch out of adjustment will cause the following:
foot board, short chain guard and chain. Under the cover at the lower left end and of Motor will be difficult to start.
the generator is a set screw. With a screw driver loosen this about one turn. This cover Motor will misfire.
which is held by a bayonet type connection, is then removed by turning it to the left as Battery will discharge prematurely.
far as it will go and pulling it from the generator. Battery will not receive full charge.
Be sure that the clearance "A" between thrust button "B" and cover "C" of the Generator armature and commutator will be burned.
centrifugal switch does not amount to mon~ than a few thousandths of an inch. If Brushes will be burned.
there is too much clearance at this point the ball action will be lost which will prevent
a good contact if any, at the points "D". If the blades require adjusting, disconnect To Adjust a Faulty Manual Ignition Switch
the ground wire from the battery box covet screw to prevent a .short circuit, which in (Used on 1918 Models only)
an instant would remove the temt>er in the !Witch blades making them useless. Never If previous tests and inspections prove that the centrifugal switch, horn, Lallery,
bend the switch blades as they are finely tempered and "set" on the switch blade sup- wiring and connections are 0. K. and the horn cannot be sounded when the motor is
pori. Always bend the switch blade support when changing position of blade. Ad- cranked, the motor will be hard starling because the manual ignition switch is faulty.
just the long blade support first. Since the manual ignition switch is a oart of the lighting switch, refer to instruc-
tions covering the removal of this switch on page I, under "To Inspect and Correct a
Faulty Lighting Switch." Hemo\e the tlm:·e ~crews holding the lihre basi' and spider
cover assembly together, and bend the t'n.! of the contact blade. This will be only
very slightly, as may be found necessary. Be careful not to hend the contact blade
too much because it will then be impos~ihle to lock the ignition wht>n the key is re~
moved. This same blade grounds or ~hort circuits the generator when the key is re-
moved from the switch so the motor will slc•p when the key is removed.

When Motor Keeps on Running with Ignition Key Removed.

This trouble can be traced to two causes which are:
I.-Failure of entire switch assembly to make a ground conncclion to the fram~.
2.- Contact blade failing to make contact or ground against the lug of the spider
as~embly cover when key is removed.
To determine whether entire as~embly is grounded, start the motor and touch a
screw driver to the switch and the frame work after removing the enamel at the points ...
of contact. If a spark occurs, it will be n<'ce~sary to remove the enamel so that switch
.~3-----M
clamp can make contact with the frame.
If no spark occurs, it will be necessary to rt>move cover and bend contact blade
until it makes contact with the lug of the spider as~embly cover. If the temper should
be burned _out of this blade, it should be replaced.
To Tell Whether Generator is Charging the Battery.
Start the motor in the usual way and disconnect the battery negative wire from
the ground terminal. If the molor continnt's to run after the battery negative wire is
removed (the battery out of circuit), the generator is charging or producing current.
When making this test it is important that the motor be run at slow speed only, because
if run at high ~peed serious damage may re,.ult.
If the motor stops upon removing the battery negative wire, the generator is not
charging or tht>re is an open or broken connection between the generator and the man-
ual ~witch. DO NOT REMOVE fHE GENERATOR FHOM TI-lE
ENGINE.

Why the Battery Must Always be Kept m Circuit

Tbe battery acts as an accumulator and governor holding the generator voltage
down to 8 volts. The current produced hy the g<'nerator at 30 miles per hour, with
the battery out •of circuit, is above 30 volts. This high voltage produces a serious
overload on !he generator and will burn and pit the hreaker points in a short time.
Other serious damage may result to the armature, spark coil, or condenser. Bulbs will
burn out at any voltage higher than 6-8 volts. Therefore, even though the storage
baltery should be exhausted and not capable of giving off current, it must be left in its
place, connected up.

Ignition Unit of the Harley~ Davidson and Remy Generator·

(All Models Between 1918 and 1920)
I~- -Distributor cap locating lug, or stop, should interlock with the slot at "6"
whenever the distributor cap "3" is replaced. Failure to lit the distributor cap prop-
erly may mean a damaged generator; 2--High tension terminals which alternately
collect the ignition current from segment "5" and carry it to the spark plug wires.
These high tension terminals clear the segment by about I j64" and should never be
adjusted; 3-Distributor cap; keep it clean; 4-Distributor segment contact spring
which carries the ignition current from cr.rbon contact "14" to segment "5" ; 5-
Distributor segment distributes the ignition current from the distributor segment contact
 Sport Model Motors
Sport Model Valve Timing Specifications
The sport model intake and exhaust be sure to have the proper gear teeth in
cams are mounted on the same cam gear, mesh, that is. a marked tooth must coin~
similar to "V.. twin cam design. The cide with a mark that is between two
cam and pinion gears are marked so that teeth. Illustration No. 4 shows correct
the valves can be timed readily. When alignment of gear marks A and B for
timing the motor according to gear marks. proper valve timing.

Valve Timing Specifications for Sport Model Motor

To check valve operation against piston ing the push rod or lifter pin while the
location. remove the front cylinder plug motor is being turned over. When the
and with a scale measure the piston travel push rod or lifter pin begins to tighten
according to the following specifications. or loosen, the valve is beginning to open
The exact time of valve opening and or close.
closing can be determined easily by turn~

Inlet .Valve Timing

Inlet valve should open when piston is should dose when piston is 9 j16" after
7;32" be/ore top dead center. Inlet valve bottom dead center.

Exhaust Valve Timing

Exhaust valve should open when piston haust valve should dose when piston Is
is 15/32" be/ore bottom dead center. Ex- I jl6"aftet top dead center.

Sport Model Breather Valve Timing

Crank case compression in the sport the cam gear and stud when the valves
model motor is relieved through a port in are timed correctly (according to marks).

Valve Tappet Adjustment for Sport Model Motors

Both inlet and exhaust valves on the correct valve timing. it is imperative that
sport model should have .006" clear~ the tappets be adjusted to have .006"
ance when the motor is cold. To insure clearance.

Timing Sport Model Motor with Generator for Ignition

Inspect circuit breaker points before with the other gears when the piston and
starting to time the motor. to make sure timer points are set according to the fol·
they are separating .020''. Use a thick~ lowing instructions.
ness gauge or the gauge provided on the Remove the front cylinder piug ana set
generator wrench for the purpose. piston between 3j8" to 7 j16" before top
The generator drive gear is provided dead center on compression stroke. It will
with three key ways, located to permit be necessary to remove the front footboard
change of timing within I j3, 2!3 and 1 support in order to remove the cylinde1·
tooth of the gear. In other words. the plug. Compression stroke is the next up
drive gear can be fitted to mesh properly stroke of the piston after the inlet valve
closes. The outside (nearest the mani-
fold) valve lifter pin is for the inlet valve.
After locating the piston at the proper
place for timing, set the generator timer
FRONT CY/JHbER
shaft as follows: The timer lever {lo- CA/1[.£
cated between coil and timer housing) must
be advanced or shifted to the rear.
Tum the timer shaft until the .. flat side..
is away from the coil. The cam must be
set just ready to separate the breaker
points. The drive gear can now be fitted
to mesh with the intermediate gear as de-
scribed previously. Hold the timer cam
with one hand when fitting the drive gear
ILLUSTRATION NO. 5
to prevent it from turning and hence
change the timing. cable) of clistributor cap leads to the front
After generator is timed, make sure that cylinder. Refer to illustration No. 5, show-
the outside terminal wire (spark plug ing proper disposition of spark plug cables.

Timing Sport Model With Magneto for Ignition

The magneto on the sport model motor The correct piston position for ignition
can be timed by merely aligning all gear is between 3 jB" and 7 /16" before top
marks after the drive gear is keyed to the dead center.
armature shaft. To check the timing, re- The front (forward) interrupter shoe
move the cylinder plug and measure the on sport model magneto times the front
piston position before top dead center when cylinder.
the magneto breaker points are just ready The magneto interrupter lever is ad-
to separate. vanced when in a downward position.
 Ignition, or !he .. kctric ~park occur; al ga~s('~ and hence cau~e compldc cornfm<-
tion, the timing of the spark's occur<'ncc i<
61" Sidecar or Low Compression Motors Using Standard Cast Iron
the time when the generator or magneto
circuit breaker points are jusi separating. always set before the piston reaches top Pistons
Since an interval of time is required for ig- dead center on the compression strokt>. (Generator or Magneto Equipped)
nition to propagate a flame through the Pistons must be set between 7 j32" and I ,14" before top dead center.

How to Locate Compression Stroke of Piston for Ignition Timing 61" Solo or High Compression Motors Using Standard Cast Iron
Pistons
(All Motors)
(Generator or Magneto Equipped)
As the inlet valve opens, the piston de- haust valves on the same cylinder will be
scends, taking in a charge of fuel. The dosed when the piston is coming up on the Pistons must be set between 9 j32" and 5 ;' 16" before top dead center.
next up stroke of the piston will be the compression stroke.
compress·ion stroke. Both the inlet and ex- 61" Sidecar or Low Compression Motors Using Aluminium Pistons
(Generator or Magneto Equipped)
Setting the Piston for Ignition Timing (All Motors) Pistons must be set between 7 j32" and I j4" before top dead center.

After locating the compression stroke, your motor) from the top of tht> stroke.
move the piston to top dead center ; then By reading the graduations on the scale,
61" Solo or High Compression Motors Using Aluminum Pistons
back it down (turn motor backward) the the distance between the piston head and (Generator or Magneto Equipped)
required distance (see specifications for top center can be determind easily. Pistons must be set between llj32" and3j8" before lop dead center.

Ignition Timing Specifications for "V" Twin Motors

The following specifications give the piston can be set and the circuit breaker
correct piston positions before top dead cen- points timed on the proper cam, to ju<t
ter for solo and sidecar motor ignition tim- separate with the spark lever advanced
ing. The measurements are given so the fully.

7 4" Sidecar or Low Compression DCA Motors

(Generator or Magneto Equipped)
Pistons must be set between 7 j32" and I j4" before top dead center.

7 4" Solo or High Compression DCA Motors

(Generator or Magneto Equipped)
Pistons must be set between I 3j32" and 7 j 16" before top dead center.

7 4" Sidecar or Low Compression Motors Using Standard Cast lr~n

Pistons
(Generator or Magneto Equipped)
Pistons must be set between 7 /32" and I j4" before top dead center.

7 4" Solo or High Compression Motors Using Standard Cast Iron

Pistons
(Generator or Magneto Equipped)
Pistons must be set between 9 j32" and 5/ 16" before top dead ct>nter. ILLUSTRATION NO. 3
 (ll" Special Fast Stock 500, M, A and E. Ty;)c Motors gear should be loosened with gear puller then force the drive gear on the shaft,
FK831, or, if this tool is not at hand, by tightening the lock nut to hold the gear in
(Generator or Magneto Equipped)
tapping it sharply with a small hammer, place.
Pistons must be set between 3 8" and 7 16" before lop dead center. preferably a brass hammer. Check the timing by observing the open-
Advance the magneto timer by shifting ing of the interrupter points and measuring
it downward. Turn the interrupter in an the distance of the piston's upward travel
To Time Generator for Ignition on "V" Type Twins anti-clockwise ( lefthand) direction, until before it reaches top dead center. If nec-
the lever fibre block is just touching the essary, retime the motor until it does check
Before attempting to time the generator, mediate gear may not mesh with th·c
rear housing interrupter shoe. Hold the with the specifications for that particular
remove the gear case cover and compound generator and large intermediate gears <'ll
interrupter in this position so it cannot turn, type of motor.
intermediate gear. Refer to illustration the first attempt. However, by turning the
No. 3. compound gear a tooth at a time, a placP
The timer cam for "V" Twins is will be found where it will slide into mesh
shaped to have a large and a small end, the easily. Ignition Timing for Model 250 Remy Generator
small end being used for timing the front It is a good policy to check the timing The 2SO model generator timing is the cam turned clockwise until the circuit
cylinder. Looking at the circuit breaker after the piston has been located, the points similar to that of the magneto. The tim"r breaker points are just ready to separate.
housing from above, the cam turns in a set and the gears meshed. This can be done cam has a small and a large end. The After the proper piston position has been
clockwise (right hand) direction. by turning the motor until the points are small end is used to time the front cylin- obtained, the generator gear can be fitted
just separated; then pass a scale der. to the shaft and secured in place with the
The timer ·advance and retard lever
must be all the way advanced (forward) through the cylinder plug hole to the The circuit breaker ring assembly ts lock nut. As in the case oi the magneto,
when timing ignition. With the front cyl- top of the pis-ton, finally turning the motor advanced when turned to the right or the drive key should be filed thin in order
inder piston set according to specifications forward until the piston reaches top dead clockwise. to allow the gear to be shifted on the shaft
center. Note the piston's upward travel
for the particular model of motor, turn the The timer should be advanced fully and if necessary.
in fractions of an inch and if it does not
timer cam clockwise, by means of the gen-
check with the specifications, retime th ~
erator gear until the small cam is just
motor as may be necessary.
starting to separate the circuit breaker or
contact points. Now that the piston and When timing ignition, the backlash of Valve Timing for 1913 & 1914 "V" Twin Motors
timer cam are set, hold the generator gear the gears and timer cam must be taken Since the cam gear used in these motors The roller arm roller for the f ron! cylindn
with the thumb of the left hand to keep into consideration. Otherwise, the piston is not marked, it will be necessary to lo- will be just riding off the first or exhaust
it from turning; then mesh the compound location and breaker points will not check cate the pistons in the proper place~ in the valve cam. Looking at the gears from th~
intermediate gear. The compound inter· according to the specifications. cyiinders and then set the cam to operate right side of the motor, the small pinion
the valves accordingly. gear turns in a righthanded direction and
It is probably easier to set the exhaust the cam gear turns in a left handed direc-
Magneto Ignition Timing for "V" Twin Motors vah·e on its chfing period because this tion. When timing valves according to this
(Roadside or Temporary Timing) takes place when the piston is just over top method, the exhaust valve tappets must, of
dead center. That is, the piston has reached course, be adjusted to have between .008"
The magneto can be timed by lining up however, it must not be taken as a factory top dead center and has just started on and .01 0" clearance.
all motor gear marks; then fitting the mass- standard. The best method is, of course, the next downward stroke.
to remove the front cylinder plug, locate Since the exhaust and inlet valve cams
neto gear to the armature shaft. The Locate the front cylinder piston betwee'l are mounted on the same timing gear
magneto drive key must, of course, be in piston and set the interrupter according
I '16" and 3 /8" after top 'dead center, (made integral) the inlet valves do not
place. This method of timing will be close to the following instructions. Refer. to
then mesh the cam gear with the pinion require independent timing.
enough for emergency or quick timing, illustration No. 2. gear so the exhaust valve is just closing.

Factory Method for Timing Magneto Ignition Valve Tappet Clearance for 1913 and 1914 "V" Twin Motors
The magneto drive key used between Locate the piston in the front cylinder On all Twin cylinder motors, prior to made in various thicknesses and if neces-
the gear and shaft should be filed thin so according to specifications for solo or side- 191 S, allow . 004" clearance between the sary, can be ground until the correct clear-
as to allow movement of the gear on the car service. Loosen the magneto drive exhaust lifter pins and the valve stems or ance is obtained.
shaft if necessary, to obtain the correct in- gear nut (do not remove the nul) and caps. The caps used on the end of the The inlet levers and valve stems should
terrupter and piston setting. loosen the drive gear on the shaft. The exhaust valve stems on these motors are be adjusted to have .004" clearance.
 Sport Model Motors closes. The outside (nearest the mani-
fold) valve lifter pin is for the inlet valve.
Sport Model Valve Timing Specifications After locating the piston at the proper
The sport model intake and exhaust be sure to have the proper gear Ieeth in place for timing, set the generator timer
rRO!IT f7LINDIR
cams are mounted on the same cam gear, mesh, that is, a marked tooth must coin- shaft as follows: The timer lever ( lo- rABll

similar to "V" twin cam design. The cide with a mark that is between two cated betweel) coil and timer housing) must
cam and pinion gears are marked so that teeth. Illustration No. 4 shows corr('ct be advanced or shifted to the rear.
the valves can be timed readily. When alignment of gear marks A and B for Turn the timer shaft until the "flat side"
timing the motor according to gear marb, proper valve timing. is away from the coil. The cam must be
set just ready to separate the breaker
Valve Timing Specifications for Sport Model Motor points. The drive gear can now be filled
to mesh with the intermediate gear as de-
To check valve operation against piston ing the push rod or lifter pin while the scribed previously. Hold the timer cam
location, remove the front cylinder plug motor is being turned over. When the with one hand when fitting the drive gear
and with a scale measure the piston travel push rod or lifter pin begins to tighten ILLUSTRATION NO. 5
to prevent it from turning and hence
according to the following specifications. or loosen, the valve is begmning to open change the timing.
or close. cable) of distributor cap leads to the front
The exact time of valve opening and After generator is timed, make sure that cylinder. Refer to illustration No. S, show-
closing can be determined easily by turn- the outside terminal wire (spark plug ing proper disposition of spark plug cables.

Inlet Valve Timing

Timing Sport Model With Magneto for Ignition
Inlet valve should open when piston is should close when piston IS 9i 16" after
7j32"before top dead center. Inlet valve bottom dead ce11lcr. The magneto on the sport model motor The correct piston position for igmtwn
can be timed by merely aiigning all gear is between 3/8" ""d 7jl6" before top
marks after the drive gear is keyed to the dead center.
Exhaust Valve Timing
armature shaft. To check the timing, re- The front (forward) interrupter sho~
Exhaust valve should open when piston haust valve should close when piston 1s move the cylinder plug and measure the on sport model magneto times the front
1s IS /32" before bottom dead center. Ex- I/ 16"after top dead center. piston position before top dead center when cylinder.
the magneto breaker points are just ready The magneto interrupter lever is ad-
Sport Model Breather Valve Timing to separate. vanced when in a downward position.
Crank case compression m the sport the cam gear and stud when the valves
model motor is relieved through a port in are timed correctly (according to marks).

· Valve Tappet Adjustment for Sport Model Motors

Both inlet and exhaust valves on the correct valve timing, it is imp<>rative that
sport model should have .006" clear- the tappets be adjusted to have .006"
ance when the motor is cold. To insure clearance.

Timing Sport Model Motor with Generator for Ignition

Inspect circuit breaker points before with the other gears when the piston and
starting to time the motor, to make sure timer points are set according to the fol-
they are separating .020''. Use a thick- lowing instructions.
ness gauge or the gauge provided on the Remove the front cylinder p~ug ana set
generator wrench for the purpose. piston between· 3 ;8" to 7/ 16" before top
The generator drive gear is provided dead center on compression stroke. It will
with three key ways, located to permit be necessary to remove the· front footboard
change of timing within I j3, 2j3 and I support in order to remove the cylinder
tooth of the gear. In other words, the plug. Compression stroke is the next up
drive gear can be fitted to mesh properly stroke of the piston after the inlet valve
 interrupter housing must be advanced fully lever set just ready to break the points with
Single Cylinder Motors (shifted downward) and the interrupter the piston located as mentioned above.
Single Cylinder Valve Timing (All Models)
The exhaust valve timing in all single On most single cylinder models the pin- Model 21 CD Single Ignition Timing
cylinder mo'lors should be such as to ion and cam timing gears are marked, tints The 1921 CD model commercial sin- I /4" to 9 j32" before top dead center.
cause the valve to open when the piston making exhaust valve timing a simple mat,
gle should be timed with the piston set
is between 3, 4" and 9 16" before bot- ter. All that is necessary in this case is
tom dead center and close when the piston to line up the pinion and cam gear marb
is between I , 16" and I, 8" after top and the valve is timed. Timing Single Cylinder Motor Ignition According to Gear Marks
dead center.
With the pinion gear and cam gear and gear, then fit the intermediate gear;
Exhaust Valve Tappet Clearance for All Single Cylinder Motors marks aligned, fit the magneto drive key so all marks are aligned.
Except Model 21 CD
Adjust the exhaust tappet to allow end of the valve stems. These caps are
.004" clearance for all single motors ex- furnished in various thicknesses, and can,
cept model· 21 CD. On early model therefore, be ground to give the correct
motors steel caps were placed over the clearance.

Single Cylinder Motor Inlet Valve Timing

All 1913 to 1918 single cylinder between I 18" and 3,:'8" after bottom
motors require independent timing of the dead center. Allow .004" clearance be-
inlet valves, becau~e the inlet cam is on tween inlet lever and valve stem when
one of the intermediate timing gears. The motor is cold.
inlet valve should be timed to open when Single cylinder motors made prior tv
the piston is 3/ 16" before top dead center. 191 3 have automatic inlet valves. which
The inlet valve should be timed to close therefore, do not require timing.

1921 CD Single Motor Inlet Valve Timing

The inlet valve in this motor is operated not, therefore require independent timing.
by the secondary or cam g'!ar and does

Valve Tappet Clearance for 21 CD Single Motor

When motor is cold, allow .004" clear- between .008" and ,0 I 0" for the ex-
ance for the inlet valve stem and lever, and haust valve stem and tappet.

Breather Valve Timing for Single Cylinder Motors

All single motors except model 21 CD gear so its marked tooth checks with the
have automatic relief or breatheT valves, I\ stamped in the crank case. Refer. to
which, of course, requires no timing. illustration No. 2 showing the proper set-
To time the breather valve on model ting for valves and breather according to
2 I CD single motors. align the pinion and marks.
cam gear marks, then mesh the breather

Single Cylinder Motor Ignition Timing

(All models except 21CD)
All single cylinder motors should be ton set between 3 I 16" and I; 4" before
timed for the spark to occur with the pis- top dead center on compression stroke. The ILLUSTRATION NO. 4
 Carburetor Parts and Their Functions
In case it becomes necessary to take the

Mechanics' Bulletin carburetor apart for cleaning (which may

be done without disturbing a single adjust-
ment) it would be well to know the parts
and their functions.
No. 101 July 15, 1924 Harley-Davidson Motor Co., Milwaukee A float chamber, or bowl A, (lllus.
No. 2), and a barrel, containing a system
of fuel nozzles and air passages, B, are the
principal parts. Fuel from the tank enters
the Union Body D, and after being
Zenith Carburetor Instructions strained through the filter screen E, passes
into the bowl through the float needle valve
The Zenith is a plain tube automatic accessible. Turning the idler adjusting
seat F. From the bowl to the motor fuel
type of carburetor, depending upon an screw 2 (lllus. No. I ) outward makes for
flows through different channels, in various
arrangement of jets and air passages to a lean mixture, and turning it inward en-
quantities and proportions, depending on ILLUSTRATION NO. 2
provide ·a satisfactory fuel mixture for the riches the mixture.
the size of the nozzles, the speed of the
various engine speeds. The operation of Once the proper combination of jets A-Bowl;
motor, and the degree of throttle opening. B -Choke tube or venturi;
the carburetor is entirely automatic, with has beeri obtained for a certain type of
the exception of a low speed (idling) air motor, no further adjustments should be To see if there is any gasoline in the D-Gasoline union body;
carburetor, remove float needle valve cap E-Fiher scr.en;
adjusting screw, which is located on the necessary. F -Float valve seal;
top of the carburetor body and is readily G. If the needle valve can be depressed G-Floal needle· valve cap;
with the finger, there is no gasoline in H-Main jel;
the carburetor. I -Compensating jet;
Starting the Motor When the butterfly throttle valve is J -Atmosphericwell;
S -Lower body plugs.
nearly closed and the motor is "turned
When the motor is cold, place choker over" there is a very strong suction at the jet which has a calibrated opening at its
lever at P (lllus. No. I, priming position) edge of the butterfly where the idling hole upper end. At this point it meets a stream
and with the switch off, operate the starter is located. Under this condition of throttle of air which· is controlled by the knurled
pedal .two or three times. Then move opening little or no gasoline is supplied by screw 2, (I !Ius. No. I), the only adjust-
choker lever to S (starting position), turn
the main and cap jets H. Gasoline from ment which can be changed on the carbu-
on switch, and start the motor in the usual the bowl flows through the compensating retor. The resulting mixture passes through
manner. Run the machine a few blocks jet I into the atmospheric well J, the the idling hole and on into the motor
with the choker lever in S (starting posi-
suction then lifting it through the idling cylinders.
tion) until the motor is warm; then move
choker lever toward R (running ·position). Jet Combinations for Various Motors
An intermediate position is provid('d
which will be found very convenient dur- ILLUSTRATION NO. Description ]DCA Factory JD Factory
ing the warming up st'lge. Choker lever P-Priming position; JDCB No. Price JE No. Price
should be moved to R position as soon as S -Starting position; Main jet, H, (lllus. No.
R-Running position: 2) Standard .......... 21 MXI728D .50 20 MXI728C .50
practicable; running in any other position I -Float needle valve cnp;
continuously will cause misfiring and will Main jet, optional as ex-
2 ~Idler adjusting knurled scr~w;
consume excessive fuel. With a warm 3 - Throllle disc control scr.w; plained below ......... 20 MXI728C .50 19 MXI728B .50
motor, it will seldom be necessary to use 4 --Sel SCT('W; Atmospheric well or idling
choker lever. 3 - Throlll• lever. jet, J, (lllus. No. 2) .... 45 MX1724 .45 45 MX1724 .45
Compensating jet, I, (II-
If a motor is difficult to start, do not carburetion is blamed. Sticky or gummy
Ius. No. 2) Standard ... 22 MXI729D .35 20 MXI729B .35
instantly condemn the carburetor but exhaust or intake valve stems and guides,
Compensating jet, optional,
rather check over the spark plugs, valve improper valve tappet adjustments, water
as explained below ..... 21 MXI729C .35 19 MXI729A .35
tappets, and manifold joints and make cer- in the gasoline, a poo-r grade of gasoline
Choke or venturi ....... 23 MXJ733A 1.50 21 MXI733 1.50
tain that there is no water in the gasoline. or leaky manifold joints can also affect
Float needle valve seat, F,
Very often difficult starting is caused by motor starting, much the same as poor car-
(IIIus. No. 2) ........ 38 MXJ720 .35 38 MXI720 .35
improperly adjusted spark plugs, and poor buretion.
Identification mark on car-
bureto•r••••••••• 0 0. 0 CA JD
 It will be noted that the two type~ of Turning it in makes th<' motor nm fastt'T;
carburetors are not interchangeable with- turning it out slows the motor down. This
out changing jets and venturi. Any of screw may be tcrmrd a quantity adjust-
these parts can be ordered from us in the ment. These screws should be used in
regular way. conjunction with each other. In an ex-
For special occasions or to meet with treme case of loading at low speeds, a
the characteristics of certain motors, the No. 21 compensating jet may also be tried
jet combinations can be changed as fol- for the CA model, or a No. 19 compen-
lows: sating jet for the JD or JE. model. This
If a motor tends to overload at moder- jet makes for a smoother running motor
ate speeds or to consume too much gaso- at low speeds, but is not quite as good
line, a No. 20 main jet can be fitted in for acceleration or hill climbing. See
the CA model, or a No. 19 main jet in that the idling jet is a 45. Some of the
the JD or JE model. If overloading is earlier carburetors were fitted with size 50
found at low speeds, it can in practically jets which had a slight tendency to over-
all cases, be eliminated by proper use of load.
the idling adjustment. All jets are plainly marked and through
The low speed (idling) adjusting the aid of illustration No. 2 with the fore-
screw 2 (Ill us. No. I ) is to be used for going descriptive matter, the various jets
varying the quality of the mixture; that and working members should be located
is, turning it QUI makes the mixture leaner, without difficulty.
while turning it in makes the mixture If you should happen to have a Zenith
richer. If the screw is turned all the way carburetor not functioning properly on one
in and the mixture is. still too lean, the of your motors, we suggest that it be
trouble undoubtedly is caused by air leaks checked over. The jet sizes should cor-
in the manifold or inlet housings. This respond with the standard settings as men-
screw cannot be used to vary the idling tioned above, for that particular model of
speed of the motor. carburetor.
The throttle valve or disc control screw
3 (lllus. No. I ) is used for this purpose.

Care of the Carburetor

Keeping the carburet<>r free from dirt the gasoline, and if it has holes, dirt can
and water is the only care necessary. This enter and stop up the jets. If necessary
should be done periodically by removing the entire carburetor can be taken apait
the Union Body D (Ill us. No. 2), filter and cleaned, without disturbing its ad-
screen E, and lower plugs S, and clean- justment; each part has its place and can
ing the openings with gasoline, compressed go in no other. If, after a considerable
air, or a straw. Do not use a wire or period, the carburetor should not idle well,
drill. It is very important that the filter inspect and clear the atmospheric or idling
screen be replaced· and that it be in good well, which may be clogged from dust.
condition. If it is dirty it will shut off
 Motor Repairs -- Continued
When cast iron piston motors are fitted with ahiminum pistons,
specify whether you want 1923 or 1924 type pistons because of the
Standard Factory Repair Prices difference in piston pin sizes. To fit 1924 aluminum pistons or iron
alloy pistons to an earlier than 1924, 1924 JD or FD, motor requires
October 15th, 1924. Huley-Davidson Motor Co. Milwaukee, Wisconsin the fitting of 1924 connecting rods. Motors must be rebalanced when
fitted with aluminum or iron alloy pistons. See prices below. Re-
balancing instructions are ~urnished upon request.
Retail
ITH the help of this list, you can establish standard
W retail prices on factory repair jobs .like cylinder re-
grinding, connecting rod rebushing and frame and fork
exchanging. The chance of under- or over-charging the rider
Regrinding 61" cylinders, any model, and fit-
ting 1923 over-size aluminum pistons (us-
ing 39/64" piston pins), rings, pistx>n pins Per set { Mat'! $11.60 list
and Jock rings .......................... .
Price

Labor 7.25 net ......... .

is eliminated. Regrinding 61" cylinders, any model, and fit-
You can exchange a damaged frame or other piece of ting 1924 over-size aluminum pistons (us-
equipment for a rider from your stock of repaired parts, and ing .790" piston pins), rings, piston pins and Per set S Mat'! $11.72 list
finish the transaction on the spot instead of having to wait un- lock rings .............................. . l Labor 7.25 net
til you learn the factory's charge. Regrinding 61" cylinders, any model, and fit-
If you supply a rider with a new part from stock in ex- ting over-size iron alloy pistons, rings, Per set { Mat'! $ 9.00 list
change for a damaged part, you can easily figure what allow- piston pins and lock pins ................ . Labor 7.25 net
ance to make him. Regrinding 74" cylinders, any model, and fit-
In estimating the cost of repairs on frames and forks, remember that ting 1923 oversize aluminum pistons .(using
the prices quoted in the first part of this list are for labor only. To arrive 39/64" piston pins), rings, piston pins and Per set { Mat'! $11.60 list
at the repair cost, add the price of the needed new parts to the labor lock rings .... .' ......................... . Labor 7.25 net ......... .
charge. You will find all frame and fork fittings listed herein. As an Regrinding 74" cylinders, any model, and fit-
example, the cost of repairing a frame needing a new head and two casing ting 1924 oversize aluminum pistons (using
clamps will be estimated as follows: .790" piston pins), rings, piston pins and Per setS Mat'! $11.82 list
Labor charge (as per this list) ................... $11.00 net
lock rings .............................. . l Labor 7.25 net
Regrinding 74" cylinders, any model, and fit-
1 - IE72P frame head . . . . . . . . . . . . . . . . . . . . . . . . . 3.75
2 - DE2 casing clamps@ .20 . . . . . . . ............ .40 ting oversize iron alloy pistons, rings, piston Per set { Mat'! $ 9.00 list
pins and lock pins . . . . . . . . . . . . . . . . . . . . . . . . Labor 7.25 net
$15.15 Reaming 6.1" cylinders for 74" exhaust valve•. Each Labor $ 1.00 net
Sandblasting and rewhitening cylinders . . . . . Per set ~abor 1.50 net
Inspect carefully any part on which you quote a repair or exchange
Cylindera are rewhitened only when apecified.
price. You may find, for example, that a frame which on firslt inspection
seems to be out of line, has one or more cracked parts such as cylinder F'tt'
1 mg overstze · 111 · 1et h ousmg · Mat'! $ :50
c1amp nut . . . . . . . . . . . . . { Labor list
net
or casing clamps. 1 25
Rebushing 61" or 74" connecting rods at both {Mat'! $ 2 16 list
All prices on parts, except where otherwise noted, are list. Where list ends and lapping steel bushings . . . . . . . . . . Per set Labor 1:56 net
prices are not subject to the usual discount, net prices are shown. All Rebushing 61" or 74" connecting rods at both
labor prices are net. All quotations are subject to change without notice. ends and fitting rollers, retainers and crank J M a t'l $ 5·36 I'
Per set tst
QUOTATIONS COVER ONLY SPECIFIED OPERATIONS pin . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . I Labor 2.19 net
Drilling 61" or 74" connecting rods . . . . . . . . . Per set Labor 1.25 net
Motor Repairs Rebalancing 61" flywheels for use with alumi-
num or iron alloy pistons . . . . . . . . . . . . . . . . Per set Labor 1.88 net
Piatona are always lapped in when cylinders are reground Rebalancing 74' flywheels for use with alumi-
Retail num or iron alloy pistons . . . . . . . . . . . . . . . . Per set Labor 2.50 net
Price These price:r apply only when flywheels without ahafts are sent in.
Regrinding 61" cylinders and fitting over-size
cast iron pistons, rings, piston pins and Per t { Mat'! $ 6.44 Jist Rebushing inlet lifter arms and fitting rollers Per set$ Mat'! $ 1.00 Jist
lock pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
e Labor 5.63 net and pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . l Labor .63 net
Rebushing exhaust lifter arms and fitting roll- Per set { Mat'! $ 1.04 list
Regrinding 74" cylinders and fitting over-size ers and pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . Labor .63 net
cast iron pistons, rings, piston pins and Per set { Mat'! 6.44 list
lock pins . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Labor 5.63 net
 Motor Repairs -Continued
Retail
Price Motorcycle and Sidecar Frames, Forks and T'anks
Refacing exhaust valve . . . . ......... Each Labor .31 net Inspect Very Carefully Before Giving Estimate to Customer.
These Price& Include Re-enameling, But No Material.
Fitting 1915 to 1922 type mechanical oiler with {Mat'! $ 1.35 list
operating shaft and bushing . . . . . . . . . . . . . . . . . . . . . . Labor 1.25 net MOTORCYCLE FRAMES
When luggage carrier studs are needed, add $1.00 net to the quoted labor charges.
Fitting 1923 to 1925 type mechanical oiler . f Mat'! $ .95 list Retail
with operating shaft .............................. l Labor .88 net Net Price
· · · · h f S Mat'!
R e b us Iung transmrsswn mam s a t ...... · . · · · · · · · · · l Labor $ .40 list
.75 net Straightening only, no new parts ...................... $6.00 to $ 8.00
2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.50
f 2 cylinder brackets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
1 axle clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
9.50
9.50
1 rear fork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.50
Generator Repairs 1 rear stay . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.50
Retail 2 casing clamps and 2 cylinder brackets . . . . . . . . . . . . . . . . . . . . . . 10.00
Price Head and 1 axle clip . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
Head and 1 rear fork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
Soldering and turning commutator Labor $ 1.25 net Head and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
Top bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
w Lower bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
~ Front loop bar and 2 casing clamps .. .. .. . .. .. .. .. . . .. . .. .. 11.00
NOTE
The price of a new armature is so low that it does not pay to rewind an old
< Rear loop bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
Cl::: 2 rear stays ................................. , . . . . . . . . . . . . . . 11.00
armature or replace a commutator. Spark coils with broken down windings or Lt. 2 rear forks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
condensers, damaged cases or terminals, cannot be repaired. A charge will 1 rear stay and 1 rear fork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11.00
be made for testing and inspecting armatures and coils. 0z Seat Post Cluster . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.00
C2 Gear Box Bracket . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12.00
List - Head, seat post cluster and 2 casing clamps . . . . . . . . . . . . . . . . . 13.00
Repairing manual switch KK385 or MK385 ................................... $1.20 ~ Head, top bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . . 13.00
W Head, lower bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . . . . 13.00
Cl::: He.ad, front loop bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . 13.00
Head, rear loop bar and 2 casing clamps . . . . . . . . . . . . . . . . . . . . . 13.00
Cl::: Loop tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.00
Carburetor Exchange Prices 0
Lt.
Seat post cluster and upper bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Seat post cluster and lower bar . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
13.00
13.00
Cl::: Seat post cluster and rear loop tube . . . . . . . . . . . . . . . . . . . . . . . . . 13.00
NOTE: We are now prepared to exchange worn Schebler H model carburetors 0 Head, top bar, lower bar and 2 casing clamps . . . . . . . . . . . . . . . . 14.00 ......... .
for Schebler De Luxe carburetors. See prices below. CQ Head, lower bar, front loop bar and 2 casing clamps ....... :. 14.00 ......... .
Net List < Head, top bar, front loop bar and 2 casing clamps . . . . . . . . . . . 14.00 ......... .
Exchanging worn 74" or 61" Schebler H model carburetor for a rebuilt ...:I Head, top bar, rear loop bar and 2 casing clamps . . . . . . . . . . . . 14.00 ......... .
H model carburetor ............................................. $4.00 $ 5.75 Head, lower bar, rear loop bar and 2 casing clamps . . . . . . . . . 14.00 ......... .
Gear box bracket and rear stays . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.00 ......... .
This exchange price does not include the cost of replacing missing parts like Gear box bracket and rear loop tube . . . . . . . . . . . . . . . . . . . . . . . . 14.00 ......... .
hot air connection or air valve casting. t Gear box bracket and loop tube . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14.00 ......... .
Exchanging worn 74" or 61" Shebler H model c.arburetor with oversize When a lower bar or loop tube is furnished the cost includes cylinder brackets or
throttle shaft, damaged bowl or broken body, for a new Schebler H crank case clamp$.
model carburetor .... : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6.50 9.00 RIGID AND SPRING FORKS
Always add lower head cone EE66P-32 cents liat, to the rigid fork repair price$.
Exchanging worn 1921 small bowl style 74" Schebler H model carbure-
Retail
tor for a new large bowl size carburetor .......................... 6.00 9.00 Net Price
Exchanging worn Schebler H model carburetor, any model, for a
Labor for repairing rigid fork-no new fittings furnished .... $2.50 to $3.00
new MK88A 1%" Schebler DeLuxe carburetor, whlch fits all 1924
Labor for repairing rigid fork with one broken side, center
and 1925 motors and 192.1 to 1923 74" m:1tors .................... 8.00 12.00 stem or crown plate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . • 4.25 ....... .
Exchanging worn Schebler H model carburetor, any model, for a new It does not pay to repair a rigid fork having more than one broken fitting.
LK744 1Ys" Schebler DeLuxe carburetor, which fits 1917 to 1923 Labor for repairing spring fork-no new fittings furnished .. 1.75 to 2.50
61" motors ...................................................... 7.50 11.25 Labor for repairing spring fork with one broken side mud-
guard bracket or tip ............................ .'. . . . . . 3.50 ....... .
It doea not pay to repair a spring fork having more than one broken fitting.
 RIGID FORK PARTS
TANKS
Retail BC100 Rigid fork side .............. 1915 ..... , .. , . . . . . . . . . . . . . . '1' $1.9.~
Net Price EC100 Rigid fork side .............. 1916 to 1923-61 models . . . . T 3.60
Labor for repairing damaged tank, depending upon extent of KC100D Rigid fork side .............. 1922 and 1923-74" models all
)924 ....................... T 3.80
damage ................................................ $3.00 to $5.00 Rigid fork side .............. 1925 . . . . . . . . . . . . . . . . . . . . . . . T 3.50
NC100
It does not pay to repair a badly damaged 1917 to 1920 tank. AC2B Rigid fork stern ............. 1915 to 1924 . . . . . . . . . . . . . . . . T .85
SIDECAR FRAMES NC2 Rigid fork ·stem ............. 1925 . . . . .. . . . . . . . . . . . . . . .. . T .95
Labor for repairing sidecar frame-no new fittings furnished .... $ 9.50 BC1B Upper crown plate (1) ....... 1915 . . . . . . . . . . . . . . . . . . . . . . . T .22
BC1A Lower crown plate (2) ....... 1915 . . . . . . . . . . . . . . . . . . . . . . . T .20
Labor for repairing sidecar frame needing one fitting ............ 10.50 HC1 Crown plate (2) ..............1916 to 1923-61" models . . . . T .16
Labor for repairing sidecar frame needing two fittings . . . . . . . . . . . . 12.00 HC1A Crown plate lower (1) ....... 1916 to 1923-61" models . . . . T .16
Labor for repairing sidecar frame needing three fittings· ......... 13.00 HC27 Crown plate assembly ........ .1916 to 1923-61" models . . . . T .80
KClD Crown plate (3) ............. 1922 and 1923-74" models, all
1924 and 1925 . . . .. . . . .. .. . . T .20
Re-enameling Motorcycle and Sidecar Parts in Olive Green, KC27D Crown plate assembly ...... :.1922 and 1923-74" models, all
Brewster Green, or Harley-Davidson Gray 1924 and 1925 .. . .. . . . .. .. . .
Crown plate spacer (4) ....... 1915 to 1925 .............. .
T .95
.04
H0388
These prices include labor for cleaning and getting the parts ready for enameling. DC15 Spring fork bracket .......... 1915 .. . . . . .. . . . . . . . . . . .. . . . T 1.30
These prices do not include labor for stripping, assembling and repairing. EC15 Spring fork bracket .......... 1916 to 1923-61" models . . . . T 1.75
Retail KC15D Spring fork bracket .......... 1922 and 1923-74" models, all
Net Price 1924 and 1925 .. . . . . . . .. . . . . T 2.00
EC32 ~igid fork side upper end .... 19.16 to 1924 . . . . . . . . . . . . . . . . T .35
Frame, motorcycle or sidecar ................................... $ 1.80
EC23 Upper end splice ............. 1915 to 1924 . . . . . . . . .. . . .. .. T .10
Set of forks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.80
Single fork ........ : . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 FRAME PARTS
Sport Model fork . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.45 (Three-Speed Frame) .
Set of tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2.50 Frame head ................... 1915 to 1924 .. .. .. .. . .. .. .. . T $3.75
IE72P
Sport Model tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.80 NE35 Frame head .................. 1925 . . . . . . . . . . . . . . . . . . . . . . . T 4.25
Mudguards, motorcycle or sidecar ........................... each .90 EE606A Top bar with seat bar bracket.1915 to 1924 . . . . . . . . . . . . . . . . T 2.10
Sidecar body two passenger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.75 NE606A Top bar with seat bar bracket.1925 . . . . . . . . . . . . . . . . . . . . . . . T 2.05
FE609 Lower bar with motor brack-
Sidecar body one passenger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9.00 ets .......................... 1915 to 1924 . . . . . . . . . . . . . . . . T 2.00
Tool box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 NE609 Lower bar with motor blocks .. 1925 . . .. . . . . . . . . . . . . . . . . . .. T 1.85
Handlebars . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 NE504 Cylinder clamp block (2) ..... 1925 . . . . . . . . .. . . . . . . . . . . . . . T .35
Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.10 DE93 Tank strip (front) ........... 1915 and 1916 . . . . . . . . . . . . . . T .12
DE75 Tank strip (rear) ............ 1915 and 1916 . . . .. .. .. .. .. . T .10
Magneto . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 Tank strip (front) ........... 1917 ro 1924 . .. .. . . . .. .. . . .. T
JE93 .10
Set of Chainguards . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1.45 jE75 Tank strip (rear) ............ 1917 tlo 1924 . . . . . . . . . . . . . . . . T .05
Stand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .40 NE622 Tank screw block (5) ........ 1925 . . . . . . . . . . . . . . . . . . . . . . . T .03
Battery box . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .90 EEl Seat post cluster ............. 1915 and 1916 . . . . . . . . . . . . . . T 1.55
Wheels, motorcycle or sidecar .............................. each .90 FE1 Seat post cluster ............. 1!U 7 to 1924 . . . . . . . . . . . . . . . . T 3.00
NEt Seat post cluster ............. 1925 . . . . . . . . . . . . . . . . . . . . . . . T 3.25
Re-enameling all parts of a motorcycle after it is completely FE607G Loop tube (head to three-speed
stripped and all fittings have been removed from parts . . . . . . . . . 15.00 bracket) ..................... 1915 to 1924 . . . . . . . . . . . . . . . . T 2.70
Re-enarneling all parts of a single passenger sidecar after all fit- EE171 Front loop bar (head to casing
tings have been removed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.50 clamp) ..................... :1915 to 1924 .. . .. . .. .. . .. .. . T 1.20
FQ86 Front loop bar reinforcement
(2) .......................... For splicing EE171 to frame. T .08
List of Spare Parts to be Used in Estimating Repair Costs NE6.18 Front tube assembly (head to
This list is made up for estimating repair costs only. lower connection) ............ 1925 . . . . . . . . . . . . . . . . . . . . . . . T 3.70
SPRING FORK PARTS IE505 Handlebar control bracket .... 1915 to 1924 . . . . . . . . . . . . . . . . T .10
NE621 Crank case and footboard
BC19 Spring fork side ............. 1915 . . . . . . . . . . . . . . . . . . . . . . . T $1.50 bracket (1) .................. 1925 ....................... T .95
EC19R Spring fork side ............. 1916 to 1919 . . . . . . . . . . . . . . . . T 1.15 NE620 Lower frame connection ..... 1925 . . . . . . . . . . . . . . . . . . . . . . . T 3.35
IC19R Spring fork side ............. All 1920 and .1921, 1922 and FE608 Rear loop tube .............. 1915 to 1924 . . . . . . . . . . . . . . . . T .75
1923 61" models . . . . . . . . . . . . . T 1.15 NE608 Rear loop tube .............. 1925 . . . . . . . . . . . . . . . . . . . . . . . T .85
KC.19DR Spring fork side ............. 1922 and 1923-74" models all NE623 Rear tube spring plug (at bot- .
1924 . . . .. . . . . . . . . . . . . . . . . . . T 1.25 tom) ........................ 1925 . . . . . . . . . . . . . . . . . . . . . . . T .06
NC19R Spring fork side ....... ·...... 1925 ................. , . . . . . T 1.15 FE735 Three-speed bracket ......... 1915 to 1924 .. .. . .. .. . . .. .. . T 5.10
AC13 Spring fork end .............. 1915 to 1925 . . . . . . . . . . . . . . . . T .50 NE735 Three-speed bracket ......... 1925 . . . . . . . . . . . . . . . . . . . . . . . T 3.45
DC20 Front mudguard support ..... 1915 . . . . . . . . . . . . . . . . . . . . . . . T .70 EE19R Rear fork only (lower) ....... 1915 to 1924 . . . . . . . . . . . . . . . . T .60
EC20 Front mudguard support ..... 1916 to 1922-61" models . . . . T 1.00 NE19R Rear fork only (lower) ....... 1925 . . . . . . . . . . . . . . . . . . . . . . . T .55
LC20 Front mudguard support ..... 1923-61" models . . . . . . . . . . . T 1.00 DE85R Rear stay only (upper) ....... l!il5 and 1916 . . . . . . . . . . . . . . T .90
KC20D Front mudguard support ..... 1922 and 1923-74" all 1924 EE85R Rear stay only (upper) ....... 1917 to 1924 .. . . . . . . . . . . . . . . T 1.10
and 1925 , , , , . , , , . , , , , , , , , , , T 1.45
NE85R Rear stay only (upper) ....... 1925 . . . . . . . . . . . . . . . . . . . . . . . T .95
AE5 Rear mudguard support ...... 1915 and 1916 ............... T .55
FE5 Rear mudguard support ...... 1917 to 1924 . . . . . . . . . . . . . . . . T 1.00
NES Rear mudguard support ...... 1925 . . . . . . . . . . . . . . . . . . . . . . . T .90
DE2 Crank case clamp ............ 1915 to 1924 . . . . . . . . . . . . . . . . T .20
CE24P Foot board support rod brack-
et ........................... 1915 to 1924 ................ T .45
AE504A Front cylinder clamp ......... 1915 to 1924 . . . . . . . . . . . . . . . . T .30
FE706 Rear cylinder clamp .......... 1915 to 1924 . . . . . . . . . . . . . . . . T .16
DE36P Seat bar bracket and bushing .. 1915 to 1924 . . . . . . . . . . . . . . . . T .75
NE36P Seat bar bracket ............. 1925 . .. . .. . .. . .. .. .. .. .. . . . T .35
FE7 Left side axle clip ........... 1915 to 1925 . . . . . . . .. . . .. . .. T 2.10
FE6 Right side axle clip .......... 1915 to 1925 . . . . . . . . . . . . . . . . T 2.10
DE42 Right luggage carrier stud .... 1915 to 1925 .. . . . . . . . . . . . . . . T .12
DE41L Left luggage carrier stud ..... 1915 to 1925 . . . . . . . . . . . . . . . . T .12
SPORT MODEL FRAME PARTS
WGE31 Front bar only ............... All sport models . . . . . . . . . . . . T $ .95
WIE41 Rear bar only ................ All sport models . . . . . . . . . . . . T 1.05
AWGE20 Upper bar ................... All sport models .. . . . . .. .. . . T 2.30
AWGEll .Lower bar ................... All sport models . . . . . . . . . . . . T 1.05
WGE70R Rear fork (upper) ........... All sport models .. . . . . .. . . .. T .75
WGE71R Rear fork (lower) ........... AU sport models . . . . . . . . . . . . T .85
WGE7 Frame head ................. AU sport models . . . . . . . . . . . . T 3.00
WGE32 Front motor bracket ......... All sport models . . . . . . . . . . . . T 3.70
WGE42 Rear motor bracket .......... All sport models . . . . . . . . . . . . T 3.60
WGE9 Front connection for lower bar.All sport models . . . . . . . . . . . . T .95
WIElOA Rear connection for lower bar.AU sport models . . . . . . . . . . . . T 1.00
WGE8 Seat post cluster .....•....... All sport models . . . . . . . . . . . . T 2.30
AWGE23 Seat bar bracket ............. All sport models . . . . .. .. .. . . T .45
WGE85 Rear mudguard support ...... All sport models . . . . . . . . . . . . T .90
WGE62 Left rear axle clip ........... All sport models .. . . . . .. . . . . T 2.20
WGE52 Right rear axle cbp .......... All sport models . . . . . . . . . . . . T 2.20
WGD15 Handlebar c Ius t e r forging
(where bar joins fork) ....... All sport models . . . . . . . . . . . . T 3.00
SIDECAR FRAME PARTS, SINGLE PASSENGER
GQ33 Main bar (next to motorcycle) .1918 to 1923 . . . . . . . . . . . . . . . . T $3.50
MQ33 Main bar (next to motorcycle} .1924 . .. .. . . . .. .. . .. . . . . .. .. T 5.20
NQ33 Main bar (next to motorcycle) .1925 . . . . . . . . . . . . . . . . . . . . . .. T 5.90
DQ6P. Axle tube (rear bar assembly) .1915 to 1923 . . . . . . . . . . . . . . . . T 3.00
MQ6RA Axle tube (rear bar assembled).1924 and 1925 . . . . . . . . . . . . . . . T 5.50
EQ37 Side bar (away from motorcy-
cle) ......................... 1915 to ,1925 . . . . . . . . . . . . . . . . T 1.00
GQ36A Front bar ................... 1918 to 1923 . . . . . . . . . . . . . . . . T 1.35
MQ36A Front bar ................... 1924 and 1925 . .. .. .. .. .. . .. T 1.55
JQ121R Truss bar, front (diagonal) ... 1918 to 1923 . . . . . . . . . . . . . . . . T 1.90
MQ121R Truss bar, front (diagonal) ... 1924 and 1925 .. . .. .. . .. .. .. T 2.15
JQ7R Truss bar, rear (diagonal) .... 1918 to 1923 . , . . . . . . . . . . . . . . T 1.60
MQ7R Truss bar, rear (diagonal) .... 1924 and 1925 . . . . . . . . . . . . . . . T 1.65
DQ9 Connection for main bar and
axle tube ......•............. 19.15 to 1925 . . . . . . . . . . . . . . . . T .75
NQ933 Connection for main bar and
axle tube .................... 1925 ............ ,. . . . . . . . . . . T .65
EQ76 Connection for side bar and
axle tube ............. 1916 to 1925 . . . . . . . . . . . . . . . . T 1.90
DQ8 Connection for main bar (cen-
ter and front) (2} ........... 1915 tx> 1925 .. . .. . .. .. . .. .. . T .70
GQ15 Truss bar center connection .. 1918 to 1925 . . . . . . . . . . . . . . . . T 1.65
IQ16 Truss bar and main bar con-
nection .................. ·.... 1918 to 1925 . . . . . . . . . . . . . . . . T .45
GQ38P Connection for side and front
bar .......................... 1918 to 1925 . . . . . . . . . . . . . . . . T 1.15
GQ10 Frame brace bracket ......... 1918 to 1924 ................ T .80
NQ10 Frame brace bracket ......... 1925 . .. .. . . . . . . . .. . . . . .. . . . T 1.10
Mechanics' Bulletin
No. 102 june 10, 1926 Harley-Davidson Motor Co., Milwaukee, Wis., U.S. A.

Complete Timing Instructions for Harley-

. Davidson Motors
All models from 191 S to date-except 1918 and earlier single cylinder models
and the opposed twin cylinder sport model. Instructions for these models furnished
on request.
The arrangement of this bulletin is as follows:
The Valves-How They Operate in Relation to Piston ....... Pages I to 3
Twin Motor Valve and Breather Timing \Vith and Without Gear lLLUSTRATlON NO.
Marks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pages 3 and 4 Graphically Explains the Four-Stroke-Cycle Principle
21.09" Single Motor Valve Timing With and Without Gear No. 2 Compression stroke-Piston This explanation of the valve action
Marks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Pages S to 7 coming up and compressing gas in cylinder applies to all Harley-Davidson motors,
Ignition Timing of Twin and 21.09" Single Models With and head. Both valves are closed. (lgni- whether single or twin cylinder models.
Without Aid of Gear Marks . . . . . . . . . . . . . . . . . . . . . . . . Pages 7 to 12 tion should be timed to occur shortly be- On twin motors, the two cylinders are
fore piston reaches top center on this timed in relation to each other, so that
stroke. The exact timing is given under they deliver power impulses alternately;
The Valves "Ignition Timing"). that is, when either cylinder is delivering a
How They Operate in Relation to Piston No. 3 Power stroke-Piston going power impulse, the other cylinder has com-
down under the pressure of the burning pleted just half of the events required for
If the valve operating mechanism (cam in the cylinder head which are opened and its next power stroke (piston is going down
gas. Both valves are closed nearly the
gear, lift arms, etc.) is removed from the closed by the action of the valves; there- on intake).
full stroke. (Exhaust valve opens shortly
timing gear case· of a motor, and the be fore piston reaches bottom center) . The exact valve timing in relation to pis-
fore, the valves must open and close at
ton, which varies for different motors, and
motor then turned, the valves will stand just the right time in relation to piston ·No. 4 Exhaust stroke-Piston coming correct method of obtaining valve timing
still and the pil;ton will move up and travel. up, forcing out burned gas. Exhaust valve for all stock models from 1915 to date
down in the cylinder without any dis- opened shortly before piston reached bot- (except 1918 and earlier single cylinder
tinguishing strokes other than just up and Four strokes of the piston (two up and tom center on last (power) stroke. It models and the opposed twin sport model,
two down) are required for each power remains open the full exhaust stroke and which are covered in separate bulletin)
.down. But when the valve operating
closes after piston has passed top center are explained hereafter under various
·mechanism is assembled in gear case and impulse. The •purpose of each stroke and
and traveled down a short distance on headings which indicate the particular
the valves thereby made to operate in a the action of the valves during the strokes next (intake) stroke. models the data may be applied to.
fixed relation to piston travel when motor are as follows:
is turned, each stroke of piston has its Read These Cautions
No. Intake stroke-Piston gomg
particular function to perform in the series
down taking in fresh g~s. The i'ntake Piston postlions in motor llmmg are in any of these positions, it must be under-
of events required for each power impulse, determined from either top (upper) or stood that the motor is to be turn.cd in the
valve opened shortly before piston passed
namely: Taking fresh gas into cylinder, bottom (lower) dead centers. Dead J!rection in which it runs.
over top center and started down on this center is point at extreme top or bottom
compressing the ·gas, delivering the energy When checking valve timing, valve tap-
stroke. Valve remains opeh during full end of piston travel-the point where pis- pets must be very accurately adjusted, as
of the burning gas, and expelling the stroke and closes after. piston has passed ton is "dead." Be very careful that you per instructions below; otherwise, timing
burned gas. The fresh gas is admitted bottom center and traveled upward a short do not become confused where the timing will not check right even though cam gear
and the burned gas expelled through ports distance on next (compression) stroke. specifications indicate "before or after top is correctly meshed with pinion gear.
or bottom center." In locating the piston Then, when turning motor to find point
2
where valves start to open or are fully be determined ea<ily by turning push rod ( 3.18 mm) past lop center and insert gear V<'ry likely isn't more than one g<'ar tooth
closed, be extremely careful that you turn or tappet while motor is Geing turned slow- back into place with exhaust cam lobe up- out of the way. To make sure, check the
motor to just the right point, because a ly. When push rod or tappet begins to ward, midway between front and rear lift valve openings and closmgs in both cyl-
little variation at tappets means a compara- tighten or loosen, the valve is starting to arms. Next. hold front exhaust lift inders, against piston positions, as per fol-
tively big difference in piston position. The open or just closing. arm up as far as tappet will permit, lowing specifications. After exhaust valve
~xact time of valve opening and clo~ing can and at same time shift cam gear timing is found to be correct, timing gear
to the right, one gear tooth at a time, until case and inlet push rods can be asserr.bled
Twin Motor Valve Timing the last position is found where gear can be
inserted without overlapping and being
to motor and inlet valve timing then check-
ed. However, as both cams are inl<'gral
Valve Tappet Adjustment blocked by the exhaust lifter arm roller. with the one gear, the inlet valves are
Twin Motors When this position is found, the gear bound to be in time, when the exhaust
When making adjustments to valve tap- Fnmt-.006" (.15mm) clear- should be in correct time and, at most, valves are correctly timed.
oets, motor must be cold in order to ob- ance.
tain accurate results. Compression release Rear-.004" (.I mm) clearance Exact Piston Positions Where Valves Should Open and Close
lever must be in running position. Turn Exhaust tappets-191 7 and later models Twin Motors
motor to a position where you are sure Front and rear-.008" (.2 mm) 1915-1916
that tappet to be adjusted is in its lowest to .010" (.25 mm) clear- Intake Valve opens when piston is Exhaust Valve opens when piston is
position. ance. I/ 16" ( 1.59 mm) to 3/32" (2.38 5/tl'' ( 15.9 mm) to 3/4" ( 19 mm)
Inlet push rods-All models 1915 to date mm) before top center (Piston coming up before bottom center (Piston going do-wn
Adjust exhaust tappet and inlet push --.002" (.05 mm) to .004" (.I mm)
rod clearance as follows: on exhaust s-troke). on power stroke).
clearance between inlet lever and end of Intake Valve closes when piston is Exhaust Valve closes when piston is
Exhaust tappets-1915-16 models valve stem. 1/8" (3.18 mm) to 1/4" (6.35 mm) l/32" (.79mm) to 1/16" (I.S9mrn)
after bottom center (Piston starting up after top center (Piston starting dowu on
To Time Valves According to Gear Marks on compression stroke). intake stroke).
Twin Motors
1917 to Date
In all twin motors since 191 5, the cam
Intake Valve opens when piston is Exhaust Valve opens when pi•ton is
gear (secondary gear) and pinion gear
3ll6" (4.76mm) to5/16" (7.94mm) 5;8" (15.9 mm) to 3/4" (l9 mm)
are marked so that i(cam gear is removed,
before top center (Piston coming up on before bottom cenler (Piston goi•1~ down
it can be replaced in correct time without
exhaust stroke). on power stroke).
going to the trouble of actually checking
Intake Valve closes when piston is Exhaust Valve clo,es when piston i•.
valve openings and closings against piston
position.
3/4" (19 mm) to 7/8" (22.2 mm) 1;16" (1.59 mm) to 1.'8" (3.18 mm)
Illus·tration 2 shows the gear marks cor- after bottom center (Piston starting up on after top c~nter (Piston starting down on
rectly aligned. compression stroke). intake stroke).
Secondary gear 3 is marked in two The Breather Valve and How to Time It According to Marks
places. Fit it to motor with one of marks Twin Motors ~
registering with marked tooth on pinion
ILLUSTRA TlON 2 The relief or breather valve is provided When marks on pinion and cam gears
gear 6 and other mark facing intermediate to allow the crank case compression to be are in perfect alignment, the breather valve
T-roin lvfolor Timing Gcar3 gear 2. The pistons and cams will then
1-0ilt'r and intermt'diate gear; 2-Intcrmcdiate expelled when the pistons descend. Be- gear must be meshed with pinioB gear so
~ear; J-Secondary or cam gear; 4-Breather valve be in proper relation and the valves will
"A"' timing mark on case; 5-Brea.thcr valve gear; sides relieving the crank case compression, that marked tooth on breather gear aligns
open and close at the right time, provided
6----Pinion or main shaft gear j 7--Pininn and the breather valve controls ihe lubricating with the "A" stamped in crank case just
seconri:uy gear marks correctly aligned; 8- lappet and push ·rod adjustments are cor- system to a large degree. The importance above breather bushing.
Secondary a11d inter mediate gear marks correctly Illustration 2
alig-ned. reel.
of correct timing for this valve is there- shows correct breather valve timing accord-
To Time Valves Without Aid of Gear Marks fore obvious. ing to gear mark&.
Twin Motors To Time Breather Valve Without Aid of Gear Marks
If the gear marks have been removed, in relation to top and bottom centers. Twin Motors
the valves can be timed as follows: In Also, timing gear case should be removed. The breather gear must be set so that in crank case. Valve continues to open
ihis case motor should be out of frame and First, fit cam gear onto its stud, regard- port in sleeve of valve is open I/ 16" as motor is turned in the direction in which
cylinder plugs removed so that a 6" scale less of timing, and get both exhaust tappets ( 1.59 mm) to 3/32" (2.38 mm) when it runs, and closes when piston is near bot-
can be inserted against the head of piston accurately adjusted to correct clearar.ce. front piston is on exact top dead center. tom center.
in order to determine exact piston position Then remove gear. Set front piston Ys" Opening must be on forward side of port
3
 Valve Timing 21.09 Cu. ln. (350 CC) Single Cylinder Side valve and shift cam gear to the left, one to the left one tooth at a time, until last
by Side and Overhead Valve Motors gear tooth at a time, until last position is position is found where cam will clear
Valve Tappet Adjustment found where cam will still clear tappet and tappet and allow gear to be inserted.
Overhead and Side by Side Valve 21.09 cu. in. Singles allow gear to be inserted. This is correct Both gears should now be in correct time,
The important things to be remembered Side by Side Valve Motor- position for this gear. and, at most, will not be more than one
when adjusting ta'Ppets on the single cyl- Intake and Exhaust-.004" (.I mm)
Now turn motor in direction in which tooth out of the way. To be sure that
inder motor are: Motor must be cold. to .005" (.125 mm) clearance.
Compression release lever ( de-compre5sor it runs until piston stands Ys" ( 3.185 timing is correct, check the valve openings
lever on overhead valve motor) must be Overhead Valve Motor- mm) after top center. This requires only and closings against piston position, as per
in downward position. Be sure that motor Intake and Exhaust-.002" (.05 mm) a slight movement of motor. Insert ex- the following specifications. Before doing
i~ turned so that tappet to be adjusted is in to .003" (.076 mm) clearance. (This haust cam gear 8 with its cam lobe for- this .checking, fit gear case cover so that
its lowest position. Adjust tappets to the clearance to be measured between end
following clearances: of valve stem and rocker arm).
rvard of exhaust tappet. Then, hold tap- gears will be supported and held in cor-
pet up 'snug against valve and shift gear rect alignment.
To Time Valves According to Gear Marks
Overhead and Side by Side Valve 2 1.09 cu. in. Singles
Exact Piston Positions Where Valves Should Open and Close
. The valve timing gears are marked
Side by Side Valve-21.09 cu. in Single
so that if removed, they can be replaced
Intake Valve opens when piston is Exhaust Valve opens when piston IS
in correct time as shown in I !lust ration
1/8" (3.18 mm) to 3/16" (4.76 mm) 7/16" (II mm) to 9/16" (14.3 mm)
3. The inlet cam gear 4, which is a before bottom center (Piston going down
before top center (Piston coming up on
compound gear, is marked in three exhaust stroke). on power stroke) .
places 3-6-7. Assemble gears m Exhaust Valve closes when piston 1s
Intake Valve closes when piston is
case with one of marks on gear 4 in 7/16" (II mm) to 9/16" (14.3 mm) 1/8" (3.18 mm) to 3/16" (4.76 mm)
alignment with mark on pinion gear 5, after bottom center (Piston starting up on after top center (Piston starting down on
another mark in alignment with mark compression stroke). intake stroke).
on exhaust cam gear 8, and third mark
Overhead Valve-21.09 cu. in. Single
facing gear 2. The cams will then be
8
timed in proper relation to piston, Intake Valve opens when piston is Exhaust Valve opens when piston Is
3/32" (2.38 mm) to 5/32" (4 mm) 7/16" (II mm) to 9/16" (14.3 mm)
and if lappets are correctly adjusted,
before top center (Piston coming up on before bottom center (Piston going down
valves will open and close at right on power s.troke) .
exhaust stroke).
time. Assemble the other two gears
Intake Valve closes when piston is Exhaust Valve closes when piston is
1-2 as per instructions under "To Time
7/16" (I I mm) to 9/16" (14.3 mm) 3/32" (2.38 mm) to 5/32" (4 mm)
Ignition." after bottom center (Piston starting up on after top center (Piston starting down on
To Time Valves Without Aid of Gear Marks compression stroke). intake stroke).
Overhead and Side by Side Valve 21.09 cu. in. Singles
If the gear marks have been removed, First, fit cam gears 4-8 (Ill us. 3) into To Time Breather Valve
the valves can be timed as follows: If a case, regardless of timing, and get tappets Overhead and Side by Side Valve 21.09 cu. in Singles
side by side valve motor, remove cylinder accurately adjusted to correct cleayance.
head so that piston position can be deter- Then remove both gears. Set piston Ys" Single motors are provided with two crank case, which is necessary for proper
mined. If an overhead valve motor, the (3.185 mm) before top center and then breather valves, which must be open dur- lubrication. These valves are simply ports
piston position can be determined by in- insert inlet cam gear 4 back into. place ing down stroke of piston to release crank in both cam gear shafts which at proper
serting a 6" ( 150 mm) scale through with the cam lobe forrvard of intake tap-
spark plug opening. pet. Next, hold the tappet up snug against case compression, and closed on up stroke time register with ports in gear shaft bear-
of piston to cause a vacuum or suction in ings in gear case cover. These shafts are
5
6
held in a fixed relation to the gear by according to gear mark or by other Locating Compression Stroke and Setting Piston for Ignition Timing
means of pins in the shafts. So when cam methods of timing, the breather ports are
Twin and Single Cylinder Motors
gears are correctly fitted into gear case, bound to be timed correctly.
When timing a twin motor, it makes no valve single, while on the side by side valve
difference whether the timing is set with single, cylinder head should be removed.
Ignition Timing the front or rear cylinder piston, provided Directly after intake closes (turning
Theoretically, ignition should occur as solo, sidecar or other heavy duty service, proper circuit breaker cam is used ; how- motor in the direction in which it runs) ,
the piston reaches top dead center on com- and variou~ other things. To enable the ever, it is customary to time with front pis- the piston is coming up on compression
pression stroke, when the gas in cylinder operator of a machine to get the best motor ton. In order to locate piston just right dis- stroke. Get the piston on exact top dead
head will be compressed to the limit. How- performance m1der all service conditions, tance before top center, a 6" ( 150 mm) center of this stroke, and then back motor
ever, there is a short lapse of time after the circuit breaker of ignition unit is so scale' can be inserted through cylinder plug up until piston stands the correct distance
spark occurs before complete combustion; constructed that it can be retarded or ad- hole in cylinder head of a twin motor, before top center, as per following speci-
so in order to have the burning gas exert vanced a limited distance at the will of through spark plug hole on an overhead fications.
the maximum pressure on the piston just as the operator, thereby changing the time
it passes over top center, ignition is always of ignition in relation to piston position. Ignition Timing Specifications
timed to occur when the piston is a little Exact timing specifications for all models
distance before top center, on compression from 1915 to date are given below (ex-
stroke.. This distance varies for different cept 1918 and earlier single cylin~r "L" Model Motor
types of motors, being governed by the models and the opposed twin sport model,
compression of rr.otor, whether. it is for which are covered in a separate bulletin).
Valve timing Same as Standard motor.
Time All Motors With Circuit Breaker in Fully Advanced Position
Ignition timing
As the timing specifications below give fully advanced position when timing a
the maximum distance that piston may be motor. The rider cannot then advance "H" Model Motor (2 cam)
before top center when spark occurs, the the spark too far for best motor perform-
circuit breaker (spark) lever must be in ance, under normal service conditions. Valve timing

Circuit Breaker Points Must Be Accurately Adjusted

Inlet valve opens when piston is 1/4 to 3/8 before top center.
Be sure to adjust circuit breaker point Adjust point gap as follows: Inlet valve closes when piston is 13/16 to 15/16 after bottom center.
gap to following specifications before tim- Exhaust valve opens when piston is 9/16 to I 1/16 before bottom center.
All Generators ..... 020" (.5 mm)
ing a. motor, because, if point gap is im- Exhaust valve closes when piston is 1/4 to 5/16 after top center.
properly adjusted when timing motor, and Bosch Magneto ..... 016" (.41 mm)
Ignition I 1/32" to 13j32".
then later the gap is adjusted correctly, Berling Magneto ..... 018" (.46 mm)
the timing will be affected to some extent. Dixie Magneto ...... 020" (.5 mm)

Spark Occurs as Circuit Breaker Points just Start to Open Equipped Motor
On a twin cylinder generator model, On a twin cylinder magneto model, the As all timing gears, including the mag- in alignment. First, set cam and pm1on
the front cylinder is timed with narrow end front cylinder is timed with rear interrupter neto drive gear, are marked in motors gears with their marks in alignment as
of circuit breaker cam. cam of a Bosch magneto, or the lower equipped with magneto, these motors can shown in Illus. 2, if a twin motor, or Illus.
interrupter cam of a Berling magneto. be timed close enough to correct timing so 3, if a single motor, and then carry align-
21.09 cu. in. single cylinder generator 21.09 cu. in. single cylinder magneto that they will run satisfactorily, by simply ment of marks right through to magneto
model has a one cam circuit breaker. model has only one interrupter earn. assembling the timing gears with all marks gear. The timing obtained by this method
7 8
is J:kdy to be very accurate and in every type of motor being timed.
ca'e v.111 be close enough to accurate so The magneto gear keyway is cut con-
that motor will perform satisfactorily. sideral>ly wider than key fitted in armature
However, play in magneto gear keyway, shaft. This allows the pos.ition of gear on
1d lash or 'Play between the gear teeth shaft to be changed slightly. In case a
due to wear, allows some variation. so motor, after being limed according lo gear
this method should not be depended upon marks, doesn't check accurately according
as accurate enough to be used in shop to piston position and circuit breaker point
practice. To be sure of accurate timing, opening, si.mply loosen armature shaft nut
it is recommended that shop m<:>chanic, and ~agnelo gear slightly and shift arm-
after setting timing according to gear ature shaft a trifle in gear. Then tighten
marks, check piston position against cir- shaft nut and check timing again. If nec-
cuit breaker setting, and make adjustments essary the shaft key may be ftled thinner
as necessary to correct the timing to speci- to allow more movement of shaft in gear,
fications given on page 8 for particular in order to obtain exact timing.

ILLUSTRATION NO. 4
To Time Ignition in a Harley-Davidson or Remy 235 Generator Timing Ignition According to Gear Marks and Circuit Breaker Settin2
Equipped Twin Cylinder Motor-According to Gear Marks
To Time Ignition in a Harley-Davidson or Remy 235 Generator
and Circuit Breaker Setting
Equipped Twin Cylinder Motor-Without the Aid of Any Marks
The generator drive gear and small intermediate gear that meshes with gener-
compound or double intermediate gear that ator gear. Next, after accurately adjust- Use this more accurate method, when meshes with the generator gear. Now set
meshes with it are not marked. However, ing the circuit breaker point gap. set circuit timing a motor that is out of frame and the FRONT piston on compression stroke
a moto~ can be· timed close enough to cor- breaker (spark) lever in full advanced on bench where cylinder plug can be re- the correct distance before tap center as
rect so that it will perform sati&factorily by (forward) position, and then turn gener- moved to allow a 6" scale to be inserted per specification for the type of motor being
ator in direction in which it operates (to against piston in order to determine its timed. (Note-Timing may be set with
setting circuit breaker in proper relation to
exact position. This method is also some- either front or rear piston; however. it is
pinion and cam gear marks and without left) until narrow end of circuit breaker
times applied when timing a motor while customary to time by front piston). Re-
reference to piston position. This method cam has separated contact points about assembled in frame, a piece of wire being member that compression stroke occurs di-
should not be considered accurate enough Vz to Y4" of their full opening. Steady inserted through spark plug opening in rectly after the intake valve closes. Next,
to be used exclusively in shop practice; · the generator in this position and after order to locate piston. However, timing set circuit breaker (spark) lever in full ad-
cannot be set as accurately with motor in vanced (forward) position, and then tu'rn
however, it can be used in emergencies noting that marks on pinion and cam gears
frame. generator in the direction in which it oper-
when necessary to make a quick job of ig- are still in perfect alignment, fit the small Assemble pinion, cam, and breather ates (to left) until narrow end of circuit
nition timing while motor is assembled in compound or double gear into place. See gears 6-3-5 into gear case with their marks breaker cam is itrst starting to separate the
frame. lllus. 4. properly aligned as shown in Ill us. 2. or, contact points. Steady the generator in
This gear may not slip into mesh freely if gear marks have been removed, assemble this position and after noting that piston
Assemble pinion, cam and breather the gears so that valves and breather are has not been moved from setting just made,
on first attempt due to its teeth not r~gis­
gears 6-3- S into gear case with their correctly timed as per valve timing instruc- fit small compound or double .gear into
tering properly with teeth on the generator
marks in perfect alignment as shown in and intermediate gears. but as the teeth tions. Intermediate gears 1-2 may now place. This gear may not slip into mesh
Illus. 2. Intermediate gears 1-2 may also on this double gear are staggered, a posi- be fitted into case, disregarding their on first attempt, due to its teeth not regis-
be fitted into case, disregarding their marks. marks. (These marks are used when tim- tering properly with teeth on generator and
tion can always be found, by turning the ing a magneto model). Fit the generator intermediate gears, but as teeth on double
(These marks are used when timing a gear a tooth at a time, where it will gear to the armature shaft and tighten the gear are staggered, a position can always
magneto model). Fit generator gear to slip into mesh freely without changing posi- shaft nut. Don't as yet fit the small com- be found, by turning gear a tooth at a time,
armature shaft and tighten shaft nut. Don't tion of either of the two gears with which pound, or double, intermediate gear that where it will mesh freely without changing
as yet fit the small compound, or double, it meshes. 10
9
 To Time Ignition in a Generator Equipped 21.09 Cu, ln. Single
posrtion of either of gears with which it starb to separate. Then check piston posi-
Cylinder Motor-Without the Aid of Any Marks
meshes. tion to see if it is correct distance before
top renter. Due to lash or play in the gear Side by Side and Overhead Valve Motors
After timing has been completed, it is
advisable to recheck it, by turning the train, it is sometimes necessary to go On the side by side valve model it will close~. Next with circuit breaker (spark)
~.1otor back slightly, and then orefully through the timing operation two or tine~ be necessary to remove the cylinder head lever in full advanced (forward) position,
turnrng it ahead until contact points just times before timing will check just right. so that exact piston position can be deter- turn generator in direction in which it oper-
mined. On overhead valve model, piston ates (to left) until circuit breaker cam has
To Time Ignition in a Generator Equipped 21.09 Cu. ln. Single can be located accurately by inserting a 6" just started to separate contact points.
Cylinder Motor-According to Gear Marks scale through spark plug hole. Steady generator in this position, and, after
and Marks on Timer Base First assemble pinion and cam gears noting that piston has not moved from set-
Side by Side and Overhead Valve Motors 5-4-8 into gear case according to their ting just made, lit intermediate gear 2 into
marks as shown in Illus. 3; or, if any gear case and into mesh with generator
The generator drive gear and inter- This gear is located in po'ltron on arma- or all marks have been removed, assem- and cam gears. If gear 2 will not slip into
mediate gear that meshes with it are not ture shaft with a key, and is provided with
ble gears so that valves are correctly mesh freely on first attempt due to its teeth
marked; however, by means of cam and three key ways, so that it can be located in
pinion gear marks and marks cut in top a position that will allow accurate timing. timed, as already explained. Fit generator not registering properly with teeth on gen-
edge of timer base, a motor can be timed Fit any one of keyways over key tempo- gear I to armature shaft. This gear. is lo- erator and cam gears as they are set, do
with a fair degree of accuracy without any rarily. Turn armature shaft nut (left hand cated in position on armature shaft with a not turn either motor or generator in order
reference to piston position, etc. This nut) up lightly. Next, hold a 6 inch scale key, and is provided with three keyways tv line gears up so they will mesh, but
method should not be considered accurate 3 (I !Ius. 5) or some small straightedge,
enough for shop practice. so that it can be located in a position that change position of generator gear on. arma-
tight and squarely against flat side of cir- will allow exact timing. Fit aay one of
Assemble pinion and cam gears 5-4-8 ture shaft by removing gear and turning it
cu:t breaker cam 2, and turn generator keyways over key temporarily. Turn
in gear case with their marks in perfect so that one uf its other keyways registers
alignment, as shown in Illus. 3. Fit gen- until scale or straightedge is in alignment
armature shaft nut (left hand nut) up with key. Then go through· the timing
erator gear I (Ill us. 3) to armature shaft. with marks I, cut in the top edge of timer
lightly. Now set piston on compression operation again. It may be necessary to
base. Steady generator in this posi-
stroke, correcl distance before top center, shift generator gear to third keyway before
tion, and after observing that marb as per specifications for type of motor be- accurate timing can be obtained. After
on pinion and cam gears are still in ing timed. Remember that compression timin~ !s completed be sure to tighten
alignment, as explained above, fit in- stroke occurs directly after intake valve armature shaft nut.
termediate gear 2 (lllus. 3) into the
case. Do not move either generator
Valve and Ignition Timing For 37 Cu. In. Single Cylinder C. D.
or cam gear in order to allow gear Model Built in 1921-22
2 to slip into mesh. If it will not The valve tappet and push rod adjust- Ignition should be timed to occur when
slip into mesh freely on first at- ments, valve timing S'pecilications (includ- piston is 1/4" (6.35 mm) to 9/32"
...,_ tempt because of its teeth not regis-
ing breather timing), and timing methods (7.14 mm) befo~e top center on com-
described for twin cylinder motor can b.e pression stroke. Use- the same methods for
tering properly with teeth on gears
applied to this model, as it is simply a timing as described for twin cylinder
with which it must mesh, change twin 74" motor with one cylinder removed. models.
position of generator gear on arm-
ature shaft by removing gear and
turning it so that one of its other two
ILLUSTRATION 5 keyways registers with key; then try
Selling the Circuit Breahr to Time Ignition in Single
Generator Mode/ agarn. After timing is complete,
1-TintinR marks cut in timer base; 2-Circuit br("aker
cam; -~-Six inch scale used as straightedge. tighten armature shaft nul.
12
II
 Nov. 14, 1927
October 10, 1927 CHANGE IN TWIN OIL
PUMP CONTROL
TWO RING PISTONS (74" AND SINGLE)
We now have an improved
We no longer furnish three (3) ring iron alloy pump control arrangement,
pistons for 74" and Single motors. The 61" iron alloy which will greatly lessen
piston still has three rings. the possibi~ity of the
rider catching the control
We have found two ring pistons in the sizes men- cable with his foot when
tioned to be more satisfactory, and they are now sup- cranking motor, resulting
plied on all parts orders. in a bent and unworkable
control or other damage.
The two and three ring pistons are interchangeable. It also eliminates entirely
For instance, it is all right to use one two ring and the pump body control clamp
one three ring piston in servicing a Twin motor. bracket, and thus the pos-
sibility of breakage at
The sa11e part numbers as applied to three ring this point due to a strain
pistons (74" - 253-24 -- Single 251-26) now apply to . on the cable as mentioned
the two ring pistons. New Oiler Control Arrangement above, or some other acci-
dent. It not only brings . the control cable closer to the gear case
and out of the way of the rider's foot, but also leads it to the pump at
.THE AIR CLEANER MUST BE CORRECTLY FITTED a different and easier operating angle. The new control coil clamp
bracket is an entirely separate fitting and in case of some strain on
'The air cleaner for maximu:n efficiency must be the cable, bending or damaging the bracket, the pump itself will not be
turned so that the dirt outlet at connection end is harmed.
directly downward. If in any other position there will
be some restriction to free escape of dirt sucked into This new arrangement is easily and quickly adaptable to any of the
cleaner, and as a result some will pass through into earlier 1928 twin models now in service. In case of an accident with a
motor. machine equipped with the original control arrangement, resulting in the
control clamp bracket being broken off the pump body, it is not neces-
The air cleaner properly fitted means longer motor sary to replace the pump. Simply cut off and smooth up with a hacksaw
life, and we, therefore, suggest that you make i t a or file the remaining stub of pump body bracket and then attach the new
point to see that this unit is correctly fitted in every fittings.
case.
You can obtain these new fittings on parts order. A complete com-
bination necessary to make the change over, together with instructions
for fitting, will be furnished, if you order part #711-28, price $ .80
list. Better order out a set or two and have them on hand.
 December 27, 1927
November 21 , 1927
TO SPOKE FRONT WHEEL ( BRAKE TYPE )
TO RENEW BUSHINGS IN SINGLE TRANSMISSION

STARTING SPOKES IN HUB

Countershaft gear bushings can be removed with an old twin model p1n1on gear
shaft. Place the large end of gear on an old Single piston turned bottom First, mark a starting point on each side of hub as follows. Draw a line
side up, and then drive the two bushings out. After pressino in new bushings, radially true with hub center, from any one of the brake shell attaching '
use reamer #4. rivets, to the rim of shell. This line will come between two of the ·
spoke.holes. Lo~ate ~he r~vet in yiqht side spoke flange that is directly
The bushing in low speed gear can be removed in the same manner, except that oppos1te brake s1de l1ne r1vet, and draw a similar line to rim of right
an old sprocket shaft is used to drive it out. This bushing has a shoulder flange. On this side the line will register exactly with one of the spoke
on the doq side of gear and, therefore, has to be driven out from the opposite holes
side. Size new bushing with reamer #4.
Insert spokes in brake side first. Holding hub with brake shell downward
To remove clutch gear bushing, first, cut a few threads in bushing with a 3/4" and starting line toward you, insert the first spoke in the hole just to '
tap, and after inserting a bolt of the same size, drive against inner end of the left starting line. Then working from this point insert a spoke in
bolt. Size new bushing with reamer #2. every second hole all the way around the hub, leaving the holes between
for the spokes to be inserted from other side of flanoe. The hub can now
The two countershaft bushings can be removed from gear box by driving or pressing be turned over (brake shell upward) and spokes inserted in the remaining
them out with an old upper connecting rod bushing. When putting a new bushing ten holes. We now have ten outer spokes (spokes inserted from inside of
in qear box cover (starter side), be sure that the flat side of bushing is flange), and ten inner spokes (spokes inserted from outer side of f1 anoe).
facing main shaft bearing, so as to allow proper clearance for countershaft Do not as yet start spokes in right side of hub. ·· ·
sprocket. After new bushings are pressed in, assemble the gear box and cover,
and pull the screws up tight to be sure that cover is in proper location. STARTING SPOKES IN RIMS
Then, with line reamer #3, ream both bushings in one operation. This will
insure perfect alignment of bearings. With the hub standing upright on the bench, brake shell downward place
the rim over hub, WITH THE TIRE VALVE hole toward you. The hub ~ust be
The gear shifter· shaft bushing has a shoulder on the outer end and, therefore, ~urne? SO TH~T STARTING LINE POINTS TOWARD YOU. A hole in your bench
has to be pressed or driven out from the inside of case. This can be accomp- 1n wh1ch to 1nsert the axle, thus allowing the spoke flange to rest flat
lished by working thru the inspection hole in top of case. Use reamer #1, to on bench mak~s the job of lacing easier. Be sure to place the rim with
size new bushing. ~he proper s1de up .. You can determine this by placing a spoke nipple
1n a hole on each s1de of rim and noting on which side the nipple sets
FRONT BRAKE COVER BEARING at the greatest angle. The side that shows the greatest angle is the
brake side and should go downward. Now, you are ready to start the
Hhen a new bushing is fitted in brake cover, it can be sized on the twin model spokes in the rim. Remember all spokes now in hub oo to the lower row
with reamer #4 - on the single model with reamer #2. of rim holes: First, tak~ inn~r spoke, makred "starting spoke No. 1"
(3rd.spoke r1ght of start1ng l1ne) to the hole in rim just to the right
o! t1re valve hole. Star~ nipples on spokes as they are inserted through
r1m. The balance of the 1nner spokes can now be started easily. The
!NN~R sooke.next to startino spoke No. 1 will go to the second hole from
1t 1n the r1m, and so on around the wheel, every other rim hole (bottom
row) being left vacant for the outer spokes.
Next, note that the hub is still standing in proper relation to rim so
that the.spokes l~ad f~om the hub at an angle corresponding to the angle
of the r1m holes 1n wh1ch they are fitted. The outer spokes can now be
SHOP DOPE - Page 2 December 27, 1927

laced into place. Start with outer spoke marked "starting spoke #2.
(3rd spoke left of startino line) and insert it in the second tire rim
hole (bottom row) to the rioht of tire valve hole. The wheel can now
be turned other side up to make it more convenient to get at these
outer spokes. The outer spoke next to starting spoke No. 2 will go in
the first vacant hole from it in the rim and so on around the wheel.
With this side of the wheel properly laced, every spoke crosses three.
INSERTING SPOKES AND LACING RIGHT SIDE
With the wheel turned brake side downward, fill the right side flanqe
with spokes,-inserting all twenty of them from the outside (upper side)
of flange. The spoke heads will all be on the one side of flange.
To start the first spoke on this side in the rim, turn the wheel so that
startinq line on hub is toward you, and take spoke marked "starting spoke"
No. 3 (1st spoke left of startinq line - NOT THE SPOKE HITH WHICH THE LINE
REGISTERS) to the fourth rim hole (top row) on the right of tire valve hole.
Now take the second spoke from this starting spoke to the second hole from
it in rim, and so on around the wheel, leaving every other spoke free and
every other rim hole vacant. This leaves ten spokes to be crossed with
those just laced in. Start this oroup with the spoke which reqisters with
the starting line. "startino spoke No. 4", taking it to the fourth rim
hole (top row) on the left of tire valve hole. The second spoke from this
starting spoke will go to the next vacant hole from it in rim, etc. With
this side of wheel properly laced every spoke crosses four.
The wheel can now be trued and the nipples tightened in the usual way. To
determine that spokes are so tiohtened that rim is true sideways with
center of hub, lay a straiqht-edqe across brake end of axle sleeve and
measure the distance from straiqht-edqe to rim. On a sinqe wheel the correct
measurement is 1.029" (approx. 1-1/32''- and on a twin wheel 1.756" (approx.
1-3/4"). If a wheel is laced with the rim off center any appreciable dis-
tance the machine in which it is used may have a tendency to pull to one
side.
 No. 416 February 20, 1928
January 9, 1928
HERE ARE SOME SERVICING TIPS ON THE FRONT WHEEL BRAKE
A free working control is one of the first essentials to smooth and effective
KEEP THE FRONT WHEEL BRAKE CONTROL PROPERLY CONNECTED braking. A sticky, hard working control means that considerable of the pressure
applied at the hand lever is lost in control friction. Frequent lubrication of
Three connection holes are provided in the front brake operating lever on every part of the control arrangement will keep it working freely.
twin models. At just which of these holes the control cable is connected
makes a decided difference in the pressure that can be applied to brake Should you have any complaint of the brake chattering at times, examine the con-
bands, by operating the hand lever. The braking power is thus adjusted to trols and see if the cable is sticking in the control coil, or the brake operating
load and traction. shaft sticking and binding in its bearing in the brake cover, preventing the brake
shoes from returning to their normal positions when hand lever is released. Such
In the case of a machine used with sidecar, the control should be condition is only the natural result of neglected lubrication. A liberal appli-
connected in the end holes (makred SC) to give most positive braking. cation of oil the full length of control and also a few drops at the hand lever
a~d ope~ating s~aft ~ea~ings \the operating shaft on the latest machines is pro-
For solo service the connection should be made at the hold marked V1ded w1th alem1te f1tt1ng) w1ll free the control action, and very likely the
(Solo) furthest from end of lever, so that rider cannot apply brake chattering will be entirely eliminated. On the latest machines two brake shoe
spr~ngs? instead_of one as on early machines, are provided to give more positive
with enough pressure to lock wheel when driving on slippery or loose act1on 1n return1ng shoes to full released position.
surfaced roads.
The center hole is Pcovided as an intermediate for the sidecar In some cases of chattering, it may be found that, while the control is free in
ac~ion, it is adjusted so tight as to hold the shoes continually expanded to the
driver who desires a less positive brake - or the solo rider who
wishes more positive brake action. po1nt where the bands are almost touching the drum, even with the hand lever in
full released position. With control so adjusted, if the wheel bearings happen
When attaching or detaching sidecar, the brake control connection should at to have a ~it~le more than t~e normal amount of play, or the brake assembly has
the same time be shifted accordingly - particularly when detaching sidecar, some play 1n 1ts center bear1ng, the brake bands and drum will come in contact
because using a machine solo with the brake connected up for sidecar service occasionally, and a chatter is the likely result. The control should be so
there is more possibility of applying brake with enouqh pressure to cause adjusted that the hand lever can be compressed about l/4 to l/3 of its full move-
skidding. This holds particularly at this time of the year in localities ment before the brake begins to take effect.
where the roads are a lot of the time wet, icy, or covered with snow and
consequently traction uncertain. ' Of course, as the brake center bearing becomes worn to the extent that the brake
assembly has_conside~able play or shak~, there will be an increased tendency to-
Vie, therefore, suggest that you caution your riders - particularly your ward chatter1ng. Th1s also hold true 1n case of excessive play in the wheel hub
solo riders- regarding proper connection of the brake control, and thus bearings. Hith everything perfect, the bands have only a few thousandths inch
lessen the possibilities of skidding and spills. cleara~ce from drum, so you can readily see what happens if there is too much
shake 1n the hub or brake. Check the adjustment of wheel hub bearings now and
then, and keep the brake bearing in good condition, by renewing the cover bushing
when.worn: A temporary repair to take up play is sometjmes made by simply fitting
a th1n ~h1m washer between the brake assembly and its thrust washer. When this
m~thod 1s used, care must be taken that the shim washer is not thick enough to
b1nd the assembly.
After a. new brake center bushing has been pressed into place, it must be reamed
to correct size. The twin model requires a 7/8" reamer, and the single a ll/16"
reamer. Both of these sizes are incorporated in the set of four reamers furnished
for servicing the single transmission (part #12660-26)
The brake shackle bushings will not ordinarily need to be renewed very often. These
bushings on the twin model require a 5/8" reamer to size them on the single, a
.4915" reamer. ·
No. 416 -2- SHOP DOPE
PART NUMBERS ON BRAKE AND SHACKLE BUSHINGS
4115-28 Center Bushing - Twin $ .40 List
4116-28 Center Bushing - Single .35
4131-28 Shackle Bushing - Twin (2) .35 "
4132-28 Shackle Bushing - Single (2) .30. "
Now as to the control cable and coil, and the various lengths used on different
models - you have no doubt noticed that on the first few machines equipped
with front brake, the control was passed down between the frame head and fork,
and thence down along the outside of fork. On later machines, the control is
shortened and leads from the handlebar directly down the fork side. The latter
arrangement has less bends and gives a freer operating control. When it becomes
necessary to service the control on one of the early machines, it is adviseable
to shorten a~d arrange it as on the late machines.
The correct lengths are as follows:
Twin models with Control Cable 52~
11

(Includes end fittings)

Standard Bars Control Coil 48~"

Twin Models with Control Cable 49\" (Includes end fittings)

Short Bars Control Coil 45\''
Single Models with Control Cable 43\" (lncl udes end fittings)
Standard Bars Control Coil 40 "
Single Models with Control Cable 40 3/4"(I 1 d
Short Bars Control Coi 1 37\;" nc u es en d f·tt·
1 1 ngs
)

On early machines where the control was passed through the forks, the lengths
of the coil and cable were in each case 3" more than the lengths given above.
Remember this, jf you retain the original arrangement of control, when
servicing an early machine.
Control cable and coil are furnished on parts order in only one length -
cable 56" with one end fitting attached -coil 48\;". Both must be cut to
correct length for the particular model on which they are to be used. Before
cutting cable, apply a light coating of solder at the point where cutting is
to be done. This will prevent the ends of cable from fraying out, making it
difficult to insert it thru coil. After .cable has been inserted, the other
end fitting must be attached. This is quite a particular job because the
end must stand considerable strain, and unless very securely attached, it may
pull off. We suggest doing the job as follows:
After placing the end fitting on cable, but before soldering it fast, spread
the end of cable as much as possible by driving a small tack between the
strands and leaving it there. A brass tack or brad about 1/2" long is best
for this job. The end can now be soldered fast. The best job can be done
by dipping it in a pot of molten solder. If, however, such facilities for
soldering are not available, a satisfactory job can be accomplished with an
ordinary soldering iron. The iron should be very hot so that the solder
will flow freely between the cable strands. Use a 50-50 grade of solder.
The ordinary wire solder is not hard enough for ~his job.
 No. 422 -2- April 2, 1928

Before fitting lower part of the tappets in the auide blocks, see that the
No. 422 April 2, 1928 roller tappet stems are a free fit in the holes machined for them in the
guide blocks. If the lower part of the tappets bind in the guide blocks,
FITTING GEAR STUD PLATE TO "H" MOTORS file tappets until they fit freely with no noticeable clearance.
Before placing gear stud plate in crank case, see that the ends of the gear Before fitting a new tappet guide block, pean over the edge of the dowel pin
studs fit in the holes provided from them in the gear case cover. hole in the timing gear case to compensate for any difference there may be
in the position of the dowel pin hole in the guide block. Use machinist's
Always place an old piston, bottom end up, under the crank case in such a blue to determine if the rollers ride squarely on the cam lobes. Shift the
position that the gear stud plate hole rests directly over the piston. This guide block to make the rollers run squarely on the cams, then drill or
prevents the crank case from becoming knocked out of shape. Pean over the ream out the dowel pin hole so the dowel pin is a drive fit.
dowel pin hole in the crank case because it is necessary that the pin be a
press fit, and variation in manufacture may prevent the hole in the gear stud Time the ignition so the spark occurs ll/32" to 13/32" before top center on
plate from lining up exactly with the original hole. compression stroke.
Allow the ends of the gear studs to remain in the qear case cover. Start the
gear stud plate in the crank case. Place a block of wood on the outside of
the gear case cover and tap lightly with a hammer, driving the gear stud plate
in the crank case far enough to start the gear stud plate bolts and a few timing
qear case cover screws. Alternate driving the gear stud plate, and drawing the
screws and bolts up lightly until the gear stud plate in in position and the
screws and bolts have been tightened. The timing gear case cover and now be
removed and the ends of the gear stud plate bolts riveted over to prevent loosening.
Ream (use l/2" reamer) or ftle out the dowel pin hole and drive the dowel pin into
place, peaning over the edge of the dowel pin hole in the gear stud plate to pre-
vent it from coming out.
Before timing the motor, make sure the gears have the proper amount {.003") of
backlash and do not bind on the studs.
REMOVING & FITTING TAPPET GUID BlOCKS & ROllER TAPPETS
(Read carefully before attempting to remove or fit guide block or roller tappets)
Tappet guide blocks can be removed from "H" motors without disassembling the motor
by removing only the inlet housings and the exhaust valves. This can be done
while the motor is in the frame.
Remove the timing gear case cover and the cam gears. Remove the inlet and exhaust
valve tappet adjusting screws, so that when driving the guide blocks out, the
roller tappets will remain in the case. If the tappets are allowed to come out
with the guide blocks, one corner of the lower, or forked part, will cut a groove
in the aluminum and cause an oil leak. This also applies when replacing the guide
blocks, but it is necessary to reverse the above directions, starting the stems of
the tappets in the guide blocks from the inside of the case.
When removing or replacing the guide block, use a light hammer and a block of
wood, ·tapping on the block of wood. When replacing the guide block, place a
block of wood at an angle on the edge of the uppermost part of the guide block.
Placing the block of wood directly across the top of !IUide block will dent the
top and ruin it.
No. 423 April 9, 1928

NEW ENAMELING PRICES April 23, 1928

No. 425
The followinq is an up-to-date list of prices for re-enamelino motorcycles, sidecars,
packaqe trucks and parts; also a list of extra charges for new parts enameled in the
standard optional colors. These prices cover enameling charges only. They do not EXTRA SPRING FOR FRONT WHEEL BRAKE
include the cost of any necessary repairs. KEEP THIS LIST AS A PERMANENT RECORDS.
ALL PRICES ARE NET AND SUBJECT TO CHANGE WITHOUT NOTICE.
STANDARD COLORS STANDARD OPTIONAL COLORS TO INSTALL EXTRA SPRING IN FRONT WHEEL BRAKE SHOE DRILL 3/16"
HOLE MIDWAY AND ON INSIDE LINE OF ELONGATED HOLES ALREADY IN SHOE.
Parts Single Twin Single Twin Add to
cost of
Olive H-D Grey; Coach Green; new parts The front wheel brakes on all machines now leaving the factory are equipped
Green Brewster Police Blue; with two springs. The new spring {part no. 4125-28A for twin and 4126-28A
Green; Maroon; Azure for single) is connected across the two brake shoes on the same side as the
Olive Blue brake operating stud.
Green
Complete Motorcycle $13.00 $15.00 $15.60 $18.00
Complete Sidecar (LT or LX) 12.50 15.00 This additional spring insures positive action the moment the pressure on
Complete Sidecar (QT) 15.00 18.00 the hand lever is released.
Sidecar Body (LT OR LX) 8.50 10.20
Sidecar Body (OT) 10.00 12.00
Truck Body (MWP) 15.00 18.00
Truck Body (MXP) 12.50 15.00
Truck Body (MW) 10.00 12.00
Frame (Motorcycle) 1.80 1.80 2.15 2.15 $.70
Frame (Sidecar/Truck-Narrow Tread) 2.00
Frame(Sidecar/Truck-Hide Tread) 2.25
Spring Fork .75 .90 .90 1.10 .40
Rigid Fork .90 .90 1.10 1.10 .50
Set of Tanks 2.00 2.25 2.40 2.70 1.20
Mudguards (each) .90 1.00 1.10 1.20 .50
Tool Box . 75 .90 .40
Handlebars .60 .60
Generator .50 .50
Maoneto .25 .25
Head lamp .60 .60
Tail Lamp .25 .25
Horn .50 .50
Set of Chainouards l. 25 1.25 1.50 1.50 .60
Stand · .60 .60 .70 .70 .20
Battery Box .75 .80 .90 .95 .70
Wheels-Each (including spokes) 1.25 1.25
Motorcycle Luggage ca·rrier 1.00 1.00 1.20 1.20 .35
Set of Sidecar Springs .80
Sidecar Tire Rack and Lugqage Carrier 1.56 1.80
FOR ALL OTHER COLORS EXCEPT CREAM OR WHITE, ADD 60% TO STANDARD COLOR PRICES.
FOR CREAM OR HHITE, ADD 80% TO STANDARD COLOR PRICES
 July 26, 1928
No. 444 September 3, 1928

THE CLUTCH PULL ROD AND BEARING KEEP MUFFLER SLOTS CLEAN

Should you experience any clutch pull rod or pull rod bearing trouble, see The slots of the new 4 tube mufflers are narrower than those
if the three studs in the actuating plate on that particular machine aren't on earlier mufflers. This construction is highly efficient
fitting too tightly in their holes in the clutch outer disc, preventing the in promoting quietness of operation, provided the slots are
actuating plate from acting freely. kept open and free of soot and dirt.
The act~atinq plate must fit freely enough so that when the clutch is fully With all muffler slots clean there is sufficient room for
engaqed (pedal all the way forward), the actuating plate will be forced out- the exhaust gases to escape freely without appreciable back-
ward by its spring to the full limit of pull rod adjustment, thus keeping a pressure. Inspect the muffler frequently to be sure all the
liqht tension on the pull rod bearing and holding the balls and races in slots are kept clean. If they're clogged, clean them thoroughly
alignment. with a stiff piece of wire or a hack-saw blade.
With the actuating plate studs fitted too tightly, the plate is not forced A clean muffler will go a long way toward insuring good motor
outward by its spring to the limit of the pull rod adjustment, when clutch performance - a dirty, clogged muffler will almost certainly
is fully engaged, and the balls and races of the pull rod bearing are then result in overheating, loss of power, and a sluggish running
free to wobble and run out of alignment. This condition is likely to job.
damage the bearing, and in some cases the head of the pull rod may be badly
worn or even twisted off. Instruct your men in the shop and have them pass the tip along
to the riders - TO KEEP THE MUFFLER SLOTS CLEAN -- BUT DON'T
If you will watch this point, and also see that pull rod is properly adjusted WIDEN THE SLOTS BECAUSE DOING SO WILL DEFEAT THE PURPOSE OF THE
and its bearing qreased occasionally, you will have no pull rod trouble. 4 TUBE PRINCIPLE.
When you find a tight fitting actuating plate, its studs can easily be aligned
with a hammer to give the desired free fit.
 -2-
As for the rivet and bushing, it will take you only a short time to install
these in your own shop. It is not necessary to remove motor from frame for
either job. A special line reamer is required to ream out the case for the
·bronze bushing. We will loan you this reamer for the asking. We haven't
had enough of these reamers made up so that we can loan them out to all
dealers at the same time, but we have quite a number on hand and it is our
idea to circulate them among the dealers as needed. We suggest the advis-
ability of fitting both the pin and bushing, but particularly the pin, on
THE 45" MODEL all the machines you have in service {below 29D3404), rather than taking a
chance on everything going along all right, or in other words waiting for
Here are some recent 45 motor improvements that can be worked into the early trouble to develop. If you wish to do this, just advise us accordingly and
motors a1ready in service. We are a 11 "up on our toes" to keep this new we will send you the special reamer together with the necessary bushings
model performing satisfactorily right from the start, and very likely you and rivets -- also detailed instructions for fitting.
will want to go as far as practical in installing any improvements in the
earlier machines, without waiting for possible difficulties to turn up. We Don't in any case be satisfied to make a "patch job" of servicing this
will cooperate to the limit in helping you do this. generator drive shaft. We would much rather replace a few drive shaft
assemblies than to gamble on the satisfaction of the early purchasers.
GENERATOR DRIVE SHAFT
THE COUNTERSHAFT SPROCKET
To overcome some generator· drive shaft key shearing difficulties which showed
up in the first machines assembled, we have made the gear a tighter press fit In connection with the very first machines assembled we found a few cases of
at each end and are using much stronger keys. These changes were made before key shearing at the countershaft sprocket. Naturally the keyways, particularly
many machines were shipped, and you are not likely to run into difficulties the sprocket keyways, were sometimes damaged as a result. This trouble was
alona this line, except with the very first machines put in service. The key discovered quickly and the necessary changes were immediately made. The
shearing occurred largely at the left, or bevel gear end of the shaft. sprocket keyway was cut enough deeper to allow fitting key 2279-26, which is
the same key used to secure the inner clutch disc, and a much stronger key
than the one originally used in the sprocket. Since these changes were made
Lately we have found that in many cases the bevel gear shaft has a tendency to there has been no further key shearing. Should you experience any difficulties
slowly but gradually work out of the gear, even though it still remains a tight along this line with the first machines sold, we suggest that you install this
press fit. As this shaft works out, it butts against the right side shaft and later combination. Only latest style sprockets will be supplied on parts orders.
forces the right side generator drive gear against the thrust boss on the cam
aear case cover, sometimes with such force as to cut and wear the thrust boss Although no such trouble has been experienced on the single~~ylinder model,
quite badly. A squeaking noise in the gear case is an indication of this con- the change has been applied to this model as well. Any countershaft sprockets
dition. To overcome this we are now fitting a pin or rivet through one of the with the shallow keyway that you may have in stock can be used up on the Single.
breather holes in the bevel gear and shaft. This not only prevents the shaft
from working out, but also gives double assurance of no further key shearing Incidentally, we will soon announce some new tools for the 45 model, and among
trouble at this end. This pin is fitted in all new motors with numbers above these is a proper wrench for the engine and countershaft sprocket nut. This
29D3403. will make it possible to more securely tighten these sprockets, than has been
possible in the past with the wrenches available.
INNER FRONT CHAIN GUARD SCREWS
The generator drive shaft bearing in the right side crank case was originally an
unbushed !bearing just a reamed hole in the aluminum case. A few cases have If one of the two screws which attach the inner chain guard to crank case
been found where for some reason or other this bearing has become badly cut and happens to loosen and work out, it may drop into the chain and do some damage
enlarged, allowing the right side drive shaft a great deal of play. This condition to chain or sprockets, or possibly both. You don't need to worry about any-
is evidenced by a bad clatter or noise in the gear case, particularly when thing like this happening on the later machines because for some time a shake-
accelerating from slow speeds. As soon as we learned of this trouble we immediately proof lock washer has been fitted under the head of each screw. Only the first
installed a bronze bushing. This bushing has been fitted in all motors with few hundred machines were assembled without these lock washers, and if you
numbers above 29D3404, as in the case of the bevel gear pin mentioned above. happen to have any of these machines in your territory, they are the ones where
you might find the screws loosened. We would suggest that as you have the
opportunity to inspect the first machines sold you note whether or not these
If you should run into any of these difficulties, here's what you should do: if ~ock washers are fitted, and if not, put them in. With the.lock washers fitted
you find either a right or left side generator drive shaft with its key sheared, and the screws pulled up tight there is no danger of their coming out. The
and the shaft quite loose in its gear rather than a press fit as it should be, part number of this shake-proof lock washer is R0-2730.
you had better replace that particular part of the assembly (gear and shaft) and
send the original parts in to us for replacement. Of course, if it happens to
be a bevel gear key that shears, and you find the shaft still a fairly good fit
in the gear, it will not be necessary to replace the assembly because fitting a
new key and also the pin or rivet described before will secure the assembly so
that there is no further danger of key shearing.
 -3-

CHAIN LUBRICATION
There has been some comment that the front chain does not receive sufficient
lubrication from the motor through the oiling arrangements provided. As a
matter of fact we have made no particular claims that it would. In designing
the 45 motor we went as far as practical in providing for chain lubrication
through the engine sprocket and breather, but you are very likely to find
that as a general thing additional lubrication is required. A removable plate
is provided on the chain guard to allow for chain greasing and inspection

It might be possible in some odd cases that the chain does not get normal
lubrication from the motor, because of lubricating bushing 421-26 having
turned from its original position, thus putting oil ways out of alignment.
Unlike any of our other models, the 45 motor has an oil hole drilled inside
the left crank case, directly above the sprocket shaft bushing, and when
lubricating bushing 421-26 is properly fitted, a groove in its face registers
with this oil hole. Oil feeds down to the groove in the bushing face, out-
ward into the sprocket, and then works through the sprocket on to the chain.
Naturally if the groove in bushing face does not line up with oil hole, the
oil supply will be cut off or at least reduced considerably. On the later
machines this lubricating bushing is locked in position by means of a short
dowel pin through its face and projecting a little distance into the aluminum
case
In the earlier motors even though this dowel pin was not fitted, there is only
a slight chance of the bushing shifting its position: however, we ran into two
or three c.ases where it had and this is what prompted fitting the dowel pin.
Although this is rather an important point, it is not of such importance that
you will need to pull down motors simply to check oil-way alignment. We are
calling the matter to your attention, and when you do have a motor apart for
any reason, you can check the alignment and if the bushing has shifted, locate
it properly and secure it with a dowel pin.
This duplex chain, if properly lubricated will give surprisingly good mileage.
On the other hand if run dry, big mileage can hardly be expected. Instruct
your riders to remove the inspection plate and apply some grease to the chain
occasionally.
HIGH COMPRESSION HEADS
Here is some dope on something you have very likely been wondering about. Last
week the Weekly New Bulletin carried an announcement of the DL model 45. You
were told that this new model is a higher compression solo machine, with
increased pep and speed. Possibly when you get a few of these jobs in service
some of the fellows who bought early 45's will raise a howl because the other
fellows have more speed. We can furnish you with special heads and other parts
to "soup-up" any of the machines you already have in service. Here's what
you'll need and what it will cost:
l-RA78TD High Compression Front Head $5.00 L st
l-RA78TE High Compression Read Head 5.00 L st
l-RK90T 7/8" Venturi .96 L st
l-RF33TB 28T Rear Sprocket 3.00 L st
 -2-
The next operation is to smooth up the inside of bushing. If the reamer pilot
bushing has not already been removed from bevel gear shaft bushing, take it
out and lay it aside. Then, inserting the reamer from this side of case, turn
the short reamer on end of pilot through the newly installed bushing. This
October 22, 1928 bushing is already reamed to correct size as furnished, but when driving it
in the ends may be burred and of course it might possibly in some cases close
up a trifle. The short reamer on end of pilot is provided for smoothing up
TO INSTALL RIGHT SIDE GENERATOR SHAFT BRONZE BUSHING WHERE NONE and to safeguard against a change in size. Our specifications call for fitting
WAS ORIGINALLY FITTED this bearing .001" to .0015" loose.
This job does not require removing motor from frame. Simply t·emove footboards, This completes the job and all parts can now be re-assembled, after carefully
bevel gear cover (#1537-29) and cam gear case cover, and take out the complete cleaning all chips from gear case. If the original drive shaft bearing was
cross drive assembly with center coupling. It will also be well to remove found in bad condition and as a result the shaft itself is cut and worn consider-
front exhaust cam gear to allow more room to work. ably it had better be renewed. Apply oil liberally to all bearings as parts are
reassembled. Since some of the oil which ordinarily remains in gear case with
Now with the special reamer furnished for this job at hand, fit the reamer pilot cover removed has been wiped out while cleaning out chips, 'it will be well to
bushing in left side bevel qear shaft bronze bushina and insert reamer from right pour a small initial supply of fresh oil over gears just before replacing cover.
side of case. After stuffing some rags or waste in the forward end of cam gear If the front exhaust cam gear and possibly other gears were removed, they must
case to catch the chips, proceed to ream out hole. Ream a trifle more than 1-1/16" be replaced according to markings, however the generator drive gear requires
deep or, in other words, deep enough so that bushing will drive in flush with out- no timing. Timing the cam gears according to marks, also automatically times
side of case. It will be necessary to remove the reamer and clean the chips from the ignition, provided the circuit breaker and timer assembly as a unit has not
it several times before the required depth is accomplished. When reamino is com- been taken apart. Simply removing this assembly does not affeft timing.
plete, thoroughly clean the hole before installing bushing.
Before replacing the cam gear case cover on a motor in which trouble has been
Now slip the new bushino on to oenerator drive shaft (#633-29) WITH THE NOTCHED experienced with the generator bevel drive gear shaft working out of gear, as
END OF BUSHING NEXT TO GEAR, and start shaft and bushino into case. Following this explained fully elsewhere, always note the condition of the cover thrust boss
method of installing will insure getting the bushing started straight. This is which takes the end thrust of generator drive gear. If it is cut and grooved
important because the aluminum box is now rather thin on one side of hole, and considerably smooth with a file.
starting the bushing out of alignment with hole in case might result in a crack at
this point. The reamer furnished is of a size to allow the bushing about a .0025"
press fit, and this is not tight enouah so that there is any danoer of damaging
case if bushing is kept in alignment.
Before driving the bushing further into case, note that bushing is so turned that
the hole near inner (starting) end is in just the right alignment to meet the oil
hole originating on upper side of bearing boss, not far from the end, and drilled
at an inward angle through the aluminum. Incidentally, this oil hole must be
thoroughly cleaned out after reaming because it sometimes becomes completely plugged
with chips. Unless this oil hole is open and registers with the hole in bushing,
this end of the drive shaft will not get sufficient lubrication and trouble is
likely to result.
After carefully following instructions this far, force the bushing into case by
driving against the gear with a hammer and soft blunt punch or block of hard wood.
Bushing must be driven in flush with case to maintain original end clearance for
gear.
Next, pull out the gear and shaft or if by any chance bushing has closed up enough
to pinch shaft, drive shaft and gear out from left side of motor, using a small
diameter rod. An oil groove must now be cut in face of bearing boss to register
with notch in end of bushing. This can be done easily with a small round nosed
chisel.
 No. 33 December 5, 1928

October 22, 1928 THE "45" TWIN CLUTCH

Should you experience any trouble with this clutch slipping, even with the
spring tension increased as much as it can be and still allow enouqh spring
TO INSTALL PIN IN BEVEL GEAR AND SHAFT action for releasing, it is probably because of oil discs; more often the
back discs. There is not usually any trouble with slippage as long as the
clutch is thoroughly dry. However, once the discs become oily, it takes very
Remove left footboard front stud nut. Footboard can now be pushed down out strong spring tension to hold the clutch.
of the way. After removing gear cover (#1537-29) bevel gear and shaft can
be pulled out. Note whether shaft has worked part way out of gear and if You may be inclined to believe that any oil gettinq into the clutch comes from
so dr1ve it back. The breather holes in gear and shaft will align when gear the front chain, but this is not often the case. We have found in nearly every
is all the way on. case we have investigated that the oil comes from the transmission. You know
there is bound to be a little leakage through the clutch gear bearing (main
Drive pin through the breather hole opposite keyway. Note that it is started left side bearing) and by the cork oil retaining washer. While most of this oil
with its head in proper alignment with the channel into which it must fit. drips away, there are two possible routes by which some of it may oet into the
Drivinq it in a cocked relation to channel way result in some damage to face clutch. One route is through the back clutch disc keyway, and then by the washer
flange.of gear. It is advisable when fitting this rivet to support the gear and nut that secure this disc - the other route is alonq the surface of the back
at the bottom of channel on the edge of a flat wrench of proper thickness, disc and over its rim. ·
clamped in a vise, and also use a punch ground to proper thickness rather than
an ordinary taper punch or chisel to drive the rivet into place. Since the beginning of the 1929 season, sev~ral improvements have been made in
this clutch. It is not li~ely that you will find many complaints of slippage
Upset the end of rivet extending through into hollow end of shaft, with a round with the later clutches. For your guidance in servicing clutches, we are qoinq
punch just slightly smalled in diameter than the inside diameter of shaft end. to give you a list of the more important improvement made to date.
l. The flat washer between back clutch disc and its lock nut is shellaked
In any instance where this rivet is not installed until such time as the shaft in assembly to insure a tight seal against oil leakaoe through the
has worked out to the extent of causing a binding and squeaking in qear case, keyway.
the cam gear case cover should also be removed and the right side generator
drive shaft bearing inspected. 2. The later clutch discs, that is the metal discs, are carefully ground
to a smooth and true surface to insure maximum friction area.
HARLEY-DAVIDSON MOTOR CO. 3. The two asbestos friction discs are now riveted to the clutch sprocket.
This alone makes the clutch action much more positive. This sprocket
with discs attached is furnished on all parts orders.
4. Stronger springs of better material are being assembled in the latest
clutches. They allow obtaining enough pressure to hold the clutch even
though the discs are somewhat oily. These springs in the initial
adjustment should be compressed to 1-3/32" and then if the clutch doesn't
hold satisfactorily, increase the tension a little bit at a time. Don't
set the tension stronger than necessary becuase this only puts unnecessary
strain on the control parts. These stronger springs are furnished on
all models.
If you run into any complaints of slippage in connection with the early clutches,
we suggest that you first inspect the discs and if found in an oily condition,
wash them in gasoline and thoroughly dry them. Then re-assemble the clutch fitting
a new cork oil retaining washer if the original is somewhat worn, and incorporating
improvements numbers 1 and 4 described above.
 -2-

This attention will most likely make the clutch hold satisfactorily. If,
however, there is still excessive slippage, the next step will be to fit
the later clutch sprocket. At the same time inspect the outer steel discs
to make sure that their surfaces where they bear against the asbestos discs
are smooth and true. A true disc surface is indicated by an unbroken,
polished ring the width of asbestos disc all the way around the rim of steel
disc. If either steel disc is found uneven and not bearing all the way
around, it should be replaced with one of the later discs with ground surface.
HARLEY-DAVIDSON MOTOR CO.
Here is some real good news - We can now furnish you that alemite connection
adapter you have wanting so long to enable you to use a large capacity or
auto type qun for greasing. Once you have this adapter you can purchase
locally the size of gun that suits you best. A list of Alemite Lubricator
Co. branch stores is attached.
Don't fail to take advantage of this equipment. Not only will you be able
to give your customers better greasing service, but you will also be able
to make "flat rate" job #6 a more profitable service operation.
Adapter part number is 11660-X, price $1.50 list.
 INSTRUCTIONS ON "OLD" MOTORS THE 1929 LIGHTING SYSTEM December 8, 1928
No. 34
and
GENERATOR CONTROL
This job requires special fuel and spark pluqs. Use Ethyl ~as, or a 50/50
mixture of Benzol and Gasoline; the latter is really the best. These fuels
work well in this motor.
The special spark plugs shipped with this motor have been tested with the
motor and are o.k. If they foul, you can easily clean them, which is not
the case with other hioh compression plugs, for instance the Lodge mica plug.
Oilinq Motor: When runnin~ wide open for any distance qive motor extra oil
with hand pump and learn from your own experience how much oil you can use at
hiqh speed and not foul the plugs or slow up the motor. The mechanical pump
can be readjusted, if necessary, to give proper oiling without plug fouling
at low speed.
Gearin~: Use a 28-tooth sprocket on rear hub, as this motor has not more
turn-over than the standard "DL", but it will pull a higher gear.
Handling Spark: You may find, in startin~ out, that you can retard the spark Il1us. No. 1
and have a tlPtter runnin~ motor than when using full advance. Operate the 1929- 45 (750cc.) Twin
E1ec~rica1 Diagram.
spark control at the point where the motor runs best.
It is advisable for a dealer or rider to run this motor a few hundred miles (Note-Wiring connections are
before expecting the best possible speed out of same. After this motor has the same on all 1929 models)
been run a few hundred miles and the valves then touched up and the motor
tuned up generally it should be a better motor than when new. The current consumption of the 1929 llghtlng system varies
with the lamps actually lighted for ntght drivlng, from 3 up to a
maximum of about 7 amperes. One headlamp and tall lamp draw 3
amperes - both headlamps, tall lamp and switch panel lamp draw 6 am-
HARLEY-DAVIDSON MOTOR CO. peres - sidecar and speedometer lamps add 1/2 ampere each. The gen-
erator ts provided with a regulating lever by means of whlch the
maxtmum output can be conveniently adjusted to charge the battery
according to the amount of current being consumed for llghtlng.
~~ile the lights are in use and at any time the battery ts in a
low state of charge the regulatin~ lever can be set for maximum
output; however, when driving mostly in daylight and especially
when making any long daylight trip the output should be reduced to
avoid overcharging battery and rapidly evaporating the solution.
Don't infer from the above that you should be able to
regulate the generator output high enough to carry the ent.tre
light load at all speeds. This cannot be done. While the output
when.regulated to its maximum should be more than enou~h to carry
all lights when driving at the speeds where the generator charges
at its best, tt cannot be regulated to carry all lights at other
speeds, particularly at low speed. When the generator output is
 - 3 -
- 2 - quite a long time. However, the machine in average service is not
run enough in daytime to offset any heavy discharge from battery
not enough, the additional.current needed is, of course, being at night. The riders h~ve got to learn that in order to keep the
drawn from the battery. At around 20 miles per hour the discharge battery in a good state of charge the lights must be used with
r1 i th all lamps lighted may be as much as three or four amperes. judgement. When driving at low speed only the left headlamp should
Such a discharge must not be allowed to continue for any length of be light.ed. This one lamp gives ample light for any speed up to
time because this would completely discharge a fully charged bat- 25 or more miles an h~ur, depending of course on road conditions.
tery in approximately four or five hours. When a bad stretch of road is encountered the second lamp can b~
turned on. Switching off the right lamp reduces current consumption
He ,-e are the things you can do in case you run into any about 2i amperes.
irstances where the battery will not stay in a satisfactory state of
charge without frequent charging from an ou~side source, even though Operating the handlebar switch to turn off the right lamp
tJ<e generator- output is regulated to its maximum as adjusted at the also directs the current through a second filament in the left lamp
factory: thus tilting the beam, or as commonly expressed dimming the light.
Some riders may object to· driving with only the one light simply
First of all you will, of course, make sure that the battery because of the fact that the beam is tilted when the other light is
is in good condition and will hold a charge. If it happen~ tha~ the off. In this case you can quickly change the wiring hookup at the
battery ts -in bad order nothing can be accomplished by giv1ng atten- switch box so that the beam no longer tilts, although the light con-
tion elsewhere. trol will re~ain the same as before. Illustration 2 with its descrip-
tion explains just how to do this.
The movement of the generator output regulator is limited
by stops secured under the main brush ~alders. On the earliest 1929
models these stops were cut to the required length to give a maximum
of approximately 7 amperes on the Single and Big Twin generators -
and about 6 amperes on the 45 Twin generator. On the later genera-
tors the stops have been shortened to allow further advance and
thus increase the maximum output to 8 to 9! amperes on the Single and
Big Twin - and 7 to 8 amperes on the 45 Twin. On all generators a
still further advance is possible by making the stops still shorter. Regular hookup Optional hookup
This should be done if there is trouble in keeping the battery in a Illus. No. 2
good state of charge. Don't, however, in any case shorten the stops l-Green wire from left head- 1-Black wire from handlebar
enough to allow the regulating brush holder to actually come in contact lamp-also black wire from light switch.
with ground brush holder. With the regulator advanced to the limit handlebar light switch.
there must be at least a few thousandths of an inch clearance between 2-Red wire from right head-
brush holders. 2-Red wires frcm both head- lamp - also green wire
lamps - albo green wire from handlebar light switch.
When testing a generator and readjusting output regulation from handlebar light switch.
it is advisable to use an accurate test ammeter rather than rely on 3-Green wire from both head-
th~ equipment ammeter. Bear in mind, too, that the maximum output 3-Green wire from right head- lamps.
to which a generator can be adjusted depends to a great extent on lamp.
the state of charge of the battery in circuit. With a fully charged 4-Same as regular.
battery in circuit the generator maximnm output will be about 2! 4-Yellow wire from battery.
amperes mo~e than with an almost completely discharged battery. There- 5-Red wires from handlebar
fore, if you attempt to adjust the m~ximum output wlt? a discharged 5-Red wire from handlebar light switch, and left head-
battery in circuit, the results obtained might wrongly indicate to you light switch. lamp.
that the generator is not performing up to standard.
The above information will most likely answer any questions
You should caution your riders of 1929 models that even you may have in mind regarding the 1929 electrical equipment. Of
though the generator output has been increased tc its limit, they the suggestions we have made, we point out the one with reference
soill cannot expect the battery to stay in a good state of charge if to educating your riders as most important. Setting them straight
they insist on using both hP.adlamps when driving a great deal of in the matter will not only leave them with the satisfaction that
the time at lower speeds. Of course, if a machine is driven a lot comes with clear understanding, but will also result in better
during the daytime, the battery will be ln con"dltton at night to service from their batterie$. A battery, continually in a dis-
supply lighting current needed ln addition to output of generator for charged condition, is short lived.

HARLEY-DAVIDSON MOTOR CO.

Milwaukee, Wisconsin
 March ll, 1929
No. 41
SINGLE AND 45 CLUTCH PUSHROD

No. 39 January 28, 1929 This illustration shows

the two cork washers (2552-29)
A NON-CHATTERING DEVICE FOR 1928 TWIN t!f..ROI.IN,() TtttfUST and the steel collar ·2551-
FRONT BRAKE 29), fitted over the clutch
p~sh rod inside the clutch
gear sleev~. The cork washers

~'~,~·:,:~-e"~
k ep any oil that may work
out through the clutch gear
and main shaft bearing from

J~~~~~~~~~~~~~~gettin~ into inside

and working the thrust cap
the clutch.
The steel collar serves as a

~.
gutde for the end of push rod
and prevents it from running
off to one side, and thus pos-
l1;,.<,~+'+!rfor!4-<rltl.lsibly
becoming damaged when
releasing load is applied.
4 This improvement went into
Here is an attachment that overcomes any tendency of the 1928 effect early in the 1929 sea-
Twin front brake assembly to chatter when play develops due to a worn son, and applies to both Sing-
cover bushing. It can be installed in a few minutes. les and 45 Twins.However at the
s~art a steel collar only 3/16
thick, installed between the
Part No. 4107-28 List Price $1.00 cork washers, was used. The
present steel collar is 3/8"
NEW CltOSS DRIVE SHAFT FOR 45 GENERATOR thick. It is important that it
be fitted as per illustration.
A one piece generator drive shaft, with right side gear fitted We suggest that whenever it is
convenient to do so, you in-
to a taper and secured wtth a key and nut is now being furnished in- t;oM WIIS/o'<. s spect all early 1929 Singles
stead of the two piece drive shaft with center coupling as originally and 45 Twins, also earlier
installed. Thei~ assemblies are 1nterchan£eable. On all part~ orders 25 S"Z-.?.9 Singles, and install these
specifying ariy part of the two piece assembly, with exception of the washers where they haven't already been fitted, correcting the arrangement
bevel gear, the later type shaft together with right side gear, key and when not according to the illustration.
nut will be furnished under part No. l532-29A Price $4.50 list.
In addition to the above Improvement, six 5/32' holes, equally s;acad
are drllled on the outside of the clutch thrust cap as indicated. These
NEW PART NUMBERS holes serve as a drain to prevent any oil that may possibly leak out by
'"e co.rk washers from eventually working inside the clutch.
You may have calls for some of these parts so suggest you make a
note of the numbers. TWIN LAPPING ARBOR
The lapping arbor wrench (11950-X) listed in the accessory catalog
Part No. Name List Price· fits only the lapping arbors as furnished at the present time. The
4171-29 Clamp nut for front brake control wire clevis .20 prese~1 t. , apping arbor ~ 5 fitted wt 'jh nuts small enough in diameter so
253-29 T~ppet guide bushing for H motor 1.00 that 1.n be used for el ther T·:1:1.n or 1$1n_gle laps whereas the older
2505-29 New type actuating plate .90 1Fpp1 J!" was fi~te~ with larger dia~etcr nuts.
1536-29A Bevel gear pin (for 1536-29) .05 !r you have an old sty1e Tv:in le.-pp1ng arbor that is in good condi-
1536-298 Bevel gear shim .05 tion and you want to .d~pt tt so rhat y:u can use one of these wrenches,
1535-29 Left side bushing for drive shaft .40 you'~l have to order out the follo~i~g parts to bring it up-to-date.
134-29 Push rod end felt washer · .05
2076-26A Starter crank & pedal assembly 3.00 Part No. Name List Price
- ----
2546-29A Clutch spring (7/16"Xlt") Heavy, for
~1Iain ~u'.:. .40
12 spring clutch .05 GK830D
.40
PK830C Adjust:~g cc:lar
GK830B :....ock Nu~ .40
HARLEY-DAVIDSON MOTOR CO.
:lo. 42 3 March 21, 1929

NOTE No. l - The original disc 1 does· not need to be replaced because it has not
been changed. Should any change in the disc be made in the future, it will then be
included. When a replacement is made, be sure to shellac the disc washer before
fitting the lock nut as explained in "Shop Dope" No. 33. This prevents oil leakage.

The splineways on steel disc 6 must be matched with splines on outer steel disc
8 so that disc 6 works back and forth freely. This is necessary for proper releasing
action. Adjust spring tension as explained farther on.

Complete clutch furnished under part No. RG555TAP,

List Price ............. $16. oo.

ADJUSTING CLUTCH - This clutch will hold with con-

siderably less spring tension than the former clutch. In
the initial adjustment set the spring tension adjusting
nut so that springs are compressed to 1-1/16 inch as shown
in Illus. 3. I f a tryout proves this adjustment not
entirely satisfactory re-adjust as necessary. changing the
adjustment only a little at a time.

This new clutch assembly is thicker and the

thrust cap protrudes farther into chain guard. When
clutch is released, the thrust cap may rub against chain-
guard. In that case, remove chainguard and support it
(inside up} on two blocks of wood a little thicker than
thrust cap housing, placed near housing. Then, drive the
housing outwa~d. or in other words, deepen it by striking
the metal with a hammer at the point where the housing
joins the guard proper.

The increased thickness of the new clutch also ex-

plains the need of a new push rod and spring adjusting
nut both of slightly greater length.

Illus. 3. -Assembled See "Shop Dope" #41 - (Single and 45 Clutch Push
Clutch with Thrust Cap Rod.}
Removed.

HARLEY-DAVIDSON MOTOR CO.

Milwaukee, Wisconsin

Note - Until such time as new clutch parts are listed in parts catalog,
vou may order any individual new parts needed according to numbers in Illus. 1. In
Jnnection with each order be sure to mention: "As shown in Shop Dope #42."
 No. 42 2 March 21, 1929

In changing over clutches, it will be

found that in the very earliest clutch the
asbestos discs are not attached to other
parts, but in later clutches they are
No. 42 March 21, 1929 riveted to the sprocket. In changing over
the former, it will be necessary to drill
A NEW CLUTCH FOR THE 45 TWIN AND 30.50 SINGLE six holes with a No. 9 drill ( .196 inch)
through sprocket and the original asbestos
A new clutch has just gone ir.to production on the 45 Twin and the 30.50 Single. disc to be used, locating holes to match the
This clutch has two more friction discs than the former clutch, and with its increased . holes already drilled in key ring 4. The
friction area, it has much greater efficiency than actually required to hold any load holes in asbestos disc must also be counter-
that may be.applied with either of these two models. This means that clutch perform- sunk to accommodate rivet heads. (It is
ance will not be at all sensitive to unfavorable conditions sometimes encountered really advisable to -use a new disc 2 when
that normally tend to decrease efficiency, such as uneven new discs that do not con- the original is not dril.led.) In getting
tact fully, oil getting onto discs, etc. This clutch requires less spring tension the later sprocket with riveted discs ready
to hold, which means, of course. less stra:n and wear in· connection with push rod, for change-over. it is only necessary to
push rod bearings, and other clutch control parts. drill off rivet heads so that rivets can be
punched out.
We suggest that when difficulty is experienced in servicing one of the earlier
clutches, you incorporate the necessary parts to convert the clutch to the late type, Next, arrange parts in group "A"
or if desirable, install a complete new assembly. Illus. 2 - Riveting (Illus. l) in their proper order as shown,
Group "A" and insert rivets through assembly from back
l - Inner steel disc (Sea or inner side (heads in disc 2). When rivet-
"Nota #l"); 2 - Asbestos ing, rest head of rivet squarely on end of a drift or punch held in a vise and
disc; 3 - Clutch sprocket; spread hollow ends of rivets with a blunt center punch as shown in Illus. 2. It i~
4 - Key ring; 5 - Asbestos best to insert all rivets and spread them just enough to hold them in place before
disc; 6 - Steel disc; 7 - riveting any permanently, otherwise after one is spread and securely tightened,.
Driving disc; 8 - Outer trouble may be experienced in getting holes lined up so the remainder can be in-
steel disc; 9 - Adjusting serted. Be extremely careful when riveting that you do not damage asbestos discs 2
nut; 10 - Thrust Cap; 1: - and 5.
Thrust cap gasket; 12 -
Push rod; 13 - Rivets with Change-Over Parts for Early 14 Spring Clutch (Group B)
which group "A" . is assem-
bled. Part No.-RG555TP--List Price ~
This Special Price Applies
Illus. l -Complete Clutch for Only a Short Time.
In Order of Assembly.
To complete above combination for early 12
CHANGING OVER EARLIER CLUTCHES, USING ORIGINAL PARTS spring clutch, ·include the following:
AS FAR AS POSSIBLE
2546-29 (14) Clutch Springs $ .05 each
The combination of parts under group "B" (Illus. 1). permits a complete change- RG730TA ( l) Spring collar .40
over of any of the earlier clutches fitted with 14 springs. 2550-26 ( 1) Thrust Cap 1.00
RG729T ( l) Thrust Cap Gasket .05
If clutch to be changed over happens to be a 12 spring clutch, it will be nec-
essary to add to the above, fourteen clutch springs, one spring collar, and or;e INSTALLING A COMPLETE NEW CLUTCH ASSEMBLY
thrust cap and gasket, as listed on next page.
When a complete new clutch assembly is ordered, all parts shown in Illus. t.
Or.e of the two original asbestos discs, if in good condition, can be used as 'xcept inner clutch disc l, are ir.cluded. ·Group "A" is furnished assembled. Key ring
Jisc 2, (Ill us. l) but disc 5 must be a new one because of its smaller outside is electric welded to sprocket 3 and asbestos discs 2 and 5 are riveted in place.
diameter. It. is furnished with parts under group B.
 No. 44 May 20, 1929
No. 4·3. April 6, 1929
SERVICING HANDLEBARS WITH WORN SLOTS HEAVIER SPOKES IN COMMERCIAL FRONT WHEEL

FIL £ St. or l LONG£R y REMOVING 16 fhtw £AC1t ENt:J

The front wheels of all 61" and 74" Twin machines intended for
commercial service are now being built up using heavier spokes.
,.,/ .. -·--~ .,
)~
'
If you have occasion to rebuild the front wheel of any earlier
Flu: Stor 7iJ WtorH Or .lJLocK
fC ;-1
~--.---,
)l
-------~~
commercial jobs, you can install these heavier spokes a.fter
drilling spoke holes in the hub and brake flanges and also holes
\ in rim to a larger size. When drilling flanges, it's advisable
to remove all insides from the hub. Use a No. 2 drill to drill
hub ~nd brake flanges. Use a 19/64" drill, or a letter "N" drill
(preferably a letter "N" drill) to drill holes in tire rim.

PART NO. NAME OF PART LIST PRICE

3943-29 Extra heavy front hub shell spoke (9-9/16" $ .07
Here's ~ow. you: can service handlebars that become 3945-29 Extra heavy front brake sheel spoke(8-l9/32) .07
worn in'the'plunger control· slot to the extent of un- 3947-29 Spoke Nipple .04
satisfactory grip operation: Repair is accompiished by
the use of a new plunger block which replaces the lower NOT PRACTICABLE TO FIT EARLIER THAN 1928 RIGID FORKS \oliTH
one of the original plunger rollers. BRAKE BRACKETS
T:12.s new block is 1/2 inch long and 7/16 inch It isn't advisable to install brake brackets on rigid forks not
wide and slot can be widened for either dimension. First originally intended for use with a front brake when forks are
file slot to meet the 7/16 inch dimension and if it does returned for repairs. The front brake subjects rigid forks to
not smooth up at this width rise the 1/2 inch dimension. certain stresses and strains for which the 1928 and later forks
File. same· amount o·f metal froar both- si'des of slot, which was are reinforced throughout. It is impossible to incorporate these
-originally a-.b·out. 3/8 inch Wide. reinforcements on earlier than 1928 front forks; consequently, if
these earlier forks were fitted with brake brackets and used for
Plunger con.trol slot will .also need to be length- servicing 1928 or later machines with damaqec forks, they wouldn't
ened so that contr(>I has the proper amount of movement to give satisfactory service.
tully ope~a:t_e ..throt-Ue or spark lever. Lengthen .slot about
r;s·inch·- 1/16 1nch_at each end.
A rec.e&a will also have to. be filed in plunge.r to
accommoda.te the new· block. ·File recess about as deep as the
original coQllterbore around roller pin hole, and at right
angles to hole.

Part No. RDlOP - - - -List Price $ .10

 No. 45 June 18, 1929 TO ATTACH 1929 OR EARLIER SIDECAR OR PACKAGE
1930 BIG TWIN MOTORCYCLE
BATTERY FILLER PLUGS
A 1929 or earlier sidecar or package truck can be attached to a 1930 Big Twin
Do not confuse battery filler plugs used in the 1929 Sin~le and 45 Twin battery motorcycle by using the 1930 connection fittings as listed below; however, you
with those used in the late 61 and 74 Twin battery. The 61 and 74 Twin battery cannot incorporate the added advantages of the interchangeable wheel and side-
is vented through holes in the top of cover and is fitted with solid fill~r car brake
plugs. The Single and 45 Twin Battery is vented through a hole in eac~ f1ller QUANTITY PART NO. DESCRIPTION LIST PRICE
plug. Do not use a filler plug intended for a 61 and 74 Twin battery 1n a
Single and 45 Twin battery because the gases that form while the battery is 1 6009-30 Frame Brace $3.50.
charging will have no way of escaping and the jar is liable to burst. 1 6023-30 Frame Brace Clevis Pin .20
1 6025-30 Frame Brace Tie Bolt .90
"45" (750 cc) TWIN IMPROVEMENTS 1 6026-30 Frame Brace Tie Bolt Nut .20
1 6029-30 Front Connection 2.00
During the 1929 season, several improvements have been made in the design of the 2 6031-30 Front Connection Clamp .50 ea.
"45" (750cc) Twin model. All of the later parts involved in these changes, except 4 6033-30 Front Connection Clamp Bolt .15 ea.
the gear case cover listed below, are listed in the Parts Book "Supplement" of 1 6035-30 Rear Frame Bracket 1.00
Marchl, 1929. The principal parts affected are forks, front mudguard, tanks, and 2 6036-30 Rear Frame Bracket Bolt .15 ea.
the timing gear case ~over and right crank case. When ordering these parts for 2 6037·30 Rear Frame Bracket Bolt Nut .10 ea.
the "45'' (750 cc) Twin, first determine whether early or late parts are needed,
and if later parts are required refer to the Parts Book "Supplement" for the Fit the rear bracket to rear axle clip of motorcycle, with outer curve of bracket
correct part numbers. towards the front of machine. Fit bracket bolts with nuts inside of axle clip.
(With left hand sidecar/package truck fit bracket bolts with nuts outside)
Front forks were made one inch longer. If you have occasion to order a complete
set of forks, it is, of course, advisable to order the latest set; however, if Fit the front bracket to front frame tube of motorcycle with the lower clamp·of
only a spring fork or rigid fork is needed, be sure to measure the old fork so bracket slightly above the highest point of frame tube reinforcement (near motor
that the proper part number can be determined. Measure the rigid fork from the support). Do not, as yet, tighten clamp screws.
lower crown plate to the tip of the fork side. Early fork measures 14-9/16
inches, later fork 15-9/16 inches. Insert frame brace tie bolt into hole provided in seat post cluster forging. Do
not, as yet, tighten tie bolt nut. Remove and discard the original frame brace on
The change in front forks also affected the dimensions of the front mudguard braces. sidecar chassis and attach the new brace.
When ordering a front mudguard, determine whether early or late forks are fitted
and order accordingly, using the proper part number. Pack a little grease in each ball sprocket; then make front and rear sidecar
connections, Front connection may need to be shifted slightly to make rear con-
Whether a machine has early or late tanks is easily determined by the outstanding nection line up properly, Connect frame brace with frame brace clevis pin. Tighten
difference in width. front and rear brackets and frame brace tie bolt sevurely; then tighten ball joints
in the usual way.
The right crank case and the gear case cover of the 45 Twin motor is now fitted
with four dowel pins instead of two, as heretofore. If you have any occasion to Adjust frame brace so that motorcycle leans slightly outward. This adjustment is
order a gear case cover for a 45 Twin motor, note how many dowel pins the right made by disconnecting frame brace from frame brace tie bolt and turning it further
crank case is fitted with and order accordingly, per the following part numbers: into or out of lower clevis on sidecar chassis.
584--29 Two dowel pin hole gear case cover TO ADAPT 1929 LIGHT SIDECAR TO 1930 - 45 CU. IN MOTORCYCLE
584-29A Four dowel pin hole gear case cover.
The only part required to adapt a 1929 light sidecar to a 1930 45 cu. in (750 cc)
NOTE: Right cr~nk case with provisions for four dowel pins is bein~ furnished on twin model, is~ new frame brace. When ordering, specify "Frame Brace to fit 1929
all parts orders, however, only two dowel pins are pressed into place. The two Light Sidecar to 1930 45 cu. in. (750 cc) Twin:.
extra dowel pins are furnished in a separate package with each crank case and The list price of this frame brace is $6.00.
should.be used only in the event the latest gear case cover (with four dowel pin
holes) is used. The frame brace connection as attached to motorcycle frame underneath saddle on
1929 model is not required on the 1930 model because the connection socket is
incorporated in frame.
§ .
.

Special Bulletin October 31, 1929

No. 49 November 4, 1929
INSTRUCTIONS FOK FITTING LATE UNITS AND PARTS TO EARLY 1930
SPARK PLUGS
74 TWIN MODELS (below 3000)
When Harley-Davidson spark plugs become shorted due to fouling, they can
easily be taken apart, cleaned, and put back in qood condition, if the
proper procedure is followed in dis-assembling and assemblinq.
Difficulties have been experienced by some in getting ra.ther old pluqs
apart without damaging some of the parts. In most cases, this was
because a monkey wrench or ordinary end wrench was used to remove the
core clamp nut, which is not strong enough for this type of wrench. Then,
too, With plugs that have seen a considerable amount of service, the
threaded parts become somewhat set together, and the nut doesn't turn
readily.
If plugs to be taken apart have seen considerable service, they should
be soaked in gasoline or kerosene to free the threads before attemptinn
to remove the core clamp nut. Hold base of plug in vice while turning out
core nut with closed end wrench (11805-29) furnished with tool kit. Don't
squeeze the base tight enough to distort it. Usinq this method, you will
find that plugs can easily be taken apart and re-assembled.
Clean the core by scraping it and finishing with fine sandpaper. If there
is any questions about the good condition of any parts, renew them. Pay
particular attention to the condition of the bottom gasket for procelain
(3B-09C) and spring washer (38-09D).
INNER CHAIN GUARDS THE 1930 TWIN IGNITION COIL
Fit the new rear support rod extension nut. The ignition coil used on 1930 Twin models differ· from that used on former
Alter inner chain guards as illustrated Twin models in that it does not incorporate the condensor. The condensor
Attach the new breather pipe. on 1930 Twin models is mounted on the circuit breaker assembly. No
The new clutch assembly is adapted to the original clutch shell and sprocket. provisions have been made for adapting the new coil to earlier Biq Twin
However, some fitting of disc splines may be necessary. models. If desired, the new ignition coil and the complete new style circuit
Remove transmission starter cover and fit the new starter gear and starter breaker assembly with condensor can be fitted to the 1929-45 (750 cc) Twin
clutch. Model; however, the new coil cannot be used without the new circuit breaker.
To be sure of proper motor lubrication, it is of first importance that the
throttle oil pump control be properly adjusted. THIS CONTROL MUST BE The ignition coil on the 30.50 (500 cc.) Single model is the same as on the
ADJUSTED SO THAT THE CARBURETOR THROTTLE LEVER AND THE OIL PUMP CONTROL former Sinqle models.
LEVER STRIKE THEIR FULL OPEN STOPS AT THE SAME TIME.
Until such time as a motor has been run-in for at least 2000 to 3000 miles,
it is advisable to recommend that when running at top speed l/3 pumpful
of oil be injected into motor with hand pump about every 2 miles.
Drain crank case and inject a supply of fresh oil (3 pumpfuls) every 750
miles or oftener.
DO NOT EXCEED A TOP SPEED OF 40 MILES AN HOUR FOR THE FIRST 500 MILES.
 No. 51 November 14, 1929
No. 50 November 11, 1929 FITTING SPECIFICATIONS FOR ALL DOW METAL PISTON
NEW PARTS IN 1930 BIG TWIN MOTORS_
SINGLE MOTORS
As a result of numerous changes made in 1930 Big Twins starting with
motor number 3000, many parts are now not the same as listed in the PISTONS: -30.50 cu. in. Single- .011" to .012" loose in cylinder
Parts Book. The parts affected are as follows: -21.09 cu. in. Side by Side Valve Single - .012" to .013" loose
in cylinder.
Valve Springs -21.09 cu. in. Overhead Valve Sinqle- .011" to .012" loose in
Upper Valve Spring Covers cylinder
· Valve Guides (Measure all pistons just below the top qroup of rings, and
Right Crank Case cylinders about 1/2" from top of bore.)
Left Crank Case
Crank Case Studs (take the place of 443-30 and 447-30) PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64"
Breather Pipe
Drain Lever Catch PISTON PINS IN PISTONS -- Plug or snuq slip fit in both sides.
Right Flywheel for Iron Alloy Piston Motors
Left Flywheel for Iron Alloy Piston Motors PISTON PINS IN UPPER END OF CONNECTING RODS --Free to .0005" loose.
Right Flywheel for Dow Metal Piston Motors
Left Flywheel for Dow Metal Piston Motors LOWER CONNECTING ROD BEARING --.0003" to .0004" loose on rollers.
Beveled Lower Piston Ring for Iron Alloy Pistons
Beveled Cushion Rinq for Dow Metal Pistons CONNECTING ROD -- .010" to .020" end play between flywheels --roller and
Iron Alloy Piston for V - VS Models retainer assembly should be narrower, but not more than .010" narrower than
Inner Front Chainguard Screws rod.
Rear Footboard Support Rod Extension Nut
Lined Clutch Friction Disc (Same as 1929) PINION GEAR SHAFT -- .0035" loose at inner end of bushing -- .0025" loose
Clutch Springs at outer end of bushing. Bushing is taper reamed with special reamer.
Clutch Spring Sector Nut
Starter Clutch SPROCKET SHAFT -- .0005" to .001" loose in roller bearinq - .006" to .007"
Starter Mainshaft Gear loose in chain lubricating bushing.
Frame (Late frame furnished on all parts orders)
FLYWHEEL ASSEMBLY -- .002" to .006" end play in crank case.
At this time, many of the early motors are being converted and fitted with
the late parts. CAM GEARS -- .001" to .0015" loose in crank case and cover bushings - free
to .005" end play.
A Parts Book "Supplement" covering all changes will soon be printed. In
the meantime when any of the above parts are needed, do not order by Part INTERMEDIATE AND OILER GEARS - .0015" to .002" loose on studs.
number, but ~imply qive name of part, and specify "Latest Part", or "Early
Part" on the order.
No. 51A November 14, 1929 No. 51B November 14, 1929

FITTING SPECIFICATIONS FOR 45 CU. IN. TWIN MOTORS FITTING SPECIFICATIONS FOR 1930 BIG TWIN MOTORS
(NOTE: These supercede all previous specifications, and apply to 1929 IRON ALLOY PISTONS -- .004" to .005" loose in cylinders.
and 1930 models.) DOvJ-METAL PISTONS -- .018" to .019" loose in cylinders
(measure all pistons just below the top group of rings,
and cylinders about 1/2" from top of·bore)
PISTONS -- .015" to .016" loose in cylinders. Measure pistons just
bel ow the top group of "i ngs, and cylinders about 1/2" from PISTON-CYLINDER HEAD CLEARANCE-- V-VL 3/64" to 5/64". VC(Commercial) -
the top of bore. 7/64" to 9/64"
PISTON PIN IN IRON ALLOY PISTON-- .0005" to .001" press fit in lock pin
PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64". hole side - plug or slip fit in opposite
side.
PISTON PINS IN PISTONS-- Plug or snug slip fit in both sides.
DISTON PIN IN DOH-~1ETAL PISTON .00025" (tight hand) to .0005" press fit
PISTON PINS IN UPPER END OF CONNECTING RODS -- .00025" to .00075" loose. in both sides
PISTON PIN IN UPPER CONNECTING ROD END -- .00075" to .00125" Loose
LOWER CONNECTING ROD BEARING -- .0004" to .0006" loose on rollers
LOVJER CONNECTING ROD BEARING --.001" to .0015" loose on rollers
CONNECTING RODS -- .006" to .0:0" end play between flywheels -- roller and CONNECTING RODS - .006" to .010" end play between flywheels - roller and
and retainer assembly should be narrower, but not more than retained assembly should be narrower, but not more
.010" narrower than front rod. than .010" narrower than front rod.
PINION GEAR SHAFT -- .0045" loose at inner end of bushing - .002" at outer PINION GEAR SHAFT - .0045" loose at inner end of bushing • .002" loose at
end of bushing. Bushing is taper reamed with special outer end of bushing. Bushing is reamed with taper reamer.
reamer. SPROCKET SHAFT- .0005" to .001" loose in roller bearing-- .006" to .007"
loose in chain lubricating bushing.
SPROCKET SHAFT-- .0005" to .001" loose in roller bearing- .006" to .007"
loose in chain lubricating bushing. FLYHHEEL ASSEMBLY - .002" to .006" end play in crank case.
CAM GEARS ••. 0005" to .001" loose in crank case and cover bushings - free
FLYWHEEL ASSEMBLY -- .002" to .006" end play in crank case. to .005" end play
CAM GEARS-- .0005" to .001" loose in crank case and cover bushings -free INTERMEDIATE GEAR - .0015" to .002" loose on stud
to .005" end play TAPPET GUIDES .0005" to .001" press fit in crank case
GENERATOR DRIVE SHAFT-- .001" to .0015" loose in bushings - .002" to .004" VALVE TAPPETS .0005" to .0015" loose in tappet guides.
end play.
GENERATOR ARMATURE SHAFT BEVEL GEAR -- .002" to .003" loose in bushings -
shimmed to give necessary clearance
between bevel gears
TAPPET GUIDES-- .0005" to .001" press fit in crank case.
No. 51 C November 14, 1929
VALVE AND IG~ITION TIMING SPECIFICATION FOR ALL 1930 MOTORS No. 51 E November 14, 1929

-21.09 CU. IN. SIDE BY SIDE VALVE SINGLE

-
INTAKE VALVE -- OPENS when piston is -- 1/8" to 3/16" before top dead center FITTING SPECIFICATIONS FOR All DOW METAL PISTON SINGLE MOTORS
CLOSES when piston is --7/16" to 9/16" after bottom dead center
IGNITION -- OCCURS when piston is -- 7/32" to 9/32" before top dead center on PISTONS - 500 c.c. Sinqle - .28mm to .305mm loose in cylinder
the compression stroke.
350 c.c. Side by Side Valve Single- .305mm to .33mm loose in cylinder
EXHAUST VALVE -- OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is --1/8" to 3/16" after top dead center 350 c.c. Overhead Valve Sinole - .28mm to .31mm loose in cylinder
(Measure all pistons just below the top qroup of rinos, and cylinders
21.09 C~. IN. OVERHEAD VALVE SINGLE about 12.70 mm from top of bore)
INTAKE VALVE -- OPENS when piston is 3/32" to 5/32" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center PISTON-CYLINDER HEAD CLEARANCE- 1.19mm to 1.98 mm.
IGNITION-- OCCURS wher. piston is- 11/32" to 13/32" before top dead center on PISTONS PINS IN PISTONS - Pluq or snuq slip fit in both sides
the compression stroke.
EXHAUST VALVE -- OPENS when piston is 7/16" to 9/16" before bottom dead center PISTON PINS IN UPPER END OF CONNECTING RODS - Free to .013mm
CLOSES when piston is - 3/32" to 5/32" after top dead center
LOWER CONNECTING ROD BEARING - .0075mm to .Olmm loose on rollers
30.50 CU IN SINGLE
CONNECTING ROD - .255mm to .51mm end play between flywheels -- roller and
INTAKE VALVE -- OPENS when piston is 5/16" to 9/16" before top dead center retainer assembly should be narrower, but not more than .255mm
CLOSES when piston is 11/16" to 15/16" after bottom dead center narrower than rod.
IGNITION -- OCCURS when pis ton is 1I 4" to 5/16" before top dead center on the
compression stroke. PINION GEAR SHAFT - .09mm loose at inner end of bushing -- .065mm loose at outer
end of bushing. Bushinq is taper reamed with special reamer.
EXHAUST VALVE -- OPENS when piston is 1/2" to 3/4" before bottom dead center
CLOSES when piston is 1/4" to 1/2" after top dead center SPROCKET SHAFT- .013mm to .025mm loose in roller bearinq -- .15mm to .18mm
loose in chain lubricating bushing.
45 CU. IN TVJIN
INTAKE VALVE -- OPENS when piston is 5/32" to 7/32" before too dead center FLYVIHEEL ASSEMBLY - .05mm to .15mm end play in crank case.
CLOSES when piston is 37/64" to 45/64" after bottom dead center
CAM GEARS - .025mm to .04mm loose in crank case and cover bushings - free to
IGNITION -- OCCURS when piston is 1/4" to 9/32" before top dead center on the .13mm end play
compression stroke.
EXHAUST VALVE - OPENS when piston is 37/64" to 45/64" before bottom dead center INTERMEDIATE AND OILER GEARS - .04mm to .05mm loose on studs.
CLOSES when pist is 5/32" to 7/32" after top dead center
STANDARD 74 CU. IN TWIN
INTAKE VALVE - OPENS when piston is 9/64" to 21/64" before top dead center
CLOSES when piston is 9/16" to 13/16" after bottom dead center
IGNITION - OCCURS when piston is 5/16" to 3/8" (Comm. 1/4" to 5/16") before
top dead center on the compression str~ke.
EXHAUST VALVE - OPENS when piston is 9/16" to 13/16" before bottom dead center
CLOSES when piston is 9/64" to 21/64" after top dead center
NOTE: ~hen.checking valve timing according to the position of the pistons, bear
1n m1nd that the tappets must first be adjusted to the correct clearance.
 - 2 - November 13, lJ29

battery charged. The other field coil ~F2) comes into play only
when the main lighting switch is turned ON. This intensifies the
magnetic field and results in enough increase in the current output
of the generator to amply care for lights et av0rage driving spn~ds.
The battery-generator and ignition circuits are th~ same as
No.52 .·ove.:ber 1.3.1.2~ with previous models; however, t~ get ~ complet~ working ~no~l~dgl
of the new system, trace it out on the wiring diagr~m accord'ng
-:-·-:::: ~~2·} HAR.LZY-I'.'·.VJDSO!'i ELECTR:CAL SYSTE~,1 to the following outline.
Wilen the igni~ion switch is turned ON preparatory to star·tlni!;
the motor, current flows from the positive (+) post of battery,
through the RED wire of main cable to post No. 6 in switch box.
From post No. 6, current flows through wire to post No. 9 (which
is one side of ignition switch), through the ignition·switch, and
then through the GREEN wire of main cable to the primary winding
of the ignition coil. From the·primary winding of coil, the
current flows through the circuit breaker points to ground.
The circuit is finally completed through ammeter and YELLOW ·;;ire
of main cable to the negative (-) post of battery.
With the motor started, the armature (A) builds up current
from the magnetism retalried permanently by the fields. Until the
generator voltage becomes higher than the battery voltage, the
circuit is open at relay switch, and the current that is generated
and picked up by the brushes simply builds up within the generator.
A small amou~t of current completes an external circuit through the
grounded winding of relay switch with the result that the switch core
becomes magnetized. The spring tension of the relay cutout switch
is so adjusted that when the generator voltage has built up higher·
than the battery voltage, the cutout core becomes suffici~ntly mag-
KE. fO '.\'IRING DIAGR.\:-,1 netized to close the contact points; thus completing the circuit b~­
tween the generator and the battery. (The cutout contact points
- Red·wires with yellow tracer- one wire from sv;i t·oh panel lamp; 8- Gree" ordinarly close at a speed of aborit 15 miles per hour in high gear. I
from handlebar light switch and one wire from ignition coil; 9 - Ignition When the motor is stopped, or is running so slowly that generator
from each headlall!p; z .., Black wires wire from No. o; also serves as a ter- voltage is lower than the battery voltage, the cutout core becomes
with red tracer ::- one rrom ·handle- minal for ·extra lighting equipment~ de-magnetized, allowing the points to open; thus preventing the
.bar · light swi t<:h. and· one !"rom each. 10 - Relay ·ouj;out $Witch·. battery from discharging through the generator .
headlamp) 3· ..:, No conneo:tion; 4 ,...
Yellow wire ·!"rom battery>: .5' ·-. Red B'-r.- Black wires will! re.d tracer;.. At the positive (+) post of battery, the current coming from
wi ros with black tracer ~ · onEI . from R~y ::;_ Red wi·r.es ·with :yellow ,tracer; generator divides, the required amount going ~o the ignition unit,
haqdlebar · light swU.ell an;i on& ·from R:::b-··Red: wires .with' blacK , tracer;. and the balance to battery, keeping it charged. When the generator
generator;: 6 -: Red· wir$ from battery, A.- Generator- ;~.rmatul"e; Fi- Regui~tt­ is charging, the ignition circuit is not completed through the ammeter
'red wire to horn: .also. wire fr(lm No. fng field ooil; F2 -Shunt fauxiliary) and YELLOW wire of main cable, as it was when starting, but directly
9; 7 ~Black wire from tail lamp, also field coil. through ground to the source of current, the generator.
The 1930 Harley-Davidson electrical system incorporates sev- ·The current that flows through the battery, flows from the
eral nex features, foremost of Nhich is a new generator that, at negative (-) post, through the YELLOW wire.of main cable to one
nor~al driving speeds, supplies about the same amount of current to side of ammeter; through the ammeter, and then through ground to
':!":e cat';ery ·,vith all lacr.ps lighted, as j_'; does ·nith no lamps t::e generator. The amount of current going through the battery is
~~;~t~d. :~!3 new gSnerat~r embodies t~o indepe~dant !ield coils. :::-egiscered on the ammeter, and is known as the generator charging
::1e :"i9:!.d coi.2..(?2.):nai:J.tair.s a ::3.gnet:c field strong er:.0ugh to enable c3.te.
~~:2 s~:-: ::~:.:.-~:::- :o 3t:;:p:y 3..::~2.9 :·...:.r:-sn: :"'or :..gu.i tion and to ~eep the
No. ~2 - 3 - November 18, 1929 - 4 - November 18, 1929
No. 52
When the main lighting switch is turned ON, the current required
by lamps flows from the positive (+) post of battery, through the RED IN THE BIG TWIN GENERATOR, the black wire of shunt (auxiliary)
wire of main cable to post No. 6, which is a terminal of the main field coil (F2) is grounded to the copper strip, which also grounds
lighting switch. In this switch, current divi~es,and part of it goes the negative brush. The red wire with black tracer is connected to
fram post ~o: 7 through the BLACK wire of main cable to the taillamp; an insulated terminal located on positive brush holder insulator.
C!:lc part ol 1t goes from post No. 5 to the toggle switch and to the The red wire with black tracer from nost No. 5 in switch box al•o
;?c~~ator field winding. Both, the toggle switch wire, and the gene- connects onto this terminal. The BLlcK wire from relay cutout switch
~s~or wire, are RED wires with a black tracer.
connects onto the positive brush.
The toggle switch wire from post No. 5, is connected with the SPARK PLUG HOODS
center prong in toggle switch. 1he position of the contac~ plunger
in toggle switch determines whether current is going to the upper If you experience any trouble with the spark jumping between
or to the lower filaments of headlamps. the lower edge of spark plug hood and spark plug base, you can cor-
rect it by changing the form of the hood slightly. This can he ac-
Tlle generator wire from post No. 5 connects with field coil complished by pressing in the top of hood (boss that fits onto plug)
f2. The current in going through field coil F2, intensifies tllc with a vise. Support base of hood on piece of flat metal larger
magnetic field, and the result is enough increase in the current than the hood diameter to avoid distortion when pressing it. Press
gene~a:ed ~o take care of lamp load.
the boss down until it is about flush with hood body.
A FEW POINlERS IN DIS-ASSEMBLING AND ASSEMBLING HARLEY-DAVIDSON MOTOR CO.
' 1930 TWIN GENERATORS Milwaukee, Wis. U.S.A.
IF A BIG TWIN GENERATOR, the first thing to do is pull the
drive gear off the end of the armature shaft. Your combination gear
and bearing puller (11849-X) will be suitable for this job after the
unthreaded end of screw is ground to a diameter of 3/8 inch. This
change is now effective on new pullers. Pulling the drive gear off
the armature shaft shears the dowel pin. Of course, a new dowel pin
.'Jill need to be used when re-assembling.

Before removing the aluminum frame end, mark it and the frame
at "· point near the two frame screws which are closest to the neo-a-
~ive (grounded) brush. The shunt (auxiliary) field coil (F2) is~ then
located directly under the mark on frame. THIS APPLIES TO ALL 1930
TWIN GENERATORS.
THE 45 (750 c.c.) TWIN GENERATOR is fitted with outside termi-
nals marked to indicate the pr~per connections. On the inside of this
generator, connections are made as follows: The uninsulated wire of
sl'lt_Int (auxiliary) field coll (F2) is grounded to the copper strip,
~h1cn is secured beneath the terminal clamp on the inside of the gene-
rator frame. The other wire of shunt (auxiliary) field coil (F2),
~h1ch 1s insulated with enameled cloth, ls attached to the terminal
marked ·s~itch". A short wire from the positive brush is connected
:o ~l:~ terminal marked "Relay". These last mentioned connections
are ~ad~ by inserting the wires through the hollow terminal rivets
and soldering on the outside.

The of regulating field coil (Fl) that extends farthest

~~re
•trce~l;S!1 aL1mir.um frame end, is connected to the regulating
c~1e
=··~s::. Tne c~~er ~ire is connected to t~e positive brush.
HIS APPLIES TO ALL 1930 TWIN GENERATORS.
 No. 54E ROLLER BEARING ROLLERS January 13, 1930
No. 57 April 14, 1930
Here is a handy chart, aiving information about roller bearing rollers. The
length of each roller is given, along with the part number, where each roller IMPORTANT NOTICE ON
is used, and the number of rollers in each bearing. It is suggested that this
data be kept in a prominent place so that it can be referred to on a moments CYLINDER HEAD BOLTS
notice. The standard diameter is the same for all types of rollers. Rollers
are furnished in diameters varing from .001" undersize to .001" oversize in
steps of .0001". Cylinder heads on some of the 1930 Biq Twins are clamped with twelve 7/16" x
l-5/8", and two 7/16" X 1-13/16" bolts threaded with 20 thre~ds to the inch;
This Shop Dope Bulletin is prompted by the fact that in many instances, mechanics and some are clamped with fourteen 7/16" x 1-7/8" bolts threaded with 16
lose considerable time in determining just what type roller is needed for threads to the inch.
certain bearings they may be servicing. Then, too, part numbers on boxes con-
taining rollers very often become unreadable through handling, causing incon- It is advisable to arrange your supply of cylinder head bolts accordingly,
venience in locating the proper place for them. and call this to the attention of your parts and service men.
PART # WHERE USED # USED LENGTH When necessary to renew a cylinder head bolt, first determine which size is
304-15 Big Twin Front Connecting Rod 24 9.12 mm needed. A mistake is likely to result in stripped cylinder threads. For
1929 and earlier Big Twin Sprocket Shaft 24 reference purposes, the various sizes and part numbers are listed below.
45" Twin Sprocket Shaft 24
·1930 Big Twin Front Brake Hub 24
1930 Big Twin Sidecar Brake Hub 24 PART NO. SIZE THREAD LIST PRICE
305-15 Big Twin Rear Connecting Rod 12 18.65 mm 14-29A 7/]6" X 1-5/8" 20 0.10
30.50" Single Connecting Rod 12
Big Twin Clutch Sprocket 12 14-30 7/16" X 1-13/16" 20 .10
305-29 45" Twin Rear Connecting Rod 12 14.28 mm 14-30B 7/16" X 1-7/8" 16 .10
306-26 21.09" Single Connecting Rod 12 15.08 mm
21 .09" and 30.50" Single Sprocket Shaft 12 Incidently, cylinder heads on all 30.50 cu. in. (500 c.c.) Sinoles are
l·etained with bolt No. 14-29A.
2289-17 45" Twin Front Connectin<1 Rod 24 7.14 mm
45" Twin and Single Clutch Sprodet 16 II II

Big Twin Transmjsston Countershaft Gear 24

1924 and earlier transm1ssion main drive gear 20
2289-25 1930 Big Twin Sproc~et Shaft 24 12.30 mm
1929 and later Big twin Transmission main drive gear24
45" Twin and Simtle Transmission Clutch Gear
(Left Side} · 16
45" Twin and S~il' Transmission afnshaft (riqht
Side) 12
1930 B1q Twin IntE!'rchangeable Wheel Hub 14
1930 Biq Twin Rear Brake Hub 14
 No. 59 August 4, 1930

June 30, 1930 IMPROVED SEAT POST SPRINGS

rlo. 58
A new seat post cushion spring combination has recently been developed
that is much improved over the spring combination used in the past.
The new combination is now being furnished in all new machines, and it
CARBURETOR BACK FIRE DEFLECTOR is also being supplied on parts orders. It can be applied to any LATER
1929 and 1930 MODEL, and since it is a much more satisfactory and de-
Latest VL and DLD model carburetors are fitted with an air intake pendable spring combination that has been available previously, we
cap in place of the air cleaner furnished as original equipment intend to furnish it complete on all parts orders calling for any of the
on all models. In connection with this air intake cap on latest cushion springs applying to later models, as mentioned. This means
machines, a deflector plate is fitted between cap and carb~retor that the new combination, which has been given the part No. 3128-29,
so that in case of motor back firing any fl arne blown out w11l be will not only take the place of the sprinq furnished in the past on that
directed away from the carburetor body and adjoininq parts that number, but will also take the place of the springs furnished heretofore
may be wet with gasoline. on part Nos. 3128-30; 3129-29; and 3129-30. Please bear in mind that
the last three part numbers mentioned have now become obsolete, and
Some of the first machines equipped with carburetor air cap did when any one of them is found on a parts order it will be changed to
not have the deflector plate and it would be well to so equip 3128-29 calling for the new spring combination.
these machines, as a precaution against possible damage from back
firing. You can check up the number of machines you have in service The new spring arrangement involves three springs, two five inches long
with air caps but without the deflector plate and order the required and a shorter spring that is to be assembled at the extreme lower end.
number of deflectors under part No. SA-111 0. He will furnish -iefl ector An extra guide collar is included 1~hich is to be fitted between the
plates no charge for machines that did not originally have this short spring and the one above. The guide collar that is found with
equipment in connection with the air cap, provided you will make original seat post combination is to be fitted between the two longer
this request on your order blank along with motor numbers of the cushion springs.
machines involved.
In connection with the 1930 SEAT POST ASSEMBLY, which is not quite as ~onq
HARLEY-DAVIDSON MOTOR CO. overall as the 1929 assembly, the recoil spring used in combination with
the new cushion spring arrangement should be only one inch long. The
recoil spring is the one in the lower end of the plunger or quide tube,
which checks or cushions the upward movement of the saddle. The early
1930 seat post assembly was fitted with a recoil spring about two inches
long, and it was not until well along in the season that this spring was
shortened. Hhen you install a new cushion sprinq combination in a 1930
seat post, pay particular attention to the recoil spring found in the
assembly and if it is a long one, cut it off as necessary or replace it
with a proper one. Hith all sprin9s properly assembled on the seat post
the initial spring tension can then be adjusted as desired by means of
the adjusting nuts at the lower end of the seat post rod.
He suggest that you order out a good· supply of the new springs, and have
them on hand for your service requirements. Order as follows:
3128-29 New Saddle Cushion Spring Combination - Price $1.00 List
3133-30 Seat Post Recoil Spring One Inch Long Price .1.0 List
 No. 61 September 15, 1930
No. 60 August 25, 1930
NEH METHOD OF TIMING IGNITION ON 1931 - 74 CU. IN. TWIN
GEAR SHIFTER LOCK FOR THE "45" AND SINGLE TRANSMISSION
On all 1931 - 74 cu. in. Twins, on the left side of the crank case and just above
The gear shifter lock as applied to 1931 "45" and Single Models can also the motor number, you will find a plug which screws into the crank case ignition
be applied to 1929 and 1930 models of both the "45" and Single. The timing hole.
necessary parts to make this change can be ordered under the following
number: The proper procedure in order to check timing or re-time a motor using the new
PART NUMBER LIST PRICE timing hole is as follows:
TG-750-TP Unit Complete $2.50 l. Remove spark plugs, to permit turning motor freely.
2. Set breaker points at .020" to .024"
The transmission must be removed from the frame in order to make the 3. Remove plug from timer hole.
installation as the new shifter shaft cannot be placed in the oear box 4. Rotate motor counter-clockwise (the direction in which motor runs)
due to lack of clearance between the front of the aear box and the seat unti1 mark which is cut into flywheel starts to show through timing
mast tube. After the new parts are insta'!led, observe through the hole. Continue to rotate motor until mark is in the correct position,
inspection hole in the top of the transmission that the shifter lock in relation to timing hole opening, for the type of motor being timed.
plunger in the bottom of case is so adjusted that when the sliding gear (see 5.)
is shifted to either high or low position, its dogs mesh completely at
the same time that the plunger registers fully with the corresponding NOTE: MAKE SURE THAT NARROW END OF CIRCUIT BREAKER CAM is about to open points when
locating notch the gear gear shifter plate. flywheel mark appears. (Mark will appear twice while circuit breaker cam rotates
once, but location of mark on flywheel is only in relation to front cylinder and
The plunger can be re-adjusted as necessary with regard to both spring front cylinder is timed by narrow end of circuit breaker cam. Therefore, if mark
tension and position by turning the eccentric plunger bushing either appears when wide end of cam is about to open points, continue to rotate motor
to the right or left. until mark comes around again. Came will then be right).
Next replace the inspection hole plate, using two of the original screws 5. The correct position of flywheel mark in timing hole for setting ignition
to fasten it on the right side and on the left side (side nearest clutch); on 3 types of 1931 motors is as follows:
fasten both the inspection plate and the release lever stop with the two VC COMMERCIAL: Flywheel mark should be just starting to disappear at front edge of
long screws sent with the assembly. The clutch release lever stop should timing hole when you look straight down at timing hole and motor is
be installed with its straight side toward the rear of the transmission. being turned counter-clockwise. With the mark in this position and
circuit breaker properly adjusted (see 6.) spark will occur l/4"
With the clutch lever against the stop, the lockfinger on the clutch release before top center.
lever should enter about half way through the slots in the locking quadrant, V AND VS; Flywheel mark should be squarely in center of timing hole. With mark
but no further. This adjustment can be obtained by bending the stop as in this position and circuit breaker properly adjusted (see 6.)
needed. spark will occur 5/16" before top center.
Finally the clutch push rod should be so adjusted that the clutch release VL: Flywheel mark should be just starting to appear at rear edge of timing
lever will have 1!16" free movement before it acts on the clutch. hole. Vlith mark in this position and circuit breaker properly adjusted
(see 6.) spark will occur 3/8" before top center.
6. If you find that with SPARK IN FULLY ADVANCED POSITION, the circuit breaker
just starts to open when the flywheel mark appears at the correct position
for the type of motor being timed, then timing is correct. If, however,
the points are not just starting to open, loosen the two screws that hold
the circuit breaker and the advance and retard plate assembly together (not
the two screws that secure adjustable contact points) and reset the circuit
breaker as necessary. With the motor in frame, the position at which
points are just startina to open can be found exactly by turning ignition
switch on. When points open, ammeter will go from discharge to zero. On
the bench a light and battery can be hooked up to circuit breaker low
tension wire and grounded to motor to serve the same purpose.
No. 62 October 6, 1930
No. 63 November l , 1930
USE 1931 TYPE CUSHION AND GUIDE RINGS WHEN SERVICING 1930 MOTORS NEW "45" MODEL G~NERATOR DRIVE
1931 type cushion and quide rinqs can be fitted to 1930 74 cu. in. engines provided
both are used together. The new guide and cushion rinqs must be used with each A new and stronger "45" model generator bevel gear drive has been in production for
other due to the new cushion ring beinq thicker than the 1930 type, therefore, the several weeks. It has been assembled in new motors, starting with #31Dl786 - and
new quide rinqs must be thinner to match. it is also being supplied on parts orders, WHEN SPECIFIED.
The new custion rings are more dependable and longer-lived than 1930 style rings. This new arive combination can also be apolied to all 1930 motors, as well as early
1931 motors assembled before the new parts were available. The only requirement is
1931 guide ~nd cushion rinqs can be ordered on the following part numbers: that the complete combination be installed (armature bevel gear - drive shaft -
and drive shaft bevel gear), because otherwise the individual parts are not inter-
NUMBER PART changeable.
NEEDED NUMBER NAME LIST PRICE
The new combinat.ion cannot be applied to the 1929 model. The reason for this is
8 267-31 Piston Guide Ring 15¢ each that the small bevel gear will not fit the armature shaft in the generator of this
model.
4 268-31 Inner Cushion Rinq 15¢ each
We recommend that the new drive combination be used altogether in giving required
CARBON AND ITS EFFECT service to the generator drive of 1930 and early 1931 motors, originally fitted
with the lighter gears. The new gears have fewer, but larger teeth; also the drive
Carbon cannot be allowed to accumulate in late type Ricardo Head motors, particularly shaft has been made stronger, with the result that the whole combination is much
the 74 cu. in. twin to the same degree as in 1929 and earlier slope head cylinder sturdier and more reliable.
motors.
In fitting the new gears, the same as with earlier gears, spacing shims (1639-29
The Ricardo principle allows only about 1/16" clearance between pistons and flat area and 1535-29B) must be applied as needed to adjust to just the right fit, as follows:
of heads. When this· soace becomes filled with carbon deposited on heads and pistons Gears should match almost exactly; or in other words, the outer edge of one should
to the extent of striking as pistons pass over top center, a loud rattle that may not extend beyond the other-- allow but little noticeable play or-lash in gears -
be mistaken for a piston rattle, a connecting rod roller bearing knock, or a valve gears must turn freely all the way around without any binding whatever at any point
noi•e, will set up in the motor and is p~rticularly noticeable if the throttle is (with generator installed).
suddenly closed when slowing down from average touring speed.
The parts of the new drive are listed in the parts catalog supplement of October 1,
Any macrines which develop the above characteristics can be taken care of by cleaning 1930 as follows:
out carbon. #164'1-31 - Armature Bevel Gear ................ $1.50 List
#1536-31 ·Drive Shaft Bevel Gear ..•.......... l.SD "
#1532-31 -Generator Drive Shaft .............. 2.00
#1536-31A- Bevel Gear Pin . . .. .. . . . . . . . . .. . . . . . .05
When you wish to order the new drive combination completely assembled and ready to
install, use the following part numbers:
TA-3298-T- Drive Shaft Assembly .............. $3.50 List
#164'1-31 - Armature Bevel Gear .............. 1.50
 NO. b4 -2- Uecember 15, 1930

6. VALVES SPRINGS In tuning up a motor always check valve spring. Motor perfor-
No. 64 DecemDer 15, 1930 mance cannot be good with springs in bad order -- replace any that are found
broken, or even weakened to any appreciable extent. un the 1930 74 cu. in.
TUNING MOTORS FOR SPEED AND POWER Twin pay part1cular attention to the early type of small diameter spring. If
any of these original springs are found broken or weakened rep·Jace all with
The following t1ps are intended particularly for 1930 and later motors, but can be "service spring No. 168-30". This spring is entirely reliable and is
applied to any motor. When you have complaint that a motor is sluggish, slow or distinguished from other 1930 small diamete.r springs by being marked with blue
poor on pulling, apply the following tuning ideas. DO NOT EXPECT ANY ONE OF THESE paint.
SUGGESTIONS ALONE TU DO THE TRICK - YOU MAY HAVe TO APPLY ALL OF THEM BEFORE A
MOTOR WILL REALLY DEVELOP ITS MAXIMUM PERFOR~1ANCE. MISCELLANEOUS - It may be only small things which are causing a motor to lack
speed, power and pull. Make sure of these details.
I. BKEAKER- POINTS - Should have a full .0<2" \ .Ol'O" to .U24") open1ng. ln a new
motor, due to wearing off of h1gh spots on the fibre block of the breaker lever Check the carburetor for wear, air leaks, and adjustments.
in the first few hundred miles of running, the points close up a l1tt1e and as
as result timinq is retarded to some exte11t and the motor may be "flat". See that va·lve tappets are properly adjusted.
Check the points and reset them.
Do not expect a high compression motor to run good on a poor grade of low test
2. SPARK TIMING - lf with points properly reset a motor is still sluggish, check or on an extremely high test gasoline- use a good blend of Benzol, Ethyl, or
ignition timing by actual measurement of piston position. (V motors should be other anti-knock fuel.
timed 5/16" before top center; Vl motors 3/8" before top center. All timing to
be done on front cylinder on compression stroke. On 1931 motors retime using lf your motor lacks turnover when using.the recommended gearing, and when tuned
crankcase timing hole) See that spark control is adjusted for full advance. according to the suggestions given here you might try a larger venturi in the
carburetor. Very often this will help greatly, particularly·in regard to speed.
3. CAKBURETOR AIR INTAKE - Some motors are equipped with air cleaner, some with The late model Vl is equipped with l-l/16" venturi.
an· cap, and some with air intake pipe. The air cleaner keeps dirt and grit
out of tne motor, but slows down top speed. The air cap gives good carburetion, Use qood oil if you expect a motor to perform. Poor oil creates fr1ct1on which
but exposes the motor to the danger of fire should the motor backfire with the results 1n heat, loss of power and speed. Harley-Davidson oil of the right
carburetor. flooded. The air intake pipe is the latest equipment. grade will give best results.

On motors equipped with air cleaner, where top speed is most important, remove Finally check spark plugs. An old, badly burned set of plugs will hold a motor
the cleaner and replace with an air intake cap, or preferably with the new air back -- fit a set of good new plugs -- play safe by using only Harley-Davidson
lntake pipe assembly (part nos. 1406-31, 1410-31 and 644030). plugs.

4. MUFFLERS - A partly closed or dirty muffler develops back pressure and back pres-
sure means overheating, loss of speed, pick-up and power. Make sure muffler is
well open on the end and is not clogged on the inside. The new "straight thru"
muffler on 1931 - 74 cu. in. motors cannot clog on the inside, but the fish tail
en? should be kept clean and open. The early 1930 muffler, two tube type,,was
qu1et, but developed some back pressure at high speed particularly when dirty.
The procedure here for best speed development is to first further open the V
slot ends of the two pipes. Then disassemble the muffler and remove the baffle
plate spot wel?ed in the lower tube between the two transfer pipes. This
?affle plate w1ll come out, but must be pounded hard with a long iron rod. It
1~ very often found that this operation makes a machine anywhere from 3 to 5
~1les per hour faster if everything else is in good shape, but· of course, it
1s understood that there is some increase in exhaust noise.
5. CUMPKESSION • ~o motor can be expected to show good performance if valves and
nnqs are leak1ng. When tuninq up a motor, be very sure that compression is
good. Touch up the valves: check the rings: clean out the carbon.
 No. b5 December 22, 1930

INSTRUCTIONS

No. b5 December 22, 1930 The lock r1ng tool involves three pieces, namely, ~ transfer c~ll~r (the smaller
collar); a compressing collar (the larger collar w1th tapered 1ns1de); and a
NEW PISTON PIN LOCK RING drift. Note the reference below to these names.

A newly developed p1ston pin lock ring recently went into production: It is now being 1. Place transfer collar on bench, either end up, and set recessed end of compressing
assembled in all Lyn1te (aluminum) and Dow-metal pist~n motors. It 1s also be:ng . collar on top of it.
supplied exclusively on parts orders. It can be appl1ed to all motors :n serv1ce w1th 2. After applying oil to lock r1ng, insert it, thin sect1on downward, into com-
the types of pistons mentioned. TEMPORARILY a set of these new r1ngs w1ll be suppT1ed pressing collar. Press ring squarely down into collar far enough so that it
with each parts order piston, however, this will be discontinued when sufficient time wi 11 stay.
has elapsed to allow everyone to obrain a supply of the new rings.
3. \Jith large end of drift, push ring on through compressing coliar until the thin
Since the new ring is of much better quality and more dependable than rings available section transfers into small collar. It may happen that ring binds to some extent
up to now, we strongly recommend that you obtain a supply at once and then discard any and will not transfer easily. In this case apply more pressure to drift. DO NOT
earlier typ~ rings you may have on hand. USE A HAMMER, as a hammer blow may "set" ring, reducing its tension greatly.
This new rinq is readily distinguished from rings supplied previously by its greater 4. Remove compressing collar and place it to one side as it is not needed further
width due to· a thin section extending from one side of the ring proper. It has much until ready for the next ring.
qreater tension than earlier rings and will hold tightly under the hardest service.
~ith proper installation, troubles resulting from lock ring failures will be reduced 5. Slip the transfer collar in which ring is now held, over small end of drift with
tc an absclute minimum. lock ring outward, and after noting that ring groove is clean insert drift into
IMPORTANT piston pin. Turn ring and collar so that ring gap is approximately l/8 turn
below removal slot at side of pin hole. (NOTE: Earlier than 1931 pistons were
For dependable service, lock rings must seat in their grooves with considerable tension. not provided with removal slot mentioned.) Do not place a new style lock ring
Take no changes with loose fitting rings and possible trouble as a result. DO NOT USE in a 1930 piston without first filing a removal slot in the piston. If this
LOCK RINGS A SECOND TIME. JUNK THOSE REMOVED IMMEDIATELY. Use only the latest, re- is not done, the ring will be extremely hard to take out.)
designed installing tool described below, and thus avoid loss of tension through over-
compressing and consequent "setting", also bending or twisting, which are likely to 6. Transfer lock ring into groove in piston boss by striking drift a quick, but light
be the result of hap-hazard methods of installing. blow with hand or hammer. Make sure that ring seats well into groove.
The part number and price of the new ring is as follows: Part #280-24 - List Price 10¢. 7. To remove ring, work a pointed tool under it at removal slot and pry ring out.
NEW TOOL FOR INSTALLING LATEST TYPE PISTON PIN LOCK RING NOTE: You will observe that the pin hole in late pistons is slightly larger at the
points where the lock rings register. In earlier pistons the pinhole is reamed one
A NEW TOOL is required for satisfactory and safe installation of the new style piston size straight through. The new construction is to allow for fitting of overslle pins
pin lock r1nq described above. The new rinq will be used exclusively in all new motors without affecting the lock ring fit. However, only one size of lock ring is furnished
equipped with Lynite (aluminum) and Dow-metal pistons in the future, and temporarily, and it applies equally well with either size of hole. It is simply a matter of a
as already mentioned, they will be sent out with parts order pistons. For these reasons slightly tighter fit with the smaller hole, and naturally the lock ring does not
together with the fact that the old lock ring is discontinued from our parts list, the drift into place quite as readily as in the larger hole in late pistons.
tool furnished in the past, one of which no doubt you have in your shop, becomes obso-
1ete. vle suggest that you do not attempt to use the o Id too 1 with the new ring, be-
cause in doing so there is too much chance of ring damage and faulty i nsta 11 ati on.
The required new tool which is especially adapted to the new ring is now available.
Order one and use it exactly according to instructions given below. You will then be
assured of qood and dependable lock ring performance.
Part No. 12052-30 Price- $1.00 list
No. 67 January 6, 1931 January 12, 1931
No. 68
TO FIT NEW RIGID FORK SIDE FIT DOUBLE FILAMENT HEADLIGHT BULBS CORRECTLY
Originally the 1931 headlight was equipped with a 32-32 candle power bult, but this
has recently been changed to 32-21 candle power bulb. With the 32-21 candle power
First, w1th hacksaw make four cuts entirely thru bulb care must be exercised to install it correctly so that the 32 candle power
forkside along filament will burn when the "bright" (higher beam) is liqhted, and the 21 candle
dotted 1ines - -· -- --"':::::::----- __ )~ power when the "dimmer" (tilted beam) is lighted.
Most bulbs are marked '"TOP" on the base, and if the side so marked is placed upward
in the lamp the filaments will be in correct positions. Bulbs not marked are
installed correctly if the filament of smaller diameter wire is placed toward the
----- top of the lamp.
INCREASE BULB LIFE BY REDUCING GENERATOR CHARGING RATE
Reduce the generator charging rate if you are experiencing trouble with bulbs burning
To fit new rigid fork side proceed in the following manner: out. A high charge rate means overloaded bulbs and the life of bulbs under that
condition is greatly decreased.
If lo>-Jer cross member has lug riveted to fork side, first remove rivet. Then with a
hack saw, or preferably a power saw if such equipment is available, make four cuts RUBBER SPEEDOM~TER DRIVE GEAR
entirely throuqh the fork side (per illustration). Start the cuts about 1/32" away
from ends of cross members that extend through fork side, being careful not to cut ADJUSTMENT
into them.
The rubber speedometer drive qear operating on the rear sprocket of the 74 cu. in. Twin
After necessary saw-cuts have been made, take a half-round chisel and cut (at points should mesh fully with the sprocket teeth. Allow just enough clearance ss that the
indicated in illustration) four grooves, one on each side of cross members, the full gear does not bottom and bind at any point. If the qear is not meshed this way, it
depth of fork side to permit breaking the remaining stock away. may wear out prematurely. When rear wheel is shifted to adjust the drive chain,
remember to move speedometer gear back accordingly.
Then with a hammer straighten peaned-cver ends of cross members (do not file off, or
stock may not be sufficiently lonq for a good re-peaning job), so a new fork side INSTALLATION
may be driven or pressed on. Do not ·heat ends of cross members to straighten peaned
over ends because they are heat treated and might be somewhat weakened. When fitting a rubber speedometer drive gear to the shaft, be extremely careful to
insert the raised hub section of the two piece hub accurately and squarely into the
flhen driving or pressing on a new fork side, extreme care should be exercised that it hole molded in the rubber gear. Make sure that the hub and the gear are matched
is driven or pressed on both the cross members evenly. If this precaution is not perfectly in this regard before putting the retaining washer and screws in place.
taken the new fork s1de may jam 1vhen part way on and it will be difficult to either Failure to install the gear in this manner will result in s.erious damage due to the
remove it or drive it on the remaining distance. To further insure that the new fork gear running eccentric.
siae will go on reasonably easily, polish ends of cross members with emery cloth and
use a small quantity af white lead for a lubricant. Rubber gears damaged obviously from mis-adjustment or improper installation cannot
be considered faulty and subject to replacement regardless of length of time or
After fork side has been driven or pressed snugly against shoulders of cross members, number of miles in service.
pean aver ends of members, beinq careful to pean the metal firmly into countersunk
holes of fork side. It is not necessar·y to replace rivet where one was originally
fitted thru lower cross member lug and fork side, as rivet is not essential and
has been discontinued on later machines.
Finally check fork for alignment.
 No. 69 -2- January 19, 1931

10. Starter gear cdjuster plunger is not necessary with new assembly, but
it must be left in gear box or replaced with a suitable plug. (At some
No. 69 January 19, 1931 time la•~r gear boxes will not have a hole at this point.)
NEW CONSTANT MESH STARTER GEARS

A new starter arrangment of a constant mesh design for the Big Twin transmission IHrORTANT PRICE CHANGE
recently went into production. All 74 cu. in twin models built lately are equipped
•vith this new started assembly. It can be fitted to any Big Twin transmission from Effective January 15, 1931, the price for exchanging worn two cam tappet guide
1926 up. The advantage of the. new starter are - first, elimination of all danger blocks and tappets was increased to $7.50 net, $11.50 list, per set. This
of gears jamming when starting, thus removing all posibil~ty of damage through figure includes the cost of new tappet guide bushings and tappets.
motor backfiring; second, easier motor turnover and start1ng because of the smoother
operation of-the constant mesh gears. The new starter assembly complete may be Some of these guide blocks have been in service so long that they have been
ordered on the following part number: repaired several times and are now getting to the point where w~ have to
Part No. 2125-26 List Price - $9.00 scrap quite a number of those returned. Usually it is a matter of the square
lower section in which the tappet slides, being worn to such an extent that
FITTING INSTRUCTIONS even oversized tappets 1till not make a satisfactory fit.
To fit this new constant mesh starter to any Big Twin transmission from 1926 models
to early 1931 models the instruction below should be carefully followed:
1. Remove the following original parts: starter cover cap, clutch pull rod, and
pull rod thrust bearings.
2. Take out clevis pin in clutch release lever (chain guard side) and shift release
lever to one side.
3. Remove starter cover and crank
4. Take off main shaft nut and remove starter clutch, keys, starter main shaft qear,
starter clutch spring and starter clutch spring disc.
(A puller for the starter clutch can be easily made from a sprocket puller, part
no. ll920X, by grinding off the backs of the jaws so that they will slip under
thP starter clutch, and fitting pull rod lock nut, part no. B0-680B on puller
screw. The threads on puller screw and nut do not match, therefore, nut will not
go on puller screw very far and will act as a surface to pull up against end of
main shaft when removinq starter clutch. Tapping starter clutch with a brass rod
will help loosen it.)
5. Install the four long studs supplied with the new assembly in place of the four
original studs located toward the front of the transmission (two on bottom, one
at top, and one between). The original studs are too short for the new starter
cover.
6. Install new starter clutch spring disc with recess for starter clutch spring facing
outward. Fit new starter clutch spring, starter main shaft gear, starter keys and
starter clutch. Replace main shaft washer and nut. Fit starter crank in new
sector gear in n~w cover.
7. Install new starter cover and TIME starter gears. TIMING IS CORRECT IF THE LOHEST
TOOTH ON STARTER SECTOR GEAR (WITH STARTER CRANK UP) MESHES BEHlE EN THE TWO
MARKEO TEETH ON STARTER MAIN SHAFT GEAR. THIS IS IMPORTANT.
8. Replace and connect release lever, pull rod, and thrust bearings.
9. Pack new starter cover cap with grea3e and install.
No. 71 March31, 1931
No. 71A March 30, l9Jl
74 CU. IN. fWIN MOfOR FITTING SPECIFICATIONS
45 CU. IN. TWIN MOTOR FITTING SPECIFICATIONS - (ALL MODELS)
(NOTE: These supersede all previous specification and apply
to an 1930 and later Biq Twin Motors.) NOTE: These supersede all previous specifications

PISTON CLEARANCE: PISTON CLEARANCE -- .015" to .017" (Measure pistons just below the top group
c!RON ALLOY PISTONS- (V & VC) . . . . . . . . . . . . . . . 004" to .005" of rings, and cylinders about 1/l'" from the top of bore)
ALUMINUM & DOW METAL PISTONS- (V & VL) . . . . . . . . . . 016" to .018"
(Measure all pistons just below the top qroup of rinas and cylinders about PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64"
l/2" from top of bore)
PISTON PIN IN PISTON -- Snug press fit -- not over .0005" tight
PISTON-CYLINDER HEAD CLEARANCE ( V & VL) .................... l/16" to 3/32"
(VC Commercial) .............. 7/64" to 9/64" PISTON PIN IN UPPER END OF CONNECTING ROD -- .00075" loose
PISTON PIN IN IRON ALLOY PISTON- .0005" to .001" press fit in lock pin LOWER CONNECTING ROD BEARING -- .0006" to .0008" loose
side - oluq or slip fit in opposite side.
CONNECTING RODS -- .006" to .010" end play between f'lywheels -- roller and
PISTON PIN IN DOH-METAL &ALUMINUM PISTONS - Snuq press fit - not over .0005" tight. retainer assembly should be narrower, but not more than .. 010" narrower than
front rod.
PISTON PIN IN UPPER CONNECTING ROD END (All models) - .001" loose
PINION GEAR SHAFT -- .0045" loose at inner end of bushing -- .002" at outer
LOWER CONNECTING ROD BEARING (All models) - .001" to .00125" loose end of bushing. (Bushing is taper reamed with special reamer.)
CONNECTING RODS (All models) - .006" to .010" clearance between flywheels - SPROCKET SHAFT- .0005" to .00.1" loose in roller bearing-- .006" to .007"
roller and retainer assembly should be narrower, but not more than .010" loose in chain lubricating bushing.
narrower than front rod.
FLYHHEEL ASSEMBLY -- .002" to .006" end play in crank case.
PINION GEAR SHAFT (All Models) - .0045" loose at inner end of bushing - .002"
lo0se at outer end of bushing. Bushing is taped reamed with special reamer) CAM GEARS-- .0005" to .001" loose in crank case and cover bushings-- free to
.005" end play. ·
SPROCKET SHAFT (All models) - .0005" to .001" loose in roller bearing- .006"
to .007" loose in chain lubricating bushing. GENERATOR DRIVE GEARS AND SHAFT -- Shaft must be free running fit; have .002"
to .004" end play, and .001" to .0015" cldarance in bearings. Small bevel
FL YVIHEEL ASSEMBLY (All models) - . 004" to . 008" end play in crank case gear should be .002" to .003" loose in bushing assembly, and shimmed to allow
.002" to .004" clearance between bevel gears.
CAM GEARS (All models) - .0005" to .001" loose in crank case and cover bushings
free to .005" end play. TAPPET GUIDES .0005" to .001" press fit in crank case.
INTERMEDIATE GEAR (All Models) - .001" to .0015" loose on stud VALVE TAPPETS .001" to .0015" loose in tappet guides
TAPPET GUIDES (All Models - .0005" to .001" press fit in crank case HARLEY-DAVIDSON MOTOR CO.
Milwaukee, Hisconsin U.S.A.
VALVE TAPPETS (All Models) - .001" to .0015" loose in tappet guides
 No. 71 C March 30, 1931
No. 71 B March 30, 1931 TIMING SPECIFICATIONS
SINGLE MOTOR FITTING SPECIFICATIONS - (ALL MODELS) NOTE: These supersede all previous specifications.
( NOTE: These supersede all previous specificationS) 1930 AND LATER 74 CU. IN. TWIN ( V AND VC MODELS)
INTAKE VALVE - Opens when piston is ll/64" to 19/64" before top dead center
PISTON CLEARANCE-- Dow metal and aluminum-- .011'' to .013". Closes when piston is 9/16" to 13/16" after bottom center
(Measure all pistons just below the top group of rings, and cylinders about
1/2" from top of bore) EXHAUST VALVE - Opens when piston is 9/16 to 13/16" before bottom dead center
Closes when piston is ll/64" to 19/64" after top dead center
PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64"
IGNITION - OCCURS when piston is l/4" to 5/16" before top dead center on the
PISTON PIN IN PISTON -- Snug press fit - not over .0005" tight compression stroke.

PISTON PIN IN UPPER END OF CONNECTING ROD -- .0005" loose 1930 AND LATER 74 CU. IN lWIN (VL MODEL)

LOWER CONNECTING ROD BEARING --.0004" to .0006" loose INTAKE VALVE - OPENS 9/32" to 13/32" before top dead center
CLOSES l/4" to l-.1/8" after bottom dead center
CONNECTING RODS -- .010" to .020" end play between flywheels -- roller and
retainer assembly should be narrower, but not more than .010" narrower than rod. EXHAUST VALVE - OPENS 5/8" to 7/8" before bottom dead center
CLOSES - l/4" to 3/8" after top dead center
PINION GEAR SHAFT -- .0035". loose at inner end of bushing -- .0025" loose at
outer end of bushing (Bushing is taper reamed with special reamer) IGNITION - OCCURS when piston is 5/16" to 3/8" before top dead center on the
compression stroke.
SPROCKET SHAFT-- .0005" to .001" loose in roller bearing-- .006" to .007"
loose in chain lubricating bushing. 45 CU. IN TWIN ( ALL MODELS)

FLYWHEEL ASSEMBLY -- .002" to .006" end play in crank case INTAKE VALVE - OPENS when piston is 5/32" to 7/32" before top dead center
CLOSES when piston is 37/64" to 45/64" after bottom dead center
CAM GEARS -- .0005" to .001" loose in crank case and cover bushings -- free to
.005" end play EXHAUST VALVE - OPENS when piston is 37/64" to 45/64" before bottom dead center
CLOSES when piston is 5/32" to 7/32" after top dead center
INTERMEDIATE AND OILER GEARS -- .0015" to .002" loose on studs
IGNITION - OCCURS when piston is 1/4" to 9/32" befor-:: top dead center on the
TAPPET GUIDES .0005" to .001" press fit in crank case compression stroke.

VALVE TAPPETS Free to .00075" loose in tappet guides. 30.50 CU. IN SINGLE (ALL MODELS)
INTAKE VALVE - OPENS when piston is 5/16" to 9/16" before top dead center
CLOSES -when piston is 11/16" to 15/16" after bottom dead center
EXHAUST VALVE - OPENS when piston is l/2" to 3/4" before bottom dead center
CLOSES when piston is 1/4" to l/2" after top dead center
IGNITION - OCCURS when piston is l/4" to 5/16" before top dead center on
the compression stroke.
No. 71C -2- March 30, 1931

21 CU. IN. SIDE BY SIDE VALVt SINGLE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 1/8" to 3/16" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center
EXHAUST VALVE - OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 1/8" to 3/16" after top dead center
IGNITION - OCCURS when piston is 7/32" to 9/32" before top dead center on the
compression stroke
.21 CU. IN OVERHEAD VALVE SINGLE (ALL MODELS)
INTAKE VALVE - OPENS when piston is 3/32" to 5/32" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center
EXHAUST VALVE - OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 3/32" to ~/32" after top dead center
IGNITION - OCCURS when piston i; 11/32" to 13/32" before top dead center on
the compression stroke.

TAPPET CLEARANCES
NOTE: When checking valve timing according to piston position, bear in mind
that tappets must first be adjusted to the correct clearances.
ALL SIDt BY SIDE VALVE MODES ( SINGLES AND TWINS) --- INTAKE - .004" to .005"
EXHAUST - .006" to .007"
OVERHEAD VALVE SINGLE INTAKE AND EXHAUST - .002" to .003"
 No. 73S -2- April 13, 1931

SlANDARlJ COLOR STANDARD OPTIONAL

PARTS & ALL OTHER COLORS
List Price List Price
Spare Wheel Carrier (Black) $ .75 *
Apri I 13, 1931 SirenProjector or Guard .40 .45
No. 735
RE-ENAMtLING PRICES Panel Switch Cover .25 *
First Aid Box 1.30 1.50
The following is a list of prices for re-enameling motorcycles, sidecars, package Pyrene Brackets (Each - Black) .75 *
trucks and parts. These prices cover re-enameling charges only. They do not
include the cost of any necessary repairs, not labor for stripping and assembling. Leqshields (Set - Black) 2.00
ALL PRICES ARE SUBJECT TO CHANGE WITHOUT NOTICE. Name Plate (Black) .25
STANDARD OPTIONAL
STANDARD COLOR &ALL OTHER COLORS
PARTS List The parts indicated by an asterisk (*) are enameled BLACK on all standard as
List Price - - Price
-- well as special colored machines.
Motorcycle Cpt. (all models) $18.50 $23.00
Sidecar Body (all models) 15.50 18.50
Package Truck Body (M-MO-MW) 14.00 17.00 For paneling tanks and mudguards any color panel add $1.00 net- $1.50 list
extra per pane 1
Packa9e Truck Body (MT-MXP-MHP-MDC-MNO) 18.50 23.00
Frame (Motorcycle) 2.30 2.85 For special shaped panels on tanks any color add $3.50 list extra per panel
Frame (sidecar/package truck)-Black 2.30
Spring Fork .90 1.15
For two-tone sidecar bodies or package truck bodies add $2.30 list to charge
Rigid Fork 1.15 1.45 for single color enameling.
Tanks (set) 3.40 4.25
Mudguards (each) 1.50 1. 90 Add transportation charge to List Prices
Tool Box 1.00 1.25
Handlebars (Black) .90 *
Generatot (Black) .40 *
Headlamp (Black) .75 *
Tail Lamp (Black) .40 *
Horn (Black) .60 *
Front Chainguard 1.25 1.50
Front Chainguard Inner plate (Each) .30 *
Rear Chainguard .40 .45
Stand (Rear or Front) .60 .75
Battery Box Cpt. 1.00 1.25
Wheels (Each including Spokes-Black) 1. 90 *
Sidecar or Package Truck Springs (set) 1.40 *
Luggage Carrier (Motorcycle) 1.50 1. 90
Tire Rack and Luggage Carrier (Sidecar) 2.30 *
 No. 74 -2- April 20, 1931

and pistons. It is not necessary to keep the throttle closed for more than a
second or two, as pistons are moving so fact that a considerable quantity of
oil is drawn up instantly,
No. 74 Apri 1 20, 19:11
FOLLOW THESE SUGGESTIONS FOR BEST MOTOR LUBRICATION SUMMARY
You wonder perhaps, why again this spring, we bring up the old story of lubrication 1. Drain, flush and replace crank case oil supply regularly.
here are the reasons. First of all, late type motors are higher compression then
ever before, resulting in more power, higher operating temperatures, and call for 2. Use the hand oil pump when motor is running at, or near, its top 1imit.
closer attention to lubrication. Second, in recent years, more and more riders
are using their machines throughout winter, regardless of how severe weather con- 3. Develop the habit of occasionally snapping the throttle shut, for an
ditions may be. In almost every locality, winter service usually means machines instant, when traveling at high speed.
must be equipped with handlebar windshields and possibly sidecars. It means, too,
motors-are often primed and choked when starting, which likely results in con- 4. Do not ride a machine, particularly a sidecar outfit, equipped with handlebar
siderJble dilution of crankcase oil. windshield, wide open for long distances without giving close attention to
lubrication, and overheating conditions possibly brought about through bad
You probably haven't worried much about the matter of lubrication during winter as spark plugs or need of general tuning-up.
you ha·1e felt machines are necessarily operated so slowly, that less effective
motor cooling due to windshield equipment, additional load of sidcar, diluted 5. Always use good oil. Our recommendation is that Harley-Davidson oil be
crank case oil, and the hard going of winter service generally, should result in used exclusively.
no harm worth mentioning. He fully agree that slow winter riding does not lead
to any great danger of motor damage, even though lubrication may not be at its
best. However, danger comes in with the first warm spring days. Immediately a HARLEY-DAVIDSON MOTOR CO.
rider gets "rip-twisting fever", or in other words, a desire to try his machine
out: whereupon, without changing oil in the crank case, without removing the Milwaukee, Wisconsin,
handlebar windshield, without tuning up his motor in any way, he travels out to U.S.A.
his favorite speed course and turns on the gas. What are the results" His motor,
not at the peak of its efficiency after a winter of plugging around, fails to
cool or lubricate properly, and heats up badly possibly to the extent of seizing.
The solution to this problem is to warn your riders against the practice of rushing
out to the open highway on the first fine day and riding their machines wide open
vllTHOUT FIRST DRAINING THE CRANK CASE AND PUMPING IN THREE GUNFULS OF FRESH OIL.
Remind them further, not to push their machines to the limit, with sidecars
attached on warm spring days - especially when windshields are fitted and motor
are in need of some tuning up.
Another thing, in connection with lubrication, which seems to have more or less
disappeared, is the good old-fasioned practice of using the hand oil pump when
riding at top speed or under conditions of high motor turnover. Since motors
have been fitted with throttle controlled oilers, use of the hand oil pump has
been almost completely forgotten except as a means of injecting fresh oil after
draining, but with the increased horse-power, speed and heat developed by late
motors, it is more important now than ever before that the hand pump be used
under certain conditions. As a safety factor, advise your riders to use their
hand oil pumps when running at high speeds. Tell them to supply about 1/3 to
1/2 pumpfuls, at least every two miles.
Another mightly important lubrication suggestion, which is entirely overlooked
too frequently, IS THE SIMPLE STUNT OF OCCASIONALLY CLOSING THE THROTTLE, FOR
AN INSTANT, HHEN TRAVELING AT EXTREt~E SPEEDS. Closing the throttle shuts off
the air supply from the air intake 9f the carburetor almost completely, setting
up a vacuum in the cylinders which draws oil up from crank case past the pistons
thus more effectively lubricating cylinder walls, upper connecting rod ends,
No. 76 May 4, 1931 No. 77 May 11 , 1931
ROLLER REARING ROLLERS CYLINDER HEAD BOLT SIZES
(Supersedes all previous lists) (Supersedes all previous information)
Here is a handy chart, giving information on roller bearing rollers. It is
suggested that this data be keot in a prominent place so that it can be Cylinder heads on some of the 1930 Big Twins are clamped with twelve 7/16" x
referred to on a monents notice. 1-5/8", and two 7/16" x 1-13/16" bolts threaded with 20 threads to the
inch; and some are clamped with fourteen 7/16" x l-7/8" boHs threaded with
The standar diameter is the same for all types of rollers. They are furnished 16 threads to the inch. (See chart below)
in di anieters varying from . 001" undersize to . 001" oversize, in steps of . 0001 ".
It is advisable to arrange your supply of cylinder head bolts accordingly,
and call this to the attention of your parts and service men.
PART NO. 1/HERE USED NO. USED LENGTH
When necessary to renew a cylinder head bolt, first determine which size is
304-15 Big Twin front connecting Rod 24 23/64" needed. A mistake is likely to result in stripped cylinder threads. To
1929 and earlier Big Twin Sprocket Shaft 24 repair a cylinder in which threads are stripped, remove cylinder head, and
45" Twin Sprocket Shaft 24 with a 33/64" drill, enlarge the hole in head that corresponds with stripped
1930 and later Big Twin Front Brake Hub 24 hole in cylinder. Replace cylinder head (without gasket) and fasten with
1930 and later Big Twin Sidecar Brake Hub 28 two or three bolts; then, using head as a guide to keep tap straight, re-
thread stripped hole, using a l/2" x 20 U.S.F. tap. Remove cylinder head
305-15 Big Twin Rear Connecting Rod 12 47/64" again, and after cleaning all chips away, reassemble completely.
30.50" Single Connecting Rod 12 ll 1l

Big Twin Clutch Sprocket 12 PART NO. SIZE THREAD LIST PRICE NO & WHERE USED
305-29 45" Twin Rear Connecting Rod 12 9/16" l4-29A 7/16" X l-5/8" 20 11. s. F.. $ .10 7 on all 30.50s, 12 on early
1930 74s.
306-26 21.09" Single Connecting Rod 12 19/32" 7/l6"x l-13/16"
21.09" and 30.50" Single Sprocket Shaft 12 14-30 20 U.S.F. .10 2 on early 1930 74s
l4-30B 7/16 "x l-7/8" 16 U.S.F. .10 14 on later 1930 and 1931 74s
2289-17 45" Twin Front Connecting Rod 24 9/32"
45" Twin and Single Clutch Sprocket 16 l4-30S * l/2" X l-5/8" 20 U.S.F. .10 Repair on all 30.50s and
Big Twin Transmission Countershaft Gear 24 1930 and 1931 74s
1924 and earlier Transmission Main Drive Gear 20
2289-25 1930 and later Bia Twin Sprocket Shaft 24 31/64"
1923 to 1929 Bia Twin Rear Wheel Hub 32
1925 and later Big Twin Transmission main drive
gear 20
45" Twin & Single Transmission Clutch Gear (Left
side) 16
45" Twin & Single Transmission Mainshaft(right side)l2
1930 and later Big Twin interchangeable wheel hub 14
1930 and later Big Twin Rear Brake Hub 28
No. 78 May 15, 1931 No. 79 July 6, 1931
TO USE NEW CLUTCH FIXTURE 1932 45 and 74 CU. IN. TWIN PISTON PIN LOCK RINGS
TO DIS-ASSEMBLE CLUTCH - Remove clutch spring nut sector locatinq pins and All 1932 45 and 74 cu. in. motors equipped with Lynite (aluminum) or Dow metal
compressino screw from fixture. Place clutch assembly in fixture. Insert pistons are fitted with a new type of piston pin lock ring. This rino fits
compressing screw through clutch assembly into threaded plate. Tighten on to the steel piston pin rather than into the aluminum or Dow metal piston as
compressing screw until clutch spring tension is relieved sufficiently to did the old. style rino. This construction insures against lock rino failure
permit readily removing c 1utch spring screws. Then take out fixture com- providing rings are correctly and carefully installed.
pressing screw, and clutch assembly is then free to come apart.
At the start of the 1932 season, we are going to discontinue shipping the
TO ASSEMBLE CLUTCH - First try each lined friction disc separately in the present type of aluminum and Dow metal pistons and send out only the improved
clutch shell. As there is slight irregularity in the spacing of splines and 1932 pistons for the "45" and "74" models. However, the present lock rings
splineways, it will be found that the discs fit better in one position than and piston pins may be obtained for servicing earlier motors in which a
in another. This applies particularly to new or only slightly used discs. chanqe of pistons is unnecessary.
Brand new discs often require slight filing or grinding of the splines before
fitting properly. Make a mark on the clutch shell and when the position is The new arrangement necessitated a chanoe in the piston and piston pin design,
found where each disc fits freely, mark the discs accordingly. The flat therefore, the new parts are not interchangeable with older pistons, pins
ste~l discs and the releasing disc should also be fitted tooether and marked. and lock rings. For this reason, on all orders for pistons, we will temporarily
After the discs are marked, proceed as explained below to place them in supply a complete combination of new style piston, piston pin, and lock rinos.
proper order in the clutch fixture with marks in alignment, and then after (The piston rings are not included.) You will find one of the lock rinos
the assembly is removed from the fixture, insert it into the clutch shell fitted to the piston pi.n and we recommend you observe it carefully, particularly
according to markings. Unless this procedure is followed, there is a possi- in regard to the tightness with which it fits on the pin. The ring you install
bility of one or more of the discs binding in the splineways with the result on the opposite end of the pin should fit equally tight.
that clutch will not engage and release properly.
IMPORTANT
viith nut sector locating pins and compressing screw removed from fixture,
place nut sectors on pads, and insert sector locating pins thru nut sectors
into holes in fixture pads. (NOTE: Use outer row of holes .for 1929 and THESE NHI RINGS CANNOT BE USED A SECOND TIME AS THEY BECOME BEND AND "SPRUNG"
earlier model clutches --- inner row of holes for 1930 and later models) 1-JHEN REMOVED. ANY ATTEMPT TO STRAIGHTEN AND RE-USE RINGS WILL VERY LIKELY
RESULT IN SERIOUS DAMAGE TO THE MOTOR BECAUSE OF LOCK RING FAILURE.
On 1949 and earlier models, place clutch springs only over nut sector locating
pins: on 1930 and later models spring guide collars are first placed over THESE"RINGS CANNOT BE SUCCESSFULLY INSTALLED EXCEPT WITH A NEW TOOL DESIGNED
nut sector locating pins, then springs and next the upper set of spring FOR THEM. OTHER METHODS OF INSTALLATION WILL EVENTUALLY CAUSE TROURLE.
quide collars. (Complete instructions covering the use of this installing toll are packed with
it).
Place releasing disc guide pin in hole between pads. (NOTE: outer hole 1929
and earlier-- inner hole 1930 and later.) Next drop releasing disc into IN ORDER TO PROPERLY SERVICE MOTORS, WE SUGGEST YOU ORDER ONE OF THESE TOOLS
position so that disc ouide pin enters any one of the three large holes in AND A SUPPlY OF THE NHI LOCK RINGS AT ONCE.
disc. Assemble inner clutch discs, remove guide pin, and place outer drive
disc in position. .
1932 LOCK RING NEW INSTAlliNG TOOL
Insert fixture compressing screw through clutch assembly into threaded plate Part No. 280-32 Part No. 12052-32
and compress springs. Remove nut sector locating pins and insert c 1utch list Price - 15¢ list Price - $1.00
spring screws. Turn screws in until 1~ threads extend through nut sectors.
HARLEY-DAVIDSON MOTOR CO.
After removing assembly from fixture, turn screws to right or left as necessary Milwaukee, His., U.S.A.
to allow keys on screw heads to drop into locking notches in outer drive
disc; then assemble clutch in shell.
No. 79A July 6, 1931 No. 80 July 13, 1931

INSTRUCTIONS FOR USING LOCK RING INSTALLING TOOL ADJUSTING THE OIL PUMP

The lock rinq installinq tool consists of three pieces, namely; 1. A TAPERED In addition to the regular oil pump adjustment described in the Rider's
EXP.~NDJNG ARBOR (the longest piece): 2. A SHORT COLLAR (used only as a Hand Book, further regulation of the pump can be made by adding or
spacer when removing rinos from "45" twin pistons); 3. A LONG COLLAR (for removing washers from under the screw located in the end of the pump body.
pushinq rinqs over expander onto piston pins). NOTE THE REFERENCE TO THESE To change the amount of oil pumped, by means of this screw and washer
NAMES AND GO THRU EACH OPERATION IN THE ORDER GIVEN HERE. adjustment, it is only necessary to add washers to increase the supply,
or remove washers to decrease it. These washers are made in two thick-
ORDER OF OPERATIONS WHEN INSTALLING RINGS nesses - 1/64" (part No. 674-22) and l/16" (Part No. 0202). It is
advisable to make all chanoes with thin washers, whether increasing or
1. After piston and pin with one rinq already in place, are assembled on decreasing the oil supply, in order to prevent an extreme change which
connectinq rod, carefully clean out groove in piston pin into which might result in a heavy oversupply, or an undersupply which would cause
other ring is to be fitted. serious damage.

2. Insert straight end of expander into piston pin starting it into pin on HARNING: - If the particular pump you are working on is one equipped with
side where ring is to be installed. the short oiler screw (19/32" overall, part No. 672-22), do not under any
conditions, fit more than a total of one thick washer or four thin washers.
3. Dip lock ring in oil and slide over tapered end of expander, with flat If the pump is fitted with the long adjustin(J screw (43/64" overall, part No.
side of ring facing inward. 672-29), do not fit more than a total of two thick or eight thin washers. ·
Fitting more washers than the numbers mentioned, will very likely injure the
4. ~lithlonq collar push lock ring over the expander into position on pump.
piston pin. Be sure uap in lock ring is at least 1/8" away from either
removal slot in piston pin. Tap long collar liuhtly with a hammer, if REAR HHEEL SPROCKETS FOR 45 CU. IN TWINS
necessary, to drive rinu on.
A number of dealers have recently requested information in regard to the
ORDER OF OPERATION WHEN REMOVING RINGS rear wheel sprockets available for 45 Twins. Here is a complete list of
sprockets in stock. (These sprockets fit all "45" and "30.50s").
NOTE: Remove only the ring on slotted end.of piston pin. The other ring
remains on pin permanently unless it becomes damaged or loose thru Part No. 2046-29 - 28 Tooth Spr?,cket
unusual service. " 2042-29 30
" 2047-29 32
l. Insert straight end of expander into piston pin, starting it into the pin " 2048-29 36
on the side which is not slotted. When doing this operation on 45 cu. in. " 2045-29 38
motor, place small spacer collar over straight end of expander before " 2043-29 40
inserting into piston pin. This small collar is not used on 74 cu. in.
motors. ~~t!Q_YO~~RANKCASE HALVES TO THE FACTORY FOR MATCHING
2. Place the edge of a screw driver blade under the lock ring at one of the To insure perfect matching of crank cases the factory method is to bolt crank
slots in the piston pin. Rest screw driver on flat area of the expander case halves together and machine them in pairs. This procedure provides a
and pry one side of ring out of groove. perfectly square area for the cylinders to rest upon.
3. Turn expander so that opposite side of ring can be pried out. Finally, Crank case halves poorly matched may result in broken cylinder bases, oil
work ring off of pis ton pin. Scrap ring removed, as it cannot be reused leakage, or possibly both. To avoid difficulty of this kind, we advise
safely. you to send your crank cases to the factory for accurate matching.
No. 82. July 27, 1931
WEttjHT OF RIDER No. 83 August 3, 1931
~t::_,:3::':0'_":.::_I'INC!!D'_U~»:__
11..::__ _~~
ll./80 7?J t:30" I tj::.·---~...! BRONZE BUSHINGS NOT FITTED IN ALL 45 CU. IN TWIN
15071)18o'' 11:'---.,
CONNECTING RODS
~F I
All 45 cu. in. twin connecting rods now have bronze bushings in the upper

~0~~1
ends. This applies to rods as assembled in new motors and also to those
supplied on parts orders.
As the weights of the bushed and the unbushed rods are· approximately the
same, they are interchangeable and motor performance will not be affected
tSPRING NO, 3128·31:__; in any way if a bushed and an unbushed rod are used together. The bushed
rods can be used in any model 45 cu. in. twin. ·

Correct Seat Post Adjustment 1932 45 CU. IN THIN CRANK PINS

The above drawing shows the standard seat post as used on 74 and 45 The 1932 45 twin has a crank pin similar to the type used on the Big Twin.
cu. in. twins, and 30.50 cu. in. singles. The 21 cu. in. single This design provides a hole drilled on an angle in the pin, which leads
seat post is the same as the above except spring No. 3133-30 is used the oil from the drilled oil hole in the flywheel to the center of the
connecting rod roller bearings, thus insuring an adequate supply of oil
instead of spring No. 186-10 in the upper group, and 186-10 iS used at this point. This new crank pin is now being supplied on all parts
in place of 3129-31 in the lower group. orders, and can be used satisfactorily in all 45 twin motors regardless
of model. However, it is not advisable to use the old style (not drilled)
To set the standard seat post for riders of different weights, ad- crank pin in the 1932 flywheels as this combination may not allow sufficient
just the lower springs to the required length, depending on weight oil to get thru to the lower end roller bearings.
of rider. (See drawing.)
ALL 1932 45 CU. IN. THINS HAVE HEAVIER CUSHION RINGS
If the standard seat post is too stiff even at its lowest adjustment,
fit the regular 21 cu. ir•. single spring combination as this assembly The 1932 45 twin is equipped with a heavy type inner cushion rino which is
is designed primarily for lighter riders. co~si~erable more.reliable than the lighter style formerly supplied. When
us1ng these new r1ngs to service an early 45 twin motor, bear in mind that
Horn Service the 1932 style guide rings must be used with them as the old ouide rinos
are too thick; the new guide rings are made thinner to compensate for the
The manufacturer O·f Remy and Klaxon horns has asked us to increased thickness of the new style inner cushion rings.
request dealers to take all service questions concerning
this equipment up with their local or nearby United Motors In addition to the cushion and guide rings just described, the 1932 45 twin
Service Station rather than to send these horns to the horn is also equipped with a new inner cushion ring (expander ring) fitted under
factory or to us directly. They maintain no service organ- the ~ottom com~ression ring. This upper cushion ring cannot be applied to
ization themselves and have promised good service on either earl1er type p1stons as the ring groove is not deep enough to allow sufficient
adjustment or repair work through authorized United Motors room for it. However, this cushion ring can be fitted to all 45 twin pistons
now being shipped on parts orders.
Service Stations.
NUMBER NEEDED PART NO. NAME LIST PRICE.
If you haven't a United Motor Service directory or if yours -------
is not up to date we will be glad to mail you the latest re- 4 262-32 Guide Ring 15¢ each
vised list. Address your request to the Service Department.
2 263-32 Cushion Ring, Lower 15¢ each
HARLEY-DAVIDSON MOTOR CO. 2 263-32A Cushion Ring, Upper 15¢ each
Milwaukee, Wis., U. S. A.
No. 84 August 10, 1931
No. 85 September 21, 1931
LUBRICATE SPARK AND THROTTLE CONTROLS REGULARLY
HOW TO FIT THE LATEST INNER CHAIN GUARD SLIDING PLATE
Spark and throttle controls should be oiled and greased at regular intervals.
To lubricate grips remove them and apply grease, or a graphite and grease On all 1930 and 1931 "74" cubic inch Twins, the inner chain ouard sliding
misture on handlebar ends, particularly around the spiral grooves cut in bars. plate, part No. 3812-30, is attached to the transmission by means of two-
Uncovered control coils (on models prior to 1932) can easily be lubricated aluminum lugs cast integral with the transmission box. On 1932 model "74"
by using a very thin, good oil applied directly to the control coil. The cubic inch twins, this construction has been altered so that the chain
oil will quickly work through to the wire. THIS LUBRICATION IS PARTICULARLY guard sliding plate is now held to the transmission by means of the same
NECESSARY ON THE OIL PUMP CONTROL COIL, AS THIS COIL IS LOCATED SO CLOSE TO cast aluminum lug at the rear of the transmission, andby a new stamped
REAR CYLINDER AND EXHAUST PIPE THAT IT DRIES OUT MORE QUICKLY THAN THE OTHER metal bracket attaching to the top of the transmission in the front. The
CONTROLS. When this control coil becomes dry, the throttle is extremely hard object of this change is to prevent possible chain jamming and gear box
to operate, but becomes loose as soon as oil works through to control wire. breakage in the event the rear chain happens to break.
The spark and throttle control coils on 1932 models are covered (excepting Gear boxes on 1930 and 1931 models can be converted to the later construction
oil pump control coil) and require lubrication only at points where wires quite easily by sawing off the lug at the front end of the gear box flush
come out of coils. with the box itself. Next, the two studs located directly above the point
where the lug has been sawed off, must be removed and replaced with the two
CORRECTING CARBURETOR LEAKAGE studs, part number 2134-31. Place the new sliding plate bracket over the
special studs just installed, first placing spacer 3813-32 over each of
To correct a leaky carburetor, check float level to make sure that float is no the studs for the new bracket to rest upon. Tighten up the stud nuts, attach
higher than 3/8" (twins), 1/4" (singles), from upper edge of bowl. Re-set if the inner chain guard sliding plate to the rear transmission lug and the job
necessary. is complete.
In connection with 1930 and 1931 carburetors (45" and 74") of the die-cast type, This change is particularly recommended for motorcycles in commercial service,
the float valve arrangement should also be given attention. See that the on which chains are run until worn to the breaking point and usually with
latest, guided, float-valve (three sided valve) is installed. This newest valve very little attention.
comes nearer to being leak proof than any arrangement used previously. It can
be applied to any 45" or 74" model die-cast bowl. The guided float valve The parts necessary to make this conversion are 1i sted as follows:
(round valve) went into production with 1931 models, and the new three sided
float .valve which uses the same guide, went into production about the middle NAME PART NO. LIST PRICE EACH NUMBER NEEDED
of the 1931 season. On die-cast carburetors supplied prior to the 1931 season
it is necessary to fit a new float lever and float valve seat before the new Studs 2134-31 .05 2
three sided float valve can be fitted.
Spacer 3813-32 .10
A gasoline strainer, which will keep dirt, etc., out of carburetor, should also
be added to effectively stop gasoline leakage. The strainer can be fitted to Sliding
old as well as late models, although it is necessary to bend the gasoline line Plate 3812-32 .75
when fitting it to older machines. A gasoline line adaptor is attached to
strainer as it leaves the factory. When replacing a strainer on a 1932 - 45"
or 74" model, this adaptor has to be removed, but on all other models it must
be used.
NAME PART NO. LIST PRICE
Three sided Float Valve 1273-31 $ . 35
Float Lever 1272-31 .25
Float Valve Seat 1284-31 .60
Gasoline Strainer 3623-32 1.50
 No. 88 uctober 19, 1931
No. 87 October 12, 1931
SERVICING INTERCHANGEABLE WHEELS
ADJUSTMENT OF REVERSE TRANSMISSION
After considerable service, and, of course, depending to a great extent on the
In the event it becomes necessary to replace any parts which disturb the kind of service in which a machine is used, interchangeable wheels may become
setting in a reverse transmission, particular attention should be given worn to some extent, causing end play in the wheel hubs, and looseness in the
to the-proper re-adjustment of the eccentric studs in the ends of ~he drive splines.
sliding-gear-fork shifter arms. These studs must be set so the sl1d1ng
gears engage properly, and have sufficient clearance from adjoining gears In case of excessive end play in a wheel hub, correction cah be made by using
when shifted to various positions. a thicker th~ust plate spacer than the one originally fitted in the hub. These
spacers are regularly supplied in sizes from .345" to .380" in steps of .005",
The proper way to adjust, and to determine when adjustment is ~ig~t, is and we can supply a .390" spacer for unusual cases.
to temporarily fit the gear box cover to the box and, after sh1ft1ng to
a certain position, carefully lift the cover straigh~ upward and n?te the Drive spline looseness can be taken care of by fitting an oversize brake shell
location of the sliding gears. As a matter of check1ng, repeat th1s test hub, which we can supply in sizes of .001", .002", or .003" oversize. A .om"
in each shift position and then turn the eccentric studs until the best oversize hub will take care of splines which have an average amount of wear; a
possible general adjustment is obtained. .002" oversize will fix up a badly worn assembly; and a .003" oversize should not
be necessary except in an extreme case where there is excessive wear.
V!hen a satisfactory adjustment has been reached, the main drive gear and
its sliding gear will interlock completely in "High" position, and all AN OVERSIZE HUB SHOULD NOT BE FITTED UNTIL WHeELS HAVE BeEN INTtRCHANGED A
aears will-have ample clearance whP.n in "Neutral" positions. With the SUFFICIENT NUMBER OF TIMES SO THAT All WHEEL HUBS ARE WORN ABOUT EQUALLY. Other-
studs turned to a point where the gears are in a position as just described, wise fitting an oversize hub to correct a badly worn rear wheel will upset the
lock the adjusting studs with the special washers provided. interchangeable wheel system because the front, sidecar, or spare wheel will
not fit on the oversize hub.
In addition to properly adjusting the eccentric studs, it may also be
necessary to do a slight amount of fitting when new sliding gear shifter OVERSIZE REAR WHtEL ~POKE SHELL HUB THRUST PLATE SPACER
forks are installed. However, this will not be required except in
isolated cases where a certain amount of grinding will be needed to com- Part No. list Price each Part No. List price each
pensate for unavoidable irregularities of the forks in order to provide
all-around clearance. Whether or not grinding is necessary can only be 0.30S $4.50 3927-30 $ .25
determined by fitting the parts and trying them. U.32S $4.50
Specify oversize wanted Specify size wanted to order
It should be remembered that reverse transmissions have more moving parts a quantity assorted
in their shifting mechanism than a standard gear box, and it is, therefore,
extremely important to keep the gear shifting levers well lubricated in
order to insure easy gear shifting. It is also important to keep the
transmission FILLED with oil if easy shifting is to be maintained.
HARLEY-DAVIDSON MOTOR CO.
Milwaukee, Wis., U.S.A.
 November 23, 1931 No. 92 December 14, 1931
No. 90
EXTRA HEAVY SEAT POST SPRING COMBINATION MECHANICS' SCHOOL DOPE
NOW AVAILABLE "All right boys -- park your Sunday clothes, ditch your
smokes, jump into your overall, and we'll proceed during
the next three weeks to discuss, .explain, demonstrate, and
For some time back, we have been receiving occasional requests for a put into practice everything that goes with the servicing
heavier seat post spring comb·ination suitable for very heavy riders. of Harley-Davidson motorcycles." -- That will be the word
Vie are now prepared to supply a stiffer spring assembly which is only passed around Monday morning, January 11th, 1932, when the mechanics'
a slight variation from the standard layout. school opens. The instructors will be servicemen who have been through
the mill of experience and who know the best and quickest ways to do
In order to change the standard seat post on 1931 or later models to things. There will be plenty of action and no time to even think about
the extra heavy arrangement, substitute the new heavy spring for the "depression". Three weeks chock-full of things every mechanic should
middle spring in the lower group of springs on the seat post rod. know.
In addition to changing the spring, it is also necessary to exchange
the two original spring guide collars for the two new collars supplied In view of the number of returns from our recent mechanics' school
with the heavy spring. inquiry, only one class with a limit of twenty-four men will be instructed
this winter. If you are interested, fill out and return the attached
To fit the extra heavy spring to a late 1929 or any 1930 model, the application blank at once. Applications received from those who pre-
entire assembly of lower springs must be exchanged for the complete viously returned inquiry forms, will, of course, be given first consider-
set listed below. This is necessary because the lower group of springs ation. Other applications will be considered on the basis of first come-
on late 1929 and 1930 models are entirely different from those now first served.
supplied.
DON'T FORGET -- THE SCHOOL DATES ARE JANUARY 11TH, 1932 TO
In the event you wish new machines equipped with the heavy seat post JANUARY 30TH, 1932. ONE CLASS -- LIMIT 24 MEN.
spring combination when assembled at the factory, specify on your
order-- "Supply extra heavy seat post spring combination." We
strongly advise you against using the heavy combination on machines
o"idden by riders weighing under 2DO pounds. The standard seat post APPLICATION FOR MECHANICS' SCHOOL
satisfactorily takes care of riders weighing up to about 200 pounds. January 11 , 1932 to January 30, 1932 )
Desk H~5 Date.______________________
COMPLETE SET OF LOHER SPRINGS - HEAVY - 3128-29A - $1.00 1ist Harley-Davidson Motor Co.
(Apply to all models from late 1929 upward) Milwaukee, Wisconsin

CUSHION SPRING ONLY ~liTH COLLARS - HEAVY - 3129-31A -- $ .65 List Reserve a place for (ME.~------ (MY MECHANIC _ _ _ _ __
(For converting 1931 and later model standard combinations}
Do you intend to come in a few days earlier to attend the Sales Conference
on January 8th?·( )
If sending employee (Name)
(How 1-o-ng__e_m_p~lo_y_e_d~)---------------------
(Is he continuing in your employ) _________________
Dealer's signature ______________________________
Address
Shall we arrange for room and board? (About $9.00 per week) _ _ _ _ _ __
 No. 96 THE NEW RIDE CONTROL October 5, 1932
Auous t 22, 1932 ( FORK SNUBBER)
No. 95
The new Ride Control recently announced is with-
out any question the outstanding accessory de-
velopment of the year, because it contributes
IMPORTANT --- NOTICE --- IMPORTANT to better motorcycle control and safer riding
at high speeds. With it attached, a rider has
complete control over fork action. It can
THIS I~ TO ADVISE THAT FOR SOME TIME TO COME WE WILL NOT quickly be adjusted at any speed to meet road
conditions and eliminate any tendency toward
RE-ENAMEL TANKS OF EARLIER MODELS WITH THE 1933 EAGLE HEAD front end bouncing and hopping.
SCROLL PANELS
While it is particularly effective in connection
with a solo motorcycle, especially a fast driven
WE ALSO ADVISE THAT WE WILL NOT SUPPLY VLD MODEL CYLINDERS one, ·it adds to the good ridin~ qualities and
AND OTHER PARTS FOR CONVERTING OTHER MODELS TO VLD MOTORS. contro"l of any motorcycle in any sort of service.
Push this attachment with your riders, expecially
your fast solo riders. It is something they will
WHEN THERE IS A CHANGE OF POLICY IN THIS RESPECT, YOU WILL need and appreciate.
BE NOTIFIED. Ride Control fits 1931 and later Twin models. It
can also be applied to any 1930 Twin model that
has been chanqed over to 1931 headlamp arranoement.
Part #11250-30 Price - $4.75 List Code Word -Biwxa
ATTACHING INSTRUCTIONS
After noting just how snubber is put together, diassemble cross member
from side members. Remove spring fork rod lock nuts- also tool box and lamp
bracket bolt"nuts. Fit snubber cross member to spring fork rods and secure with
lock nuts.
Remove tool box and lamp bracket bolts, one at a time, and fit snubber side members.
Note that side members are right and left. Discard plain washer found between lamp
and tool box brackets. Lower end of side member fits over both lower tool box brackets
but, underneath lamp bracket, as per sketch.
When tightening bolts that secure lamp bracket- tool box bracket, and snubber side
members, see that side members are adjusted so they bear liohtly against cross member
.friction washers.
Loosen nut at joint in side member and adjust upper end so that slot lines up exactly
with hole in cross member. Snubber control nut can be assembled on right or left
side as desired. It is usually assembled on left side. ·
SPECIAL February 23, 1932 No. 92 March 28, 1932
EXCHANGE EARLY SERVI-CAR CROSS SHAFTS FOR
LATtA TYPE WITH LOCK PIN
1925 to 1929 61 cu. in., and 74 cu. in. Motors
Any Servi-Car shipped from the factory prior t~ February 8~ 1932, is equipped
PISTON CLEARANCE: with a tow-bar cross shaft which has no lock-p1n (cotter-p1n). These early
Jr?,n Al!,oy Pistons 1925 to 1929 shafts are too short to allow fittinq a lock-pin, and in order to fit one
61 cu. in - .002" -----.00275" the cross shaft must be replaced with one of the later type.
74 .003" -----.004"
Aluminum & Dow Metal 61 .0115" ----.0135" To remove old shaft, support tow bar on a solid surface and knock shaft out
Pistons with a raw hide mallet. Install new shaft so cotter pin hole is at right
Aluminum & Dow Metal 74 anales to tow-bar.
.0135" ----.0155"
Pistons
(Meas~re all pistons just below the top group of rings and cylinders about A lock pin is important because under certain unusual conditions, such as an
l/2" from top of bore) extremely sharp dip in a driveway, or an exceptional]~ steep ga~aqe ramp,
the old type tow-bar may become unlocked. Even more 1mpo~tant 1s the fact
PISTO~ PIN IN IRON ALLOY PISTON .0005" to .001" press fit in lock pin that with a lock-pin the tow-bar shaft must be correctly 1nserted so the
side -- pluo or slip fit in opposite side. retainina lip on the tow-bar is inside the anchor~ng projection on tow-bar
connection, before the lock-pin can be fitted. ~J1th the old ar~an~ement~ .
PISTON PIN IN ALUMINUM & DOW METAL PISTONS -- Snug press fit -- not over it was possible to insert the tow-bar incorrectly and not lock 1t 1n pos1t1on.
.0005" tiaht.
The parts necessary to make the chanqeover are as follows:
PISTON PIN IN UPPER CONNECTING ROD END (all models) -- .001" loose NAME PART NO.
LOHER CONNECTING ROD BEARING:
Motors fitted with Iron Alloy pistons ------------ .0002" to .0003" loose Tow-bar Shaft 7009-32
" " "Aluminum or Dow Metal Pistons --- .0004" to .0006" loose Lock-pin and Chain UC-824
CONNECTING RODS (All models) .006" to .010" clearance between flywheels - We will allow full credit for original shafts returned and received at the
roller and retainer ossembly should be narrower, but not more than .010"
narrower than front rod. factory prior to June 1, 1932. After that date this offer is void.

PINION GEAR SHAFT Remember to give your Servi-Car owners qood service. Arrange for regular
Motors fitted with Iron Alloy Pistons. .0035" loose at inner end of inspections so you can keep all adjustments in order. Always keep in mind
bushina -· ,002" loose at outer end of bushina your Servi-Car customers are service specialists and they judae your service
Motors fitted with Aluminum or Dow Metal.Pistons -- .004" loose at by their standards.
inner end of bushfna -· .0025" loose at outer end of bushing.
(Bushina is taper reamed with special reamer.)
SPROCKET SHAFT (a 11 models) -- . 0005 • to . 001" loose in ro 11 er bearing.
FLYWHEEL ASSEMBLY (all models}-- .003" end play in crankcase
OILER GEAR, INTERMEDIATE GEAR, & GENERATOR DRIVE GEAR (all models) -- .001"
to .0015" loose on studs
 No. 98 - 2 - October 24, 1932

(Do not confuse axle end play with differential side play as
described under No. 4.) Occasionally it may be necessary to
No. 98 fit thicker lock rings on one axle than on the other to obtain
October 24, 1932
proper adjustment.
Servi-Car Rear Axle Assembly
7. Spacer for small differential gears.

8. Shaft for small differential gears.

9. Felt washer and retainer (both sides).

10. Axle housing.

11. Axle nut.
12. Axle nut lock washer.
13. Axle spacer.
14. Wheel key.
15. Outer end bearing spring ring.

1. Differential unit 16. Left end bearing cup, (left thread). The right end bearing cup
is right thread.
2. Right side differential bearing (not adjustable).
17. outer end bearing cup lock washer. After bearing cup is securely
3. Left side differential bearing (adjustable). tightened, upset lock washer in notches in axle tube and beari~g
cup.
4. Bearing housing (right thread) for left side differential bear-
ing, by means of which side play of differential unit 1 is ad- 18. Outer end axle roller bearing.
lusted. To determine amo~nt of side play insert screw driver,
or other suitable t~ol, through chain opening in axle housing 19. Roller bearing thrust bushing - slip fit in bearing cup.
10 and shift differential unit from side to side by applying
pressure to sprocket. There should be .007" to .010" side play. 20. End bearing felt washer.
To adjust side play loosen lock screw 5 sufficiently to disengage
from slot in bearing housing 4. Insert screw driver, or other 21. End bearing plain washer.
suitable tool in small opening provided in axle housing 10 (op-
posite lock screw 5) and turn bearing housing 4 to left for less IMPORTANT
-- to right for more side play.
Servi-Car rear chain should be checked up frequently for adjust-
50 Bearing housing lock screw. ment, lubrication and wear. A chain that finally breaks in serv-
ice due to lack of attention may jam between rear sprocket .and
6. Axle lock rings (half rings - four used) secure axles in large diffe 1· - axle housing with the result that housing is broken or damaged,
entlal gears, and adjust axle end play in differential unit. End beyond further use.
~lay can be determined by holding differential unit and chec~ing
.rom end of axle. End play can be readjusted bv disassembling Keep chain well adjusted and lubricated, and also inspect oc-
differential unit and fitting thicker lock ring~ whic!l. can be o':l- casi nally for damaged links and badly worn condition. Do not
tained (.l25"Std)-.l30"-.l35" thick. Axles must not be :;:.nc:1 e::: try o get the last possible mile out of chain, or in other words
against spacer 7 and they sho~ld not have more ~han .005 1
' ~nj pl~~-
r'.lr. t to the cri~ical point before installing a new chain. It
(over)
 - 3 -

is an easy enough matter to give this attention to Servi-Cars

that come to your shop regularly for check-up. Owners who do not
send their Servi-Cars to your shop regularly should be advised or
warned of what may result from neglect of chain.
PART NUMBERS ACCORDING TO ILLUSTRATION NUMBERS.
(Note: Order parts by part numbers only.)

Illu~. No. Part No.

2 & 3 7157-32
4 7148-32
5 7150-32
6 7129-32
7 7116-32
8 7114-32
9 7160-32
10 7135-32 left, 7140-32 right
ll 2050-12
12 7270-32
13 7266-32
14 7263-32
15 7180-32
16 7165-32 left, 7166-32 right
17 7169-32
18 417-30 retainer; 2289-25 roller
19 7173-32
20 7176-32
21 7178-32

1933 Scroll Tank Design Obtainable.

Effective November lst the factory order (Shop Dope #95)against re-
enameling early model repaired tanks 1933 style is rescinded. After
that date the eegle head scroll, if specified, and any 1933 color
combination desired will be applied to any tanks returned for repair
and re-enameling.

The order prohibiting shtpment of VLD motor parts for converting

standard motors is still in effect.
HARLEY-DAVIDSON MOTOR CO.
Milwaukee, Wis.
U.S.A.
 Decemoer 12, l93Z
?:EE?I:IJG OIL OUT OF BIG T't:IN C LUTCE

No. 97 November 7, 1932 (\<~~R\_

{ ·:---....,..
\.
.-- "- -·. •·
___
..
.,......
I f.--r.
1929 - "45" AND SINGLE MODEL TRANSMISSION REAR CHAIN SPROCKET
\ I - - rc----'- ~
1929 type, 16 tooth rear chain sprocket, part #2035-29 is no longer supplied.
Covered by the same part number, the later type rear chain sprocket as applied to
1930 and later "45" and Single models, it is now furnished with all necessary Sketch Showing New Clutch
fittinos to-adapt it. In other words, when you order sprocket #2035-29, you will ?ull :1od o::.·l 'Hasher and
receive-the latest sprocket along with bearinq race #2290-26 and felt washer Retaining Cap
#2294-28. Price $2.00 list.
Asse~bled :.n lJ~O ~~d
In applying the later sprocket and fittings, it is necessary to remove trans-
mission side cover. Cover has to be taken off because oriqinal bearino race
1.· I~-.:J.:-7'7 -~ late~ r~n ~ode! Clutch

~-~~.-~;~:~:
behind sprocket must be pressed or driven out and new race- put in. It. will be
found much easier to remove old bearino race and install new one if aluminum
cover is heated and expanded before ~oing through the operation. To avoid 1'
damaging ~over, rest it squarely on the bottom of an old piston, or on the end
of a piece of pipe of larger diameter than bearing race, while driving race out
.- ~~::~~-11
/?~
and in. Be sure to start new bearing race straight in relation to hole in '''hen the discs in a Big Twin model clutch accunmlate oil to the extent
cover, and drive it all the way in so that its flange is tight against cover that clutch finally doesn't release •;;ell and gea~s clash when sh:..ft:'.ng,
all the way around. ?a~t:..cularly :'.n gett::.ng i.nto lov! sear when sta~t:'.ng out ::.n tte :::orr.::.n~;,
:.t is usually taker! for granted tl:at the o::.l cu.:r.e f~or. tr.e r,•ont ceca:'.:-:
After new bearino race has been installed, smooth and polish the outer face of ar:d cr..aih guard. :.:ore l:..kely tl:e oil cor.-Les f:>o~:! tt.e sta:-te:- s2.de of
ccver around race, where sprocket felt washer will take bearing. Unless cover
t:-c.ns::1issio.;: th:>ough !:;1-!e ~~a.:..nsi:aft. ~i:'or:: tl:.e clutct.. e!"""!d of r.:a.:..:J.s~~a.:""'t
is perfectly smooth at this point, the felt washer is naturally likely to be
~"!: foll?~·.-s a~onc tL: ~ctua~:.~e p_late :!.cgs to t1:.e :.:'~side of cl'...l.tct. _-:__s
damaged and worn out rapidly. ::: 9..':_., ':"~S t::e o:.l on CL~:..n S.~C. .:.n c~:.G.:_n gua:-d :_g CO!":C8:'ne8. tests f_s.ve
;:'oven z~at ve:-y l:..ttle of th.:..s o.:..! gets :..nto clutch ev~n ~~ough c~:.a~~
When r2fittinq cover to qear box, be careful that holes in flange of three-step ::!&..~· Ce o:.l.:.ng ·1u:.. te f:>eely. :n odd cases so~e oil -::;.n.y e;et .:..n t:--.e
qear bronze bushing reqister with pins in cover. cj.utch d::.rectly from transmi.ssion through main gea~ and clutch bea:·in,;:s
This later sprocket with parts to adapt it is being furnished because it is but as mentioned before we have found that in most cases the oil come;
stronger, much more dependable and more satisfactory in every respect than the th:·ough the mainshaft along the pull rod.
discontinued earlier type sprocket.
:'he above sketch shows the new cork oil washer and retaining cao now
asserr.bled in latest transmission to prevent oil from com::.ng through tte
~a::.nshaft. This oil retaining arrangement canoe read::.ly installed in
any Big Twin transmission from 1930 up.
";t.en you find a 19:::0 o::o later B::.g Twin model clutch that d~ac-s after
:::ac:1.:.ne has been left stand::.ng, C.nd:!.cati.r:g that probably d:'.s~s are oily,
~="' :'"o'-l ·:::.11 take cl,.J.tch apa:-t, thoroughly ·.vast: a:1.d clean d:..scs to :--e-
:~~~e ~:~:~·~~u;~;~da~~l fu~~~e~e~~~~~;.~~ ~~:1-~.~~~:;~g e~~:~~:~c·~~~:ie~, ~ ~ :_
3

,10 ::..:.s:
.oc
 No. 107 THE 1934 OIL PUMP December ll, 1933
No. 106 December 11, 1933 (All Twin Models)
SERVICING EARLY LINKERT CARBURETORS
1. Control lever.
Linkert carburetors supplied on 1933 and first 1934 VLD and RLD motors have 2. Adjusting sorew for low and moderate
qiven some trouble with a lean or flat spot just off closed throttle, with speeds.
carburetor needles adjusted just right for idling (closed throttle running) 3, Adjusting plate for high speed.
and also top speed. This flat spot ties up with complaint of uneven motor 4. Adjusting screw for front chain oiling.
running and popping back through carburetor when running with only slightly 5. Pump fastening nuts (secure pump to
open throttle, also when accelerating from low speed. gear case cover).

This flat spot has been corrected in later Linkert carburetors by enlarging, ADJUSTMENTS
with a No. 55 drill, the larger idling hole in side of carburetor at throttle 1. The adjustment or control lever No. 1 is
disc. Late carburetors corrected in this manner are identified with a center o~ ~irst import~ce because it determines
punch mark fo 11 owing the model number stamped in top of carburetor. It is a the stroke or pump plunger and thereby regulates the output or pump in due relation
simple matter for anyone to correct an earlier carburetor in this manner. to carburetor throttle lever and working load or engine. Witho~t this control ac.
Simply remove idle pocket screw from back side of carburetor and carefully curately adjusted, pump will not respond as it should to otfter adjustment~ de·
run a No. 55 drill through the larger idling hole. scribed below:
CORRECT ADJUSTMENT • Set control wire between carburetor and oil pump so that when
Thorouoh tests have proven that this change make carburetion O.K. in connection throttle is opened until ·carburetor lever strikes its full open stop, oil pump lev.
with any motor reasonably well tuned up otherwise. We refer particularly to er lacks just a trirle, not more than 1/64 11 , or striking its full open stop. Dis-
circuit breaker point gap, ignition timing and condition of spark plugs. If regard closed position or pump lever because this is determined ~ movement or car-
ignition is a little late, which is very often found to be the case after a buretor lever. NOTE • As a safety, pump control lever is provided with a spring
new motor has run considerable mileage, or if plugs are partially fouled or that throws it wide open in case of control wire breakage.
in bad order otherwise, naturally carburetion is likely to be poor even
thouoh the carburetor itself is O.K. in every respect. Always check all these 2. Screw No. 2 with washers under its head is the adjusting screw for low and moderate
things when correcting an early carburetor as explained aobve, or in any case speeds. (Four to eight .002 11 washers as required • and four .012 11 w&.shers on early
when adjustin9 difficulty is experienced, because the carburetor can't be pumps, or one 1/16 11 washer on later pumps, is the factory setting). Add washers
expected to have broad enough range of adjustment to overcome other faults for more oil - take off washers for less oil. When re-adjusting, add or take off
about the motor. only one or two thin washers at a time, and do not rem'>Ve the rour .012 11 washers or
the l/16 11 Washer, as doing SO will sfiut orr this adJUstment too rar for safety.
Here's another thing about the Linkert carburetor. It will take a somewhat NOTE " Applying to pump on 74 ou. in. engine, the grcup of washers under head of
leaner adjustment of high speed needle than other carburetors we have used, screw 2 includes in ·addition to the usual number cr washers, a ,015 11 brass washer.
without developing a complete dead spot at throttle opening where fuel supply This washer should be removed if engine is put in steady sidecar service. Also
switches over from low to high speed jet. Therefore, be careful you don't this brass washer will be found on pump only ordered for replacement. It should be
adjust high speed needle just barely rich enough to avoid a decided dead spot, removed if pump is installed on any 45 cu. in. engine or a 74 cu. in. engine in
but still so lean that mixture is very weak. A moderately rich adjustment of sidecar service.
high speed needle is required for best all around results. 3. Adjusting plate No. 3 regulates oil supply for high speed. It shifts a cam inside
control housing and thus affects the stroke of pump plunger. TO RE-APJUST - Loosen
clamp nut ai)d shift adjusting plate as per marking on pl'ate. Don't re-adjust more
than 1/16" at a setting. The original factory setting is indicated by a. mark cut
in pump body. NOTE - Inasmuch as the same pump with different setting applies to
both 45 and 74 cu. in. models, a new pump only ordered for replacement will be
found with proper setting marked for both models. Set the adjusting plate a~cord·
ingly when pump is installed.
4. Screw No. 4 with washers under its head is the adjusting screw for front chain oil·
ing. Add thin washers for more oil • take orf thin washers for less oil. This ad-
ju&tment has nothing to do with oil supplied to motor. NOTE • This chain oiling
adjustment does not give complete control of oil supplied to chain, because some
motors exhaust considerable oil spray directly rrom crank case through breather
 -··stem. Tl1is varie.s with service condi tians, driving speed, S'lpply of oil to
orank case, etc. Because of some irregularity in this respect, the chain oiling
adjuscing screw will need to be re-adjusted to meet individual requirements.
TRACING OUTPUT IRREGULARITIES
In a case of unquestionable over-supply that isn't corrected to a marked extent by
setting adjustments back for less oil, check as follows:
.~.. ~:Iaybe control Ho. 1 i~ nc""C accurately adjusted. Check this first.
2. Fcssibly there is a leak through l:and pump due to dirt ti:at prever.ts cneck ball
:;."'~c;n s~a"ti::1g perfect::y, or maybe ball check spring is so weak that crar..k case suc-
-:ior.. Fulls ball away from.its seat. Remove hand pump.body and examine and clean
:_ t thoroushly. ?;!ake sure th<it spring tension is strong enough so ball is held
fi~ly against its seat, and that ball seats perfectly without even tne slightest
indication of leakage. Where continued over-supply may leave some doubt about
nand pump being free from leakage, even after pump has been examined and given the
ac;tention described, a good way to double check is by rtuming; a fmv days with oil
pipe discor~ected at hand· pump and end of pipe plugged.
3. If an engine is in bad condition or poorly tuned up and adjusted, with reg;ard to
;:cor-ly seating valves, weak compression, circuit breaker !JOint gap, igni-cion tim-
:i:J.g, carburetor adjustment, etc., the oil pu.'11p, even though in perfect order, 1Yil:!.
feed more than the normal amount of oil. This is because a weak engine requires
opening the throttle further than normal to hold any desired speed, and oil pump
is regulated by throttle.
Take pump apart and examine it for some fault, or return it to the factory for
test and needed repair.

Where there is apparent under-supply that is not corrected by setting up adjustments

for ~ore oil, check as follows:
1, :,laybe control 'lo. 1 is not accurately adjusted and as a result it shuts off too
~~r. ~heck this first.

2. See that ta!l..k ca~ vent is open.

3. Diecor~ect pipe from pump and see that oil runs freely from pipe.
4. See if pump nipple is possibly clogged with chips, waste, or some foreign matter
that has gotten into oil t~~.
5. Take pump apart for inspection, or return it to the faoto~J for actention.
REMARKS
To remove p1.mtp it is not necessary to disturb gear case cover. After disconnecting
oil pipe and control, and taking off the two pump fastening nuts No. 5, pump can be
pulled off its mounting studs~

':Then there is occasion to take pump apart :r."'or examination, be careful that rotarJ
7al7e ~~d front end of ?ump body Rga~nst which valve seats, are ~ot scratched or i~~­
e.g;ed i::"!. some :r:.ar..:~er. Tbi3 7al ve must seat perfectly for proper ;:t:..":'lp reguls.tior:. ..-.~...
::..::: :-:.ct ad'r.'isabi.e ~o use shell~1c on gasket ·.vhen re-i:1ste.lling end cover tha-t houses
'7.S.l7e! because oi' the chance of some shella.c workir:g under the YO.l7e e.r:d causing a
:eak .at least tenpora.rily. Bet't:er use 9. !:9W gasket every t.i:.:.e "tiut ::o 3!:el2.ac. ::.. .
:~c·..:. :"':.:!l.C. !?.!: ear~y :::.234 ';~~"? -::nat les2:s at the e!"_.:i ~over joi::-t, e~e!'l -:::::.::·.:;:--. ~n.3keo::: :.s
·.~;-::o.:-~:-:.t:y .:.n good. order a:-:.C. screws ~ave b.~e~ ~e-tig!:te!'"!.eC., :.::s~al: ~( ::e:>t ~r:~ ~o'ie::"
'- :~~-.34) :i!::i '::ew gasket :3~0-34}. ·:.-:~e :9.<:er co7~!" :.s :::a.:ie :..es."':':e:::- -:::o ·:e-:-:e!" ::-~­
::-....L.'o=--~t; "'::::-_e ,::ci~t s~r::"'~c
 SPECIAL April 27, 1934
No. 107 January 5, 1934 CARBURETION TIPS
CYLINDER HEAD INFORMATION
(Bia Twin Models Only) To overcome apparent faulty carburetion that shows up in engine sluffing and popping
back throuah carburetor at lower speeds, or missing and muffler explosions when eng1ne
We have three different cylinder heads for the Big Twin model and the followinq is accelerating to high speed, especially in low and second gear, the following pro-
is to straiahten out considerable confusion as to their application to various cedure is recommended:
1934 and earlier models. l. See that soark control fully advances, also that circuit breaker points open to
correct qap (.022") and then check time of iqnition accordina to flywheel mark.
The different heads are stamped on their around joint surface 9.3 - 10.5 - Do this iob very accurately and re-set, if necessary, as proper ianition advance
and 12.5. This markina indicates cubic inch combustion space with the (3/8" before top center-solo) is the first essential for good carburetion and
respective heads. qood all around enaine performance. The later Rider's Hand .Book 0ives a very good
description of best procedure in checking timina.
The 9.3 head, which is called our hioh compression head, always has and still 2. Try a new set.of spark plugs. Even thou 0h original plugs appear O.K., maybe they
applies to all VL and VLD motors. are partially gouled, or there is a leaky procelain. It frequently proves out that
The 10.5 head became the standard compression head at the beainnina of the 1934 apparently o.k. plugs are faulty to the extent of causina irreqular performance.
seascn and it reaalarly applies to all except the VLD model, and also the VFDS ATTENTION TO LINKERT CARBURETOR.
model since January l, 1934.
3. Take carburetor apart and clean out.
The 12.5 head applied to all except VL and VLD models up to and including 1933. 4. Set float lever 5/16", takin~ this measurement directly opposite float needle,
This head, over the period-mentioned, was called our standard head, but now it holdina bowl up-side-down.
is known as our low compression head. It is now used as reqular equipment only
on the VFDS motor (since January 1, 1934) but will be furnished as optional 5. Measure over all lenqth of main nozzle. If you find this lenath approximately 2-
equipment on the VDS model if specified on order. (The models to which this l/8" (early Linkert nozzle was this length) shorten it to 2-l/16" by turninq l/16"
head originally applied included the VC commercial model which had iron alloy off bottom end. This should be done in a lathe and the oriainal 45 degree chamfer
pistons and small carburetor and manifold, however, this model had extra low maintained so-that nozzle retaininq sprina will locate centrally.
compression due to beinq fitted with piston (part #256-30A) l/6" shorter than 6. See Shop Doep #106 about re-sizinq laraer idlinq hole with #55 drill. (This applies
o~r standard iron alloy piston. The VC model was discontinued at the end of
the 1933 season.) only to early Linkert Carburetor).
7. Thorougly clean qas strainer and its screen.
Since the VC model has been discontinued as our heavy dut commercial machine,
its place is taken by the VFDS model, however, some orefer the VDS model for 8. Re-assemble and attach carburetor and aas strainer. Before attaching qas line to
this service. These models are alike with the exception of pistons and cylinder strainer connection "turn on" tank qas cock and allow qas to flow for an instant to
heads. Both have standard cylinders, manifold and carburetor, the same as the force all air from line. ·
VLD model. The VFDS model is fitted with 12.5 heads (since January l, 1934) 9. In adjusting carburetor, set low speed needle for smooth motor idlina as you always
and iron alloy pistons No. 253-30 (pistons are not 1/16" short as in the old VC have done. Set high speed needle about l-l/2 turns open and make further readjust-
model). The VDS model is fitted with 10.5 heads and standard aluminum pistons. ment from this point, if necessary. lY, turns is the average adjustment for solo
service with a slightly richer adjustment for sidecar service. Bear in mind that
NOTE: - In ordering a VDS model for commercial or other heavy dut service, where the aeneral tendency is to adjust the hiah speed needle too lean. With such adjust-
low compression is desirable, we recommend that you specify 12.5 heads. Be sure ment, motor may hit evenly at top speed, but run lean when acceleratinq.
to mark your order plainly when this equipment is desired.
10. See that intake tappets are not set with less than specified clearance, as too little
clearance increases over-lap of intake opening and exhaust closina and affects car-
buretion to some extent.
11. In an obstinate case of apparent bad carburetion, it is well to try a new ignition
coil and condenser. Also note that battery had the proper level of solution over
its plates and that it is in a fairly qood state of charae. If battery is question-
able, try another. The mistake of diaanosina ianition faults as bad carburetion
and vice versa, is often made even by the most experienced trouble-shooter.
 -2-

the ammeter needle jumps to zero, they flywheel makr should be just appearing at the rear
sideof inspection hole. Be sure circuit breaker is fully advanced during this operation.
rr-timing does not check correct, it will have to be reset by shifting the circuit breaker
assembli
Bear this in mind, while it is not good to have timing set further advanced than specifi-
catlons call for, neither is there any advantage in the way of motor performance in ex-
SPECIAL tremely fast timing. If there is variation either way, it is better to have timing slightly
fast than a little late. Timing specification for solo 74 model are 3/8" and for 45 model
First of all it must be remembered a standard motor is not a racina type motor fitted up 9/32" before top center. This is according to flywheel mark.
loose for best top speed. Since motors have to be fitted up tiaht to satisfy with regard
to quietness of operation when new, they require considerable running-in. The faster a 3. Check valve tappets and be careful about setting with too little clearance. It is best to
motor is rated as to normal top speed that can be expected, the more running-in it requires, have them set with exact clearance, but if not exact, it is better to have them a trifle
because it must turn up higher rpm. Too many riders expect too much at the start whereas loose rather than with less clearance than specified. After valves have been freshly
the truth of the matter is, running-in wear that loosens up a motor so it rolls its best ground-in, the initial tappet adjustment should be rechecked and readjusted, if necessary.
is very slow. Of course running-in affects other things besides the motor. Wheel hubs, 4. The best spark plug for high speed service is our Hot-Stuff plug with k7 core. Our regular
transmission, chains, and brakes also have to be considered. Even at 3000 miles or more standard equipment plug is best suited to normal service conditions involving the average
some machines are not run-in. It is a waste of time to attempt to tune it up to compete amount of low and moderate speed driving, but the Hot-Stuff plug is the better olua and
with other well tuned-up machines that have seen a lot of mileage. more dependable for high speed operation. Where a motor may show loss of performance for
After a motor has gone through a fair running-in period, the next requirement is a thorough no apparent good reason, it is a good idea to try a new set of plugs, even though the plugs
tunino-up. Don't expect mileage alone to develop its best performance. At the end of the to be taken out seem to be all right. Quite often loss of performance as a result of over-
running-in period, even though motor is then well loosened up for free rolling it is not heating is traced down to bad spark plugs even though a plugs looks to be in good shape.
in favorable condition in other respects. Invariably there is a heavy accumulation of 5. AlI standard l~ model carburetors are fitted with 1-1/6·· venturi for best all-around per-
carbon, valve seats are in bad shape, valve stems and guides are gummy and sticky, muffler formance. Some motors show slightly better top performance w1th ventrU1 turned out to
outlet mav be nart.ially clogged up with soot and possibly ignition timing has retarded some- 1-1/8". Nothinq is gained by going over 1-l/8". He do not supply a 1-1/8" venturi. How-
what due to wear and seating at various points in connection with timing arrangement. ever it is not a big job to enlarge the standard venturi when the larger opening is desired.
FOLLOWING ARE THE SUGGESTED STEPS IN TUNING-UP: Remember advantage through this change applies only where a motor is tuned up to its best
in every other respect. A motor not tuned up does its best with l-1/16" and noth1ng wil 1
1. Remove cylinder heads and valve and thoroughly clean all carbon from cylinder and piston be gained by simply changing to a larger size.
heads and from around valve seats and ports. Clean the valves and run a reamer through
valve guides to take out carbon and gummy deposits. Turn motor until pistons are at bottom 6.Standard gear ratios are determined as best suited for all around service. Good accele-
center and carefully examine the cylinder walls with inspection lamp. If any marks or ration as well as top speed are taken into consideration. In a case where best possible
scores other than a few slight dark streaks are found, cylinders should be removed and top speed is desired above everything, usually something can be gained through slightly
oiston nngs inspe"cted for tension, gap and freeness side-ways in grooves. Valves should higher gearing provided motor is tuned up. Higher gear can be affected by fitting larger
be refaced with grinder and then ground-in to perfect seating in cylinders. If cylinder engine sprocket or smaller rear wheel sprocket. Engine performance and power output
seats are pitted, burned, or warped so valves do not readily grind-in to a good, complete come first and gear ratio comes last. In other words, attempting to improve speed through
seat, the cylinders should be removed and seats re-cut. changing gear ratio without first giving motor attention is working backwards and nothing
will be gained.
In the matter of piston rings, the compression rings, or, the two top rings, should be re-
newed if they show any damaqe, loss of tension, or wear to the extent that gap is quite A motor run-in and carefully tuned-up should turn up average or better than average top
wide. However, in connection with cushion rings, it is not advisable to change change speed for the model involved. If it does not, there is questions-as to what may be at
these rings too frequently if best top speed is the thing most desired. A little piston fault. It may be something minor 1ike a dragging brake or it may be more serious. Where
slap usually aoes along with a fast motor. As cushion rings wear and the spring rings a motor shows way below average performance, it should be torn completely down and the
take a set, cylinder wall pressure is naturally relieved and not so much power is required entire base assembly inspected for a damaged or seized bearing.
to move the pistons. With new cushion rings, cylinder pressure is brouaht back to trie 1934 STANDARD GEAI< RATIOS
point where it was when motor was new and motor performance is affected somewhat until new SPROCKETS
rings have had time to seat and relieve their tension to some extent. MODELS E. c. c.s. R. HIGH GEAR RATIO APPLIE~ TO
26 63 16 40 1 to 6.06 21" Side Valve Single
2. The next step in tuninq-up is checking ignition timina. Fully advance ignition timing, C & CB 31 63 16 45 l to 5. 71 30.50 Side Valve Single
accordina to specit"ications. Th1s is particularly important, and should be qiven very close G,GA,GD/T 26 63 lb 37 1 to 5.b Servi-Cars - 45" Twin
attention. Don't just guess that timing is somewhere near right and let it qo at that. If R/RL 26 63 16 30 1 to 4.54 45" Twin - Solo
ignition is even 1/16" late in relation to piston position, it may be enought to knock two RLD 31 63 16 34 1 to 4.32 45" Twin-Solo (High Compression)
to five miles per hour off top speed. The first step in checking ignition timing is making RS 26 63 16 34 1 to 5.15 4511 Twin - Sidecar
sure of proper circuit breaker point gap. 022" is the proper gap. Also make sure that VD/VFD 22 51 28 51 1 to 4.22 74" Twin - Solo
spark control fully advances circuit breaker assembly. VOS/VFDS 19 51 28 51 1 to 4.89 74" Twin - Sidecar
After giving c1rcuit breaker the attention just described,· turn motor until front piston is VLD 22 51 28 ~~ 1 to 4.22 14" Twin - Solo - Standard
on compression stroke and then remove inspection pluq from left crank case and check with VLD 25 51 28 51 1 to 3. 71 OPTiONAL - 14" lwin - For speed purposes
flywheel mark. ~lith ignition switch turned on, turn motor slowly and watch ammeter. As
No. Ill May 15, 1934
74 CU. IN. !WIN MOiOR ~ITfiNG SPECIFICATION (ALL MODELS) No. lllA May 15, 1~34
45 CU. IN. TWIN MOTOR FITTING SPECIFICATIONS (ALL MODELS
NOTE: These supersede all previous specification and apply to all lY30 and later NOTt: These supersede all previous specifications)
B1g Twin Motors.

PISTON CLEARANCE - .OO~" P!SlON CLEARANCE -- .014" to .016" (Measure pistons just below the top group of
IRON ALLOY PISTONS .......................................... 004" to rings, and cylinders about l/2" from top of bore)
ALUMINUM & DOW METAL PISTONS ................................. 016" to .018"
(Measure all pistons just below top qroup of rings and cylinders about l/2" from
top of bore) PISTON-CYLINDER HtAD CLEARANCE -- 3/64" to 5/64"

PISTON-CYLJNDtR HtAD CLEARANCE -(Ali models except VC Commerical .... l/16" to 3/32" PISTON PIN IN PISTON-- .0005" to .001" press fit in piston.
\VC Commercial -dis-continued 1934) ............... 7/64" to 9/64" PISTON PIN IN UPPER END OF CONNECTING ROD-- .001" loose
PISTON PIN IN IRON ALLOY PISTON - .0005: to .001" press fit in lock pin side -
plug or slip fit in opposite side. LOHER CONNECTING ROD BEARING -- .0005'" to .0008" loose
PISTON PIN IN DOW-METAL & ALUMINUM PISTONS - ....................... 0005" to .001'" CONNECTING RODS-- .006" to .010" end play between flywheels- roller and retainer
(Press fit in piston) assembly should be narrower, but not more than .010" narrower than front rod.
PISTON PIN IN UPPtR CONNECTING ROD END - .001" loose
LOWER CONNECTING ROD BtARING - .001" to .00125" loose PINION GEAR SHAFT -- .0045" loose at inner end of bushing -- .002" at outer end of
bushing. (Bushing is taper reamed with a special reamer).
CONNECTING RODS - .006" to .010" clearance between fly-wheels - roller and retainer
assembly should be narrower, but not more than .010" narrower than front rod. SPROCKET SHAFT -- .0005" to .001" loose in ro"Jler bearinq - .006" to .007" lo()Se
in chain lubricating bushing.
PINION GEAR SHAFT - .004~" loose at inner end of bushing -- .002" loose at outer
end of bushing. (Bushing is taper reamed with special reamer). FLYWHEEL ASSEMBLY -- .004" to .008" end play in crank case.
SPROCKET SHAFT - .0005" to .001" loose in roller bearinq -- .006" to .007" loose CAM GEARS-- .0005" to .001" loose in crank case and cover bushings --free to .005"
in chain lubricating bushing. end play.
FLYHHlEL ASSEMBLY - .004" to .008" end play in crank case
CAM GEAR- .0005" to .001" loose in crank case and cover bushings -free to GENERATOR DRIVE GEARS AND SHAFT (1931 and earlier models) -- Shaft must be free
.005" end play. running fit; have .002" to .004" end play, and .001" to .0015" clearance in
bearings. Small bevel gear should be .002" to .003" locse in bushing assembly,
INTERMEDIATE GEAR- .001" to .0015" loose on stud. and shimmed to allow .002" to .004" clearance between bevel gears.
TAPPET GUIDES- .0005" to .001" press fit in crank case
TAPPET GUIDES .0005" to .001" press fit in crank case.
VALVf: TAPPETS- .0005" to .001" loose in tappet guides.
VALVE TAPPETS .0005" to .001" loose in tappet guides.
 No. 111 C May 15, 1934
No. lllB May 15, 1934 TIMING SPECIFICATIONS
SINGL~ MOIOR fiTIINb SPtCIFICATION- (ALL MODELS) 1930 AND LATER 74 CU. IN. TWIN - ALL MODELS EXCEPT 1930 and 1931 V AND VC MODELS
INTAKE VALVE -- Opens 9/3<'" to 13/32" before top dead center
PISTON CLEARANCE- IJow metal and aluminum-- .011" to .013" (Measure all Closes 7/8" to l-l/8" after bottom dead center
pistons just below the top group ot rings, and cylinders about l/2" from
top of bore) EXHAUST VALVE -Opens 5/8" to 7/8" before bottom dead center
Closes l/4" to 3/8" after top dead center
PISTON - CLYINDER HEAD CLEARANCE -- 3/64" to 5/64" IGNITION -- OCCURS when piston is 5/16" to 3/8" before top dead center on the
compression stroke.
PISTON PIN IN PISTON -- Snug press fit - not over .0005" tight
1930 AND 1931 74 CU. IN. TWIN V AND VC MODELS
PISTON PIN IN UPPER tND OF CONNtCTING ROD .0005" loose
INTAKE VALVE -- OPENS when piston is --ll/64" to 19/64" before top dead center
LOVJER CONNECTING ROO BEARING -- .0003" to .0004" loose Closes when p1ston is -9/16;, to 13/16" after bottom dead center
CONNI::CTING RODS -- .010" to .020" end play between flywheels -- roller and EXf1AUST VALVE -- OPENS when piston is -- 9/lb" to 13/16" before bottom dead center
retainer assembly should be narrower, but not more than .010" narrower than rod. Closes when piston is ll/64" to 19/64" after top dead center
PINION GEAR SHAFT -- .0035" loose at inner end of bushing -- .0025" loose at IGNITION -- OCCURS when piston is 1/4" to 5/16" before top dead center on the
outer end of bushing (Bushing is taper reamed with special reamer) compression stroke.
SPROCKET SHAFT-- .0005" to .001" loose in roller bearing-- .006" to .007" 45 CU. IN. THIN ( ALL MODELS)
loose in chain lubricating bushing.
INTAKE VALVE -- OPI:NS When piston is 5/32" to 7/32" before top dead center
FLYWHEEL ASSEMBLY -- .002" to .006" end play in crank case Closes when piston is 37/64" to 45/64" after bottom dead center
CAM GEARS- .0005" to .001" loose in crank case and cover bushings- free to EXHAUST VALVE - OPeNS when piston is :J7/64" to 45/64" before bottom dead center
.005" end play Closes when piston is 5/32" to 7/32" after top dead center
INTERMEDIATE AND OILER GEARS -- .0015" to .002" loose on studs IGNITION -- OCCURS when piston is l/4" to 9!:J2" before top dead center on the
compression stroke.
TAPPET GUIDES .0005" to .001" press fit in crank case
30.50 CU. IN SINGLt (ALL MODELS)
VALVE TAPPETS Free to .00075" loose in tappet guides.
INTAKE VALVE OPENS when piston is 5/16" to 9/16" before top dead center
CLOSES when piston is ll/16" to 15/16" after bottom dead center
EXHAUST VALVE -- OPENS when piston is 1/2" to 3!4" before bottom dead center
CLOSES when piston is 1/4" to 1/2" after top dead center
IGNITIOI'I -- OCCURS when piston is l/4" to o/16" before top dead center on the
compressi.on stroke.
No. 111C May 16, 1 ~34

21 CU. IN. SlUE BY SIDE VALVE SINGLE ( ALL MODELS)

INTAKe VALVE -- OPENS when p1ston is l/8" to 3/16" before top dead center
CLUSES when p1ston is 7/16" to 9/16" after bottom dead center
EXHAUST VALVE --OPENS when piston is -- 7/16" to 9/16" before bottom dead center
CLOSES when piston is 1/8" to 3/16" after top dead center
IGNITION -- OCCURS when piston is 7/32" to 9/32" before top dead center on the
compression stroke.
21 CU. IN. OVERHEAD VALVE SINGLE ( ALL MODtLS )
INTAKE VALVE -- OPENS when piston is -- 3/32" to 5/32" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center
EXHAUST VALVE - OPENS when oiston is 7/16" to 9/16" before bottom dead center
CLOSt:S when piston is 3/32" to 5/3:0" after top dead center
IGNITION -- OCCURS when piston is ll/32" to 13/32" before top dead center on the
compression stroke.
TAPPEl CLtARANCES
NOTE: Vlhe~ checkino valve timino accordinq to piston position, bear in mind
that tappets must first be adjusted to the correct clearances.
ALL SIDE BY SIDE VALVE. MODELS (SINGLES AND THINS) -- INTAKE .004" to .005"
EXHAUST -- .006" to .007"
OVERHEAD VALVE SINGE -- INTAKE AND E.XHAUST -- .002" to .003"

CIRCUIT BREAKER OPENING - (ALL MODELS)

GENERATOR .020" to .024"

MAGNETO .014" to .018"
 -2- December 17, 1934

It 1s o.k. to use T-slot piston in servicinq a motor originally fitted with earlier type Dow
metal or aluminum piston, where only one replacement piston is needed. It is not necessary
to rebalance flywheels whether new piston is f1tted in one or both cylinders.
T-Slot piston can also ~e use? in servicing a motor originally fitted with iron alloy piston,
but 1n th1s case, both 1ron p1stons should be replaced. Piston pin bushinas will also have
to be shortened or replaced as explained below. With this combination it is not altoaether
necessary that flywheels be rebalanced for good motor performance, as the liqhter piston
No. 112 December 17, 1934 affects smoother motor performance without this attention. Reba 1anc i no 1vi 1 I of course reduce
T-SLOT ALUMINUM PISTON motor vibration to the minimum. ~
74 model piston furnished on parts order differs slightly from oiston used in new motor pro-
1935 Twin model motors are fitted with T-slot piston. 1934 Twin models are a 1so fitted with duct!on in that the latter oiston has about 1/8" less space between pin bosses for piston pin
this type piston startinq with motors numbered 34-R-4000 and 34-VLD-9000. T-slot piston bush1na. This is to gain the maximum pin bearing in piston bosses. In other words the latest
has not been used in Single models, neither has it been used in the VFD model motor in which Ria Twin piston oin bushing (1-1/il" long) is 1/8" shorter than bushing used in the ~ast. How-
iron alloy piston has been standard equipment. :ver: pisto~ furnished on parts o~der has enough_space between_pin bosses to permit install-
lnq 1n earl1er Dow metal and alum1num p1ston equ1pped motors w1thout chanqina because of
T-.slot pistons are now available for service in standard size, and oversizes up to .OSO". lenqth, the original bushing (l-1/4"). This makes carts order piston ada~table, without
This piston in available sizes supersedes earlier type Dow-metal and aluminum pistons applying busl1inq change, to either early or late motors, excepting motor originally fitted with iron
to side by side valve Twin motors. For a time the new piston will not be available in over- alloy oiston which has piston pin bushinq 1-9/16" lona. It will simoly be a matter of a
sizes above .050", but eventually it will be. l1ttle extra clearance between pin bushing and piston bosses when a carts order piston is
fitted to a motor originally equipped with T-slot pistons. This is o.k. The 45 model T-slot
Cylinders used in new production with T-slot piston are straight bore. T-slot piston can, how- piston does not involve any change in piston pin bushing as used in the past.
ever, be fitted with satisfactory results in taper bored cylinder
as used in the past, when there is occasion to do so in connection Piston pin in T-slot piston is fitted a light hand press fit. Pin cannot be made a tiqhter
with earlier motors in service, or taper bored cylinders in stock. ore~s fit, because_piston is cam around and must be free to work on pin so that it shapes to
!n fittinq this type piston to straiqht or taper finished cylinder cyl1nder as e~pans1on take~ Place. S~nce the factory job of sizing pin holes in p1ston is
1t must be remembered that different fittinq applies, because a done w1th a h1qh speed bor1ng tool wh1ch makes a more perfect job than can be done with a
new straight bore cylinder is the same diameter in full length reamer, and piston p-in of exact flt is matched to every piston, it is advisable to install
that a new taper bore cylinder is at the top end. A taper bore n:w oiston using standard pin furnished with it. If rod bushing is in bad order, requiring
cylinder is .005" to .007" larger at the bottom end. Fittina in- e1ther reaming oversize and fitting oversize pin or a new bushing, it is advisable to rene~
structions follow: bushing and ream standard. In reconditioning motors that have seen considerable service an
oversize pin will of course have to be fitted now and then where original pin has loosen~d
The T-slot piston is a cam shaped oiston and the point at which it and developed play in piston bosses. In this case a reamer should be used to resize piston
is checked for cylinder fit is directly at the bottom of skirt, hole. A good, smooth cutting reamer should be used and a little kerosene applied as a cuttina
front and rear, exactly midway between pin bosses, (see illustration) lubricant. ~ith piston hole sized with reamer, new pin can be fitted sliahtly tighter than
Side clearance can be disreqarded. the f1t spec1f1ed for factory fitted pin, inasmuch as a reamed fit will very soom free itself
to some extent. In t"eamed hole, pin can be made a tight hand press fit.
Piston fitting specifications applying to straight bore cylinder,
WHICH PISTON CLEARANCE IN call for ~ size to size fit with little if any drag, to .002" clear- Size piston pin bushing to give pin .001" clearance.
CYLINDER IS DETERMINED ance. Th~s, of course, applies to new cylinder and new piston, of
. . matched s1ze. In checkina T-slot piston fit when overhaulina and Pi stan ri ~q gap for taper bored cylinder has a 1ways been about . 006" near top of cy 1 i nder.
ref1tt1ng a motor that has been in service for some time, up to .006" to .007" clearance can In a stra1ght bored cylinder, rings should be fitted with .010" gap. Note that straight
be allowed before worth mentioning piston slap should be noticeable. The best method of bore cylinder requires wider gap. It is important that this be observed, because in straight
d:termining clearance is to use a feeler gauqe between cylinder wall and fittinq point on ~ore_cyl1nd:r there ;s more chance of rings expanding to the extent of tightening in cylinder
p1~ton. Select f:eler t~at just fills the space between piston and cylinder without re- 1f f1tted w1th too l1ttle gap. Specified ring clearance side way in groove is .0015 to .002".
qu1r1nq for:e to 1nsert 1t. Using force to insert feeler will result in clearance being 74 model T-slot piston uses the same compression ring used on earlier type pistons. 45 model
determ1ned 1ncorrect~y as piston_is q~ite flexible at skirt and it will simply be pushed out T-slot piston uses new narrow rinqs(3/32" wide).
of shape. A closer JOb of check1nq p1ston clearance can be done with no rings on piston.
Instal I piston in either front or rear cylinder with T-slot forward. This puts power thrust
A :005" ov:rsi~e T-slot piston is a proper fit in a new standard size taper bore cylinder. load on unslotted side of piston.
Th1s _overs1ze 1s al~o a satisfactory fit in a standard tapered cylinder that has seen some
serv1ce and 1s poss1bly worn as much as .002 to .003 inch. Where there is more wear cylinder When fitting T-slot piston to rod, do not use piston pin pusher tool as piston skirt is
should be returned for reborinq and_refitting. Piston clearance in a taper bore cylinder easily pushed out of shape if pin is fitted too tight or starts cocked and becomes jammed.
cannot be checked very accurately Wl th a feeler gauge because of cylinder tapering to 1arger If pin is properly fitted to piston, it can be pushed into place without the aid of pusher
d1ameter at bottom. If this is attempted, piston head should be about flush with top of tool. _use to?l #12052-32 for installing_pint?n pin lock ring. This will assure getting
cylinder when gauging. lock r1ng on 1n good shape w1th a snug f1t Wh1Ch 1s 1mportant to avoid any chance of ring
coming off and damaging both cylinder and piston. ·
No. 11 l' -3- December 17, 1934
After fitting piston to rod, check for alignment with piston squaring plate in the same
manner as with earlier type piston. It is even more important with T-slot piston that this
operation be carefully done.
It is not necessary to reshape or "round" piston after installing on rod because first of all
piston is cam ground and, therefore, not round to begin with, and furthermore if pin is prop-
erly fitted, piston will not be pushed out of shape through forcing pin into place.
MISCtLLANEOUS THINGS TO BE REMEMBERED
Straight bored cylinders, new and rebored, (excepting cylinders on about the first 150 motors
eouipoed with T-slot oistons) are identified with letterS stamped in base flange, left side,
near rear corner.
1930 and later Twin model cylinders, also 1929 45" model cylinders returned for reboring in
the future will be finished straight and fitted with T-slot piston, except cases where T-slot
piston may not be available in oversize required. In this case, reboring will be taper as in
the past and·earlier type piston with cushion rings will be fitted. Cylinders returned to
be refitted with iron alloy piston will also have-to be rebored taper as in the past. In
finishing cylinder to be fitted with T-slot piston. a smooth surface pretty much free from
grinder marks is important, because piston skirt bears directly on cylinder wall instead of
being carried on cushion rings as with earlier pistons. Unless cylinder bore is very smooth,
piston skirt is ·likely to be owrn prematurely.
Oversize pistons to be furnished as regular stock oversizes, start with .005" oversize and
qo up in steps 0f .005". Pistons will be furnished in any odd size specified on order. For
the present the top oversize is . 050" but later it wi 11 be . 070". There is a charge of 40¢
list, extra for regular oversize above 035" and any odd oversize.
When ordering oversize use standard piston part number and indicate oversize desired. Size
stamped in oversize piston head indicates exact thousandths of an inch above standard size.
BEAR IN MIND- when fitting T-slot piston in straight bore cylinder, standard or oversize,
piston must be of size to match cylinder size~ EXample:
standard straight cylinder- standard piston
.010" oversize cylinder - .010" oversize piston
In fitt i nq taper borecyl i nder, piston should be . 005" above cylinder size. Example:
Standard taper cyl1nder - .OOb" oversize piston
.010" oversize cylinder - .015" oversize piston
Remember this when ordering pistons.
In the future 74 model connecting rods, 28b-30 front and <86-30 rear, returned to the factory
for rebusninq wi 11 be refitted with short (1-1/8") upper end bushing. Kods can then be used
without bushing change with either T-slot or earlier type Dow-metal or aluminum pistons.
Following are number and pr1ces applying toT-slot pistons and other new parts that go with
them:
2:>6-308 T-slot piston complete with rings and pin (74 Model) $5.75, List
2b3-<9A T-slot oiston complete with rings and pin (45 model) 5.50, List
293-34 Piston pin bushing 1-1/8" long, used with 74 model
T-slot piston · .40, 1ist
260-34 Piston ring, used with 4b model T-slot piston .25, List
vlhen there is occassion to order a replacement cylinder for a motor originally fitted with T-
slot piston, use catalog part number of cylinder desired and specify forT-slot piston"
 No. 118 2 January 16, 1935

10. Axle Housing

11. Axle Nut
12. Axle nut lock washer. To lock nut after tightening, bend over edge of lock washer
against nut at one point.
No. 118 January 16, 1935
13. Axle spacer.
14. Wheel Key
Servi·Car Rear Axle Assembly
15. Left end bearing cup (left thread). Right end bearing cup is right thread.
(Note: This Supersedes Shop Dope Sheet No. 98)
16. End bearing cup lock washer. After bearing cup is securely tightened, upset lock washer
in notches in axle tube and bearing cup.
17. End bearing spring ring.
18. End bearing plain washer
19. End bearing felt washer
20. Roller bearing thrust bushing - slip fit in bearing cup.
21. Roller bearing. Axle to have .002" clearance in bearing.
22. Roller retainer.
23. Brake Shell
24. Inside brake shoe ·and lining.
25. Outside brake band and lining.
26. Outside brake operating shaft.
27. Sprocket. Differential unit, sprocket and brake shell are all fastened together with
eight bolts. A wire is run through ends of bolts to prevent nuts coming off if they loosen.
28. Inside brake operating shaft.
1. Differential unit.
29. Turnbuckle lock nut - (two to each turnbuckle) left thread for truss rod and right
2. Right side differential bearing (not adjustable) thread for turnbuckle studs.
3. Left side differential bearing (adjustable). 30 & 33- Turnbuckles - (Truss rod end left thread- stud end right thread).
4. Bearing housing (right thread) for left side differential bearing, by means of which ;ide 31. Differential gear shaft lock plate- (two used).
play of differential unit 1 is adjusted. To determine amount of side play insert screw
driver, or other suitable tool, through chain opening in axle housing 10 and shift differ- 32. Truss rod, stiffens axle assembly. After assembly has been in service awhile, truss rod
ential unit from side to side by applying pressure to sprocket. There should be .007" to should be checked and tigtened if needed to take up any slack that may have developed. To
.010 side play. To adjust side play loosen lock screw 5 sufficiently to disengage from tighten truss rod, first loosen lock nuts at end of turnbuckles 30 and 33 and readjust turn-
slot in bearing housing 4. Insert screw driver, or other tool in small opening provided in buckles just enough to take up slack and tighten truss rod so it will bear snufly against
axle housing 10 (opposite lock screw 5) and turn bearing housing 4 to left for less - to bottom of axle housing. CAUTION: If turnbuckles are tightened too tight, axle assembly
right for more side play. will be spring out of line.
5. Bearing housing lock screw. 34 & 35. Turnbuckle coupling studs.
6. Axle lock rings - (half rings - four used) secure axles in large differential gears, and IMPORTANT
ad,just axle end play in differential unit. End play can be determined by holding differ- Servi-car rear chain should be checked often for adjustment, lubrication and wear. A chain
ential unit and checking from end of axle. (Do not confuse axle end play with differential that finally breaks in service due to lack of attention may jam between rear sprocket and
side play as described under No. 4) Axle end play can be readjusted by disassembling dif- axle housing with result that housing is broken or damaged beyond further use·. Keep chain
ferential unit and fitting thicker or thinner lock rings which can be obtained .125" - .130"- well adjusted and lubricated and inspect occasionally for damaged links and badly worn con-
.135" thick. Care must be taken that neither axle is pinched against spacer 7, nor should dition. Do not try to get last possible mile out of chain, or run it to the critical point
either axle have more than .005" end play. Occasionally it may be necessary to fit thicker before installing new chain. Rear brake shoes and linings are attached to right axle housing
lock rings on one axle than on the other to obtain proper adjustments. and before brakes can be relined, axle truss rod must be removed and housing taken apart. To
7. Spacer for small differential gears. remove truss rod 32, loosen turnbuckle lock nuts and turn studs 34 and 35 into turnbuckles
far enough to free truss rod.
8. Shaft for small differential gears.
9. Felt washer and retainer (both sides).
 No. 120 February 15, 1935

January 29, 1935

SEAT POST
No. 119
Spring combinations with part numbers that make up seat post
assemblies (3121-30) (3122-30) (3123-30) (3124-30).
New machines furnished with standard seat post unless other
than standard specified on order.

1935 - 45 CU. IN. (750 cc) MODEL BRAKE LOCK 0 Ste.ndard Light Heavy Extra Heavy
130/F-150# Under 130/F 150/F-230# 230/F &Jld '-'!'
P-t.No,3123-30 pt,No.3122-30 Pt.No.312l-30 Ft.l'o.3l24-30

(This assem-
bly was stand
ard for 1932-
1934 B Single)

When removing demountable rear wheel 3135-30

of 1935 - 45" model, it is necessary <;;---- <!:----
to apply and lock brake to hold brake
drum and sprocket assembly while
pulling wheel off. This applies to
all 45" models except Servi-Cars.
To lock, apply brake with foot pedal, 3133-30 3133-30. 186-10 186.10
and shift lock back against battery
box bracket as shown in illustration.
When not in use, tighten securely
on brake rod a little forward of
battery box bracket. ~133-30 <!:----

Explain to your riders that lock is

to be used when removing wheel, and
that it can also be used to lock brake 312s-:n .;:::----
when machine is parked.

3129-31 186-10 3129-31 3l29-31A

3128-31

1&C· lbs.
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No. 123 March 15, 1935
No. 124 March 22, 1935

1935 - 74 MODEL TIMER ADJUSTING SCREW

45 (750 C. C.l DEMOUNTABLE REAR WHEEL
When you have occasion to check and re-adjust igni-
tion timing in connection with a 1935, 74 cu. in.
Demountable rear wheel clamp screws must be model, you will observe that the circuit breaker
securely re-tightened two or three times full advance stop is now provided with an adjusting
within the first few hundred miles after a screw similar to the carburetor throttle stop screw.
new machine goes in service. In other words, This might properly be called a micrometer ·adjust-
the connection between brake assembly and ment for very accurate re-setting of ignition.
wheel must not be allowed to work loose and With earlier models, to re-set timing, it is neces-
develop play, because if this happens and sary to loosen the circuit breaker assembly and
wheel is allowed to run loose for some time shift the advance and retard plate. Re-setting in
the mounting holes in hub flange will becom~ this manner, it is not such a simple matter to get
badly elongated and then it will not be pos- altogether accurate setting.
sible to keep a tight connection. In new as-
sembly, wheel clamp screws are pulled very Proper procedure in cheaking and re-setting with
tight but a certain amount of give and set- the new adjusting arrangement is as follows: First
ting takes place in service and re-tightening adjust circuit breaker point gap to exactly .022".
is necessary. After everything about the Next remove timing plug from left crankcase, and
connection becomes thoroughly seated, clamp aheck timing with flywheel mark as illustrated and
screws will no longer require frequent re- described on page 16 of·7~ model Rider's Hand Book.
tightening, although they should be inspected If timing is f01md not correct, re-adjust circuit
occasionally. breaker &top screw a little at a time and re-check flywheel.position, until flywheel
mark comes to just the ri~~t point when ammeter indicator drops back to ~ere indicat-
Advise all your 45 model riders that when there is occasion to remove and re- ing that points have separated.
place wheel in making roadside tire repair, it is very important that all five clamp
screws be pulled very tight.
A lot is expected of motors these days in the way of performance and speed. The first
ussential for good all around performance end best possible top speed is accurate ig-
HARLEY-.DAVIDSON MOTOR CO. nition timing. New motors arc nccurntely timed in new assembly, but due to running-
Milwaukee, Wis., U.S.A. in and normal woar, timing changes to some extent. Encourage your riders to have
timing of their motors checked periodically - be a "specialist" with this tuning up
operation as concerns accuracy, and you will find yourself hearing less performance
complaints.

HARLEY-DAVIDSON MOTOR CO.

Milwaukee, Wis., u~s.A.
 No. 126 -2- April 3, 1935

CYLINDER REBORING AND PISTON FITTING INFORMATION

No, 126 April 3, 1935 Straight Bore Cylinder and T-Slot type Piston
CYLiliDER REBORING AliD PISTON FITTING IllFOR!!ATION (NOTE: Dimensions given are standard size)
Ta~er Bore Cylinder Jcnd Solid Skirt Type Piston
(l\ote: Dimer,sions given are standard size.)
Top
= '=
~
--, ·=
;.= Standard bore
l!.o:iel Size dimension of
___! .:;::::: straight bore
2.870" ~ ~ cylinder for
;;:so" 3.0885"
~ S; T-Slot piston
,___; Top ~ !i: (1923 &: earlier)
2.745"
3.307"
=:
:=;:! ;=
I<-'-="='-'- - -
{45
74 It
11
2.745"
:::::) ~ 61" (1924 to ltl29) 3.305" 3.422 11

~...!..---i..C
.____J ,- 74" 3.422"
--, .~
·=
'---; =
'=::J ~
. : p
-=:J ~ Note: Take orlinder measurement

J ~ f*;,.
about 2 " from top of bore, Note: When checking fit of T-slot
rather than at extreme top, piston in straight bore cylin-
when determining piston der, insert piston part way in
2.875q clearance given.be1ow. cylinder bore.
3.0935"
2.750"
u__ _ _ _--1. <:"~.161" (1923 &: earlier) 3.310"
61" (1924 to 1929) 3.312"
74 11 3.429"
Piston site
at measur-
ing point -
Solid Skirt just below
type piston. top group Y
:Jodel of rings Piston Clearance

21" (all mo1els) Dow r.letal & Lynite

30.50" Dnw r.etal
45" Dow r.etal
2.8585 11
3.0767"
2.730"
.oll" to .013"
.Oll" to .013"
.014" to .016"
0 C'-----
T-Slot piston should be fitted
size to.size,-to .002" clearance
in straight bore cylinder, check-
45" Lyr..ite 2.731" .014" to .016" ing fit at bottom of skirt, front
61" Iron J..lloy ( 1924 to 1929) 3.3035" .002" to .003" &: rear, ~~th feeler inserted be-
61" Dow r.etal (1924 to 1929) 3.293" .Ol15"to .Ol:'oE" { t:·:een piston and cylinder bore.
74 '' Iron A.l1cy (1929 & ~arlier) 3.419" .':'03" to .004"
74 tJ ~.-:....... '!:".'2~5..~ (1929 & :arlier) 3.4:•5 tt .~lZ5"-:o .01E2·"
-:-''' !:-or. .-.--or (2?3: l: :~:a) 3.4:sn .. -_..- 'f
~
'":.

(:;.;;z::; 6: :ater) 3 L.- c-tt •.=..: ~" -:o .Clt. ,.

(lSZ-2 6: h::,r) 3 . .;::7" to .~:: ,. :~i::.·::r.'..:.:-:ee, .. :.:., - •..J . r.•

.""';'"·.'
 No. 127 April 9, 1935 No. 128 1935 ±£ MODEL TRANSMISSION April 10, 1935

SERVICING 1936, AND EARLIER INTERCHANGEABLE WHEELS

After considerable service, and, of course, depending to a great extent on the kind
of service in which a machine is used, interchangeable wheels may become worn to
some extent, causing end play in the wheel hubs, and looseness in the drive splines.
Excessive end play in a wheel hub (end play should be .004" to .008") can in most
cases be corrected by simply fitting new bakelite thrust washers. In a case where
new bakelite thrust washers will not readjust end play, fit narrower thrust plate
spacer than the one originally fitted in hub. These spacers are regularly supplied
in sizes from .345" to .380" in steps of .005", and we can supply a .390" spacer
for unusual cases.
Drive spline looseness can be taken care of by fitting an oversize brake shell hub,
which we can supply in sizes of .001", .002" or .003" oversize. A .001" oversize
hub will take care of splines that apparently have considerable play when checked
at rim of wheel; a .002" oversize will fix up a badly worn assembly; and a .003"
oversize should not be necessary except in an extreme case.
AN OVERSIZE HUB SHOULD NOT BE FITTED UNTIL WHEELS HAVE BEEN INTERCHANGED A SUFFICIENT
NUMilER OF TIMES SO THAT ALL WHEEL HUBS ARE WORN ABOUT EQUALLY. Otherwise fitting an
oversize hub to correct a badly worn rear wheel will upset the interchangeable wheel
system because the front, sidecar, or spare wheel will not fit on the oversize hub.

(Illustration of Reverse Transmission)

OVERSIZE REAR WHEEL BRAKE SHELL HUB THRUST PLATE SPACER
Part No. List Price Part No. List Price Part Number
1. Sprocket cover •••••••••••••••••••••••••••••••••••••••••••••••••••• 2345-33
4030-30S $4.50 3927-30 $ .25 each
4030-32S 4.50 2. Sprocket •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2035-33

Specify oversize wanted Specify size wanted or order a 3. Shifter fork shaft (held in place by sprocket cover) •••••••••••••• 2245-33
quantity assorted.
4. Shifter fork (low and reverse) ................................... . 2247-33

5. Spacing washer (same as No. 9) ................................... . 2253-33

6. Adjusti.ng shims (same as No. 10) with which shifter fork No. 4 is
adjusted to fully engage shifting clutch No. 25 in low and reverse
positions. Shims are .007" and .014" - one to six required for
correct adjustment in new assembly •••••••••••••••••••••• Shim .007" 2253-33B
Shim .014" 2253-33A

7. Shifter fingers .................................................. . 2248-33

8. Shifter cam - must be free, but should not have more than
.005" end play ................................................... . 2243-33
 - 4 - - 5 -

TAKING APART, RE-ADJUSTING, AND RE-ASSEMBLING Assemble countershaft gear and starter parts in case first, then mainshaft assembly,
and side cover, then go ahead with the assembly of shifter mechanism and other parts~

Transmission should be removed from motorcycle, drained and flushed out with gasoline, in the reverse order of dis-assembly.
and given fl.ttention at the bench.
Before assembling clutch on clutch gear, give attention to thrust washer and cork oil
To dis-assemble transmission as necessary to only re-adjust shifter forks and shift- retainer No. 12. Steel thrust washer is usually a rather snug fit on clutch gear
ing clutches, proceed as follows: First, remove inspection plate from transmission sleeve. Just start it and let clutch inner disc push it to its proper position as
top. and use gauges to determine what re-adjustment is required as described in para- disc is tightened. Inspect cork in recess in clutch disc, and if it appears to be
graphs No. 17 and No. 23. Next, remove shifter cam No. 8 as described in paragraph at all worn, renew it.
No. 29. Remove sprocket cover No. 1 and drift out shifter fork shaft No. 3. This
shaft comes out through transmission side cover. With shaft out7 shifter fork assem- See that shifter cam lock plunger seats with sufficient tension so that a fair amount
blies are free to be lifted out and re-adjusted. Bear in mind that the shifter fork of effort is required to move cam from one position to another. This is important to
assemblies are not interchangeable, and before taking them apart for re-adjustment, stop cam in just the right positions and thus be su.re of shifting clutch driving dogs
the exact arrangement of parts in each assembly should be carefully noted so they being fully engaged. Plunger spring tension adjusting screw is in the front of trans-
will be put back together the same way. It is also well to note the number of shims mission case. Adjusting spring tension too strong will, of course, make shifting dif-
used in original factory setting 7 as the original adjustment will not be found far ficult so don't overdo it.
off, and losing track of it may mean re-assembling, gauging, and re-adjusting two or
three times before correct new adjustment is accomplished. When re-adjustment of See that shifter controls from transmission to tank lever are well oi~ed and free
shifter fork assemblies has been completed, reverse the order of dis-assembly to put working. Observe that at no point in the shifting range is there binding or inter-
transmission back together. ference with shifter rods. This is something that may be found now and then due to
rods becoming bent. Be sure shifter rod is correctly adjusted so that when tank
To take transmission all the way apart for co~plete inspection, re-adjustment and re- shifter lever is shifted from one position to another, transmission lever moves to
newal of parts, proceed as described above for only re-adjusting shifter forks, and just the right position for full engagement of lock plunger in cam notch, and thus
then remove sprocket No. 2 and take off transmission side cover. All remaining in- full engagement of shifting clutch. Recommended adjusting procedure is to discon-
ternal parts can then be taken out through the side. nect shifter rod from tank lever, set trans:nission lever in 11
neutral" position, and
then re-adjust shifter rod so that tank lever has correct gate position. Bear in
The first sttp in re-assembling and re-adjusting is assembling roller bearing No. 13 7 mind that wrong adjustment of control~ or in other words, wrong relation between
thrust bearing No. 14, and clu.ch gear No. 15 in case. Next, install mainshaft with tank lever and transmission 1ever7 may mean running with shifting clutches only par-
only adjusting spacer No. 16, thrust washer No. 24, and reverse gear No. 26 (or tially engaged which soon leads to trouble.
s~andard transmission spacer bushing assembled on shaft). Now install transmission
side cover with roller bearing No. 27, tighten cover securely, and check mainshaft To convert a standard three-speed transmission to a reverse unit, it is only neces-
for end play as described in paragraph No. 16. It is important that mainshaft be ad- sary to fit gear No. 26 in place of original spacer bushing, and install reverse
justed with the least possible end play and still have it turn freely. After main- idler gear No. 32. No other changes are required in the transmission itself, but
shaft adjustment has been completed, remove transmission side cover and take shaft new shifter controls are required, namely, tank shifter gate 7 shifter lever 7 and
out, but be careful the adjusting spacer with which correct adjustment was obtained shifter rod. Tbe complete combination of parts required for changeover are covered
is not misplaced .or mixed up with other washers that may be lying around. In other by part number 2203-35, price $9.75 list.
words, be sure you use this same washer in final assembly.
HARLEY-DAVIDSON MOTOR co.
Now assemble just the following parts on mainshaft: Both thrust washers No. 24, re- Milwaukee7 Wisconsin
verse gear No. 26 (or standard transmission spacer bushing), low gear No. 22, ad- u. s. A.
justing spacer No. 21, and second gear No. 20, also have mainshaft adjusting spacer
No. 16 in place. With this assembly together, install it in case, fit side cover
Conversion Table
with roller bearing No. 27, and tighten cover securely. Now see how much side play
low and second gears have between \J8sher No. 24 at end of shaft splines, and second Inches to Millimeters
gear retaining bracket No. 19. They must have enough clearance to turn freely, but .003' .08 mm.
should not have more than .003" side play. Re-adjustment as needed can be made by .005" .13 mm •
fitting thicker or thinner adjusting spacer No. 21. With this adjustment completed, • 007" .18 mm.
transmil?,sion is ready to go together in complete assembly. .014' .36 mm •
• 030' .76 mm.
See that shifting clutches No. 18 and No. 25 are a good free fit without binding on .032" .81 mm.
shaft splines. Also observe that engaging dogs on clutches are in good condition .037" .94 mm.
without chipped corners and da~ag~ as results from shifting without clutch fully dis- .041' 1.04 mm.
engaged. Shifting clutches with chipped and battered engaging dogs creep out of en- .090' 2.29 mm.
gagement under steady driving load, and the tremendous side pressure brought about .140" 3.56 mm.
through this condition eventually results in serious damage to the shifting mechanism 1/16" 1.59 mm.
and all thrust points along the mainshaft assembly. l/8" 3.18 mm.
l/4' 6 ••35 mm.
 - 2- - 3 -
Part Number ~!:l_Numbe!:

9. Spacing washer (same as No. 5) •••••••••.••••••••••.••••••••••••••• 2253-33 25. Shifting clutch (low and reverse) ••••••••••••••••••••••••••••••.•• 2298-33

10. Adjusting shims (same as No. 6) with which shifter fork No. il is 26. Reverse gear (In the standard transmission a spacer bushing is
adjusted to fully engage shifting clutch No. 18 in second and high used instead of this gear.) Install spacer with flange side out-
positions •••••••••••••••••••••••••••••••.••••••••••••••••••••••••• 2253-33A & 33B ward •••••••••••••••••••••••••••••••••••••••••••••••••• Reverse gear 2296-33
Standard transmission sp3cer 2296-33A
ll. Shifter fork (second and high) ••••••••••••••••••••••••••.••••••••• 2246-33
27. Mainshaft roller bearing, (Twenty-one needle rollers, no retain-
12. Roller bearing steel thrust washer, and cork oil retainer behind er. Rollers furnished undersize and oversize in steps of .OOOl".)See 11 Shop Dope"
clutch inner disc •••••••••••••••••••••••••••••••••••• Steel washer 2520-33 on Rollers
Cork retainer 2524-33
28. Roller bearing steel thrust washer and felt oil retainer on main-
13. Clutch gear roller bearing. (Thirty-one needle rollers, no retain- shaft behind sprocket ••••••••••••••••••••••••••••••••• Steel washer 2291-33
er. Rollers furnished undersize and oversize in steps of .COOl" •• See "Shop Dope" Felt retainer 2293-33
on Rollers

14. Thrust- bearing •••....••••••••••••••••••••.•••••• Retainer and balls 2521-33

Thrust race 2522-33

15. Clutch gear ••••••••••••••....•.••••.•••••..••••••.•.•••..•••...••• 2513-33

16. Mainshaf't end play adjusting spacer - between end of splines on

shaft and end of clutch gear. This spacer furnished .090'' to .140»
thick, in steps of .005». Use thickness required to adjust main-
shaft, free running to not more than .005 11 end play ..•••••..•••••• 2516-26

17. Clearanca between shifting clutch and clutch gear with shifter cam
in neutral position. With clutch gear turned so that highest
points of driving dogs on shifting clutch and clutch gear overlap
about 1/16" to 1/8 11 , insert narrow feeler gauge down through in-
spection opening in t~ansrnission top and between the ends of dogs.
Gap should be not less than .030 11 and not more than .037". Re-
adjust a~ necessary with shims No. 10.

18. Shifting clutch (second and high) ................................ . 2298-33A

19. Second gear retaining bracket •••••.••••.•••••••.•••••.••••••••••.• 2299-33

20. Socond gear •••••••••••••••••.•••••••••••••.••••••••••••••••••••••• 2295-33

21. Adjusting spacer - for adjusting side play of second and low gears,
between washer No. 24 at end of shaft splines, and retaining 29. Shifter cam shaft. To take out shaft and cam No. 8, it is first
bracket No. 19. This spacer furnished .032" to .041" thick, in necessary to remove complete clutch. Then, unlock shaft inner nut
steps of .003". Correct adjustment of this gear assembly, free washer, turn inner nut completely off its thread, and pull out
running to .003" side play •••••••••••••••••••••••.•••••••••••••••• 2294-33A shaft from clutch side ........................................... . 2235-33

22. Low gear •••••••••••••••••••••••••••••••••••••••••••••••••••••••••• 2294-33 30. Starter clutch •••••••••••••••••••••••••••••••.•••••••••••••••••••• 2165-32

23. Clearance between shifter fork and low and reverse gears, with shift- 31. Countershaft gear. Floating bronze bushing at right end. Roller
er cam in high position, should be l/4" either side of fork. Check bearing at left end (nineteen needle rollers with steel thrust
this adjustment with a l/4" thick gauge or feeler inserted through washer at each end of rollers, no retainer. Rollers furnished in
inspection opening in transmission top. Insert end of gauge all the undersizes and oversizes in steps of .OOOl") ••••• Countershaft gear 2303-33
way against shifting clutch so that spacing will be determined from Bronze bushing 2304-33
raised thrust face on side of low gear rather than near ends of teeth. Rollers See "Shop Dope,.
Re-adjust as necessary with shims No. 6. This adjustment applies also on Rollers
to a standard transmission without reverse gear, but fn the standard Inner washer 2305-33
transmission it is only necessary to gauge clearance between shifter Outer washer 2308-33
fork and low gear.
32. Reverse idler gear. (This gear left out in standard transmissions
24. Thrust washers {two) on rnainshaft at ends of splines •••••••••.•••• 2292-33 and nothing takes its place) ..................................... . 2365-33
No. 129 May 2, 1935 No. 130 May 8, 1935
A NEW AIR CLEANER
(Part No. 1401-35 -List Price $4.50)
A MORE POSITIVE GROUND FOR ELECTRIC SYSTEM
A new and very effective Harley-Davidson carburetor air cleaner is now
available. It is of the oiled screen~ and does a very thorough job In the past the grounded side of generator-battery circuit (from ammeter
of cathcinq any dust in the air that goes through it. When the screen to generator) was completed through fork fittings and frame head bearings.
has accumulated considerable dirt it can be easily removed, washed in Difficulties reported now and then such as repeated burning of lamp bulbs,
gasoline, and re-oiled. The cleaner has exactly the same appearance as excessive burning of circuit breaker points, missing, etc., have indicated
the regular 1935 carburetor air intake, but the end is closed and screen the probabilities of an occasional motorcycle with faulty ground through
pack is fitted in the back side. head fittings.
We strongly urge the immediate installation of cleaner on any motorcycles To be sur: of every motorcycle having positive ground hereafter, we are
operated under conditions that are at all dusty. This applies to motor- now shunt1ng the fr~me h:ad fittings out of the ground circuit by running
cycles driven all or part of the time on dirt roads, and particularly to a separate ground w1re d1rectly from grounded terminal of ammeter (left
motorcycles running in the sections affected by the unusual dust storms side terminal) to motorcycle frame. Ground wire is attached to frame with
being experienced this year. the screw that secures control coil clamp on left side of frame head. Com-
pleting the circuit in this manner eliminates any chance of faulty ground
Bear in mind that considerable road dust or abrasive dust from any source, as a source of trouble.
taken into motor through carburetor can bring about as much cylinder,
piston and ring wear in 3000 miles as normally should occur in 15,000 The new ground wire can be attached to any motorcycle now in service, with
miles or more. The result is loss of compression and piston slap at low switch panel and ammeter attached to fork triple clamp. We suggest you
mileage. Several cases of such premature wear have been called to our ·order out a supply of these ground wires and encourage installation on all
attention during the past few weeks from the dust storm sections. motorcycles not so equipped originally, particularly early 1935 models.
The cost is small and it is a safeguard against electrical difficulties.
While the air cleaner is not considered altogether necessary equipment
o~ motorcycles driven on hard surface roads in localities not affected Part number of ground wire- 4706-29. List price-$ .20
by dust storms, there is nothing against this equipment for general use.
It does not restrict intake to the extent of any appreciable loss in
motor performance.
NOTE: Air cleaner as equipped on new motorcycle is oiled when it leaves
the factory. When shipped on parts order, air cleaner is not oiled to
avoid possible oil damage to other parts packed with it. To place in
service, remove metal mesh pack, dip in oil, hang where hot to drain until
there is no further drippage, then re-assemble and attach.
No. 131 May 18, 1935 No. 132 May 22, 1935

ADJUSTING PRE-FOCUSED HEADLAMP

ADJUSTABLE BRAKE SHOE PIVOT STUD
Comparing the pre-focused type headlamp with earlier lamps, the pre-
focused lamp projects a smaller but much more intense beam of light.
In other words, it does not spread so much light to the roadside, but Starting with late 1934 models, all brakes are provided with adjustable
projects a high candlepower, clear vision beam a considerably greater shoe pivot stud. Previously this was a fixed stud.
distance ahead, where it is needed for fast night driving.
l~hen re-lining brake with adjustable pivot, attach new liners in the
This being the case, it is necessary that the pre-focused lamp be ad- usual way, but before re-assembling brake in motorcycle, loosen pivot
justed or aimed with greater accuracy. It's like the difference be- stud nut.
tween shooting with a shotgun or a rifle. If lamp is aimed too high
or a little to one side, the main light beam simply won't hit the After re-lined brake and wheel have been completely re-assembled in
road directly ahead as it should for good vision. motorcycle and axle tightened, apply brake with the maximum pressure
ordinarily applied in braking, and while brake is applied, tighten
Make provisions in your shop for very accurate adjustment of headlamp pivot stud nut.
when assembling on new motorcycle or when re-adjusting. Don't just go
by apparent correct setting of lamp body in relation to fork and This adjustment offsets irregularities about new or relined shoe
handlebars. Adjust according to light beam. At a distance of 25 feet, assemblies, and allows shoes to find positior. where liners have full
with handlebar switch in upward (bright) position, top of main beam of contact with drum when brake is applied. The result is maximum brake
light should be no higher than the center of lamp. Some moderate speed efficiency.
drivers are better satisfied with the light beam a trifle lower. See
Rider's Handbook for further lamp adjusting suggestions. After p1vot stud adjustment has been made, brake control can then be
correctly re-adjusted.
 No. 137-E December 9, 1935
No. 137 November 18, 1935
NEW OIL WASHERS FOR TRANSMISSION - 1935 45 MODEL INSTALLING LATEST (1936) OIL RETAINING WASHERS IN 1935 TRANSMISSION 45" MODEL ONLY

A new type oil washer is now used behind clutch in the 45 model transmission. This The latest oil retaining washer behind clutch is a much more dependable oil seal than
change went into production starting with motor #35R3466 and including a few lower the original washer used in 1935, which was a cork washer, The new washer is leather
motor numbers, listed at foot of this bulletin. The original oil retainer behind with a rubber expander and metal retainer. It has applied to a 11 1936 45" models,
clutch was a cork washer. The new washer is leather with rubber expander, in a and a few later 1935 models starting with motor 35R-3466.
metal retainer.
This new oil washer behind clutch is not interchangeable with earlier cork washer, but
The new oil washer is not interchangeable with earlier cork washer, but can be applied can be applied to earlier transmissions (all 1935 45"s, including Servi-Car and 1934
to earlier transmissions (all 1935 45's, including Servi-Car, and 1934 45 reverse) by 45" reverse). By exchanging clutch inner disc for a later one, or by enlarging some-
installing new inner clutch disc, part#2528-33. Latest inner disc under this part No. what in a lathe, the retainer recess in back side of original inner clutch disc.
furnished on parts order is complete with the improved washer. Part No. of the new
washer only (complete with retainer) is 2524-36. The original cork washer used with Part numbers and prices applying to inner disc complete, and old and new oil washers
earlier disc c~n also still be obtained under part #2524-33. are:

If you have any early 1935 45 models that have been giving you considerable trouble with Part No. List Price
transmission oil leakage behind clutch, which you haven't been able to correct satisfac- 2528-33 Inner clutch disc, complete with latest oil 11asher $ 4.80
torily by installing new cork washer, we suggest you change the inner clutch disc for one 2524-36 New Oil washer only (complete with metal retainer) .50
with the improved washer. For machines that need this service, you can order in the 2524-33 Cork Washer (as originally equipped 1935) .10
regular way the required number of new discs, exchange them, and then if original discs
are returned with no damage other than normal wear and tear, we will give you full credit.
There is also an improved oil washer behind the 1936 countershaft sprocket. This new
When you order discs for this no charge exchange, please order only a reasonable number was'her cannot be fitted to countershaft sprocket equipped on 1935 models. However, all
at a time, and be sure to mark your order plainly "for exchange" because for this service, new countershaft sprockets supplied on parts orders will be furnished with new type
we rnay furnish slightly used discs that have been returned and corrected to adapt the washer installed, and therefore as original 1935 sprockets become worn and have to be
new washer. When you return for credit original discs that you have exchanged, see that replaced, this oil washer change will take care of itself. The following part numbers
each one is tagged with motor number so we can keep our records straight at the factory. and prices apply to new sprocket and old and new style oil washers:
Rernember, the name and part number are: Inner Clutch Disc #2528-33. Bear in mind also Part No. List Price
that tnis disc fits only the later 45 transmission (all 1935's and 1934 reverse). Models
only with motor # below 35R3466 are to be considered for disc exchanges. 2035-33 16 tooth sprocket complete, with new oil washer $ 1.50
2293-36 New leather oil washer only (with metal retainer) .25
This inner disc no charge exchange offer is good only til February l, 1936. After that 2293-33 Felt Washer as used with 1935 sprocket .05
date there will be a service charge of 85¢ net, per disc.
In removing and replacing clutch inner disc, you will need a new wrench to take off and
There is also a new oil washer behing the countershaft sprocket in later 45 transmission, replace disc nut. If you already have 45 clutch wrench 12745-26, all you will need to
but as the original felt washer at this point has done a good job, we are not suggesting order is adapter 12745-36, which completes this wrench for the later type clutch disc
that this washer be replaced with the new type until the original sprocket becomes worn nut. If you don't have this wrench, you should order it with your next parts order.
out and has to be renewed. All new sprockets furnished on part order will be furnished Part numbers and prices follow:
with new type washer installed. The new washer cannot be fitted to earlier sprocket.
The following part numbers apply to this sprocket and oil washers: Part No. List Price
16 tooth sprocket compete with new oil washer #2035-33 12745-26 Wrench complete with adapter $ 5.00
New leather oil washer only with retainer #2293-36 12745-36 Adapter only for late clutch disc nut 1.00
Original felt washer #2293-33
The transmissions in following machines below #35R3466 are fitted with latest oil washers:
35RL 3222 35RL 3225 35RLD 3391 35R 3456 35R 3463
RL 3223 35RL 3226 35R 3452 35R 3459 R 3464
RL 3224 35RLD 3381 35R 3453 35R 3461 R 3465
No.l40 April 20, 1936 No. 142
61 OVERHEAD MOTOR - OIL REGULATION
lj:,:fddVE !Cf S!IAU lltp P!/KCH
(Refer to 61 rider instruction folder to look up illustration numbers given below)
tufK 1/t Hd(/_5(Ht; A,ff SNtJW/t
JIY AUYHI"'f£1'1' r Late 61 motors are running much higher oil mileage than earlier motors. This is not a
matter of pump readjustment. It is a change in pinion gear shaft through which oil
passes into motor. This change went into production with motor No. 36EL1755 and also
applies to a few odd motors of lower number, listed at bottom of this bulletin.
We suqoest this chanoe in all earlier motors for better oil control. Pinion gear and
shaft assembly No. 1~ Illustration 5, is the part to be changed. Order No. 356-36A
Original gear and shaft assemblies are returnable for credit, if returned within rea-
sonable time, tagged with motor number, and not damaged outside of normal wear.
It is a simple job to make this change. First remove gearcase cover as shown in Illus.
5. Removino front exhaust valve pus rod will relieve cam gear of valve load (with gear
marks in alignment) while making the change. Bear in mind that pinion shaft tongue and
groove register if off center for one-way assembly. Don't start it wrong and try to
force it. Be careful to get all gears back in place with marks in correct alignment.
Note that gear case cover gasket is in good order, particularly around breather pocket
in lower, rear corner of gear case as a leak betwben gear case and breather pocket will
likely result in excessive oil discharge through breather into chain guard no matter how
chain oil regulating screw in pump body may be readjusted.

Lat~ - Cl 11 :.!odels Normally high oil mileage also depends to a great extent on regulation of oil to valve and
front chain so there is not over-oiling and oil waste at these points. Furthermore, close
~~~~i~~ of rocker 3tafts regulates oil to v~l~es. regulation so that valves don't over-oil, but get only the slight smount of oil necessary
for lubrication has a lot to do with good carburetion and good motor performance. If
~rig:r'-al f::tctory :;eT;"t::..::.g is ir:dicnteC. by groovA i~ :ig!tt ~":.d o.:.~ o?ac!: s}:a:'t ·;.:-:i :-ur.c~ intake valve particularly are over-oiling, too much oil will be sucked into cylinder heads,
:<.ark i::. alur.:.ii'.U::L ::ousi:1g. through valve guides, on intake stroke, and over-oiling from this source has the same
results in the way of heavy exhaust smoke and plug fouling as over-supply of oil to crank-
Sir:ce adjustme!1t must be very fi:-:.e for only a very small amount of oil to ·ralves, case and too much oil passing pistons and rings. Plugs wet with oil and partially fouled
original setting may not be jt:st right for all valves and fur-':her adjustment >Tl:?..Y be make a motor lope and miss at low speeds and pop back through carburetor.
rel!_'.lir9d. :'oo little oil will be indicated '0y valves rurtr.ir..g jry ar~d squea:{ing ..
OvProiling ·.'fill be indicated by oil splashing from sprir..g covers. Of course t.~ere Readust screw that regulates front chain oiling until only a small amount of oil is dis-
will :to1'1!:ally be a llttle oil va~or or spray f'rom covers even ·rith correct oiling. charged occasionally from front chain guard, rather than a continual heavy discharqe that
not only wastes oil , but also smears up rear wheen and rear end of motorcycle. Descriptc
I'o adjust for rr..or~ or less oil to any valve, remove rocker shaf't ::1uts, and -;::'...aT.. ion No. 33, below Illus. 2 explains chain oiling adjustment. Chain oiling in connection
as indicated by arrown.
s;;.a.:.... t with early motors will take finer regulation after pinion gear shaft change described
above because with decreased oil supplied to motor base, there will be less oil mist exc
"N:b.e:-1 ren.d.~usting, turn shaft onlv 11 little at a time, about l/32n to l/l3". hausted through breather directly from crankcase.
C-::~c r.e'."l ~or;or -.r3.lve oilir..g tas been :"'?g;uln.t:e·:<.. ar,d }:as ;;one n.lon;s sat:!..3f'J.c"'cor:l:r ~'or Shop Dope No. 140 explains how to regulate oil to valves. Readjust for lightest possible
'l ::!..:.1e, :J::o·.1: i f:\ ·rn.l-T'3 ccYer tr.~r. :""':.:i.l ·v:tL oi~ :1~d S?lash ov~r, it is ?rob:3.';--l~-p L~:"! oil supply.without shuttin9 off entirely. Valves require very little oil for good lub-
-c -::::e :-.o.-r·.,:--. ~ .:.::.<? ~:~Q:·~ 0o~rer to :-oc!..:e!" :~o:..:si:.g ::eco:r:.:!.:.;s clogt;"'ci ·vit:-t ::'fl.r-::c~es of rication. Over-supply affects motor performance as explained above, besides wasting oil
-::.,..--::: cr -:-;.:---o;.. =:!""": ::·.1.:-: Go.::;P -:.:!.:;co;::-:ec>: r~L".Jr:: 2.i~e f:-o:-:1 rocke1~ >.O"'J.si::;: ~::.:. :-:o"r
around valve spring covers. If now and then a valve cover accumulates and splashes out
~:- ~ :- ~~ ~~~, --.~ ~ ~:-~~:. -::o··:~~: . ,.c~~ ~~-:~~~-~~e~~: . ~;~e _~;~:~~~; ~ f~~~~a:~~::. ~ ;~~~~~-;: ~~:~: 0 ::~~;:~; •
an excessi.ve amount of oil, and readjusting rocker shaft for less oil doesn't seem to
correct this condition, it is likely that pipe from spring cover to aluminum rocker
housing is clogged with dirt and consequently surplus oil in spring cover is not being
sucked back by motor base vacuum. The remedy in this case is to disconnect pipe from
aluminum housing nipple, blow out pipe with air hose, and clean out hole in nipple.
No. 142 -2- July l, 1936

In any case where a rocker arm shaft and valve appear to get too little oil, or no oil
at all, and readjustment for more oil doesn't get results, first disconnect oil feed
pipe at aluminum rocker housing to be sure oil is getting that far, then clear obstruc-
tion with air hose or remove rocker shaft and clean out oil passages. A light obstruction
can very often be cleaned out with air hose without removing shaft.
With the new pinion shaft and other attention described above, oil mileage may run any-
where from 200 to 400 miles per quart or possibly even more, depending on speed and op-
erating condition>. Moderate driving means high oil mileage, but as drivinQ speed goes
up, oil mileage goes down. A motor in sidecar service can naturally be expected to use
more oil than a solo motor.
Use "Regular Heavy" oil for summer service. This grade of oil is heavy enough for any
kind of service and heavier oil should not be used.
Latest ignition timing for the 61 motor is 7/16" before top center. Earlier 61 motors
were timed 3/8". As 7/16" timing effects worthwhile improvement in carburetion and all
around performance a 11 early motors should be checked and reset accordingly.

Motors below 36EL1755 fitted with latest pinion shaft:

1754 1732 1687 1420
1753 1731 1680 1400
1752 1730 1666 1363
1751 1729 1645 1347
1750 1727 1629 1307
1749 1726 1595 1298
1748 1725 1594 1294
1747 17~4 1588 1235
1746 1723 1581 1203
1745 1721 1566 1183
1744 1720 1542 1175
1743 1719 1531 1135
1742 1716 1521 1134
1741 1714 1519 1121
1740 1712 1518 1118
1739 1708 1507 1089
1738 1704 1506 1087
1737 1703 1489 1083
1736 1700 1480 1081
1735 1699 1441 1053
1734 1697 1436 1018
1733 1693 1434
 In some oases best results may be found using a colder plug in one cylinder
than in the other. In this case it is usually the front cylinder that takes
the colder plug as this cylinder is not as likely to foul plUg at low speed.
Here's the thing to bear in mind: The colder the plug that can be used with-
No. 144 September 9, 1936 out running into fouling difficulties and hard starting, the longer plug life
will be, and the less chance there is of engine failure and damage from pre-
HE71 SMALL-BASE PLUG ignition and overheating.
Cnly this t~r~e plug will be supplied from now on. It supersedes all other big-base 4 - The core tip of a plug in hot service will in time, possibly only a si1or'o ti::1e,
regular ~~d special plugs supplied in the past. acquire a brownish, glassy coating. This oxide coating is a conductor ,.;,:en
hot, and will cause missing at high speed or under heavy motor load. ?cugs
shou1d be cleaned regularly to remove this coating.

5 - Do not take plugs apart to olean, nor try to save a few oents by installing
new core only when a plug has to be renewed. Reassembling without proper
equioment for adjusting and testing, runs into a hie;h percentage of !'ailur~s
due to leakage and oore oraoking. These things very often contribute co
serious motor trouble.
T!-le recommended method of cleaning is ·.vi th a. sand-blast cleaner found :!1 ~carl:l
every servioe station.

6 -Correct plug gap is .025 to .030 inch. Since g~p increases slowly with use due
to gradual burning away of electrodes, plugs should be checked and reset occa-
sionally. When re-gapping, adjust only the base electrode, as bending center
electrode will break porcelain oore. For high speed service it is '.<ell to act-
just gap to low limit ( ,025") ,

Nllr ANJ.-.!17~11 .37-<>,JI 7 - This new series of plugs gives you an assortment with which you can :neet the
requirements of any normal engine in any sort of use. Carry a compler.e stock.
&6NIA AIIIMLII~S-t:l:l.t.lJI.e Pl/Mr , - HI6H
_._I".Uit>N' .IN» #ll.eZ> MIVEN Mt>""-S
(irate - Tl>e two-piece cast !lluminum plug shield furnished ·.'rith 1935 ar:d earlie!"
radio-eqt'dpped motorcycles requires ~L"l adapter to fit it to t~~e nevr ::lug. r::e
nu;:>ber of this adapter set for two plugs is 8371-36, list price 50ft'.· Tioe lat-
er stamped plug shield fits either largo or small base plug.)
1 -. Plugs Nos. 1 and 2 are equipment plugs in new motors. No. l in low compression
motors, and No. 2 in high compression motors.
Nos. 3, 4 and 5 are special plugs, particularly No. 5 which is an extra cold HARLEY-DAVIDSON MOTOR CO.
plug for extremely hard service. Milwnukee, Wis., U.S.A.

2- After a new motor~ gone through its running-in period, colder than equipment
plugs may be needed, depending on compression ratio and how hard motor is driv-
en. This cannot be determined by compression ratio alone, as some high compr.es-
sion motors see very moderate service, and some low compression motors are
driven very hard.

3- If, in a ~otor in average good condition as concerns valve seating, compression,

timi!'lg,. etc., plugs after a short time in use are found. -.vi th cores blistered,
cracked or par"tis.lly burned a-..vay, this indicates the !'leed of either a !'icher
hi~~ speed car~uretor adjustment or colder ?lugs. I~f !Jl'.lgs are fou.."'!d ·~tith an
accu.":lula-cion of oily soot or carbon, and ?Ossibl~\~ fouling di~!'iculty :..s exper-
:enced, t:1is ind:.cates -t:b.e need of ei-i;her reduced oil supply or hotter ?lugs.

(See cthe~ s::.e)

 No. 147 November 4, 1936
No. 146 November 4, 1936
USE THIS RETAINER
NEW TRANSMISSION MOUNTING
Applying to all 1937- 61, 74 and 80 models, also a few of the latest 1936 61 models, the
transmission is secured at five points instead of only four as in the past. Besides the
four clamping studs with which you are familiar, there is a clamp bracket on frame under-
neath starter side of transmission, and a cap screw through this bracket secures the
transmission at this point. When this change was first made, a bracket fitted to trans-
mission end completed the clamping arrangement, however, in connection with later trans-
missions this bracket has been eliminated by a boss cast interoral with transmission case.
Either way, the frame bracket remains the same. ·
Bear this in mind and caution your riders of the models mentioned that when there is
occasion to free transmission when re-adjusting front chain they have four nuts and a cap
screw to loosen instead of just four nuts as mentioned in all instructions that have gone
out up to this time. Also remind them to be sure to tighten cap screws as well as nuts
after chain adjustment is completed.
You will recall that earlier 1936 - 61 models had only an adjustable supporting screw
under the riqht side of transmission to take the kick starter load and as this screw
head merely rested on frame tube, it did not require atte"ntion when loosening transmission
for chain adjustment.

This is a reminder that you should use only retainers identified with
groove around the outside diruneter in servicing lower connecting rod
bearings, all models, as this is an improved and stren&thened retainer
developed especially for lcwer rod bearing. For sane time, only this
type of retainer has been used in new motor assembly and supplied on
parts order and with rod assemblies sent back to the facto~J for recon-
ditioning.

In overhauling older motors that may need refitting of lower connecting

rod bearing to take up excessive clearance, unless inspection proves that
the retainers are of latest type with identifying groove, it is advisable
to replace them with new ones even though they may appear to be in good
condition.

If you have any retainers of earlier type in stock set them aside to be
used in servicing other than lower connecting rod bearings.

HARLEY-DAVIDSON MOTOR CO.

Y!ilwaukee, Wise .. 11 U.S.A.
No. 149 18. 1936
SPECIAL November 30, 1936
74 CU. IN. TWIN MOTOR FITTING SPECIFICATIONS
NOTE: These supersede all previous specification (last
Ap.rv.s T//Y~ specication sheet dated May 15, 1934) and apply to all
1930, and later 74" motors.
PISTON CLEARANCE -- ALUMINUM PISTON - 2 slot, cam ground type - New
piston fitted in straight bore cylinder, .001" to .002" clearance. Piston
shapes to cylinder and acquires more clearance after short· time in service.
Measure 2-slot piston at bottom of skirt, front and rear
PISTON-CYLINDER HEAD CLEARANCE --(All models except VC Commerical)
1/16" to 3/32" (VC CoTmJercial, discontinued after 1933) 7/64" to 9/64"
PISTON PIN IN ALUMINUM PISTON -- 2-slot type - light hand press fit.
PISTON PIN IN UPPER END OF CONNECTING ROD . . . . . . . . . .001" 1oose
PISTON RING GAP AND GROOVE CLEARANCE-- Straight bore cylinder .010" gap Y,"
from top of cylinder. Rings should be .0015" to .002" loose in piston grooves.
LOWER CONNECTING ROD BEARING . . . . . . . . . . . . . . . 001" to .00125" loose
),!AKE THIS READJUSTMENT
CONNECTING RODS -- .006" to .010" clearance between flywheels -- roller and
Readjust oi1 pressure regulator of all - retainer assembly should be narrower, but not more than .010" narrower than
front rod.
1937 - 45 motors below 37 W 1289
PINION GEAR SHAFT .0045" loose at inner end of bushing -- .002" loose at
1937 - 74 and 80 motors below 37 UL 2177 outer end of bushing (Bushing is taper reamed with special reamer).
Turn regulator adjusting screw all the way down until it bottoms lightly SPROCKET SHAFT -- .0005" to .001" loose in roller bearing -- .006" to .007"
against ball. Do not force it. Then, back up adjusting screw~~ loose in oil retaining bushing.
turns.
FLYWHEEL ASSEMBLY -- .004" to .008" end play in crank case
Normal oil mileage for these models is 200 to 400 miles per quart, de-
pending on nature of service, fast or moderate driving, etc. With the CAM GEARS -- .0005" to .001" loose in crank case and cover bushings -- free
above recommended readjustment made, if it is then found after further to .005" end play.
service that oil mileage is not running within the normal range, read-
just further. INTERMEDIATE GEAR -- .001" to .0015" loose on stud
Turning adjusting screw imvard (to right) increases pressure and lowers TAPPET GUIDES .0005" to .001" press fit in crank case
oil milea~e. Turning adjusting screw outwarr~ lowers pressure and raises
oil mileage. VALVE TAPPETS .0005" to .001" loose in tappet guides.
EARLEY-DA'JIDSON MOTO.. : CO.
:~ilwaukee, 7lis., U.S.A.
::OTE - Be sure to insert screw dri"Ter in shallow slot in adjusting screw
c.ead. If inserted in deep slot, screw hee.·i ·:Jill be expanded and ·:redged
ma~ng it very hard to turn.
 No. 150 January 8, 1937
January 8, 1937 74 AND 80 CU. IN. TWIN MOTOR FITTING SPECIFICATION (1930 TO AND INCLUDING 1936)
SPECIAL
MOTOR FITTING SPECIFICATIONS PISTON CLEARANCE - Iron Alloy Pistons -Used in 1930-34 motors fitted with taper bore
cylinder- .004" to .005".
1925 to 1929 61 cu. in., and 74 cu. in. Motors ALUMINUM & DOW METAL PISTONS -Solid skirt type - used in 1930-34 motors fitted with
taper bore cylinders- .016" to .018".
PISTON CLEARANCE: Iron Al;,oy 1925 to 1929 61 cu in. motor - .002" to .00275"
Pis~ons ALUMINUM PISTON - Slotted, earn ground type - New piston fitted in straight bore
74 cu. in. .003" to .004" cylinder, .001" to .002" clearance. Piston shapes to cylinder and acquires more
Aluminum &Dow Metal Pistons 61 cu. in. .Oll5" to .0135" clearance after short time in service.
74 cu. in. .0135" to .0155" Measure solid skirt piston at bottom of skirt, front and rear. If piston has vertical
(Measure all pistons just below the top group of rings and cylinders about 1/2" from slot in addition to horizontal slots, fit with vertical slot forward.
top of bore, front and rear)
Measure cy·l i nder about !," from top of bore, front and rear.
PISTON PIN IN IRON ALLOY PISTON --.0005" to .001" press fit in lock pin side -- plug or PISTON - CYLINDER HEAD CLEARANCE - (All modes except VC Commercial) l/16" to 3/32"
slip fit in opposite side. (VC Commercial, discontinued after 1933) 7/64" to 9/64"
PISTON PIN IN ALUMINUM & DOW METAL PISTONS -- Snu9 press fit - not over .0005" tight PISTON PIN IN IRON ALLOY PISTONS -- .0005" to .001" press fit in lock pin side - plug
or slip fit in opposite side.
PISTON riN IN UPPER CONNECTING ROD END (all models) - .001" loose PISTON PIN IN DOW METAL &ALUMINUM PISTONS - Solid Skirt type - .0005" to .001" press
fit in piston.
PISTON RING GAP AND GROOVE CLEARANCE -- .025" to .035" measured l/2" from bottom of bore.
Rings should be .0015" to .002" loose in Dow Metal piston grooves, and just free in Iron PISTON PIN. IN ALUMINUM PISTON - Slotted type - Light hand press fit.
piston grooves. PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose
LOWER CONNECTING ROD BEARING -Motors fitted with Iron Alloy Pistons-.0002 to .0003" loose PISTON RING GAP AND GROOVE CLEARANCE - Taper bore cylinder .006" !laP !," from top of
Motors fitted with Aluminum or Dow Metal Pistons - .0004" to .0006" loose cylinder. Straight bore cylinder .010" gap!," from top of cylinder. Rings should be
.003" loose in Dow Metal &Aluminum piston grooves and just free in Iron piston grooves.
CONNECTING RODS (All models) -- .006" to .010" clearance between flywheels - roller and LOWER CONNECTING ROD BEARING - .001" to .00125" loose.
retainer assembly should be narrower, but not more than .010" narrower than front rod.
CONNECTING RODS - .006" to .010" clearance between flywheels - roller and retainer
PINION GEAR SHAFT - Motors fitted with Iron Alloy Pistons - .0035" loose at inner end of assembly should be narrower, but not more than .010" narrower than front rod.
bushing -- .002" loose at outer end of bushing. . . PINION GEAR SHAFT - .0045" loose at inner end of bushing - .002" loose at outer end of
Motors fitted with Aluminum or Dow Metal Pistons -- .004" loose at 1nner end of bush1ng bushing (Bushing is taper reamed with special reamer.)
.0025" loose at outer end of bushing (Bushing is taper reamed with special reamer.)
SPROCKET SHAFT-- .0005" to .001" loose in roller bearing - .006" to .007" loose in
SPROCKET SHAFT (all models) - .0005" to .001" loose in roller bearing oil retaining bushing.
FLYWHEEL ASSEMBLY - .006" to .010" end play in crank case
FLYt•IHEEL ASSEMBLY (all models) -- .003" end play in crankcase
CAM GEARS - .0005" to .001" loose in crankcase and cover bushings - free to .005" end
OILER GEAR, INTERMEDIATE GEAR & GENERATOR DRIVE GEAR (All mode 1s) -- . 001" to . 0015'' play.
loose on studs. INTERMEDIATE GEAR- .001" to .0015" loose on stud.
CRANK CASE BREATHER -· 1/16" to 3/32" open when front piston is on top dead center lAPPET GUIDES - .0005" to .001" press fit in crank case
(opening must be on forward side of port in crank case) VALVE TAPPETS - .0005" to .001" loose in tappet guides
 No. 150B January 8, 1937
No. 150A January 8, 1937
61 CU. IN. TWIN MOTOR FITTING SPECIFICATION (O.H.V. MODELS)
74 AND 80 CU. IN. TWIN MOTOR FITTING SPECIFICATION (1937 MODELS)
PISTON CLEARANCE -ALUMINUM PISTON -- Slotted, cam ground type -new piston fitted in
PISTON CLEARANCE - ALUMINUM PISTON - Slotted, cam ground type - New piston fitted cylinder .001" to .002" clearance. Piston shapes to cylinder and acquires more clear-
in straight bore cylinder, .001" to .002" clearance. Piston shapes to cylinder and ance after short time in service. Measure piston at bottom of skirt, front and rear.
acquires more clearance after short time in service. Measure cylinder about 1/2" from top of bore, front and rear.

Measure piston at bottom of skirt, front and rear. If piston has vertical slot in PISTON PIN IN PISTON -- Light hand press fit
addition to hbrizontal slots, fit with vertical slot forward. Measure cylinder about
1/2 11 from top of bore, front and rear. PISTON PIN IN UPPER END OF CONNECTING ROD -- .001" loose

PISTON-CYLINDER HEAD CLEARANCE - 1/16" to 3/32" PISTON RING GAP AND GROOVE CLEARANCE-- .010" gap~" from top of cylinder. Rings
should be .003" loose in grooves.
PISTON PIN lN PISTON -- Light hand press fit
LOWER CONNECTING ROD BEARING - .001" to .0015" loose
PISTON PIN IN UPPER END OF CONNECTING ROD .001" loose.
CONNECTING RODS .006" to .010" end play between flywheels - roller and retainer
PISTON RING GAP AND GROOVE CLEARANCE - Straight bore cylinder .010" gap Y," from top assembly should be narrower, but not more than .010" narrower than front rod.
of cylinder. Rings should be .003" loose in grooves.
SPROCKET SHAFT & PINION GEAR DRIVE SHAFT - .0005" to .001" loose in roller bearing
LOWER CONNECTING ROD BEARING --- .001" to .0015" loose .007" to .009" loose in oil retaining bushing.

CONNECTING RODS - .006" to .010" clearance between flywheels - roller and retainer PINION GEAR STUB SHAFT ASSEMBLY- Cork sealed, oil tight fit in flywheel shaft with
assembly should be narrower, but not more than .010" narrower than front rod. copper washer behind - .001" to .0015" loose in cover bushing. Oil hole in caover
bushing is centered with drilled oil feed channel in cover.
PINION GEAR SHAFT - .0005" to .001" loose in roller bearing - .007" to .009" loose
in oil retaining bughing, and .0005" to .001" loose in cover bushing. Oil hole in FLYWHEEL ASSEMBLY - .012" to .014" end play in crank case.
cover bushing is 30 ahead of top center, and in line (on opposite side) with drilled
oil feed channel in cover. CAM GEAR - .001" to .0015" loose in crank case and cover bushing - free to .005"
end play.
SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .007" to .009" loose in oil
retaining bushing INTERMEDIATE GEARS - .001" to .0015" loose - free to .005" end play

FLYWHEEL ASSEMBLY .012" to .014" end play in crank case TAPPET GUIDES -- .0005" to .001" press fit in crank case.

CAM GEARS -- .0005" to .001" loose in crank case and cover bushings - free to .005" VALVE TAPPETS - .0005" to .001" loose in tappet guides.
end play.
ROCKER ARM FIT ON SHAFT - .0005" to .0015" loose - .003" to .006" end play
INTERMEDIATE GEAR -- .001" to .0015" loose on stud
OIL PUMP DRIVE SHAFT - .001" loose in crank case bushing.
TAPPET GUIDES - .0005" to .001" press fit in crank case
CRANK CASE BREATHER - Timed with front cylinder - opens 1/8" before top center to 1/8"
VALVE TAPPETS -- .0005" to .001" loose in tappet guides after top center, and closes 13/16" to 15/16" after bottom center.

CRANK CASE BREATHER- ~~ich is a part of, and drives scavenger pump, is timed
according to instructions in Rider Instruction Folder.
~~.~~Et:
':P. ~ )OC
:,··, Cll.
Jamwrv 9.

IN. TIHN ~!OTOR FTTTfN<; SPECTFICAT10NS - (1930 to and JNCT.lmTNC 1936)

No. l50n Jnnn;Jl ,. H, In ~7

f,!f1TE: These sup2rcede all prE>vious specification and apply to all 1930 to, and in-
PTSTON CLEARANCE- i\JJJ~fTNUH PTSTt)N -- Slotted, cam gronnd typ(~ - lW'-'l pi~;t(•!l fit tr·cl in
l'll!di;Jg 19'36 45" motors except RLDR model.
straight horP. cylinder, .001" tP .002" clearnnce. "Plst0n .<>lmpf's to , . .,.J ind 1 'l" nnd "' qnir".';
PISTON \.Lf.ARANCE - ALllNTNTlH AND DOW HETAL PISTONS - Solid Skirt type - used in 1934 mort' c1enrance after short time ir. :=.ervicP.
;md earlier ffi(1tors fitted with taper hnre cylinders - .014" to .016" HeasurP piston at bottom of skirt, front and rear. If piston lms vert it :!1 :dpf in
,\J.f1!1IN\TH PISTON- Slotted, cam ground type - ne>; piston fitted in straight bore cylinder. addition to horizontal slots, fit with vertical slot forward. r-fe,,sure r:y! indt•r .1h"ut
.001" to .002" clearance. Piston shapes to cylinder and acquires more clearance after ~2" from top of bore, front and rear.
short. time in service. Measure solid skirt piston just helow the top group of rings.
HPas 11 rc slotted piston at bottom of skirt, front and rear. If piston has verticial slot PISTON-CYLINDER HEAD CLEARANCE -- 1/16" to 3/32"
in addition cr-horizontal slots, fit with vertical slot forward. Measure cylinder about
1;;" from top of hare, front and rear.
PISTON PIN IN PISTON Light hand press fit

PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64" PISTON PIN IN UPPER END OF CONNECTING ROD -- .001" loose

PISTON PIN IN ALIJNINUM AND DOH METAL PISTONS - Solid skirt typE> - .0005" to .001" press PISTON RING GAP AND CROOVE CLEARANCE -- Straight bore cylinder - .OJO" gap,, .. from top
fit in piston. of cylinder. Rings .should be .003" loose in grooves.

PISTON PIN IN ALIJNINTJH PIS'! ON - Slotted type - light hand press fit. LOWER CONNECTING ROD BEARING -- .0007" to .001" loose

PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose CONNECTING RODS .006" to .010" end play between flywheels -- roller and reta irwr
assembly should be narrower, but not more than . 010" narrotver than front rod.
PISTON RINC GAP AND GROOVE CLEARANCE - Taper bore cylinder - .006" gap !-:;" from top of
cylinder. Straight bore cylinder- .010" gap!-:;" from top of cylinder. Rings should be PINION (;F.AR SHAFT -- .00075" to .00125" loose in roller bearing - .006" to .007" lnor;p
11
.003 loose in grooves. in oil retaining bushing, and .0005" to .001" loose in cover hushing. Oil lwl<' in
cover bushing is 30° ahead of top center and in line (on opposite sid~) with rlrifled
LOHER CONNECTING ROD BEARING - .0007" to .001" loose oil feed channel in cover.

CONNECTINC RODS - .006" to .010" end play between flywheels roller and retainer SPROCKET SHAFT-- .0005" to .001" loose in roller bearing- .006" to .007" loosp in oil
assembly should be narrower, but not more than .010" narrower than front rod. retaining bushing.

PINION CEAR SHAFT - .0045" loose at inner end of bushing - .002" at outer end of bushing. FLYWHEEL ASSEMBLY -- .012" to .014" end play in crank case
(Bushing is taper reamed with special reamer)
CAH GEARS -- .0005" to .001" loose in crank case ang cover bushings -- free to .nor,"
sPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in oil end play.
retaining bushing.
TAPPET C:\liDES - .0005" to .001" press fit in crank case.
FLYHHEEL ASSEHBLY - ,004" to .006" end play in crank case.
VALVE TAPPETS -- .0005" to .001" loose in tappet guides
CAN C:F.ARS - . 0005" to . 001" loose in crank case and cover bushing - free to · 005" end play
CRANK CASE BREATHER - Which is a part of, and drives scavenger pump, is timed accord inr,
r.ENE~\TORDRIVE CEARS AND SHAFT (1931 and earlier models) - Shaft must be free running to instructions in Riders Instruction Folder.
fit; have .002" to .004" end play, and .001" to .0015" clearance in bearings. Small
bevel gear should he .002" to .003" loose in bushing assembly, and shimmed to allow
.002" to .004" clearance between bevel ~ears.

TAPPET CUIDES - .0005" to .001" press fit in crank case

VALVE TAPPETS - .0005" to .001" loose in tappet guides

 No. 150F January 8, 1937
150E January 8, 1937
TIMING SPECIFICATIONS
SINGLE MOTOR FITTING SPECIFICATION - (ALL 1934 AND EARLIER) 1930 AND LAT~R 74 & 80 CU. IN TWIN ALL MODELS EXCEPT 1930 and 1931
PISTON CLEARANCE -- Dow Metal and aluminum -- .011" to .013" (Measure piston just below V AND VC MODELS
the top group of rings, and cylinder about 1/2" from top of bore, front and rear.·)
INTAKE VALVE - OPENS when piston is - 9/32" to 13/32" before top dead center
PISTON-CYLINDER HEAD CLEARANCE (Side by side valve models) -- 3/64" to 5/64". CLOSES when piston is - 7/8" to 1-1/8" after bottom dead center.

PISTON PIN IN PISTON -- Snug press fit -- not over . 0005" tight. EXHAUST VALVE - OPENS when piston is 5/8" to 7/8" before bottom dead center
CLOSES when piston is 1/4" to 3/8" after top dead center
PISTON PIN IN UPPPER END OF CONNECTING ROD -- .0005" loose
IGNITION OCCURS when piston is 5/16" to 3/8" before top dead center on compression
PISTON RING GAP AND GROOVE CLEARANCE -- .006" gap 1/2" from top of cylinder. Rings should stroke. 3/8" timing (flywheel mark at rear of crankcase inspection hole) applies to
be .0015" to .002" loose in grooves. moderate compression motors in solo service. High compression solo motor (8.2 heads)
also all motors in sidecar service should be timed 5/16".
LOWER CONNECTING ROD BEARING -- .0003" to .0004" loose
1930 AND 1931 74 CU. IN. TWIN V AND VC MODELS
CONNECTING R0DS .010" to .020" end play between flywheels -- roller and retainer
assembly should be narrower, but not more than .010" narrower than rod. INTAKE VALVE - OPENS when piston is 11/64" to 19/64" before top dead center
CLOSES when piston is 9/16" to 13/16" after bottom dead center
PINION GEAR SHAFT -- .0035" loose at inner end of bushing -- .0025" loose at out end
of bushing. (Bushing is taper reamed with special reamer.) EXHAUST VALVE - OPENS when piston is 9/16" to 13/16" before bottom dead center
CLOSES when piston is 11/64" to 19/64" after top dead center
SPROCKET SHAFT -- .0005" to .001" loose in roller bearing - .006" to .007" loose in
chain l~bricating bushing. IGNITION - OCCURS when piston is 1/4" to 5/16" before top dead center on compression stroke

FLYWHEEL ASSEMBLY -- .002" to .006" end play in crank case 1936 AND LATER O.H.V. TWIN MODELS

CAM GEARS -- .0005" to .001" loose in crank case and cover bushings -- free to .005" INTAKE VALVE- OPENS when pi'!ton is 15/32" to 17/32" before top dead center
end play. CLOSES when piston is 15/16" to 1-1/16" after bottom dead center

INTERMEDIATE AND OILER GEARS -- .0015" to .002" loose on studs EXHAUST VALVE - OPENS when piston is 49/64" to 55/64" before bottom dead center
CLOSES when piston is 15/32" to 17/32" after top dead center
TAPPET GUIDES . 0005" to . 001" press fit in crank case NOTE: Timing is check with tappets adjusted with .004" clearance .

VALVE TAPPETS Free to .00075" loose in tappet guides. IGNITION- OCCURS when piston is 7/16" before top dead center on compression stroke.

45 CU. IN TWIN (ALL MODELS)

INTAKE VALVE- OPENS when piston is 5/32" to 7/32" before top dead center
CLOSES when piston is 37/64" to 45/64" after bottom dead center

EXHAUST VALVE- OPENS when piston is 37/64" to 45/64" before bottom dead center
CLOSES when piston is 5/32" to 7/32" after top dead center

IGNITION- OCCURS when piston is 1/4" to 9/32" before top dead center oncompressibn stroke
No. 150F -2- January 8, 1937

30.50 CU. IN SINGLE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 5/16" to 9/16" before ·top dead center
CLOSES when piston is 11/16" to 15/16" after bottom dead center

EXHAUST VALVE - OPENS when piston is 1/2" to 3/4" before bottom dead center
CLOSES when piston is 1/4" to 1/2" after top dead center

IGNITION - OCCURS when piston is 1/4" to 5/16" before top dead center on compression
stroke.

21 CU. IN. SIDE-BY-SIDE VALVE SINGLE

INTAKE VALVE - OPENS !vhen piston is 1/8" to 3/16 before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center

EXHAUST VALVE - OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 1/8" to 3/16" after top dead center

IGNITION OCCURS when piston is 7/32" to 9/32" before top dead center on compression
stroke.

21 CU. IN. OVERHEAD VALVE SINGLE

INTAKE VALVE - OPENS when piston is 3/32" to 5/32" before top dead center
CLOSES when piston is 3/32" to 5/32" after top dead center

EXHAUST VALVE- OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 3/32" to 5/32" after top dead center

IGNITION OCCURS when piston is 11/32" to 13/32" before top dead center on compression
stroke.

TAPPET CLEARANCES

NOTE: When checking valve timing according to piston postion, bear in mind that tappets
must first be adjusted to the correct clearances.

ALL SIDE BY SIDE VALVE MODELS (SINGLES AND TWINS) -- INTAKE --.004" to .005"
EXHAUST .002" to .003"

OVERHEAD VALVE SINGLE -- INTAKE AND EXHAUST .002" to .003"

OVERHEAD VALVE TWIN -- INTAKE AND EXHAUST Correctly adjusted when tappet has just
noticeable play or shake, and can be turned freely with finger tips, complete around,
without any trace of bind.

CIRCUIT BREAKER OPENING - ALL MODELS

Generator - .020" to .024"
Magneto -- .014" to .018"
No. 151 January 7, 1937 No. 153 January 26, 1937

BuMPffl AHp SroNt GUR!j'D

NEW OIL SEAL OLD OIL SEAL

O.P.:.V. ~. :CDEL

NEW SERVI-CAR BUMPER CLAMP The original cork oil seal he.s been replace-:! in new mot0r assembly and f<Jr serv-ice
·.vith a seal of synthetic rubber, which is a much more effective seal. :::o:tor 2io.
Only nsw outer clamp is needed. Clamp base attached to tawbar is not changed. 37 E 1672 and all later motors have the new seal. A few earlier motors were r-.lso
Part Number below covers only new outer olamp. changed over before shipping. See footnote.
The new clamp is designed particularly for 1937 Oldsmobile bumper. It also fits Discard any cork seals you may have in stock: and use only the new seal for service.
many other oars, however, the standard outer clamp as furnished in the past will The part number of the nevt seal is 120-36, price 15 cents list each. ( 4 required)
be continued as regular equipment with new Servi-Cars as it fits every type of
bumper, except Oldsmobile. Rocker assemblies must be removed from cylinder heads to install new seals. Before
removing, take off large hex nuts at right end of shafts and make sure that sloai't
Illustration shows clamp attached to 1937 Oldsmobile bumper whioh ha.s oamplete setting for valve stem oiling is clearly marked us each shaft is found to be set
stone shield enclosure at top of bumper. Soma cars with stone shield at lower at the time. See "Shop Dope" l!o. 140A. After this ':las been done, disconnect oil
side of bumper require attaching clamp upside down. pipes from altuninum housings, take out cf'.p screws (three) that secure each housing
to cylinCer hen~~.,. turn off' left side shaft nuts, ar..d remove as assemblies, :1ousi::gs
To attach clamp, hinge "hooked" eye bolt forward out of the way, rock top of clamp ·:r:.. th ::---:ocker ar:as 1 and shafts. 5e Yery cnrei'·..:l e. bout driving shafts Gut of 9.!ld i::;.'to
backward, insert shoe behind bumper, a.nd then rock top of clamp forward a.nd insert cylinder ~ea.:: '::r2.cl.:ets, when removing ::tnd replacing rocker assemblies, as it does
eye bolt in clamp base. Tighten wing nuts securely. r..ot talce c. ver/ :-.,.er;..~rJ blo7r '.'lith a ?lammer t::> break a head ':)racl<:et. Sbafts ·will :lrif"t
o·..:.~ e.::-:. i~ ea.s:.:..~·, i.:' ~ot.h s:"i.ai'~s of an 2.ssem'cly are dr::'ted evenly .:o assembly
Part number and price of new outer clamp, extra with new·Servi-Car, or ordered sep- :se.:: :::o;: ":::ecc:;.:.e -:::::eke~
arately -
Part ~o. 7034-37 List Price . . . $5 . 00
( ':ver)
HARLEY-DAVIDSON MOTOR CO.
Milwaukee, ·/lis., U.S.A.
l!o. 153 January 26, 1937

After e.ssemblies are off, removP. rocker shafts, cork seals, and rocker arms from
aluminum housings. It is necessary to remove rocker ~s from aluminum housings~
as ne1-; se::'.ls must be installed over push rod end of arms. While assemblies are
apart it ,·:ill oe well to clean out with an air hose all oil passages in shafts,
rocker ar:.:s, c::d aluminu:n housings. Also blow out spring cover pipes.

Illustr~tion sho..,·:s corlc seal assembly, and hew ne'\'i seal is assembled. If reeker
ar::1 s:toulde!'"s at s0al end of' arm are fov.nd quite sharp, 3mooth and ro~'"ld them off
cvith a file RO ne" seal can be installed easily and without being d31!lage<i,

When re-ass~Jr.bline; rockers and shafts in aluminum housings, see that housin;;; steel
thrust wao::ers are in place, With this washer overlooked and left out, rocker arm
will have excessive end play and if shaft nuts are pulled up very t~ght, aluminum
hC'lSing or cylin-ier head bracket, or both, are likely to be brokon. ?ush seals
into place in roc!:er housing with a blunt punch. Do not use a sharp tool as ;:;e~.ls
ITifiJ bo -.:!a"':1a.ged. :;ote that when replacing cork seal v:ith the new see.l, outer steel
"'rasher is to ~e dT:'C"arded. Only the sprin~ lock rin~; is '..lsed at outer side of ne-:·r
seal.

1Vhen re-installin~ rocker and housi~ assemblies on cylinder heads, drift shafts
into heal brackets very slowly and carefully, Tie;hten cap scrEiws and nuts evenly
to avoid cocking and strain that may cause bin~in5 and possibly breakage, First,
pull up right e.nd left scde shaft nuts lightly - just tight enough to seat shaft
shoulders ag;o.inst aluminum housings and head brackets, then, securely tighten alu-
minum housing cap screws. Finally, after noting that shaft ~arks indicating valve
oilin~ adjustment are in correct alignment, securely tiGhten left an~ right side
shaft nuts. :·.;·ith sho.~... t nuts ti:)1tenecl, check roclcers to see that they have suf-
ficier..t en~ ?l:J.y ..:"'or free action, but not m..ore than • 008 inch.

J..fter e.sse:-:1Jl:r i3. CGI!lpleted, tc.p"9ets ft·:jus~ed, etc., turn motor over zlc·,:rly ·.:ith
s~·.-itch CFY to be: :;ure everything is free ar~.c! ~·.'ith required clee.rt:tnce. T~is is sug-
::;ested beco.u.E'e i!l odd cases, alu..ninu.""ll honsil:g or l:ead bracket bree.kc_€e has been
trrlced to be.~ ta!=l· -et adjustment (too "';ight), possibly due to cha!lging ~Jush rods
from one posO.tion to another, with readjustment of tappets overlooked, In this
case, a valve spring may bottom or a rocker strike top of aluminum housing before
tappet :1e.s its :':!ll lift, and ,-,hen t:1i-s happens, somethill€; is going to be broken.

!L'-'lLEY-DAVIDSON :.!OTOR CO.

:lilvro.uk:ee, Wis., U.S.A.

:.iotors bdo':l 373 1672 fitted ·fith latest oil seals:

1670 1641 1690 1580

lo48 1535 1587 1578
1647 1034 :sas 1370
:!.:::.;G l5.S2 lE85 1575
::.:43 1229 15'34. :674
::..o..;.4 :323 1533 l573
12.;2 1322 1ee1 1571
 157A -2- April 13, 1937

Rear brakes from 1931 to and including early 1937 brakes that become severe and develop
chattering can be serviced with the new bushing. Two reamers are needed to install bushir
an end reamer to enlarge hole in steel sleeve, and a reamer for sizing bushing after it iE
pressed in. The finish reamer is stepped for three sizes - .001" steps. (Use end reamer
No. 157A in lathe or drill and drive at low speed, about 100 to 150 r.p.m. Apply a little oil as
a cutting lubricant. Finish ream bronze bushing by hand.)

Part numbers and prices of reamers and bushing are as follows:

No. 12666-31 Set of Reamers (2) $4.00 net·, per set

No. 4037-37 Bronze Bushing .30 list, each

BRAKE RELINING AND ADJUSTING

When servicing rear brake with new liners, grind off the ends of liners as shown in
illustration. This lessens self-energizing action and contributes considerably to smooth
braking. After brake with new liners is completely re-assembled, loosen pivot stud nut,
apply heavy pedal pressure, and while brake is applied tighten stud nut. This adjusts
shoes so that new liners have maximum contact with drum.

Ilf.S.IP€ lf£Jt'l?, llRACICH€&,

MD S#ti.F ISSEH.B.I.Y

liOI'l TO SERVICE A BEAR WBEEL BRAKE THAT CHATTERS ABD GRABS

(61. 74. IUid "80" li>DELS)
To what extent rear brake becomes self-energizing and its action severe, depends to a great
extent on the amount of clearance or play in brake operating shaft bearing. Too much play
allowed in fitting, or excessive play developing with wear, may make brake self-energizing
to the extent of chattering and grabbing at times, particularly when brake is applied hard
for emergency stop. The shock that goes with severe chattering and grabbing sometimes breaks
off brake cover torque stud or lug which allows cover to turn, and breakage of operating
shaft follows putting brake completely out of commission.

Brake operating shaft bearing sleeve in rear brake cover has not had a removable bushing
since 1930. The steel sleeve itself has been sized to fit operating shaft. There has
been no proyision for installing a bushing in the event of excessive clearance developing
and causing chatter.
Now. starting with motorcycles shipped from the factory January 11, and applying to all
later machines, a bronze bushing is used, and it is finish reamed for a closed fit than
has applied in the past.
 No. 159 February 11, 1937 Recommendation:- If you are in a locality that has below freezing winter tempera-
ture, out and open up screen so there will be no doubt about oil supply getting to
feed pump line nipple. Use a long heavy screwdriver, a carpenter's pinch bar, or
some similar tool sharpened at the end to out screen. Insert tool through filler
opening, punch through screen as riear the top as possible, out down through screen
to the bottom, and push it aside to make the largest possible opening. It is ad-
visable to out screen only once from top to bottom as attempting to out it several
times may leave some loose pieces in tank,

([) Opening up screen and leaving it out of later tanks simply means that more precau-
tions will have to be taken to avoid getting foreign matter into tank when adding
oil.
WINTER ATTENTION FOR OIL SUPPLY
All 1937 Models

0 /.L E.KTF/Y./7$
S<R£F/Y In below freezing winter weather possible congealing of oil to a point where it ·:Till
CR<?<'tlizk not flow through lines is one thing to be watched, Another winter condition that
has to be given some attention is water getting into oil supply due to normal crank-
Borrt?Ct Oe J&r-r case condensation. With a motor frequently driven far enough to heat up crankcase
to normal operating temperature, water from condensation is evaporated and discharged
through breather. However, a motor driven only on short runs and not often thorough-
ly warmed up about motor base may possibly accumulate en~ugh water so there is a
chance of ice forming and shutting off oil supply to feed pump.

Use "Me<H um Heavy" Oil for winter service with temperature below freezing, and in
localities where temperature goes down to 15 to 20 degrees above zero or colder,
add enough kerosene to prevent congealing. The needed amount of kerosene depends
upon how low the temperature goes. Don't add more than necessary to keep oil in a
0 fluid state. A maximum of 20% kerosene (about 1-3/4 pints to a tankful of oil)
should be sufficient for extreme oold operating conditions. Adding kerosene will
not only keep oil fluid, but will also hinder freezing of any water in the oil
supply.
Where winter weather is quite consistently below freezing, it is advisable to com-
pletely drain oil tank and put in a fresh oil supply at shorter intervals than
OIL 'l'ANK SCREEN recommended for summer service.
Until recently, the oil tank of the 61, 74, and 80 inch models has had a screen to HARLEY-DAVIDSON MOTOR CO.
catch any foreign matter that may get into tank through carelessness when adding Milwaukee, Wisconsin
oil. Illustration shows location of screen. Motorcycles shipped from the factory u.s.A.
on and after January 20 have the screen cut and opened up. The screen will be
left out of tanks of later production.

Reason for this change•- Cases have come to our attention where in freezing weather
oil supply has been permitted to congeal to the extent of not passing freely through
screen and as a result, oil returning from motor base to tank accumulates in the
compartment ahead of screen, and the compartment behind screen which supplies oil
feed pump runs short of oil. ·

- over -
 No. 163 March 22, 1937

YES! CHROMIUM DOES NEED ATTENTION

~:o. 162 !.,'arch lC, 19 37 There seems to be a mistaken notion that chromi~m plate is a finish that is impervious
to weather conditions and that it never requires any care or attention. This is not
correct and in this connection it might be interesting to note what British opinion is

'' - :m!t!!lti•Hiitlna on this subject. Incidentally, they should be able to speak with authority since many
English machines have chrome plated tanks, mudguard and numberous smaller fittings.

We quote from "The Motor Cycle", leading British Trade Journal, issue of February 18,
1937:

"Recent grouses about the somewhat rapid deterioration of chromium plating

when neglected by its owners make it evident that the motor cycling corn-
unity labours under delusions with regard to chromium. It is not proof
against neglect and will, in fact, quite speedily present a truly appaling
appearance if grossly neglected. Its chief merit is that it can be kept
in good condition with far less labour than nickel. If a nickelled article
is left in damp air for a few days, it will promptly being in turn orange
and pit, hweras after such brief mal-treatment a chromiumed article will
merely lose its sheen. Once the nickel has oranged and pitted, it may be
impossible to restore it fully; but dulled chromium can usually be brought
up by merely wiping and rubbing.

"Next, i f the two surfaces be compared after longer neglect, any three
Use The New Spoke months in damp air, there is precious little to choose between them. The
chromium is likely to be quite as ruined as the nickel, and nothing much
A r.e'.'f spoke with shorter head end has been develooed to overcome stretch- can be done about it. Users should note that ordinary metal polishes should
or.g and breakage in heavy service. New wheels are now laced with this never be applied to chromium, as they normally contain abrasive matter,
spcke, and it is supplied on parts orders. It applies to all 1937 wheels which is fatal to chromium; if chromium has been seriously neglected, a
exropt 45 and Servi-Car front wheels.
special polish shold for the purpose should be applied.
Use only this new spoke for your service requirements. Order a supply
under part #3943-36. "So reads who occasionally leave a machine untended for weeks in damp air
should eschew chromium tanks, and prefer enamel. The latest complain to
reach me concerns a machine which is only nine mont;1s old, and has done
If you have a supply of old style spokes of this type, you can return
them for exchange. 5,500 miles, so that it obviously has not been sotred for very long: yet
its chromium tank is past praying for.

HARLEY-DAVIDSON MOTOR COMPANY

"During storage for a lengthy period, any plated tank or other part should,
of course, be heavily smeared with pure vaseline or painted over with
Milwaukee, Wisconsin
u.s.A. cellulose varnish."
No. 164 No. 166 llay 6, 1937

1937 - 1,5 CRANK PIN IS DIFFERENT FROM 1936 - 45 CRANK PIN

The crank pin used in 1937 - 45 motors has the oil hole drilled in a different position
than the oil hole drilled in the crank pin applying to the 45 models for 1929 through
1916. Aside from this difference both crank pins look exactly alike, but because motor
lubrication hinges on getting the right crank pin fitted to each type of motor, you should
I ~arn to identify these t\VO different crank pins on sight.

CHANK PIN NO. ')48-2~

applies to all 45's from 1929 through 1936. This crank pin has the
oi1 hole drilled at an angle of 90 degrees or 1/4 turn around from the key way. The in-
t<Jkt: end of this oit ho]e or channel starts at a distance of 11/32 11 from the outer edge
of the ground taper on crank pin. From this point the agnle of the drilling brings the
hole out exactly in the centec of the roller bearing surface of crank pin.

C~~NK PIN NO. 348-37 applies to 1937 - 45's. This crank pin has the oil hole drilled at
an agle of 52 degrees or about 1/6 turn around from key way. The intake end of this oil
hole or channel starts at a distance of 5/32" from outer edge of ground taper on crank
pin .:1nd drill~ng is on an angle that brings other end of channel out at the center of the
rnller hearing surface of crank pin.

Thi:s Jifference in crank pins also prevents assembled sets of connecting rods with rollers
and crank pin from heing interchangeable. The individual front and rear connecting rods
:ore· interchangeable from 1932 through 1937. The 1931 and earlier front and rear rods as
well as the assembled sets for these models are of course not interchangeable with 1932
and later model parts. We are allotting a new part number to the assembly applying to
1917 -45's and we are listing this number as well as the numbers of the other assemblies
beluw:

Part No. 289..-37 set connecting rods complete with rollers and crank pin ... 1937 45 11

Part No. 289-32 set connecting rods complete with rollers and crank pin - 1932 to
1936 45" twins.

Part No. 289-29 set connecting rods complete with rollers and crank pin 1929 to 1931 OUT AND DISCARD THIS FIBRE DISC (OUTER
45" twins. FIBRE DISC)
t"'II----PUT THIS NEW "SPRUNG" STEEL DISC IN ITS PLACE
(BETWEEN STEEL DISCS)
We suggest that you turn to page 13 of your 1937 spare parts catalog and mark the assembly
numbers as given above so there will be no misunderstanding in placing orders for these
items or in assembling the wrong parts when rebuilding motors. Furthermore, if you did
A NEW CLUTCH CUSHION (SPRUNG)
not previously change the crank pin numbers in your parts book, we suggest that you turn DISC FOR SMOOTHER ACTION
to page 15 and do so at once.
PART N0.2487-36A
New Big Twin motorcycles snipped from the factory after May 1st
REMEMBER - THE TWO CRANK PINS REFERRED TO ABOVE ARE DISTINCTLY DIFFERENT AS FAR AS OIL PRICE .75 LIST are fitted with this new disc.
HOLE LOCATIONS ARE CONCERNED AND TO GET TilE WRONG PIN IN TilE WRONG MOTOR MEANS SHUTTING
OFf 11lE OIL SUPPLY WITH CONSEQUENT SERIOUS DAMAGE. THEREfORE, CAUTION TIJOSE WHO HANDLE Use it (only one to a clutch) for servicing earlier clutches that grab and chatter-
TIJESE ITEMS NOT TO GET THEM MIXED UP AND NOT TO GET ASSEMBLED SETS OF CONNECTING RODS 1936 - 61 model, 1937 - 61, 74 and 80 models.
MIXED liP \.]JIERE THIS CRANK PIN DIFFERENCE IS INVOLVED.
Remove and discard original "sprung" (humped) steel disc used in early clutch which
is usually the one indicated by arrow 14. although it is not always in this location.
Replace it with a regular flat steel disc. part No. 2487-36.

HARLEY-DAVIDSON MOTOR CO., Milwaukee, Wis., U.S.A.

Special SERVICING FIRST 1938 - 45" TRANSMISSION
CASE WITH INSUFFICIENT FRAl.!E CLEARANCE No. 172 January 20, 1938
FITTING 1938 TYPE VALVE SPRING COVERS TO 1936 and 1937 61" OHV CYLINDER HEADS

1. Remove tanks and cylinder heads

2. Strip fittings from cylinder heads and strip rocker housings. Put some identifying
LOOKING ])OWN ON TRANS,WISS/0# mark on valve guides as they should be pressed back in their respective holes if some
guides are used again.
FICAM£ M(}(/NT/NG BRACKET- 3. Discard original 3/32" thick steel spacing-thrust washers that will be found between
right ends of rocker arm shafts and inside faces of aluminum housings. The 1/16" thick
washers included with new parts are to be substituted for 3/32" wasliers discarded. Also
discard original rocker arm oil seal washers and spring lock rings, but save four plain
steel oil seal retaining washers (eight were used with earlier cork seals and four with
earlier rubber seals) to use in the change-over.

4. Sort out new covers, screw plate and cover plates. Covers come in three lengths -
longest one for front exhaust; shortest one for rear inlet; other two covers are of same
length and are identified by length of oil return pipes - cover with longest pipe is for
rear exhaust. The front and rear exhaust spring cover screw plates which partially en-
circle covers must be assembled on covers before covers are fitted to cylinder heads.

5. No comes the job of grinding additional cylinder head clearance for new covers and
--;--BOTTOM OF return pipes. There is no way of describing just where this grinding is necessary or
how much material must be ground off as heads vary somewhat. All we can tell you is that
rHIM orr-J"Ar TRAN5M/5S/ON ON additional clearance must be provided so that new covers seat squarely and firmly against
m1s coRNER AN.]) RIGHT oe STA~TE/i! SIP£ cylinder head and flanges do not interfere with oil return pipes. Additional clearance
Ft/1./.0W :OOTTFZJ J./IIIF for front exhaust will require the most grinding and rear exhaust comes next. Inlets
.BACK AZ!OV r /" require little if any grinding .
The ends of rocker arm shaft cylinder head brackets must be ground off slightly to allow
clearance so covers can seat firmly against heads. This clearing away metal for new
covers can be done altogether with a small portable or flexible shaft grinder with about
For full range of front chain adjustment, this corner must be out away a 1" wheel. I f a burning torch is at hand, it can be used to take out larger sections.
to conform with curve of frame and have sufficient clearance so that If you are not equipped to do this job, and on't want to trust having i t done in another
transmission backward movement is not limited by interference at this shop, you can send head to the factory for necessary clearance grinding.
point. Movement should be limited by transmission bottom studs striking
L------'-ends of slots. Interfering corner can be cut away without removing If you have several heads to change over, you may want to send the first set to the fac-
transmission, (after removing battery and laying machine over on left tory so you can see just how the grinding job is done and do the rest yourself. In this
side) with a small straight side chisel. case it is advisable to send stripped heads and have them returned to you without any
assembly. Once covers are assembled, guides pressed in, etc., you cannot see very well
After corner has been cut away as shown in above cut, front chain where additional grinding was done, and it wouldn't be practical to disassemble just for
should be disconnected and transmission moved all the way back (check- inspection.
ing clearance as transmission is being moved) to make sure there is no 6. After thoroughly cleaning heads, fit new covers. An asbestos oil seal gasket must
interference. be placed. between each cover and cylinder head. Then press in valve guides as close as
possible to a tight seat and still be able to shift cover slightly.
CAUTICN: If a transmission has this corner interference, attempting
to move it further than the point of interference by simply applying Fit rocker arm shafts only to bar aluminum housing and fit housings and shafts temporarily
force to adjusting screw will result in a broken ·gear box. to cylinder heads to line up spring covers. Rocker shaft holes in covers will of course
have to register exactly with hole in cylinder head rocker shaft brackets before shaft
mL'lEY-JAVIDSON ~OTOR CO. ends will pass through. Open ends of covers must be lined up as well as possible with
Mil·:.ra.uk:ee, i'Hs., U.S.A. holes in aluminum housings. They will not in every case center in holes but must not
bear against aluminum housings. (kcasionally it may be necessary to spring covers
 No. 172 -2- January 20, 1938 No. 172 -3- January 20, 1938

slightly to make them line up. After they have been lined up, finish pressing in valve 11. The order in which oil seals and retainers should be fitted in housings, is shown
guides to secure covers. If covers are not firmly secured, oil leakage will result. in illustration. Be sure to get the 1/16" steel thrust washers properly located in
After covers are adjusted and guides tight, remove aluminum housings and rocker arm shafts. aluminum rocker housings because if they are not in place, spacing between aluminum
housings and cylinder head brackets will not be right and one or more brackets will
It is of primed importance that valve guides fit tightly in clyinder heads. If they don't probably be snapped off, when shaft nuts are tightened.
valves may not seat properly, spring covers will be loose and oil leakage between covers
and cylinder heads will result. If original guide or new guide is not a tight press fit, 12. After rocker arms, oil seals and rocker arm shafts have been assembled in housings,
an oversize guide must be fitted. Oversize guides can be obtained .001" and .002" oversize. apply a thin coat of aluminum paint on under side of aluminum housings, where they rest
on cylinder head brackets. This will insure against oil leakage around oil passage plugs.
7. When guides are removed for any reason and replaced, or new guides fitted, valve seats
must be trued up because it is impossible to get guides back so seats will be concentric 13. Attach aluminum housings with assembled rockers to cylinder heads. Drive rocker
with them. If a valve guide is not true with seat, valve, valve breakage may result due shafts carefully into cylinder head brackets. Do not force them as it does not take a
to cocked seating and deflection of valve stem. To do this job requires a grinder because very heavy blow with hammer to break a head bracket. If shafts are drifted evenly into
the material from which the seat inserts are made is so hard a regular seat cutter will brackets to avoid cocking the assembly, they will go in easily. Fit plain washers tempo-
not work. Special attention must be given to the pilot to make sure it fits snugly in rarily, on left end of both inlet rocker arm shafts next to cylinder brackets to take up
guide (before expanding if of that type), otherwise it will be impossible to true seat. space. Tighten all shaft nuts evenly and (disregard overhead oiling adjustment for pre-
The standard automobile pilot of corresponding size is usually too small to fit guides sent) securely to-imbed ends of spring covers in rubber seal washers.
snugly due to the lesser clearance required for automobile motors.
Now that all shaft nuts are securely tightened, and width of the assembly determined, see
Reface valves and if the ends of stems are goove and uneven, smooth and square them up on that holes line up so cap screws securing aluminum housings to cylinder heads can be
a grinder. Don't put valves back in with heads and stems so badly worn as to likely soon fitted without any binding. If screws will not enter freely something is wrong and they
need renewal, requiring another head job at low mileage. should not be forced into place. In this case inspection should be made to see that
Before assembling valve springs, check their length to be sure none have been overheated spacing-thrust washers are in place. If everything seems in order but holes are slightly
and shrunk losing considerable of their normal tension. Badly weakened valve springs not misalinged, they can be elongated with a round file to permit entering screws.
only knock off top motor performance, but also allow valves to bounce in seating which Following this procedure in securing aluminum housings is also of prime importance be-
accounts for abnormal wear of valves and seats and possible valve head breakage. cause if spacing and alignment are not correct and screws and nuts are pulled up tights,
Standard length of new outer spring is approximately 1-15/16"- inner spring 1-9/16". When mounting brackets will be under stress and breakage will probably result.
either spring becomes set more than 1/8" below standard length, it is advisable to fit
new spring. (Note - a few new motors have been fitted with special springs identified >lith 14. After head assemblies are tightened up, and before cover plates are fitted, note that
red paint applied to end coils. These springs measured when new - outer 1-13/16" - inner- rockers arms are not pinched endways. This is not likely to be found the case, expecially
1-15/32". Allow the same shrinage allowed standard springs before replacing. Replace- when using old rocker arms, but it is possible. As long as rocker arms are free endways,
ments can be made with new standard springs.) that is all that is necessary.
If it is found there is binding enways, rocker arm will have to be shortened by grinding
8. Remove oil return pipe nipples from aluminum housings and elarge the holes in nipples off either end slightly. It is desiraole to have a 111ini111um of . 005" to • 010" end clear·-
with a 1/8" drill. Replace them and tighten securely. ance to allow for possibility of assembly closing up a little bit as rocker arm shaft nuts
are loosened and tightened later on. You don't have to worry about too much end clearance.
9. Fit tubular cover spacer in rear (exhaust) aluminum rocker arm housing after painting
outslde where it enters hole with aluminum paint to prevent oil leakage. Make sure Determining whether or not there is end play and how much is not so easy with an assembly
spacer bottoms in housing. just put up with new covers and new seals, as new sealing wahsers pinch rocker arms very
tightly and make them work hard as though they were a tight fit on shaft or were tight
10. Before assembling rocker arms into aluminum housings, inspect rocker pads and ball endways. This w'll have to oe considered when determining end clearance.
studs. Worn rocker pads, if not too badly worn, can be dressed up on a grinding, main-
taining original pad curve. Worn and flattened ball studs will have to be replaced, other- 15. Apply a thing coat of shellac on underside of cover plate gaskets and fit them on
wise satisfactory tappet and push rod adjustment cannot be made and upper end push rod coyers so holes line up. Now that assembly has been completed and rocker arm endplay
trouble is likely to be experienced. (All 1936 and some 1937 rockers do not have drilled check to make sure there is no binding. fit cover plate.
oil nassage through arm directly to ball stud, as applies with later 1937 and 1938 rockers. One way to fit cover plates is to use two tapered rods and insert them through screw holes
This later oiling arrangement effects more dependable lubrication of ball stud and push to align plates so screws can be entered straight and not become cross threaded.
rod upper end. Some owners of earlier motors may want the later rockers installed.)
An easier method is to loosen rocker and housing assemblies, that is remove cap screws that
All washers must be assembled on rocker arms before arms can be fitted in aluminum housings. secure aluminum housings 1 Rnd also remove nuts on left ends of rocker arm shafts and drift
Sometimes it is necessary to grind off the rear edge of read exhaust rocker arm before it the assembly away from ends of spring covers about 1/8". Fit cover plates and tighten
can be entered in housing. An oil seal steel retaining washer is furnished for small oil screws securely~ then drift assembly back in place and replace and tighten shaft nuts~
seal. For the large oil seals use the four steel retaining washers mentioned in No. 3.
and cap screws in aluminum housings, as explained in paragraph No. 13.
The smallest oil seal is to be fitted to rear exhaust rocker arm with cupped side of washer
toward push rod. One of the large oil seals has n~ fabri~ on either side and is to be 16. Attach oil return pipes, bending pipes as needed so they line up with nipples in
fitted to rear exhaus-t rocker arm either side against end of spring cover. The three re- housings.
maining 0il seals are to be fitted with fabric side against ends of spring covers.
17. Adjust overhead oiling before replacing cylinder heads.
172 -4- January 20, 1938

Remove the four large nuts on ends (right side) of rocker arm shafts, and erase all marks
on aluminum housings that were originally used for setting rocker arm shafts. Also
slightly loosen left side shaft nuts.
Place rear aluminum housing drawing over rocker arm shafts in rear housing and front alum-
inum housing drawing over rocker arm shafts in front housing. Using a center punch or
other sharp instrument, indent aluminum housings, registering the rool with setting marks
on drawings. Remove drawings and turn rocker arm shafts so slots in shafts line up with
marks made on housings. Tighten left side shaft nuts to hold shaft setting.
Fit fibre washers over shafts and replace large nuts and tighten securely. Tite base of
nuts should bottom against fibre washers when tight and there should be approximatly .010"
clearance between corners of nuts and aluminum housings. If necessary renew or add extra
fibre washers to get clearance. If corners of nuts bottom against aluminum housings, oil
leakage around nuts will probably result.
It may be necessary in some cases to readjust overhead oiling after motorcycle has been
put back in service. Squeaking at rocker arm assembly indicates not enough oil and re-
peated plug touling may be caused by over-oiling of inlet rocker arms.
Adjust tappets very carefully and be absolutes sure none are left too tight. A tappet left
too tight may bottom valve spring before cam has reached its full lift, and when this
happens some damage results. After motor is completely assembled, turn it over slowly by
hand to be sure of no interference about valves and rockers before attempting to start it.

WHEN ORDERING 1938 VALVE ENCLOSURE TO CHANGE OVER - SPECIFY: PART NO. 173-38D "COMPLETE
SET VALVE ENCLOSURES AND FITTINGS" -- List price $8.90 - EACH SET INCLUDES THE FOLLOH!NG:
NO. OF NO OF
PIECES PART U NAME PIECES PART U NAME
34 018 R.A. Cover Screw 1 174-38B Front Exh. R.A. Cover Cap
2 176-38 Plate 174-38 Rear Exh. & Front Intake
2 176-38A " R.A. Cover cap
1 176-38D " 1 174-38A Rear Intake R.A. Cover Cap
1 176-38E " 1 177-38 Rear Exh. R.A. Cover adapter
1 176-38C " 3 120-38 R.A. Housing Oil Seal
1 175-38A " Gasket 1 120-38A R.A. Housing Oil Seal
1 175-38B Front Exh. R.A. Cover Gasket 1 120-38B
2 175-38 Rocker Arm Cover Gasket 1 178-38 R.A. Cover adapter Washer
1 173-38C Rear Sch. R.A. Cover & Tube 4 176-37 Asbestos Oil Seal Gasket
Assembly (between bottom of spring cover and
1 173-38 Front Intake R.A. cover & cylinder head)
Tube Assemblv 1 2806-38 Motor Brace Assembly
1 173-38A Rear Intake R.A. Cover & 1 1233-38 Garb. Choke lever assem.
Tube Assembly 4 119-36A R.A. Housing Washer, 1/16"
173-38B Front Exh. R.A. Cover &
Tube Assembly

SPECIAL NOTE: The 1/16" spacking washers (part llll9-36A) are required with 1938 valve
cover combinations installed with original 1936 and 1937 aluminum housings. These
housings with the earlier cover arrangement required 3/32" thrust washer (part 11119-36)
for correct spacing.
New aluminum housings used on 1938 motors and now supplied on parts orders are counter-
bored 1/32" deeper and must be used with the following spacings washers: On 1936 and 1937
motors with earlier valve spring covers use 1/8" washers as supplied with housings. On
1938 motors, also on 1936 and 1937 motors fitted with 1938 complete valve enclosures,
use 3/32" washers (part 11119-36).
 No. 175 April 15, 1938
No. 174 March 28, 1938

A NEW CLUTCH PUSH ROD & BEARING FOR 1938 - 61, 74 AND 80 MODELS

(This applies to 1938 models only)

(?) cQ]
L,d ~----~
2
I COPPERPLATED
4-

New bearing which has heavier and stronger races is identified by copperplated
housing. New push rod has longer pilot for bearing. Use only these latest
parts for your service requirements. When servicing with new bearing, see that
push rod is also latest type and that end against which bearing seats is in
good condition.

1938 - 61 OHV models shipped from the factory after February 25, 1938, have NEW CLUTCH DISC AND SPRING COMBINATION
the new push rod; and after March 8, 1938, the new bearing.
(Illustration shows shell and discs in
1938 - 74 and 80 models shipped from the factory after February 18, 1938, have correct order of assembly)
the new push rod; after March 8, 1938, the new bearing.
No. Part
If you have new motors in stock not yet sold and delivered, that were shipped Symbol Reg. Ntunber List Prices
from factory before the dates mentioned replace bearing, and also push rod if
not the latest, before delivery. A 2 2481-38 Lined steel disc ••••••••••••••••••••••••• 1.20 each
B 2 2487-36 Plain steel disc .......................... .35 each
Order at once, in the regular way, enough bearings and rods to take care of c 1 2481-36 Notched fibre disc •..••..••••••••.••....• .35
your requirements. Parts that you replace, new or damaged, return to factory D 1 2487-36A Sprung steel disc •••••••••••••••••••••••• .40
for credit. Also when you have obtained a stock of the new parts, return for E 1 2453-36 Long adjusting screW •••••••••••••.•.....• .10
credit a~ new bearings or rods of earlier 1938 type you may have in stock. {2275-38 Clutch hub nut (later 1937-1938 61,74,80) .90
F 1
2275-36A Clutch hub nut (1936-61 and early 1937-
NOTE: -When a push rod bearing goes bad, the clutch release finger and push 61, 74, 80) ••••••••••••••• .90
rod adjusting screw may or may not be damaged, depending on how far motorcycle G 10 2511-38 Clutch springs •.•..••••.••.•..••.•....•.• .10 each
is run after bearing goes bad. In every case where bearing fails, inspect H 1 2512-38 Spring insulating gasket ••••••••••••••••• .10
these parts and renew if necessary. If bearing has jammed and worn a flat on
release finger contact radius, finger should be replaced. Discs "B" and "C" are old style parts the same as we have been using right
along and which also apply to the new clutch. When ordering parts to con-
HARLEY-DAVIDSON MOTOR CO. vert early clutches, it will not be necessary to order these parts if ori-
Milwaukee, Wis., U.S.A. ginal 0nes are in good condition or if you have some of them in stock.

New clutch hub nuts ''F", which are longer, are copper plated for identifi-
Part No. Description cation when furnished on parts order. Nuts used at the factory in new ma-
2448-38 Push Rod Bearing c~ine asse~bly are not copper plated. (Clutch hub nut has left hand ~hread.)
2446-38 Clutch Push Rod
2436-38 Clutch Release Finger .~1 51, 74 and 80 models shipped ~~am t~e facto=y af~er ?ebr~ary 1, 1938, are fitted
2463-36 Push Rod Adjusting Screw w:t~ this !lew cl:..ttch.

(over)
No. 172A January 20, 1938 No. 174 March 28, 1938

61 OHV UPPER END JOBS A NEW CLUTCH PUSH ROD & BEARING FOR 1938 - 61, 74 AND 80 MODELS

Following are recommended flat labor rates to apply regularly to 61 OHV model uppper (This applies to 1938 models only)
end jobs. (Head changeover to fit new covers i a combination with one of these jobs)
LABOR
1. Remove tanks and cylinder heads and clean carbon and grind
valves only - Does not include disassembling rocker housings
and rocker arms for new seals or other attention nor inspect-
ing pistons and rings: Does not include removing cylinders -
Includes blowing out valve cover oil lines, installing one or
more new valve guides or valves or both, refacing valves and
seats as necessary. Fit new valve spring if needed. Remove
G)
I COPPERPLATEO

and clean carburetor bowl Adjust circuit breaker points and

check ignition timing. Inspect and clean spark plugs and New bearing which has heavier and stronger races is identified by copperplated
check spark plug gaps. Check, and if necessary, readjust housing. New push rod has longer pilot for bearing. Use only these latest
overhead oiling. Adjust chains. Adjust carburetor and test ..••.. $ 6.75 parts for your service requirements. When servicing with new bearing, see that
push rod is also latest type and that end against which bearing seats is in
2. Everything under #1 and disassemble housings for new seals, good condition.
new rockers, or any other attention............................... 8.00
1938 - 61 OHV models shipped from the factory after February 25, 1938, have
3. Everything under #1 and removing cylinders for piston and the new push rod; and after March 8, 1938, the new bearing.
ring inspection. Includes fitting either new rings or new
pistons as may be needed. Does not include honing cylinders 1938 - 74 and 80 models shipped from the factory after February 18, 1938, have
O.S. nor fitting new upper rod bushings or O.S. pins ............ . 8.25 the new push rod; after March 8, 1938, the new bearing.

4. Everything under #1 and #2 and #3 9.50 If you have new motors in stock not yet sold and delivered, that were shiooed
from factory before the dates mentioned replace bearing, and also push rod- if
Add- to #3 and #4 for each upper rod bushing or O.S. Pin ....... . .50
not the latest, before delivery.
The job of initial fitting of new 1938 valve covers to a 1936 or 1937 motor is
Order at once, in the regular way, enough bearings and rods to take care of
necessarily a combination with regular upper end job either #2 or #4 along with
your requirements. Parts that you replace, new or damaged, return to factory
the following extra charges:
for credit. Also when you have obtained a stock of the new parts, return for
credit a~ new bearings or rods of earlier 1938 type you may have in stock.
Extra charge of extra work and fitting that goes with the initial LABOR
installation of new covers, seals, etc . ........................... . $1.25
NOTE: - Vfhen a push rod bearing goes bad, the clutch release finger and push
rod adjusting screw may or may not be damaged, depending on how far motorcycle
Grinding additional cylinder head clearance, when done locally ..... . 2.00
is run after bearing goes bad. In every case where bearing fails, inspect
these parts and renew if necessary. If bearing has jammed and worn a flat on
COMBINATION COMBINATION WITH release finger contact radius, finger should be replaced.
FOR EXAMPLE WITH FLAT JOB 112 FLAT JOB 1/4
(Job 1/2} $8.00 (Job 114) $9.50 HARLEY-DAVIDSON MOTOR CO~
Clearance grinding 2.00 2.00 Milwaukee, Wis., U.S.A.
extra labor 1.25 1.25
NeW' covers 8.90 8.90
New O.S. Valve guides, valves, Part No. Description
etc. , as needed
2448-38 Push Rod Bearing
$20.15 $21.65 2446-38 Clutch Push Rod
2436-38 Clutch Release ?inger
2463-36 Push Rod Adjusting Screvr
Lined steel discs "A" must fit completely free in clutch shell with a little
eiie play to allow for expa!lsion. If the fit is very close, clutch may function
normally when cold, but when hot discs may expand enough to bind in shell; in
:'i~ic::: 8ase ~lute~ will d:-ag and ·.vill neither engage nor release properly.

~~-=c.:. :!.::.sc.:.la:i:Ig 5as~et "::" is to be e.ssembled on d:::-:vin.g -:iisc 1be.ck of spri:J.€S•

sp:::-i:J.g tension ad.~ustment with the new combination is the se.me as

~:o:-:r.al clu~c!:
s~eci:'iedfor earlier clutches - 11/32" from face of spring collar to shoulder
on thrust plate mounting studs. See "Adjusting Clutch Spring Tension" in ?.ider's
Ins~ruction Folder.

~~is new clutch combination was developed to meet particulerly tte ex~:::'e~ely ~ard
u.se to ·.·;:-_ic:: clutcl:es in city police and ccrnmerciA.l service H.!'9 sub:Acted. It :10t
o:ll~r is a positive clutch for !lard se:-vice, but also releasing actior;. !s ve-::y ~ooC.
:·:::icl: ::e}.::es gear shi:'ting eesy. r-: can be applied to any 1936 - 61 a.:-_:: 1?37 e.:ld
:e:er 61, 74, and SO models originaily fitted with earlier clutch assembly by
s:i.r.:ply installing the parts indicated in illustration as ''New Style Pa:-ts". It
is recommended that it be applied generally to earlier clutches when disc ser-
vice is required.

?~-DAVIDSON MOTOR CO.

Milwaukee, W1s., U.S.A.
 Idle Hole Idle Hole
Nearest Mani- farthest from
Ven.turi fold Flange Manifold Flange Slot
Model Size (Drill size) (Drill size) ~
M-4 7/8" #70 #54 ,009"
M-11 7/8" #9fJ #54 ,009"
M-16 7 /8" ff?O #54 ,009"
M-2 1-1/16" #70 #55 .009"
No, 176 June 14, 1938 l-1/16" #'70 #53 ,009"
M-5
M-5F 1-1/16" #'70 #53 ,009"
M-21 1-1/16" #'70 #55 .009"
M-31 l-1/16" #70 #55 .oogn
Attention is called to ca~bu­ M-3lF 1-1/16" #70 #55 .009"
retors '/.,rhich have C:::"Usted up M-31Fl 1-1/8" #70 #55 .009"
with carbon, ~tc., around the M-41 1-1/16" #'70 #55 .009"
throttle disc, etc., throwing M-4lF 1-l/16" #'70 #55 .009"
adjustment and calibration of M-4lFl 1-1/8" #'70 #55 .009"
carburetor off normal and M-4lL l-1/8" #70 #55 ,009"
causing a lean spot off idle, M-4lLF l-l/8" #'70 #55 .009"
M-51 l-1/16" #'70 #55 ,009"
In some cases carburetors ~e­ M-5lF l-1/16" #'70 #55 .009"
come crusted or ca~ed around M-5lL 1-l/8" #'70 #55 ,009"
the throttle disc, throttle M-5lLF 1-1/8" #'70 #55 ,009"
bore, in the idle holes at
#4&£S &VA'.£Sr
the closed disc, in the pas- (Model numbers followed by letter "F" or "Fl" apply only to carburetors used on Cali-
-'d"PC?' ...o/'...,,.,.../,......g""R sages from the idle holes fornia Highway Patrol motors,)
~A'#'£L ..,...-#A' .S/.r.IS
down to the idle or low speed
needle valve, This crust 5. Clean out the slot by inserting the tool with the blade in it through the slot be-
should be removed, particular- tween the two idle holes.
ly when a lean spot comes in
at speeds off idle up to 30 6, Clean out the idle channels with the #42 drill, When cleaning vertical· idle chan-
M.P.H. with the low speed nel don't completely bottom drill as doing so may damage low speed needle seat.
(idle) adjustment set proper-
ly for idling. The idle adjustment should not be set to the very lean side when check- 7, Clean out the low speed (idle) needle valve seat hole with the proper size drill.
ing this point, but to a point about·five clicks rich from the setting where the motor All li" ''M" carburetors are cleaned with the #53L drill, and all 1" "M" carburetors
dies from leannessg are cleaned with the #56L drill.
How To Remove The Crust 8. Blow out all channels and holes with compressed air and wash all parts in gasoline,

l. Back off the idle stop screw so that the throttle disc closes tightly, With a 9. Re-assemble the parts, being ~ the lift lever spring seat or washer is between
sharp pointed tool like a sharp pen knife or scriber scratch a line on the closed the spring and carburetor body when assembling the low speed lift lever and needle
throttle disc and also on the throttle barrel so that the lines on the disc and on the valve assembly back into place, This spring seat or washer limits the air bleed to
barrel meet, These lines should jibe up again when you replace the disc. Remove the the idle and must be in place, Also be sure the throttle disc is assembled in the r
throttle lever, throttle disc and shaft, the idle hole body plug next to the idle holes barrel properly and closes off tight before the disc screws are pulled down. Be sure
in the throttle barrel, the body plugs in the carburetor flange and carburetor body to push up the shaft collar on the throttle shaft firmly against the body before
idle channels and the low speed (idle) lift lever and needle valve assembly. Also re- tightening the throttle disc screws, Also have the disc in place with the correct
move the venturi and nozzle, side of disc up or tou~rd the flange and with the lines you scratched lining up with
each other exactly. The throttle lever should be clamped to the shaft with the disc
2. Scrape out the caking or crust in the throttle barrel with a scraper or knife, be- wide open and with the throttle lever wide open stop against the body lug and with
ing sure not to cut into the metal. the wear take-up spring between the throttle lever and bearing,
3. Clean up the throttle disc by rubbing it on both sides on emery cloth on a flat CARBURETOR CLEAN-UP TOOLS
plate and clean the edge of tr.e disc all a:round, being careful not to round the cor-
ners or cut into the metal, A set of tools consisting of an idle slot cleaner and seven handled drills· of sizes re-
quired for cleaning out Linkert carburetor channels and openings is available, These
~. C~ean out tbe idle holes :~ the throttle Oar~el next to the jisc with the proper drills are for hand cleaning only. Do not use in pov:er drill. Order set No, 12012-38,
s:2e Cr:lls. See list for proper sizes for both ~oles for all models of carburetors. price $2.00 net.
HARLEY-DAVlJlSON li!O'IDR CO.
(over) Mil->Jaukee, Wis • , U.s .A.
 August 16, 1938 No. 179 October 18, 1938
No. 177
NEW OIL SEAL PISTON RINGS IMPORTANT CLUTCH THR1JST BEARING INFORMATION

For Motors with Circulating Oiling System We have recently been able to improve clutch push rod thrust bearings,
part Nos, 2448-38 and 2448-36, so that these bearings are now decidely
better and more dependable bearings than they have been in the past.
Oil scraper ring with channel at edge of ring which has been used the past two years You will find that as a general thing these i~proved bearings will stand
was recently discarded and a new more efficient oil seal ring is now being used in up satisfactorily in any sort of service.
new motor assembly and supplied on parts orders. The new ring can be distinguished
from the old one by the location of oil channel. New ring has a wide channel in the Bearing No. 2448-38 is the 1938 type bearing used in all 1938 big twins. Bearing No.
center of ring face. 2448-36 applies to 45 model and also 1936 - 61" model, and all 1937 big twins.
In new motor assembly the new ring is being used only in lower ring groove of rear Only these ne'" bearing are now supplied on all parts orders. They are distinguished
clyinder piston. However, in connection with a moderately driven motor where high from earlier bearings of the same type by a whitened (cadmium plated) cover.
oil mileage is desired, it can also be used safely on front piston.
If you have not already received some of these new bearings with a parts order of a
The new oil rings for 61, 74, and 80 inch pistons have the same width as compression recent date, order a supply and use them for all future service requirements.
rings and earlier oil rings and, therefore, are fully interchangeable with earlier
type oil rings. Oil ring for 45 model is wider than the standard 45 compression ring When replacing a worn out or damaged thrust bearing with a new one, always closely
and the lower ring groove must be .129" wide (standard 45 ring groove is .0935") inspect end of push rod and release finger for damaged condition resulting from failure
of bearing. Replace with new, either that may be found damaged, as the parts that work
All 45 pistons~ front and rear, now used in new motors and also piston supplied on with a new bearing must also be in good condition if bearing is expected to stand up
parts order have the wider lower ring groove. In new motors the front piston, which and give long service,
does not have an oil ring, is fitted with a plain ring in the lower groove the same
width as the new oil ring. Do not fit a 1938 type bearing and push rod to a 1936 - 61" or any 1937 Big Twin model
without also fitting 1938 type release finger which is wider and requires widening the
Since pistons for all models supplied on parts order may be used in either front or slot between bosses in aluminum cover in 01:der to get finger correctly located and
rear cylinder, all pistons are supplied fitted with all plain rings. When a piston is centered with end of push rod. A 1938 type bearing cannot be used with a 1936 and 1937
used for servicing rear cylinder, (of a motor with circulating oiling system) an oil release finger, because this finger was designed to be used with the samller diameter
ring should be fitted in lower groove. This being the case, you should order a supply bearing and does not have sufficient cleaTance for larger diameter 1938 bearing.
of new oil rings and have them on hand.
Numerous inquiries have been received with regard to possibilities of using 1939 type
NEW OIL SEAL RINGS Big Twin thrust bearing for servicing earlier models. This is possible but not very
practicable, Besides a new thrust bearing, the change requires a new starter clutch,
~- MODEL ~E release finger and oil deflector, Also a new aluminum starter cover must be used or
266-36 61 and 74 .25 list the original cover returned to the factory to be~achined out to provide clearance for
266-37 80 .25 the new bearing. As a general pTactice it is advisable to service an earlier machine
263-38 45 . 25 with new bearing of theoriginal type •

New plain ring for 45 front piston lower groove (same width as new oil seal ring) part NOTE - Before installing a new· thrust bearing to replace one that has gone bad, trans-
No. 262-38, price 25¢ list, Remember that all 45 parts order pistons are furnished with mission case, particularly the starter compartment, should be thoroughly washed out to
this ring in lower grnave. get rid of any small metal particles that may have been scuffed off the damaged balls
and races,. If these particles are not removed they will circulate through transmission
If you have any 1936 - 61 models or 1937-38 motors of any model that are heavy oil users with the oil and may not only damage the new bearing but may also damage the gears and
and possibly plug foulers, even though breather timing has been checked and found o.k. other parts,
and oil pump readjusted for lower pressure~ install the new oil seal ring. Bear in mind
that the first essential for normal oil control and norrna1 oil mileage (200 to 400 miles
per qoat·t for side valve motors and 250 to 500 miles for the overhead model) is correct
breather timing. Pump pressure regulation and rings come next.
 No. 187 March 15, 1939
No, 182 December 28, 1938
FURTHER 1938 AND EARLIER CLUTCH THRUST BEARING INFORMATION
NEW OIL SEAL FOR 45" INNER CLUTCH DISC
(This supplements Shop Dope No. 179)
New oil seal is made of softer material than formerly used and although it is
As explained in Shop Dope Bulletin No. 179, clutch push rod thrust bearing Nos. 2448-
just as effective an oil seal it does not grip the roller race so tightly.
38 and 2448-36 were improved and made stronger some time ago.
Therefore, when clutch is released the gears and shifter clutches have less
draf and shifting is easier.
Bearing No. 2448-38 is the 1938 type bearing used in all 1938 Big Twins. Bearing
In new clutch assembly, oil seal with retainer is pressed into inner clutch No. 2448-36 applies to 45 models and also 1936 - 61" model, and all 1937 Big Twins.
disc and locked by rolling over metal at outer edge of retainer.
Only these new bearings are now supplied on all parts orders. At first they were
After removing old seal, a suitable scraper should be used to cut away the distinguished from earlier bearings of the same type by a whitened (cadmium plated)
cover. However, because the cadmium plating didn't clearly enough distinguish these
rclled-over edge before installing new seal.
late bearings from the earlier ones, we are now further distinguishing them by
To install a new oil seal, proceed as follows: drilling a l/16" hole in the cover. This hole is in addition to the cadmium plating.

Place the cork washer in bottom of recess in inner clutch disc, and then place Only bearings with cadmium plated cover or those with cadmium plate and a hole in
the retainer and oil seal over the end of an outer roller race - part No. 2518-33. the cover should be used for your future service requirements.
The roller race will expand the oil seal to fit the retainer and will also be used
to drive or press in the retainer and oil seal. We want to mention, too, that clutch release fingers (both No. 2436-38, used on all
1938 Big Twins, and No. 2436-36, used on 1936 61" models and all 1937 Big Twins) have
The retainer must be pressed down just below flush with edge of inner clutch been changed and are now much stronger.
disc and staked in place by peening over metal at four equidistant points with
a dull punch. When replacing a worn-out or damaged thrust bearing with a new one, always closely
inspect both ends of push rod as well as the release finger for damaged condition
Only the new seal is now furnished on parts order under part No. 2524-36. resulting from failure of bearing. If either is found damaged, replace with new,
as the parts that work with a new bearing must also be in good condition if bearing
2518-33 Roller race - to ube used a pilot and driver is expected to stand up and give long service.
to install new oil seal ...................... $ 2.00 list
Do not fit a 1938 type bearing and push rod to a 1936 61" or any 1937 Big Twin model
2524-36 Set oil retaining washers~ clutch side . 60 list without also fitting a 1938 type release finger which is wider and requires widening
the slots between bosses in aluminum cover in order to get finger correctly located
and centered with end of push rod. A 1938 type bearing cannot be used with a 1936
and 1937 release finger because this finger was designed to be used with the smaller
diameter bearing and it does not have sufficient clearance for the larger diameter
1938 bearing.

IMPORT~T.= Before installing a new thrust bearing to replace one that has gone bad,
transm1ss1on case (particularly the starter compartment) should be thoroughly washed
out to get rid of any small particles of metal that may have been suffed off the
damaged balls and races. If these particles are not removed, they will circulate
through_transmission with the oil and may not only damage the new bearing but may
also damage the gears and other parts.
No. 188 March 28, 1939
No. 189 April 12, 1939

FIXED OILING ON 61 OVERHEAD VALVES AND ROCKERS

NEW DUCKWORTH FRONT CHAIN On all 1936-37-38 and early 1939- 61 OHV motors (up to and including 1939 EL1902),
it was necessary in initial factory assembly, to adjust rocker arm shafts for correct
oiling to valve stems, and further re-adjustment, if needed, could be made by dealer.

All later - 61" motors, starting with 39 EL1903, have fixed oiling arrangement to
Tbere has been a change in Duckworth 1/2" pitch, double row front chain applying valve stems. No re-adjustment will be needed and no means of re-adjusting is provided.
to all big twin models from 1930 to date. This later chain, in a new endless In assembling, the shafts are placed into the rocker arms without regard to location
chain, is fully interchangeable with a chain of earlier production but, inasmuch of oil feed holes,
as the chain pin ·diameter has been changed, connecting links and repair links for
one chain or the other are not interchangeable. This makes it necessary for you In servicing motors, with motor number above 39 EL 1902, that require new rocker arms
to carry two different types of repair links in stock. or shafts, be sure to use the new parts listed below.
Here is how you can distinguis between old and new style chains and their repair 98 - 39 Front intake rocker arm
links. From the beginning, the later style chain and its repair links have been 99 - 39 Rear intake rocker arm
identified by the number D515 stamped in side plates. The very latest chain and 100 - 39 Front exhaust rocker arm
also its repair links are further identified by copper plated center plates. Tbis 101 - 39 Rear Exhaust rocker arm
manner of identification of new chain repair links applies to all but roller block
only. For this reason we recommend that you order complete repair link assemblies
to insure having proper type of roller blocks for servicing old or new chains. 105 - 39 Front intake rocker shaft
Complete repair link for old style chain is #2015-30 and for new style chain is 106-39 Rear intake rocker shaft
1/2015-39. 107 - 39 Front exhaust rocker shaft
108-39 Rear exhaust rocker shaft
Although the pin diameter of the new Duckworth D515 chain is same as regular
Diamond 1/2" pitch, donble"front chain, Duckworth and Diamond links are not Tbese parts are listed on page 7 in your 1939 Spare Parts Catalog and are marked "Later
interchangeable. Diamond chain is about .010" wider and if the new D515 connector 1939 - 61" twins". Rocker arms and shafts for earlier 61" motors are also shown on
link is used, the spring clip will not go down into its retaining groove in link pins. page 7. Do not get them confused.

HARLEY-DAVIDSON MOTOR CO. HARLEY-DAVIDSON MOTOR CO.

Milwaukee, Wis., U.S.A.
Milwaukee, Wis., U.S.A.
No. 191 April 28, 1939
FITTING 1939 CLUTCH THRUST BEARING TO EARLIER HODELS Xo. l91A April 28, 1939
(This applied to 1936 - 6ls, and 1937 and later 61, 74 and 80 models)

We have had a number of inquiries about the possibility of servicing with 1939 type
thrust bearing, earlier models that, for one reason or another, have given an unusual
amount of trouble with original type thrust bearing. We advise that this change-over ·:'he 1939 type bearing can be usBd for servicing 1936, 1337, 1938 models, by c=:a::tg:ng
can be made, applying to the models mentioned above. As a matter of convenience when all of the parts indicated by part number in illustration on reverse side.
ordering, we have established a special part number covering the entire group of parts
required and have set a special price on the group. Any of these parts ordered Oil deflector is assembled as shown in illustration and is held with one of the
individually will be billed at catalog prices. screws that secures mainshaft bearing ·retaining plate. After this screw has been
securely tightened, lock it by setting metal into screw head slot with a :cunc:-,. It
When ordering; specify: Part No. 2125-38 - 1939 Starter cover with is important that this oil deflector be properly assembled as i t provides le!b:ci~a­
clutch thrust bearing & other fittings . . $5.00 Net tion for the ·mainshaft start~r gear.
(Suggested list price $7.50)
.A!'ter the ne.v starter clutch is assembled on th2 mainsheft and S<3cu::-ely t:.~:.t::::r:~C.,
The group of parts you will receive under the above number consists of: try the new bearing on it to be sure bearing is an entirely free fit and sl!des on
and off with no more bind than should normally be accounted for by the bell plunger
1 2126-38 Starter cover in starter clutch. Occasionally it may be found that while the stc.rter clutch is e
l 2436--3') Release finger free fit in bearing befor3 assembly, tightening the starter clutch on main sC.aft ex-
1 2430-38 Release finger shaft pands it enough to make it a tight fit in bearing, or possibly enough so it can't
1 2448-39 Thrust bearing even be started into bearing. In this case you will either have to polish the out-
l 2146-39 Starter clutch with pin and spring side diameter of starter clutch and the inside diameter of bearing witf. emery cloth
l 2151-39 Oil deflector to effect a free fit, or try another combination of parts that may fit better. Cne
1 2149-39 Lock washer way or another the combination must be made an entirely free fit, otherwise clutch
action will not be norr.ml. After this fit has been ctecked, bearing is to be ::::-e-
In applying the 1939 thrust bearing combination to 1937 or 1936 models, it will be moved from starter clutch. because in final assembly, it has to be assembled witi1 t::.:::
necessary, also, to fit the later push rod, part No. 2446-38 - 60¢ list. sta~ter cover. Starter crank gear interfere~ce Joes not p6r~it assembling it ~o
transmission first a~d then installing alumin~~ cover.
A new aluminum starter cover is included in the group of change-over parts because to
use the 19.39 type thrust bearing, more cover clearance is required for bearing, and it If motorcycle being serviced has a late type push rod as shown in illustration (part
is either a matter of using a new cover of having original cover re-machined. The #2446-38) and end of push rod is in good condition, push roo 1s O.K. for the new
earlier style cover can be machined for this added bearing clearance; and for those bearing. Any earlier type of push rod or one of this type that is worn or damaged
who want to send in original covers for machining, with 1939 style bearing and parts at the end as a result of bearing failure must be replaced with a new one~
to be furnished and shipped with covers, we are willing to make a special combination
price of $4.00 net. Considering the packing, transportation, and other expense con- l\11en making final assembly of aluminum cover and bearing to transmission case, pull
nected with returning old covers to the factory for re-machining and the small dif- the end of push rod out a few inches and insert it into bearing to act as a pilot ~or
ference between this change-over price as compared to the $5.00 net price established bearing as the cover is pushed into place. Although asse~bly will be easier if start-
on the group of new parts, it will hardly be worth the dealer's while to send back er clutch and bearing are turned so that the ball plunger in starter clutch registers
any old covers for converting. with groove in bearing race, it is not altogGther necessary that assembly be made
with this register. If assembled 1dth the ball at some other point, it will find its
SPECIAL NOTE - Because of the special low price established on new parts and because place after transmission is put in use.
we have no outlet for used. parts, we cannot permit dealers to order sets of these
parts in advance and then return old covers for credit less repair costs. Ai"'-:2r asser.1bly is completed, adjust clute!: controls in tho 'JSUc:!l mc:.nner.

:on' t ~""'or;:~t to rsi"'i2.1 t:-CJ.nsmi3si.on with oil.

Shop Dope Sheet No. l91A furnished with each set of parxs, contains complete fitting
specifications.
::....:U~L2-:J.n.-,. . =2c:; :.1C:'·:?. 2C.
:.:~:-.;~::.v..K~.S, -,iis., 'J • .3 •.
"""l..
THIS DOPE SHEET WAS SENT OUT WITH FIRST SHIPMENTS OF 1939 BEARINGS AND PARTS PRIOR TO
TIME DOPE SHEETS 191 & 191A WERE PUBLISHED. SKETCH SIMILIAR TO ONE IN 191A WAS INCLUDED No. 193 May 22, 1939
WITH THIS SHEET. CYLINDER REBORING AND PISTON FITTING INFORMATION
NEW CLUTCH PUSH ROD BEARING FOR 61, 74 AND 80 MODELS (1939 TYPE) Taper Bore Cylinder and Solid Skirt Type Piston
(NOTE: Dimensions given are standard size)
This bearing can be used for servicing 1936, 1937 and 1938 models, by changing all of
the parts indicated in illustration. While the aluminum starter cover in one of the MODEL SIZE
parts to be exchanged, the original cover can be returned to the factory to be machined
for necessary clearance so it can be used for exchange on some other machine to be 21 11 2.870"
serviced with the new bearing. 30.50" 3.0885"
45" (1934 & earlier) 2.745"
Oil deflector is assembled as shown in illustration and is held with one of the screws 61" (1923 & earlier) 3.307"
that secures mainshaft bearing retaining plate. After this screw has been securely 61" (1924 to 1929) 3.305"
tightened, lock it by setting metal into screw head slot with a punch. It is important 74 & 80" (1934 & earlier) 3.422"
that this oil deflector be properly assembled as it provides lubrication for the main-
shaft starter gear. NOTE: Take cylinder measure-
ment about ~~~ from top
After the new starter clutch is assembled on the mainshaft and securely tightened, try of bore, rather than at
the new bearing on it to be sure bearing is an entirely free fit and slides on and off extreme top, when de-
with no more bind than should normally be accounted for by the ball plunger in starter termining piston clear-
clutch. Occasionally it may be found that while the starter clutch is a free fit in ance given below.
bearing before assembly, tightening the starter clutch on main shaft expands it enough
to make it a tight fit in bearing, or possibly enough so it can't even be started into
bearing. In this case, you will either have to polish the outsdie diameter of starter 21" 2.875"
clutch and the inside diameter of bearing with emory cloth to effect a free fit, or try 30.50" 3.0935"
another combination of parts that may fit better. One way or another the combination 45" (1934 & earlier) 2.750"
must be made an entirely free fit, otherwise clutch action will not be normal. After 61" (1923 & earlier) 3.310"
this fit has been checked, bearing is to be removed from starter clutch because in final 61" (1924 to 1929) 3.312"
assembly, it has .to be assembled with the starter cover. St~rter crank gear interference 74 & 80" (1934 & earlier) 3.429"
does not permit assembling it to transmission first and then installing aluminum cover.
Piston Size
If motorcycle being serviced has a late type push rod as shown in illustration and end of at measuring
push rod is in good condition, push rod is o.k. for the new bearing. Any earlier type SOLID SKIRT point - just
Type Piston below top Piston
of push rod or one of this type that is worn or damaged at the end as a result of bearing
failure must be replaced with a new one. Model group of rings Clearance

When making final assembly of aluminum cover and bearing to transmission case, pull the
,..
2 1 "(all models) Dow metal & Lynite
end of push rod out a _few inches and insert it into bearing to act as a pilot for bearing 2.8585" .011" to .013"
as che cover is pushed into place. Although assembly will be easier if starter clutch 3 0.50 Dow Metal 3.07f,7" .011" to .013"
4 5" Dow Metal * 2.730" . 014" to . 016"
and bearing are turned so that the ball plunger in starter clutch registers with groove
in bearing race, it is not altogether necessary that assembly be made with this register.
4 5" Lynite* 2.731" .014" to .016"
If assembled with the ball at some other point, it will find its place after transmission
6 1" Iron Alloy (1924-1929) 3.3035" .002" to .003"
is put in use. ,. 61" Dow Metal (1924-1929) 3.293" . 0115"to . 0135"
74" Iron Alloy (1929 & earlier) 3.419" .003" - .004"
After assembly is completed, adjust clutch controls in the usual manner. 0 7 4" Dow Metal (1930 to 1934)
7 4 & 80" Dow Metal (1930-1934)*
74 & 80" Lynite (1930-1934)*
3.418"
3.405"
3.407"
.004" to .005"
o:-'.016 11 to .018 11
.016" to .018"
Don't forget to refill transmission with oil.

"'
NOTE: Solid skirt pistons marked with * are no longer furnished on regular parts order.
These pistons are superseded by slotted pistons. Cylinders should be straight ground -
See other side.
No. 193 -2- Hay 22, 1939

CYLINDER REBORING AND PISTON FITTING INFORHATION

Straight Bore Cylinder and Slotted Type Piston
(NOTE: Dimensions given are standard size)

Standard bore dimension

of straight bore cylinder
for slotted piston

45" 2.745" (1935 and later)

74" 3.422'·' 1935 and 1936, and all 80"
61" 3.3125" OHV and 1937 and later 74"

Slotted piston should be fitted .001" to

.002" clearance in straight bore cylinder
checking fit at bottom of skirt, front and
rear.
No. 198 October 30, 1939
74 and 80 CU. IN. TWIN MOTOR FITTING SPECIFICATION (1930 TO AND INCLUDING 1936) No. 198A October 30, 1939

(THESE SUPERSEDE ALL PREVIOUS SPECIFICATION AND APPLY TO ALL 1930 TO AND INCLUDING 74 AND 80 CU. IN. TWIN MOTOR FITTING SPECIFICATIONS (1937 AND LATER MODELS
1936 - 74" and 80" MOTORS
(NOTE: These supersede all previous specifications)
PISTON CLEARANCE - IRON ALLOY PISTONS - Used in 1930-34 motors fitted with taper
bore cylinders - .004 11 to .005" clearance. PISTON CLEARANCE - ALUMINUM PISTON - Slotted, cam ground type - New piston fitted in
ALUMINUM AND DOW METAL PISTONS - Solid skirt type - Used in 1930-34 motors fitted straight bore cylinder, .001" to .002" clearance. Piston shapes to
with taper bore cylinders - .016 11 to .018 11 clearance cylinder and acquires more clearance after short time in service.
ALUMINUM PISTON- Slotted, cam ground type- New piston fitted in straight bore cylinder Measure piston at bottom of skirt, front and rear.
.001" to .002 11 clearance. Piston shapes to cylinder and acquires more clearance after When fitting oversize piston which has vertical· slot in addition to
short time in service. Measure solid skirt piston just below the top group of rings. horizontal slots, fit with vertical slot forward.
Heasure slot~ted piston at bottom of skirt, front and rear. When fitting oversize Measure cylinder about l/2" from top of bore, front and rear.
piston which has vertical slot in addition to horizontal slots, fit with vertical slot
forward. Measure cylinder about ~~~ from top of bore, front and rear. PISTON-CYLINDER HEAD CLEARANCE - 1/16" to 3/32"

PISTON - CYLINDER HEAD CLEARANCE - (All models except VC Commercial) 1/16" to 3/32" PISTON PIN IN PISTON - Light hand press fit
(VC Commercial. discontinued after 1933) 7 /64" to 9/64".
PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose
PISTON PIN IN IRON ALLOY PISTON - .0005" to .001" press fit in lock pin side - plug or
sljp fit in opposite side. PISTON RING GAP AND GROOVE CLEARANCE - Straight bore cylinder .010" to ,020" gap 1/2"
from top of cylinder. Rings should be .004" loose in grooves.
PISTON PIN IN DOW METAL AND ALUMINUM PISTON - Solid skirt type - .0005" to .001" press
fit in piston LOWER CONNECTING ROD BEARING - .001" to .0012" loose.

PISTON PIN IN ALUMINUM PISTON - Slotted type - light hand press fit CONNECTING RODS - .006" to .010" clearance between flywheels - roller and retainer
assembly should be narrower, but not ·more than .010" narrower than forked rod~
PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose
PISTON RING GAP AND GROOVE CLEARANCE - Taper bore cylinder .006" gap !," from top of PINION GEAR SHAFT~ .00075" to .00125" loose in roller bearing and .0005" to .001"
cylinder. Straight bore cylinder .010" to .020" gap !," from top of cylinder. Rings loose in cover bushing. Oil hole in cover bushing is 30° ahead of top center, and
should be .004" loose in Dow Metal and Aluminum piston grooves and just free in Iron in line (on opposite side) with drilled oil feed channel in cover.
Piston grooves.
LOWER CONNECTING ROD BEARING - .001" to .00125" loose SPROCKET SHAFT ~ .0005" to .001" loose in roller bearing - .007" to .009" loose in
oil retaining bushing
CONNECTING RODS - .006" to .010" clearance between flywheels - roller and retainer
assembly should be narrower. but not more than .010" narrowere than front rod. FLYWHEEL ASSEMBLY ~ .012" to .014" end play in crank case
PINION GEAR SHAFT - .0045" loose at inner end of bushing - .002" loose at outer end
of bushing. (Bushing is taper reamed with special reamer.) CAM GEARS ~ .0005" to .001" loose in crank case and cover bushings - free to .005"
end play.
SPl\OCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in
oil retaining bushing. INTERMEDIATE GEAR - .001" to .0015" loose on stud.
FLYWHEEL ASSEMBLY - .006" to .010" end play in crank case
TAPPET GUIDES - .0005" to .001" press fit in crank case.
CAM GEARS - .0005" ro .001" loose in crank case and cover bushings - free to .005"
end play. VALVE TAPPETS - .0005" to .001" loose in tappet guides
INTERMEDIATE GEAR " .001" to .0015" loose on stud
CRANK CASE BREATHER- Which is a part of, and drives scavenger pump, is timed according
TAPPET GUIDES - . 0005" to . 001" press fit in crank case. to instructions in Riders Instruction F~lder.
VALVE TAPPETS- .0005" to .001" loose in tappet guides.
No. 198B October 30, 1939
No. l98C October 30, 1939
61 CU. IN. TWIN MOTOR FITTING SPECIFICATIONS (O.H.V. MODELS)
45 CU. IN TWIN MOTOR FITTING SPECIFICATIONS (1930 TO AND INCLUDING 1936)
(NOTE: These supersede all previous specifications.) EXCEPT RLD MODEL ( These supersede all previous specification and apply
to all 1930 to, and including 1936 45" motors
PISTON CLEARANCE - ALUMINUM PISTON - Slotted, cam ground type - New piston fitted in
cylinder, .001" to .002" clearance. Piston shapes to cylinder and PISTON CLEARANCE - ALUMINUM AND DOW METAL PISTONS - Solid skirt type - used in 1934
acquires more clearance after short time in service. and earlier motors fitted with taper bore cylinders -- .014" to .016" clearance.
Measure piston at bottom of skirt, front and rear. ALUMINUM PISTON Slotted, cam ground type - new piston fitted in straight bore
Measure Cylinder about 1/2" from top of bore, front and rear. cylinder~ .001" to .002" clearance. Piston shapes to cylinder and acquires more
clearance after short time in service. Measure solid skirt piston just below the top
PISTON PIN IN P-ISTON - Light hand press fit. group of rings. Measure slotted piston a bottom of skirt, front·and rear.
When fitting oversize piston which has vertical slot in addition to horizontal slots,
PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose fit with vertical slot forward.
PISTON RING GAP AND GROOVE CLEARANCE - .010" to .020" gap ~" from top of cylinder. Rings Measure cylinder about ~" from top of bore, fiont and rear.
should be .004" loose in grooves.
PISTON CYLINDER HEAD CLEARANCE - 3/64" to 5/64"
LOWER CONNECTING ROD BEARING - .001" to .0012" loose
PISTON PIN IN ALUMINUM AND DOW METAL PISTONS - Solid skirt type - .0005" to .001" press
CONNECTING RODS - . 006" to . 010" end play between flywheels - roller and retainer assembly fit in piston
should be narrower~ but not more than .010 11
narrower than forked rod.
PISTON PIN IN ALUMINUM PISTON - Slotted type -Light hand press fit.
SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .007" to .009" loose in oil
retaining bushing. PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose

PitiiON GEAR SHAFT - (Solid and two piece type) - .001" loose in roller bearing, and .001" PISTON RING GAP AND GROOVE CLEARANCE - Taper bore cylinder - .006" gap~" from top of
to .0015" loose in cover bushing. Oil hole in cover bushing is centered with drilled cylinder: Straight bore cylinder - • 010" to . 020" gap V' from top of cylinder. Rings
oil feed channel in cover. Two piece stub shaft assembly - cork sealed, oil tight fit should be .004" loose in grooves
in flywheel shaft with copper washer behind.
LOWER CONNECTING ROD BEARING - .0007" to .001" loose
FLYWHEEL ASSEMBLY - .012" to .014" end play in crank case.
CONNECTING RODS ~ .006" to .010" end play between flywheels - roller and retainer
CAM GEAR - .OOI" to .0015 11 loose in crank case and cover bushings - free to .005" end assembly should be narrower\ but not more than .010" narrower than front rod.
play.
PINION GEAR SHAFT - .0045" loose at inner end of bushing - .002" at outer end of bushing.
INTERMEDIATE GEARS - .001" to .0015" loose - free to .005" end play. (Bushing is taper reamed with special reamer.)

TAPPET GUIDES .0005" to .001'' press fit in crank case. SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in oil
retaining bushing.
VALVE TAPPETS - .0005" to .001" loose in tappet guides.
FLTIIF!EEL ASSEMBLY - . 004" to . 006" end play in crank case.
ROCKER ARM FIT ON SHAFT - (1936 to 1937 models) .0005" to .0015" loose - .003" to .008"
end play. (1938 and iater models) .0005" to .0015" loose - .007" to .016" end play. CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005"
end play.
OIL PUMP DRIVE SHAFT - .001" loose in crank case bushing.
GENERATOR DRIVE GEARS AND SHAFT (1931 and earlier models) - Shaft must be free running
CRANK CASE BREATHER Timed with front cylinder - opens 1/8" before top center to fit; have .002" to .004" end play, and .001" to .0015" clearance in bearings. Small
1/8" after top center, and closes 13/16" to 1-5/16" afte'r bottom center. bevel gear should be .002" to .003" loose in bushing assembly, and shimmed to allow
.002" to .004" clearance between bevel gears.

TAPPET GUIDES - .0005" to .001" press fit in crank case

VALVE GUIDES - .0005" to .001" loose in tappet guides.
No. 198D October 30, 1939 No. 198E October 30, 1939
SINGLE MOTOR FITTING SPECIFICATIONS - (ALL 1934 AND ·EARLIER MODELS)
45 CU. IN TWIN MOTOR FITTING SPECIFICATIONS
(1937 AND LATER MODELS EXCEPT WLDR MODEL) PISTON CLEARANCE -Dow metal and aluminum - .011" to .013" clearance. (measure piston
just below the top group of rings, and cylinder about 1/2" from top of bore, front
and rear.)
PISTON CLEARANCE- Aluminum Piston- Slotted, cam ground type- new piston fitted in
straight bore cylinder, .001" to .002" clearance. Piston shapes PISTON - CYLINDER HEAD CLEARANCE (side by side valve models) - 3/64" to 5/64"
to cylinder and acquires more clearance after short time in service.
Measure piston at bottom of skirt, front and rear. PISTON PIN IN PISTON - Snug press fit - not over .0005" tight.
When fitting oversize piston which has vertical slot in addition to
horizontal slots, fit with vertical slot forward. PISTON PIN IN UPPER END OF CONNECTING ROD - .0005" loose.
Measure cylinder about ~~~ from top of bore, front and rear.
PISTON RING GAP AND GROOVE CLEARANCE - .006" gap 1/2" from top of cylinder. Rings
PISTON-CYLINDER HEAD CLEARANCE - 1/16" to 3/32" should be .0015" to .002" loose in grooves.

PISTON PIN IN PISTON - Light hand press fit LOWER CONNECTING ROD BEARING - .0003" to .0004" loose.

PISTON PIN IN UPPER END OF CONNECTING ROD - .001" loose CONNECTING RODS - .010" to .020" end play between flywheels - roller and retainer assembly
should be narrower,·but not more than .010" narrower than rod.
PISTON RING GAP AND GROOVE CLEARANCE - Straight bore cylinder - .010" to .020" gap !,;" from
top of cylinder. Rings should be .004" loose in grooves. PINION GEAR SHAFT - .0035" loose at inner end of bushing - .0025" loose at outer end
of bushing (Bushing is taper reamed with special reamer).
LOWER CONNECTING ROD BEARING - .0007" to .001" loose.
SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in
CO!-i"NECTING RODS - . 006" to . 010" end play between flywheels - roller and retainer chain lubricating bushing.
assembly should be narrower, but not more than .010 11 narrower than forked rod.
FLYWHEEL ASSEMBLY - .002" to .006" end play in crank case.
PINION GEAR SHAFT - .00075" to .00125" loose in roller bearing, and .0005" to .001"
loose in cover bushing. Oil hole in cover bushing is 30° ahead of top center and in CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005"
line (on opposite side) with drilled oil feed channel in cover. end play

SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in oil INTERMEDIATE AND OILER GEARS - .0015" to .002" loose on studs
retaining bushing.
TAPPET GUIDES - .0005" to .001" press fit in crank case.
FLYWHEEL ASSEMBLY - .012" to .014" end play in crank case.
VALVE TAPPETS - Free to .00075" loose in tappet guides.
CAM GEARS - . 0005" to . 001" loose in crank case and cover bushings - free to . 005"
end play.

TAPPET GUIDES - .0005" to .001" press fit in crank case.

VALVE TAPPETS - .0005" to .001" loose in tappet guides.

CRANK CASE BREATHER- Which is a part of, and drives scavenger pump, is· timed according
to instructions in Riders Instruction Folder.
 No. 198F -2- October 30, 1939

IGNITION- OCCURS when piston is 7/32" to 9/32" before top dead center on compression
stroke.

21 CU. IN SIDE BY SIDE VALVE SINGLE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 1/8" to 3/16" before top dead center
No. 198F October 30, 1939 CLOSES '"hen piston is 7/16" to 9/16" after bottom dead center
TIMING SPECIFICATIONS EXHAUST VALVE- OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 1/8" to 3/16" after top dead center
(NOTE: These supersede all previous specifications)
IGNITION- OCCURS when piston is 7/32" to 9/32" before top dead center on compression
1930 AND LATER 74 & 80 CU. IN TWIN ALL MODELS EXCEPT 1930 & 1931 V AND VC MODELS stroke.
INTAKE VALVE - OPENS when piston is - 9/32" to 13/32" before top dead center
21 CU IN OVERHEAD VALVE SINGLE (ALL MODELS)
CLOSES when piston is 7/8" to 1-1/8" after bottom dead center
INTAKE VALVE - OPENS when piston is.3/32" to 5/32" before top dead center
EXHAUST VALVE- OPENS when piston is 5/8" to 7/8"·before bottom dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center
r:LOSES when piston is 1/4" to 3/8" after top dead center
EXHAUST VALVE- OPENS when piston is 7/16" to 9/16" before bottom dead center
IGNITION - OCC!JRS when piston is 5/16" to 11/32" before top dead center on compression
CLOSES when piston is 3/32" to 5/32" after top dead center
stroke.
11/32" timing (Flywheel mark at rear of crank case inspection hole) applies to moderate IGNITION - OCCURS when piston is 11/32" to 13/32" before top dead center on compression
compression motors in solo service. High compression solo motor (8.2 heads) also all stroke.
motors in sidecar service should be timed 5/16".
TAPPET CLEARANCE
1930 AND 1931 - 74 CU. IN TWIN V AND VC MODELS
NOTE: When checking valve timing according to piston position, bear in mind that
INTAKE VALVE - OPENS when piston is 11/64" to 19/64" before top dead center tappets must first be adjusted to the correct clearance.
CLOSES when piston is 9/16" to 13/16" after bottom dead center
ALL SIDE BY SIDE VALVE MODELS (SINGLE AND TWINS) - INTAKE - .004" to .005"
EXHAUST VALVE - OPENS when piston is 9/16" to 13/16" before bottom dead center
EXHAUST - .006" to .008"
CLOSES when piston is 11/64" to 19/64" after top dead center
IGNITION - OCCURS when piston is 1/4" to 5/16" before top dead center on compression OVERHEAD VALVE SINGE - INTAKE AND EXHAUST - .002" to .003"
stroke.
61" OVERHEAD VALVE TWIN - INTAKE AND EXHAUST - Correctly adjusted when tappet has just
1936 AND LATER 6l.CU. IN OVERHEAD VALVE TWIN MODELS noticeable play or shake, and can be turned freely with finger
tips, completely around, without any trace of bind.
INTAKE VALVE - OPENS when piston is 5/16" to 3/8" before top dead center
CLOSES when piston is 15/16" to 1-1/16" after bottom dead center
CIRCUIT BREAKER OPENING - (ALL MODELS)
EXHAUST VALVE - OPENS when piston is 49/64" to 55/64" before bottom dead center
CLOSES when piston is 5/16" to 3/8" after top dead center GENERATOR - .020" to .024"
NOTE: Timing is checked with tappets adjusted with .004" clearance
MAGNETO - .014" to .018"
IGNITION- OCCURS when piston is 7/16" before top dead center on compression stroke.

45 CU. IN. TWIN (ALL MODELS EXCEPT WLDR)

INTAKE VALVE- OPENS when piston is 5/32" to 7/32" before top dead center
CLOSES when piston is 37/64" to 45/64" after bottom dead center
EXHAUST VALVE- OPENS when piston is 37/64" to 45/64" before bottom dead center
CLOSES when piston is 5/32" to 7/32" after top dead center
IGNITION - OCCURS when piston is 1/4" to 9/32" before top dead center on compression
stroke.
30.50 CU. IN. SINGLE (ALL MODELS)
INTAKE VALVE - OPENS when piston is 5/16" to 9/16" before top dead center
CLOSES when piston is 11/16" to 15/16" after bottom dead center
EXHAUST VALVE - OPENS when piston is 1/2" to 3/4" before bottom dead center
CLOSES when piston is 1/4" to 1/2" after top dead center
 No. 199 -2- November 11, 1939

oil for some time forms sludge that is harmful to motor and causes undue wear of
various working parts. Sludge also contains acid which causes parts to wear and
fatigue very rapiJly.
In extremely cold weather if motorcycle (particularly Servi-Car) is used daily even
though total mileage run is quite low, interval between drains should be approximately
one week. As a matter of oil economy during the frequent drain period and also to
No. 199 November 11, 1939
circulate the complete oil supply at shorter intervals and warm it up quicker to the
WINTER TROUBLE SAVER
point of evaporating any water in the system, consideration can be given to filling
tank only about half full when fresh oil is added. This should be applied only to
Winter is here or just around the corner. If you already have or will soon have below-
motorcycles where you are quite sure that the mi~eage between drains will be very
freezing weather in your territory, now is the time to get a card or letter to all of
low or you can depend upon the operator to watch closely to see that oil supply is
your riders suggesting a winter tune-up job. Here are some of the things that need
not exhausted. You will have to be very cautious about doing this to avoid running
attention in getting ready for winter service:
into claims, where a machine is run far enough to exhaust the oil supply and damage
Battery - Charge, inspect terminal connections and oil terminal felt washers. the motor, with the owner or operator contending he understood the oil tank was
Generator - Clea8 commutator. Inspect brushes and renew any nearly worn out. Check completely filled as in warm weather and therefore, he feels you ar.e responsible. When
only partial filling of oil tank may be practiced it might be well to paste a warning
charging rate and if low, adjust higher. Remove bearing cover and pack bearing with
sticker on oil tank cap or on tank near the filler opening.
Grade A grease-.
Circuit Breaker Points - Clean and adjust, or renew. When putting in fresh oil, in below-freezing weather, add a little kerosene - just
enough to keep oil liquid to the point where it flows freely and will begin to circulate
Spark Plugs - Clean and adjust, or renew.
immediately when motor is started.
Valves - Clean carbon and grind valves, or if this is not done, on side valve motors
raise valve covers and flush out thoroughly with kerosene while motor is running, to
correct possible sticky, sluggish action. Adjust tappets.
Carburetor - Remove and clean thoroughly. At least, remove and clean bowl assembly, or
if late carburetor with drain plug, remove plu-, drain and flush bowl. In re-adjusting
set throttle stop screw for somewhat faster than normal summer idling. Remove and
clean gas strainer.
Clutch - Check for slippage and also for complete disengagement.
Cha!ns - Adjust and report condition, if bad.
Brakes - Adjust and report condition, if bad.
General Lubrication - Thoroughly grease complete machine. Oil control cables and control
joints •·ith light oil.
Transmission Oil - Same as motor. When cold enough so that shifting becomes difficult
(even with "Medium Heavy" oil, after a motorcycle has stood for a time) add 1/3 to 1/2
pt. of kerosene, to thin oil. Late four speed transmission and also three speed and
reverse transmission of the constant mesh type may become very difficult to shift unless
this attention is given. Difficult shifting due to stiff oil also means har cranking
when starting.
Motor Oil - When temperature is below freezing, change to "Medium Heavy" oil (61 OHV
model uses "Medium Heavy" oil year-around)
SPECIAL INFORMATION ON MOTOR LUBRICATION APPLYING TO CIRCULATING OILING SYSTEM
Combustion in any engine generates water vapor. tfhen starting and warming up in cold
weather, considerable of the vapor that gets into crankcase condenses to water before
crankcase is hot enough so it no longer acts as a condenser and exhausts. the vapor
through outside breather. If a motor is driven enough to get the crankcase thoroughly
"armed up frequently, most of this water is again vaporized and blown out the outside
breather. However, a moderately driven motor, seldom tho~oughly warmed up, is likely
to accumulate an increasing amount of water in oil tank. This water will, in freezing
weather, become slush or ice and if allowed to accumulate too long, there is the chance
that oil lines may be blocked with resulting damage to motor. Also, water mixed with
August 7, 1940 CURRENT AND VOLTAGE REGULATOR No. 208 September 5, 1940
The part number of the current and voltage regulator used on California Highway Patrol CONNECTING ROD REPAIR EXCHANGE PRICES
motorcycles and other radio-equipped machines is listed in the spare parts catalog as
8375-38. However, this part number includes besides the regulator, the mounting bracket On July 1, 1940, the following charges became effective on connecting rod repair exchanges:
and wiring necessary to use the regulator on a motorcycle not originally equipped with Rebushing set of connecting rods at both ends and List Net
re9ulator. It has been reported by CHP headquarters that when replacement of current fitting rollers, retainers and crank pin (any 61-
and voltage only has been required, dealers have been using part number 8375-38 even 74-80 model, to and including 1941 models) ............ $ 7.30 4.75
though the wiring and fittings were not needed. In the future, when only the regu-
lator is needed, order Part No. 8375-38A Cureent & voltage regulator only. Rebushing set of connecting rods at both ends only 5.00 3.25

While on the subject of current and voltage regulators, we want to mention that the Rebushing set of connecting rods at both ends and
regulator is apparently in a good many cases being blamed for bringing about trouble fitting rollers, retainers, and crank pin (any 45
for which it is not actually responsible. In other words, in the case of a generator model, except WLDR and 1929 to 1931 model without
found overheated and damaged and also in the case of a regulator found with points in bushings at upper end.** 7.00 4.50
bad condition or damaged, it is in many instances taken for granted that the regulator Rebushing set of connecting rods at both ends only 4.60 3.00
went bad first and caused the generator to burn up. More likely what has actually
happened first in most cases is that a poor or loose pattery terminal connection or Rebushing set of WLDR rods at both ends and fitting
a loose connection elsewhere took the battery out of the circuit. The regulator then ll,;" crank pin with rollers and retainers (fit 1937
tries to act as both battery and regulator in controlling output of the generator but to 1941 models) 12.55 8.15
of course with the high output of a radio generator, the regulator can't stand this
condition very long before it becomes overheated and damaged, with generator damage Rebushing WLDR rods at both ends only 8.10 5.25
naturally following. We suggest that closer attention be given to keeping battery
terminals in good order, battery wires in good condition and connections tight. If On the basis of the new price schedule, it will obviously be to your advantage and to the
you will do this, it is a safe bet you'll not run into any amount of serious trouble advantage of the customer not only to have all connecting rod repairs taken care of at
either with regulators or generators. In fact, every flat rate job No. 7 on CHP motor- our factory but also to have repaired rods come through fitted with rollers and crank pin.
cycles and particularly on those with radio generator-and current regulator should At these prices you are able to offer your customers a factory repair at a large saving
include a close inspection of battery terminals and terminal connections and any over the cost of new parts and still make a fair margin of profit on each exchange. We
faulty conditions discovered then should be corrected at once. suggest, too, that you offer these repair exchanges to your customers at our recommended
list prices as a little later they will be published in a bulletin to riders.
At this time we want to remind you that the servicing of a current and voltage re- **Since for the most part connecting rods of the type without bushing in the upper end
gulator when trouble has been traced to the regulator should be referred to a United as used in 45 cu. in. motors from 1929 through part of 1931 either are badly worn at the
Motors Service Station. This equipment requires adjusting too closely as concerns upper end or have been reamed to large oversizes, we do not consider it practicable to
setting gaps, spring tensions. and current and voltage values to be satisfactorily make further repairs on such rods. Consequently, ·they should not be sent in for exchange
handled in the average motorcycle repair shop. As mentioned before, giving closer or repair, because they will not be accepted but will be scrapped.
attention to wiring connections will reduce to a minimum attention required by
regula tors.
It will also be necessary under the foregoing low exchange prices that rods returned for
exchange be in perfect condition aside from requiring new bushings. Rods that are badly
bent or twisted .or otherwise damaged, or rods that have been plated or ground down or
polished to a point of weakening them will not be accpeted for exchange; neither will we
be in a position to recondition such rods individually. Therefore, you should watch care-
fully any connecting rods you accept for exchange.

In cases where 1936 45-74-80 rods with thin upper bushings have been sent in for repair,
we have in the past made a point of shipping rebuilt rods with same type bushings. Since
having thin or thick piston bin bushings does not affect interchangeability of these rods,
we will not hereafter make any distinction between the two types. Consequently, i f you
send in rods with thin bushings and you get rods with heavy bushings in exchange, or
vice versa, pay no attention to it.
No. 211 November 5, 1940
NEW SERVI-CAR TOWBAR CLAMP TO FIT 1941 MODEL AUTOMOBILES
No. 215 January 2, 1941
In spite of everything we have been doing to speed up production, there is going to be some
further delay in shipment of 1941 style twobar clamps as redesigned to fit latest 1941 car AN ADDITION TO THE HARLEY-DAVIDSON OIL FAMILY
bumpers. The best delivery promise we have been able to get is around December l, with a
possible chance a limited number of clamps will be available somewhat sooner. Up to now we have furnished three grades of Harley-Davidson Oil: "High Speed
Now that all points of design of the new clamp have been settled, we can at least tell you
Special" (140) for unusually hard and fast summer driving; "Regular Heavy" (105)
for all ordinary service, all models excepting OHV motors, with temperature above
what you are going to need to bring up to date the clamps on the 1941 Servi-Cars you have
freezing (32°F.); "Medium Heavy" (75) for year-around service in OHV motors and for
already received: 7030-39 Set of upper and lower clamp jaws with hand wheel and bolt below freezing service in all other motors. This ·has been the lightest oil furnished
7006-39 New longer safety cable and in localities where winter weather becomes so cold this oil gets stiff or con-
At the time we start using the new clamp ie. new Servi-Car assembly, our records will sho\>7 geals (approximate +10°F.) it has been recommended that enough kerosene be added to
how many 1941 -Servi-Cars you have received with old clamp. Without further follow-up on keep oil fluid so it circulates freely immediately when motor is started.
your part, we will ship you as many combination of the new fitting as you have received 1941
Servi-Cars with old clamp. The fourth grade of oil we will supply from now on is identified as "Light" oil (58)
and is recommended for use in all models when winter ·temperature is below +10°F.
The combinations we are furnishing you for your early 1941 models will be furnished on a no This will eliminate, until temperature reaches several degrees below zero, the need
charge exchange basis if you want it that way. We are actually going to bill these combin- of adding kerosene to keep oil fluid.
ations to you at $1.50 net each. If you want to return the original 1941 clamp parts and
safety cable, tagged with motor number, you will be credited with the full $1.50 charge. Every dealer located where temperature goes to +10°F. or colder for a longer winter
We repeat - it will not be necessary to follow up further for the clamp exchange fittings period than just .an occasional snappy morning, should order a supply of this new oil
due you for early '41 Servi-Cars you will have received before we start shipping Servi-Cars and furnish it to his riders. It will make starting easier and since it will cir-
with new clamp. All you have to consider are the additional changeover combinations and culate freely immediately on starting, it will lessen the possibility of starting
complete clamps you may need to take care of your owners of earlier than 1941 models. and warming up motor damage. It will also have less tendency to form sludge in short
SERVICING EARLIER THAN 1941 SERVI-CARS WITH NEW CLAMP FITTINGS run motors. Riders will go for this oil in a big way~ some because they have been
skeptical about it being o.k. to add kerosene to thin heavier oil, all of them because
1940 ·servi-Cars require the same combination of fittings as list·ed for early 1941 Servi- it eliminates the extra work of adding kerosene and deciding how much to add.
Cars. Prices of these fittings are listed below. THERE IS NO EXCHANGE ALLOWANCE APPLYING
TO OTHER THAN JUST YOUR EARLY 1941 SERVI-CARS. This new light oil is available only in one quart sealed can, in case lots of 24 quarts.
1939 Servi-Cars require same combination of fittings. In addition, fork bracket 7009-39A Prices are the same as for "regular Heavy" or Medium Heavy" oil. Shipments can be
to which clamp is secured when not in use, will have to be reshaped to raise it so clamp made from our stocks in Milwaukee or Coraopolis, Fa., depending on whichever has the
clears headlight, or a new bracket installed. lowest freight rate to your city. Order by part number 11700X and send your order
to MILWAUKEE.
Earlier than 1939 Servi-Cars not equipped with permanently attached towbar but fitted with
late vise-type clamp can be serviced with just new jaw combination, but towbars still
fitted with earlier type clamp will have to be serviced with new clamp of latest type.
New safety cable will be needed for Servi-Cars up to and including 1937, and new cable
for 1938 Servi-Cars.
NEW PARTS FOR 1940 MODELS
list
70.:10-39 Set clamps only with hand wheel $6.00
7006-39 New Safety Cable 3.50
NEW PARTS FOR 1939 MODELS
700~·-39A Towbar clamp bracket 1.50
7030=39 Set clamps only with hand wheel 6.00
7006-39 New Safety cable 3.50
NEW PARTS FOR 1932 TO 1938 MODELS
7030-32 Towbar clamp and swivel complete 10.00
7006-32 Longer safety cable (1932 to 1937) 2.80
7006-38 Longer safety cable (1938) 3.80
 No. 216 -2 February 10, 1941

LARGE ROLLERS
PART NO. WHERE USED NO. USED LENGTH

2306-32 Counter shaft gear-left side (1933-1934 45" Twin and

single reverse, 1935 & later 45" standard & reverse
transmission 19 5/8"
No. 216 February 10, 1941
ROLLER BEARING ROLLERS 2289-36 Countershaft Gear (1936 61"' 1937 & later 61" 74" & 80" 44 .615"
Here is a handy chart, giving information on roller bearing rollers. It is suggested that Main Drive Gear (1936 61". 1937 & later 61", 74" & son 44
this data be kept in a prominent place so it can be referred to on a moment's notice. Clutch Gear (1941 45") 40
Standard roller diameter is as follows: Large roller .250" - needle rollers (used without 2289-39 Countershaft Gear - right side (1939 & later 45") 24 3/4"
retainers) .l52n, .125", .114" and .0625". .250" and .152 11 rollers are furnished from .OOltl
undersize to .001" oversize in steps of .0002". .125u and .114" rollers are furnished in 2289-36A Countershaft Gear (1936, 74" & 80" - 4 Speed) 78 39/64"
.0004" and .0008" oversize only. .0625" roller is furnished in .0008" oversize only.
LARGE ROLLERS When assembling needle rollers in outer race preparatory to final assembly, apply a small
PART NO. WHERE USED NO. USED
_2_4_ _ LENGTH amount of grease to hold rollers in place. Assemble specified number of rollers and
304-15 Forked end Connecting Rod (1915-1939 61", 74" & 80") .360" observe that the last roller goes all the way into place freely and' without requiring
L~ft crankcase (1929 & earlier 61" & 74" Twins) 24 any effort to force it. If it doesn't go into place freely, leave it out. This is
Left crankcase (1929 & later 45" Twins) 24 sometimes necessary when fitting oversize rollers, because they not only take up radial
Front Brake Hub (1930-1936 71," & 80" Twins) 24 clearance, but also take up circumferential clearance. Roller must not be crowded.
Sidecar Brake Hub (1930-1936, except LE Model) 28
CONVERSION TABLE
304-40 Forked End Connecting Rod (1940 & later 61", 74" & 80") 36 .344"
305-15 Single End Connecting Rod (1915-1939 61", 74" & 80") 12 . 726" .270" - 6.86 mm •
Connecting Rod (30.50 Single) 12 . 344" - 8.74 mm .
Clutch Sprocket (192hl936 61", 74" & 80" except 61" OHV)l2 . 360" - 9.15 mm
.490" - 12.45mm
305-40 Single End Connecting Rod (1940-later 61", 74" & 80") 18 .694" .550" - 13.97 mm
305-29 Single End Connecting Rod (1929-later 45" Twins) 12 .550" .600 - 15.24 mm
Right Crankcase (1937~later 45" Twins) 12 .615" 15.62 mm
.694" - 17.63 mm
306-26 Right Crankcase (1936-61"; 1937~later 61", 74" & 80") 12 .600" .726"- 18.44 mm
Connecting Rod (21" Single) 12 39/64" - 15.48 mm
Left Crankcase (21" & 30.50" Single) 12 5/8" - 15.87 mm
2289-17 Fork~d End Connecting Rod (1929-later 45" Twins) 24 .270" 3/4" - 19.05 mm
Clutch Sprocket (1926-1934 Singles & 45" Twins) 16
Countershaft Gear - Standard Transmission (1931-earlier .001 - .025 mm
61" & 74" Twins) 24
Main Drive Gear (1924-earlier 61" & 74" twins) 20
2289-25 Left crankcase (1930-later 61", 74" & 80" Twins) 24 .490"
Rear Wheel Hub (1923-1929 61" & 74" Twins) 32
Main Drive Gear (1925-1936 61", 74" 80" except 61: OHV) 20
Clutch Gear (1934-earlier 45" & Single Standard Trans) 16
Mainshaft (1934-earlier 45" & Single Standard Trans) 12
Interchangeable Wheel Hub(l930-36 74" & 80" Twins) 28
Countershaft Gear-Right Side-(1931 Reverse, 1932-36
Reverse & Standard transmission - 74" & 80") 12
Servi-Car Axle Outer Ends (1932 & later) 24
Wheel huhs(l935-later 45" rear wheel & 1941 Servi-Car
front wheel, 1936 61", 1937-later 61", 74" & 80"-both
wheels, "LE" model sidecar wheel 26
2306-32 Countershaft Gear-left side (1931 74" reverse, 1932-
1936 74" standard & reverse transmission) 21 5/8"
Clutch Gear-left side(l933-34 45" Twin & Single Reverse
1935-40 45" standard & reverse transmission 31
Mainshaft-right side-(1933-34 45" Twin and Single Reverse
1935 & later 45" Standard & reverse transmission 21
 --
No. 217 April 15, 1941 - 2 -

Ignition-Light Switch Change-Over

connections at switch. Diagram of late type switch shows switch (No. 26) in correct
The first Harley-Davidson motorcycles with factory-e'luipped "blackout lights" 'fur-
position in relation to speedometer and switch panel. Switch is mounted with igni-
nished the V. S. Army were 1941 'HLA modele. bearing U.S.A. numbers W-64291 to W-64939
inc~usive, a:1d '!1~65448 to W-65747 inclusive. These motorcycles were fitted \•lith an tion key forward. Note that while early type switch and late type switch differ as
ignition-light switch operated with only a rl:ey and. lockout button. concerns location of terminals and order of numbering, wiring connections according
to terminal numbers are the same for both. In other words, wires from early type
Later "blackout light" equipped 1941 WLA models furnished the Army are fitted with switch transfer to terminals with same numbers on late type switch. Bear in mind that
a new type switch which has a key for ignition only, and a lever and lockout button late type switch diagram shown applies only to a switch change-over. It is not exactly
to operate lights. U.S.A. numbers of motorcycles fitted with latest switch furnished like the wiring diagram in Rider Instruction Folder 45-E applying to motorcycles orig-
to date of this Bulletin are W-65748 to W-66647 inclusive, and W-67848 to W-68447 in- inally equipped with the later type switch.
clusive.
Two wires disconnected from early type switch will be found too short to reach their
Only the later type switch will be sunnlied on narts order in the future for renlace- respective terminals on late type switch. These are~ wire to No. 6 ter~inal,
mer..t requirements applying to all 11 bl~~kout light 11 equipped motorcycles. It wiil be and red wire to No. 7 terminal. The required extension wires with corresponding
supplied '"i~h all necessary extra fittings so it can be used either to replace -c.i.:e colorsare furnished with new switch. Connect these extension wires with small
earlier type switch, or one of the same type. Harley-Davidson part numbe~ of this bolts furnished and tape thoroughly so there will be no chance of shorting.
switch with fittings is 4527-41M.
New type switch is operated as follows: Turn key to right (1/4 turn) to turn igni-
tion on. Key can be removed only when in off position. Removing key locks ignition.

Lights are controlled by lever. Lights are off when lever is in extreme right posi-
tion, marked OFF. 'l'urn lever to first left position (EO) for "blackout lights."
After pressing down lockout button (located above and to right of light switch lever),
lever can be turned to second left position (ERT) for bright (standard) running light.

Bear in mind that above installation instructions apply only when early type switch
is replaced with late type switch.

When a motorcycle equipped with late type switch ~squires a replacement switch, ex-
tra fittings furnished with new switch can be discarded as they will not be needed.
WIRING CONNECTIONS WIRING CONNECTIONS WHEN REPLACING EARLY In making this installation, the wiring will of course be connected to replacement
TO EARLY TYPE SWITCH TYPE SWITCH 'NITH LATE TYPE SWITCH switch exactly the same as it is found connected to switch being ~aplaced.

Note that the same wires connect to terminals with same numbers on both switches:-
1--]lack wire from blackout headlight No. 24 and green wire of tail lamp cable from RARLEY-DAVIDSO!r MOTOR CO.
blackout tail lamp No. 23. 2--Elack wire from speedometer light No. 11; green wire Milwaukee, Wis., U.S.A.
of gene,-ator cable from generator terminal No. 15 marked 11 Switch"; black wire of
tail lamp cable from service tail lamp No. 22; red wire of horn and light cable from
ter~inal No. 18. 3--Red wire of generator cable from relay terminal marked 11 EAT. 11 ;
red wire of :nai.n cable from terminal No. 19 (under saddle). 4--Elack wire from No.
10. 5--Yellow wire of tail lamp cable from blackout atop light No. 23. 6--Black
wire of main cable from terminal No. 20 (under saddle). 7--Red wire of tail lamp
cable from service stop light No. 22.

·Ni::--:'..~sdiagrams and. in:t'or::r.ation above show and explain wiring connections when early
:y~e swicch .:..:; :-eplaced wit;-. later ~ype. )To 'Hiring ctanges are necessary oti:er t.han

- over -
 --- .... - ....
·~ ' -- ·-~ .... :---
... -:.. ..- . .-"·J• ..... .:;,

Carburetors on Army Motorcycles

The .lolodel 11 M'' Li.ckert carburetors used on A:r'I!rf motorcycles are as follows:
No. 218 Date-April 4·141 11&-64 11&-90
11&-65 .11&-97
CRANK CASE BAFFLE PLATES AND CONNECTING 11&-84
It ..
Jl-641
).£..88
ROD ARRANGEMENT
.:... :.~ o:-. ~hese r:.odels ha~e ':;he model nwnber stamned on the pad on top of ~he ca.rbure-
1936 end Later Engines with Circulating Qi!;,lg System ':or. A brief :!ascription of these. carburetor; follows:

The 11&-64 and 11&-65 models have external or outside nozzle and bowl vents; that is,
45" MODELS 1940 & Later the air bleed to the nozzle and to the bowl are from external holes drilled in the
body· casting. These two models are exactly alike except that one ha.s a different
size Fixed High Speed Jet than the other. (See instructions below). These two. mod-

®
Forked Connecting Single End Connect- els are used with a standarc'. (not oil bath) air cleaner.
Rod front ing Rod front
cylinder. cylinder. T:.e ::.1-84 model has an internal vent in the form of a· tube extending bo.ck of the 7er.-
~uri a:1d pointing into the air stream. This vent supplies the air bleP.d to the noz-
zle. r;,e bowl is vented through a hole drilled in the body a12d o~.;"L',6 exterr.ally
or outside. This model is used with an oil bath air cleaner and is equipped with a
Single End Connect- Forked Connecting Fixed High Speed ·Jet (see instructions below).
ing Rod rear Rod rear
cylinder. cylinder. The 11&-88 model has an internal vent to the noz~e in the form of a slot out in the
lower side of the venturi on the air intake end. The bowl vent 'is external and the
same as in 11&-64, 11&-65 and .11&-84. This model is equipped with a Fixed High Speed Jet
(see instructions below) and is used with an oil bath air cleaner.
1936.:.37.!38 &'39 O.H.V. MODELS 1940 & Later
61" QH~ Models O.HV. Models

Forked Connecting Single End Connect-

Rod front ing Rod - front
cylinder. cylinder.

Single End Connect- Forked Connecting

ing Rod rear Rod rear
cylinder. cylinder.

1937-'38 74"& 80" SIDE VALVE 1939& Later

MODELS
Forked Connecting Single End Conned-
Rod front ing Rod - front
cyiinder. cylinder.
J£CTIOWA#L VI,CI-Y.$ O '
LINifltC. . T Mt:>D.Et.. ..,.,..., ..
CAM~U_..£.,-OM .S1¥0W'IIVC.
OE'r.AIL $ AND .S 4. 0 T
IN ,S<IT'1""0AA <11" V4'1VTV~J
Single End Conned- c-:>r!<ed Cohneding T'::JR ~OZ Z L .,r "'"'"N ~

ing Rod nor ~od rear .... NO £,KT'£'.~NAL ~CJ..-!..-L

c~tiinder. c:,finder. Y£.v.,. A.S u..s~::: -:JN vf~t!s

Harley-Davidson Motor Company, Milwaukee, Wis.

 - - .:;

HOW TO REMOVE THE CRUST

:'~e :..;.::c ::-:.o<iel ::.3.s a1~ i::ter~al ver..t to the nozzle in the form of a slot cut in the
lower side of -::he venturi on the air intake ~nd. The bowl vent is external and the 1. Back off t:,.e throttle lever stop screw so -cnat the throttle disc closes tightly.
sa::-,e as i:1 ~64, M-65, :1>-84 and M-88. This model is equipped with Fixed High Speed With a sharp pointed tool like a sharp pen knife or scriber, scratch a li~e deeply
Jet (see instructions below) and is usad with an oil bath air cleaner. Bowl on on the closed throttle disc and also on the throttle barrel so that the l1nes on
M-90 model is different than on M-64, M-65, .lol-84 and 1&-88 in that this bowl uses a the disc and on the barrel meet. These lines should 11 jibe up" again when you re-
special gasket between upper edge of the bowl and the lower face of the body. This place the disc. Remove the throttle lever, throttle disc and shaft, the. idle hole
gasket !1\Ust always be located in its proper plaoe to seal the bowl to the body. body plug next to the idle holes in the throttle barrel, the l)ody plu~s 1n t?~ car-
Use a new :asket if the old one is the least damaged or defective. If gasket is not b_uretor flange and carburetor body ic'le channels, and ';;he low speed (1dle) h_ t
-::~.. c~.~~::.:~ J.;;.;).-:ed, g~.soli::e lea\:3.~~ at bo·.vl ·nill r9sult. iever &nd needle valve asserrbly. · Also·remove the venturi and nozzle.
:_;_.?,.., ::o-.:. :?=. :-.~;..:: ··:t:2. i.:.:e:-!"!~1 -.,rer:.t ~~;: :::.e :'or=:1 o:' 3: tube extendi:l2.' i:!to -:!:e 9.i: ..::-::.~:-:.= ~. 3cr~pe aut the caking or "crust!! in the t~ottle barrel ·nith a scrape!' or !:.:-.i:. . ~,
'1 ..:.:. ·.::-:.·:i~·- ::.:.' ':C.c -::-~:~~-:~i. T:;.L:: Vi3::t :::.:.:::r~lies both -:::-:.e air bleed for the :-.o::.:::!.o :-.:..:.:::!
being sure not to cut into the metal.
t::.e "re~-c for the bo-;1l. Tl'lere are no e~tel~nal vents on this model. The special bowl
gasket be-;,.;,een the upper edge _of the bowl and the lower face of the body must al-:1a;rs 3. Clean up the tl~ottle disc by rubbing it on both side~ on emery cloth on a flat
be properly located and in plac·e to seal the bowl to the body. Use a new gasket if plate and clean the edge of the disc all around, being careful not to round the
the old one is the least damag"d or defscti ve. If this gasket is not correctly corners or cut into the metal.
asse~bled, leakage of air will take place at the bowl edge and will cause the intcr-
!i.C.l :1oz.z=.e ::t.:~ Jo·;;l ven-t ~o be ino'Oera~i7e. This model is used with an oil 1:';!.-t;:..._ 3-i:- 4. Clean out the idle holes in the throttle barrel next to -the disc Vlith the prop'Or
::.:::.:.=~ ·;,.·_-:_ :.s ac~:.i:::Gd ilit.:"1 <:!. iii~<:~d :iigh Speed Jet (see instructior-3 bel.:r:,r,'• -~­ size drills. See list for proper s~zes for both holes for all models of carburetors.
~.;_.]:~ ~:-.cd.=l ·;;:·.en repi~cer::.e.!'.lt Ct..:Oburetor is needed.
:_:o,:el S::all Idle Hole Idle Hole ?::::eC.
.:'~::o :..-,.:..;,..:. .~:cr..:.::.."j_ ::;:.s -::-.e se.::-.1e s.rrar:ge:rr..ent of ven~s as the ~as an~ ~s use-o:J. ·:::. -.--. -·-- Venturi Nearest Ml.ni- Farthest from Slot Jet
(Stanped Carb.
oil oath air cleaner. The M-641 carburetor is not equipped with a Fixed High Speed fold Flange M>.nifold Flange Width
Jet. It has a standard High Speed Needle adjustment (adjusting needle near the air
in top of Size Size N"•
Carb.Bodv) Drill Size- Drill Size
intake eLd of the carburetor and to the left iooking at the air intake end). This
adjustment should be set to l t turns open for initial adjustment and then set in M-64 11." 1-1/16 11 #'TO #55 .oo9" #4
operation to the best setting for power, being sure not to adjust it too lean thus M-65 11" 1-1/16 11 #'TO #55 .oo9" #5
oausing excessive engine heating. M-84 11" 1-1/16 11 #'TO #55 .009 11 #5
M-88 11" 15/16 11 #'TO #55 .OG3 11
#1
The 11-G4, l<>-6G, :1>-84, M-88, M-90, and M-97 carburetors with Fixed High Speed Jet M-90 11" 15/16 11 #70 #55 .009 11 #1
e.~'3 ei_'..!i?~~Jd. ·:li !;h a special sPort needle valve to shut o:..".t' the opening pro7i:i9d ~cr :1>-97 11" 1-1/16 11 #72 #55 .oo9" #5
~e.~ia'o:!. 3 ::.ic;!-1 s?eed adjusting needle which is standard instead o£ fixed jet :,o:- e.l: :11-641 11"
4 15/16 11 #70 7fo55 .GQ9"
.zc::r:-~-=r-:i.::..: ::o;:orc:rcle carbureto:--s and also applies to M-641 Arrrr'f carbure-:;or. _;_
rH~OrTl..._E~ 5. Clean out "ti'.e slot of all
l:.:~::.:·:.; -:;-::.:.:-:; ~o~e-.'1'='-~ in abo'Ve i~ locks it i:l :;lace. r:,.is ~eedla "7al7'3 ?.:::. i-:::; ~.::::... ~-.-a.- sC:~-e-~--1 ~-= models by i.:~3er·-r;L:,; tie -::col
:...:-.::: -:~.::.~ ~re lcca.teci i!l t::e sa::1e place as ,jus~ described for the Hi€h Sp~ed ~d..~u.::~­
:::.a;~- i:;.- ~::a ~;..c~l ::nodel. This needle valve in 1J-64, ~65, lJ-84, ~as, ~20~ <l.::.d. with the .009 11 bl~~..!.e throu<S!-1 ;;:-:.e
A-97 carburetors :nust e.l·Nays be fully seated or screwed down to a tight sea-c and the slot between the two idle 'Ioles.
looking plug must· be screwed down firmly to hold this needle valve in place. All
high speed fuel in these models is delivered through High Speed Fixed Jet and there 6. Clean out the idle channels
is no other adjustment for the high speed mixture, with the #42 drill. When clean-
ing ver.tical idle ohannel do !lot
All models have exaotly the same bowl both in casting shape and in the complete completely bottom drill as doing
flo&t mechanism, except the M-90 and M-97 which both use the same special bowl. so may damage the low speed
However, this special bowl contains the same parts as for all of the other carbu- needle seat.
retors.
7, Clean out the low speed
SERVICE NOTES APPLYING TO FAULTY CARBURETORS (idle) needle valv~ seat hole
with the proper drill size.
·r:-~e3e ::o"tas a:::r:l·.- to oarb•J..:"etors 7fhioh have been in service for so:ne ti~e 9.!1d !-.s:ve The M-64, M-65, ~84, ~88, '.S..?C.,

;~c,~~-~ ~~~~~~~~"~;o~!r ~~:·ls~:-o~~l~h~c_!n:~~=~: ~~r:;!~s ~~~e ·~:r;o~~d ;~u~~ "d;~;;~~~n 11

and :11-97 carburetors ar~ ~loaned
·.vi th the :+531 drill. ~:-:e )&-04,1
:.!1 t·~.>e carbur9"tor throttle barrel, s.round the t~.rottla disc ar..d i!l the :'uel :r.ixture
IO£ao' ~I""' t.I"V..CI'.O"r ~OO.CL. ~-., CA~L;I<.JM.C7'0A'!
is cleaned "Ni th the =:f53lr.?=2 drill
::;:.2~9.<;'=71::t:rs, :..s ~o ~ause -the carburetor to ha'"'Te 9. lean spot oi'':' idle. T::is "~rus'tn .SNOW'ING LOa' ..SP~EO -~401.£ >"AL.V~, ·.vhich :~e.s a Sl":"'.aller ha::C.la.
3:.o,.:.:.:. Je :-:=:.o7"=C., ?ar~icularly ".'1~3n a lean. 3?o-:; co:-:es in ~s-: speed.s or,~ i'i:a ·..;.-p -:o L_:~T :_£VE,.f!! ..$.......~1·'-G ~.!;A':"""", t...=..V .:f ..::::O~£~
(This tool !"\as t·.vo rL:.gs :::.rour..C.
1\.E<::.-.::;11..~ ""'01..~,
"''--~ -=-·-:.· ··::..::.: :::-;::; :.v.v speed (:.3.:.3) a.G..jus-t:::.en.t se7; pro!=erl:.r :,or iC.linb•
VAL../.!; ..S.i'A-:- •'Ct..r ,_.,OLJ:.".$
·~:-.e :....:.~.e ANO ..St..oT, <300Y P.o:..,:.;a..S~"-.NJ it.JJ.$ f:'N1._N#~!~- i7;s C..a!:dle.)
s.C.~·-::::-:::-.~.:- ~.-::)·.:::...:. :::o-: ":e :e-: :;:, :::e -ve-:::t lea:: s:..:.a ··tl:e:.. ;::ec~::...:.'5 ~:-.:..s ?oi.:~::, .::"-:; -:o
a :::c:....:::: ·~··.::;·.:.-: .:·:..-s -:0 :~::. .:o-::::-.es ric~ :,ro!:l. -:De se1;-::..:..; ·:1::e.re ~ie ::o"t;or :lies .f'ro~
 - 5 -

necessary body clearance, Tighten the float screw and cement the top of the float
screw to the float with Dupont Household Cement, or with a mixture of celluloid ·dis-
9, Re-asse:r.ble tioe parts, being sure the lift lever spring seat (washer) is bet·.veen solved in acetone, or with thick shellac, When the cement has dried thoroughly,
the spring and carburetor body when assembling the low speed lift lever and needle check the float height and adjust as explained in 12.
valve assembly back into place. This spring seat or washer limits the air bleed to
the idle system and must be in place; otherwise carburetor cannot be adjusted for 12, Check float level, and if necessary, re-set to 1/4", Measure directly opposite
satisfactory motor idling. float lever with bowl held up-aide-down (top of float to top of bowl), When re-
adjusting Linkert carburetor float, do not attempt to do so by simply bending float
'e 3~.:.:-e 1;~e -throttle disc is ?-• .<:~H:En-oled in the barrel properly and closes of~ tight. lever upward in some ma~~er, without dis-assembling from bowl, Re-adjusting in this
::_.:.:":"'e :::-:s Jor:-'1c"t si:ie ~=" :::..._e Lii.:;::. ·.:.p or toward 1~he flange ar..d ·Nith the li!les :rou manner bends and spreads the fingers between which the head of float needle fits,
~~:-·~<~::;:-:·:.':i ::.~:.~.~~ ·.::: ·::i-.-. ~1.~:1 ~;,,~.=·.~ -a:cactly. F'.!sh up the s:--.a.:~t collal"' (o!1 t.-:e and thus develops lost motion between float and needle. Float and lever asseilily
~-~~':":-::;-:~.:- :;;.-.:. .::':;.! .:"~.... -:-..:..:- ..:..;:'.:..~.--: 7'"'.<;! ·~c~7 ":e:'ore ti;;h::er-i.:!~ -:.~.e -:::::.!"ot-:.le :.:.~c sor~::G. should be removed from bowl, and lever then bent as required,
T::e t:1.ro-:tle le"'ier s~ould ts .!lar.-.ped to the sl-JB.ft with the disc 7dde open ar.d ·;1itil
t:1e throttle lover wide open stop against the body lug and with wear take-up spring Before re-assembling, see that needle head is a good free fit between lever fingers
between the throttle lever and bearing. with not more than approximately ,003 11 play, This clearance can also be checked
after the lever is assembled in bowl, by carefully placing a small .screw driver or
a small rod against the valve head in such a position that it will hold the valve
firmly against the seat and yet not bind the lever, Moving the lever up and down
·.vill then show the amount of' actual clearance bebyeen the valve head and fir.gers,
If this clearance is excessive, the float mechanism will not feed properly, After
asse~bling note that float is approximately square with top of bowl.

13, The bowl drain plug now being used in the M>del "M" carburetors can be removed
for quick flushing of' the bowl. Before removing this plug, turn off the gas at the
tanka. Be sure to pull this screw up tight when replacing.
I
I
ADJUSTING CARBURETOR ON MOTOR
14. The low speed needle is the adjusting needle to the right (looking at the air
intake end). If' low speed needle is so far out of' adjustment that motor does not
start readily, screw it down until needle knurl bottoms, then unscrew it about tr~ee
~O..e>AIN Pt..UG to four turns, After starting the engine, unscrew it further if too lean or turn E
~~CI"'..:ST"Al.VOA.WC
.(.INf<~,qr '\AOO£..., 'i'fl::-;;;-C....V'L.
down if too rich, After motor has •L.varmed up" set low speed needle for smooth idlL,.g.
S'-rOW"~NQ-/-t..~?::i~·.=~-·_..:,,;,...J.Y1 Be sure ohoke is wide open before making idle mixture adjustments, Too rich an idle
.........._-~--:;:. ~"-'£" S£~-~ .-4NO 01""...-.SCT o...- ·"""- OA-:""" adjustment will cause excessive rolling, and too lean an adjustment will result in
1
1
rt..oAr u:.tLVE idle dying or very rough and unsteady operation. Starting and all-around carbure-
tion are better with low speed adjustment slightly rich rather than as lean as it can
CW?'f:MitLV4" ~rARING PIN
be made and with throttle stop screw set for r£asonably fast idling.
ATTENTION TO MODEL "M"
LINKERT CARBURETOR BOWLS 15. There is no manual high speed
adjustment on the ~64, ~65, ~84,
10, If the carburetor bowl continually leaks or runs over. remove it from the car- ~88, ~90, and ~97 carburetors
buretor body and first remove all dirt by cleaning it out with gasoline and com- as explained above. These models
pressed air. Hold the bowl up-side-down so that the float valve closes and suck on are equipped with Fixed High Speed
the bottom of' the float valve seat. The valve and seat should hold this suction. Jet as listed in the chart. Fixed
If the valve and seat leak after repeated testing, replace with a new float valve high speed jet in these carburetors
and float valve seat. is effected by replacing one of the
small drill hole plugs, near lower
11. If the float is tlR1l'l.aged or "logged n replace ~itil a new float. Remove the old end of carburetor body, with a
:~:o?.. -: "::r cu-l;ti::.~ -;:---.5 seal 9.rotU:d ~he :'loa~ screw 7lhi::h :'3.stens tl:-:> flo9.t "::o the ~ . /·v~-::~~~_f.Q=-~~~ special jet plu~. The. size of hole
:~:.;a."; 2.::;~~er. ·~:-.i~ seal Ja.c be cut 7li"::h a ;:ocket ~:::.:.:a. Remove -:~e tloat sc:-e-.v !lnd in jet plug varies '"ith carburetors
f/:.!!...,.., ~--~ver
'l.sse:r:Ol-:.: -:::e =.e-:: float ~o ~he lever. This should be done ..,vith the float valve;
~~oa~ ~~:7e 2.e~er, ~!oat ~i~~e pin and screws~ float valve seat and gasket assembled 0s' ---- of di£~erent models. Bear in mind~
however, that this special jet plug
::. :::.3 ·:cr:::.. 3:?.:'lJ:-~ -:;-;. '::-cec:..::~ ~loat screw securely, ?.d.~ 1 .:.~t S.3 :"'ollows: Looki~g canna~ be duplicated by si~ply

~~~ ~ ~r;:~~;~~~~~:: :~~~~~: ~~e;~~~~ :.;;~~ ~r~~;~; ~~~~~ :~~~~ ;~ ~e;~:~ ~ :~~:~ri :~~~~ ~~o!f~es
0 1 d~il:i;:g a hole with a drill of
certain size ~trough one of :~e
regular solid ·drill hole plugs.
:;.4-€.~VRE .,.?Iii! .,5M0...V'NG .:tX£.;) ..;£T.
Several plugs drilled -.'li~h -che sa!':le
.J.-.;0~7"' VE.E~.c.~

_=c.< ·vG -~L.:JG

 - 6 -

drill will vary considerably in the amount of fuel they flow, Therefore, each jet
ITade at the carburetor factory must be tested individually on a flow meter to be
sure of uniform flow, or in other words, uniform carburetor adjustment. In no case
should jets be manufactured or re-drilled to different size, If a new jet is needed,
order by number from the factory.

All fixed jets are numbered on the face next to the sorew slot, Be very careful in
handling. Particularly do not mar the screw driver slot, Use a sere-.> driver blade
th~t fits the slot and pull up the jet so that the taper end of the jet seats
slightly i.n the carburetor body. Al'Nays place the fixed jet in the carburetor bod;r
hole pointing to the rear of the motorcycle,

16, To set th~ High Speed adjustment on the M-641 model, see the instructions given
in the note about this model at the beginning of these notes.

HARLEY-DAVIDSON MOTOR CO,

3-6-41 Milwaukee, Wis., U,S,A,
 May 1, 1941 No. 221 June 6, 1941
No. 220
74 CU. IN TWIN MOTOR FITTING SPECIFICATION (1941 O.H.V. MODELS)

PISTON CLEARANCE --ALUMINUM PISTON -- Slotted, cam ground type - new piston fitted
in cylinder, .001" to .002" clearance. Piston shapes to cylinder and acquire more
USE OF PISTON SQUARING GAUGE ON THE 74" OHN MOTOR
clearance after short time in service.
Measure piston at bottom of skirt, front and rear.
Measure cylinder about 1/2" from top of bore, front and rear.
Due to the miller reliefs in the low<er skirt edge of the O.H.V., 74"
pistons, it is impossible to accurately check rod alignment against PISTON PIN IN PISTON --Light hand press fit.
piston squaring gauge #11919X.
PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose.

The mechanic can slip an O.H.V. 61" piston temporarily on the rod for PISTON RING GAP AND GROOVE CLEARANCE -- . 010" to . 020" gap ;,'' from top of cylinder.
Rings should be .004" loose in grooves.
the purpose of making this check. The 61" piston skirt is not relieved
permitting it to seat squarely on the gauge. LOWER CONNECTING ROD BEARING -- .001" to .0012" loose

CONNECTING RODS .006" to .010" end play between flywheels -- roller and retainer
In the absence of a 61" piston a side valve 74" or 80" piston may assembly should be narrower, but not more than .010" narrower than forked rod.

be used, although the greater skirt length will not give quite as SPROCKET SHAFT -- .0005" to .001" loose in roller bearing - .007" to .009" loose
favorable a· check. in oil retaining bushing.

PINION GEAR SHAFT -- .0008" to .0012" loose in roller bearing - .0005" to .001"
loose in cover bushing. Oil hole in cover bushing is centered with drilled oil
feed channel in cover .

HARLEY-DAVIDSON MOTOR CO. FLYWHEEL ASSEMBLY • 012" to .014" end play in crank case.
Milwaukee, Wis., U.S. A. CAM GEAR-- .001" to .0015" loose in crank case and cover bushings -- free to .005"
end play.

INTERMEDIATE GEARS -- .001" to .0015" loose - free to .005" end play

TAPPET GUIDES .0005" to .001" press fit in crank case

VALVE TAPPETS .0005" to .001" loose in tappet guides.

ROCKER ARM FIT ON SHAFT .0005" to .0015"loose - .007" to .016" end play.

OIL PUMP DRIVE SHAFT -- .0008" to .0012" loose in crank case bushing.

CRANK CASE BREATHER -- Timed with front cylinder - opens l/8" before top center
to 1/8" after top center, and closes 13/16" to 1-5/16" after bottom center.
 No. 221B June 6, 1941
No. 221A June 6, 1941
74 AND 80 CU. IN TWIN MOTOR FITTING SPECIFICATION (1937 AND LATER S.V. MODELS)
61 CU. IN TWIN MOTOR FITTING SPECIFICATION (1936 AND LATER O.H.V. MODELS)
PISTON CLEARANCE -ALUMINUM PISTON - Slotted, cam ground type - New piston fitted in
(NOTE: These supersede all previous specifications.) straight bore cylinder, .001" to .002" clearance. Piston shapes to cylinder and
acquires more clearance after short time in service.
PISTON CLEARANCE -- ALUMINUM PISTON -- Slotted, cam ground type -- New piston
fitted in cylinder, .001" to .002" clearance. Piston shapes to cylinder and Measure piston at bottom of skirt, front and rear.
acquires more clearance after short time in service. When fitting oversize piston which has vertical slot in addition to horizontal slots,
Measure piston at bottom of skirt, front and rear. fit with vertical slot forward.
Measure cylinder about 1/2" from top of bore, front and rear. Measure cylinder about 1/2" from top of .bore, front and rear.

PISTON ~IN IN PISTON-- Light hand press fit. PISTON-CYLINDER HEAD CLEARANCE - 1/16" to 3/32"

PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose PISTON PIN IN PISTON- Light hand press fit.

PISTON RING GAP AND GROOVE CLEARANCE -- .010" to .020" gap !,;" from top of cylinder PISTON PIN IN UPPER END OF CONNECTING ROD - .0008" to .0012"
Rings should be .004" loose in grooves.
PISTON RING GAP AND GROOVE CLEARANCE - Straight .bore cylinder .010" to .020" gap !,;"
LOWER CONNECTING ROD BEARING - .001" to .0012" loose from top of cylinder. Rings should be .004" loose in grooves.

CONNECTING RODS .006" to .010" end play between flywheels - roller and retainer LOWER CONNECTING ROD BEARING - .001" to .0012" loose.
assembly should be narrower, but not more than .010" narrower than forked rod.
CONNECTING RODS - .006" to .010" clearance between flywheels - roller and retainer
SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .007" to .009" loose assembly should be narrower, but not more than .OlOu narrower than forked rod.
in oil retaining bushing.
PINION SHAFT - .0006" to .0012" loose in roller bearing, and .0005" to .001" loose in
PINION GEAR SHAFT - (Solid and two piece t)·pe) - .0008" to .0012" loose in roller cover bushing. Oil hole in cover bushing is 30° ahead of top center, and in line (on
bearing, and .0005" to .001" loose in cover bushing. Oil hole in cover bushing is opposite side) with drilled oil feed channel in cover.
centered with drilled oil feed channel in cover. SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .007" to .009" loose in oil
retaining bushing.
Two piece stub shaft assembly -- cork sealed, oil tight fit in flywheel shaft with
copper washer behind. FLYWHEEL ASSEMBLY- .012" to-.014" end play in crank case.

FLYWHEEL ASSEMBLY - .012" to .014" end play in crank case. CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005" end
play.
CAM GEAR - .001" to .0015" loose in crank case and cover bushings - free to .005" INTERMEDIATE GEAR - .001" to .0015" loose on stud.
end play.
TAPPET GUIDES .0005" to .001" press fit in crank case.
INTERMEDIATE GEARS -- .001" to .0015" loose - free to .005" end play.
VALVE TAPPETS - .0005" to .001" loose in tappet guides.
TAPPET GUIDES - .0005" to .001" press fit in crank case.
CRANK CASE BREATHER- Which is a part of, and drives scavenger pump, is timed according
VALVE TAPPETS -- .0005" to .001" loose in tappet guides to instructions in Riders Instruction Folder.

ROCKER ARM FIT ON SHAFT - (1936-1937 models) .0005" to .0015" loose - .003" to
.008" end play. (1938 & later models) .0005" to .0015" loose - .007" to .016" end play

OIL PUMP DRIVE SHAFT - .0008" to .0012" loose in crank case bushing.

CRANK CASE BREATHER - Timed with front cylinder - opens 1/8" .before top center to
1/8" after top center; and closes 13/16" to 1-5/16" after bottom center.
~~o. 221C June 6, 1941 No. 221D June 6, 1941
74 AND 80 CU. IN. TWIN MOTOR FITTING SPECIFICATIONS (1930 TO AND INCLUDING 1936 MODELS) 45 CU. IN TWIN MOTOR FITTING SPECIFICATION (1937 AND LATER MODELS) EXCEPT WLDR & WR
(NOTE: These supersede all previous specifications) NOTE: These supersede all previous specification. Last specification sheet 10/30/39

PISTON CLEARANCE -- IRON ALLOY PISTONS Used in 1930-34 motors fitted with taper bore PISTON CLEARANCE - ALUMINUM PISTON - Slotted, cam ground type - new piston fitted in
cylinders -- .004" to .005" clearance. straight bore cylinder, .001" to .002" clearance. Piston shapes to cylinder and acquires
ALUMINUM AND DOW METAL PISTONS - Solid skirt type - used in 1930-34 motors fitted with more clearance after short time in service.
taper bore cylinders - .016" to .018" clearance.
Measure piston at bottom of skirt, front and rear.
ALL~INU}f PISTON -- Slotted, cam ground type - New piston fitted in straight bore cylinder
.001" to .002" clearance. Piston shapes to cylinder and acquires more clearance after When fitting oversize piston which has vertical slot in addition to .horizontal slots,
short tiMe in service. fit with vertical slot forward.
Measure solid skirt piston just below top group of rings. Measure slooted piston at Measure cylinder about ~" from top of bore, front and rear.
bottom of skirt, front and rear.
PISTON-CYLINDER HEAD CLEARANCE - 1/16" to 3/32"
When fitting oversize piston which has vertical slot in addition to horizontal slots, fit
with vertical slot forward.
PISTON PIN IN PISTON - Light hand press fit.
Measure cylinder about ~u from top of bore, front and rear.
PISTON PIN IN UPPER END OF CONNECTING ROD - .0008" to .0012"
PISTON - CYLINDER HEAD CLEARANCE (all models except VC Commercial) l/16" to 3/32" (VC
Commercial, discontinued after 1933 7/64" to 9/64")
PISTON RING GAP AND GROOVE CLEARANCE - Straight bore cylinder - .010" to .020" gap Y,"
PISTON - PIN IN IRON ALLOY PISTON -- .0005" to .001" press fit in lock pin side -- plug from top of cylinder. Rings should be .004" loose in grooves.
or slip fit in opposite side.
LOWER CONNECTING ROD BEARING - .0007" to .001" loose.
PISTON PIN IN DOW METAL AND ALUMINL~ PISTONS - Solid skirt type - .0005" to .001" presu
fit in piston.
CONNECTING RODS - .006" to .010" play between flywheels - roller and retainer assembly
PISTON PIN IN ALUMINUM PISTON - Slotted type - light hand press fit. should be narrower, but not more than .010" narrower than forked rod.

PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose. PINION GEAR SHAFT - .0008" to .0012" loose in roller bearing, and .0005" to .001" loose
in cover bushing. Oil hole in cover bushing is 30° ahead of top center and in line
PISTOl': RING GAP AND GROOVE CLEARANCE - Taper bore cylinder .006" gap Y," from top of cylinder (on opposite side) with drilled oil feed channel in cover.
Straight bore cylinder .010" to .020" gap Y," from top of cylinder.
Rings should be .004" loose in Dow Metal & Aluminum piston grooves and just free in Iron SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in oil
Piston grooves. retaining bushing.
LOWER CONNECTING ROD BEARING - .001" to .00125" loose.
FLYWHEEL ASSEMBLY - .012" to .014" end play in crank case.
CONNECTING RODS - .006" to .010" clearance between flywheels - roller and retainer
assembly should be narrower, but not more than .010" narrower than front rod. CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005" end
play.
PINIO!: GEAR SHAFT - .0045" loose at inner end of bushing - .002" loose at outer end of
bushing (Bushing is taper reamed with special reamer)
TAPPET GUIDES - .0005" to .001" press fit in crank case.
SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in oil
retaining bushing. VALVE TAPPETS - .0005" to .001" loose in tappet guides.
FLYWHEEL ASSEMBLY - .006" to .010" end play in crank case
CRANK CASE BREATHER - Which is a part of, and drives, scavenger pump, is .timed according
CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005" end to instructions in Riders Instruction Folder.
play.
INTERMEDIATE GEAR - .001" to 0015" loose on stud.
TAPPET GUIDES - .0005" to .001" press fit in crank case.
VALVE TAPPETS - .0005" to .001" loose in tappet guides.
 June 6, 1941 No. 221F June 6, 1941
No. 221 E
45 CU. IN THIN MOTOR FITTING SPECIFICATIONS (1930 TO AND INCLUDING 1936) EXCEPT RLDR SINGLE NOTOR FITTING SPECIFICATIONS - (ALL 1934 AND EARLIER NODELS)
(NOTE: These supersede all previous specifications)
PISTOl>< CLEARANCE - ALUMINUH AND DOW METAL PISTONS -- Solid skirt type - used in 1934
and earlier motors fitted with taper bore cylinders -- .014J1 to .016" clearance. PISTON CLEARANCE - Dow metal and aluminum - .011" ·to .013" clearance. (Measure piston
AL~INUM PISTON - Slotted, cam ground type - new piston fitted in straight bore c~linder just below the top group of rings, and cylinder about 1/2" from top of bore, front
11
.001 to .002" clearance. Piston shapes to cylinder and acquires more clearance after and rear).
short time in service.
Measure solid skirt piston just below the top group of rings. PISTON - CYLINDER HEAD CLEARANCE (Side by side valve models) - 3/64" to 5/64"
Measure slotted piston at bottom of skirt, front and rear.
When fitting oversize piston which has vertical slot in addition to horizontal slots, fit PISTON PIN IN PISTON - Snug press fit - not over .0005" tight.
with vertical slot forward.
Measure cylind~r about ~~~ from top of bore, front and rear. PISTON PIN IN UPPER END OF CONNECTING ROD - .0005" loose

PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64" PISTON RING GAP AND GROOVE CLEARANCE - .006" gap 1/2" from top of cylinder. Rings
should be .0015" to .002" loose in grooves.
PISTON PIN IN ALUMINUN AND DOW NETAL PISTONS - Solid skirt type .0005" to .001" press fit
in piston. LOWER CONNECTING ROD BEARING - .0003" to .0004" loose

PISTON PIN IN ALUMINUN PISTON -- Slotted type - light hand press fit CONNECTING RODS - .010" to .020" end play between flywheels - roller and retainer
assembly should be narrower, but not more the.n . 010" narrower than rod.
PISTON PIN IN UPPER END OF CONNECTING ROD --· .0008" to .0012" loose
PINION GEAR SHAFT - .0035" loose at inner end of bushing - .0025" louse at outer end
PISTON RING GAP AND GROOVE CLEARANCE - Taper bore cylinder .006" gap lz" from top of cylinder of bushing. (Bushing is taper reamed with special reamer.)
Straight bore cylinder - .010" to .020" gap lz" from top of cylinder
Rings should be . 004" loose in grooves. SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in chain
lubricating bushing.
LOWER CONNECTING ROD BEARING - .0007" to .001" loose
FLYWHEEL ASSEMBLY - .002" to .006" end play in crank case.
CONNECTING RODS - .006" to .010" end play between flywheels - roller and retainer assembly
should be narrower, but not more than .010" narrower than front rod. CAN GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005"
end play
PINION GEAR SHAFT - .0045" loose at inner end of bushing - .002" at outer end of bushing
(bushing is taper reamed with special reamer). INTERMEDIATE AND OILER GEARS - .0015" to .002" loose on studs
SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in oil TAPPET GUIDES - .0005" to .001" press fit in crank case
retaining bushing.
VALVE TAPPETS - Free to .00075" loose in tappet guides.
FLYWHJ:EL ASSEMBLY- .004" to .008" end play in crank case.

CAN GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005" end play.

GENERATOR DRIVE GEARS AND SHAFT (1931 and earlier models) - Shaft must be free running fit;
have .002" to .004" end play, and .001" to .0015" clearance in bearings. Small bevel gear
should be .002" to .003" loose in bushing assembly, and shimmed to allow .002" to .004"
clearance between bevel gears.

TAPPET GUIDES - .0005" to .001" press fit in crank case

VALVE TAPPETS - .0005" to .001" loose in tappet guides.

 No. 221G -2- June 6, 1941

30.50 CU. IN. SINGLE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 5/16" to 9/16" before top dead center
CLOSES when piston is 11/16" to 15/16" after bottom dead center
EXHAUST VALVE - OPENS when piston is 1/2" to 3/4" before bottom dead center
No. 221G June 6, 1941 CLOSES when piston is 1/4" to 1/2" after top dead center
TIMING SPECIFICATIONS
IGNITION -- OCCURS when piston is 1/4" to 5/16" before top dead center on compression
1930 and LATER 74 & 80 CU. IN. S.V. TWIN -ALL MODELS EXCEPT 1930 & 1931 V AND VC MODELS stroke.
INTAKE VALVE -- OPENS when piston is 9/32" to 13/32" before top dead center 21 CU. IN. SIDE BY SIDE VALVE SINGLE (ALL MODELS)
CLOSES when piston is 7/8" to l-l/8" after bottom dead center
INTAKE VALVE - OPENS when piston is 1/8" to 3/16" before top dead center
EXHAUST VALVE-- OPENS when piston is 5/8" to 7/8" before bottom dead center CLOSES when piston is 7/16" to 9/16" after bottom dead center
· CLOSES when piston is l/4" to 3/8" after top dead center.
EXHAUST VALVE - OPENS when piston is 7/16" to 9/16" before bottom dead center
IGNITION -- OCCURS when piston is 5/16" to ll/32" before top dead center on compression CLOSES when piston is 1/8" to 3/16" after top dead ce~ter
stroke.
IGNITION- OCCURS when piston is 7/32" to 9/32" before top dead center on compression
ll/32" timing (flywheel mark at rear of crank case inspection hole) applies to moderate stroke.
compression ~otors in solo service. High compression solo motor (8.2 heads) also all
motors in sidecar service should be timed 5/16". 21 CU. IN OVERHEAD VALVE SINGLE (ALL MODELS)
1930 AND 1931 74 CU. IN TWIN V AND VC MODELS INTAKE VALVE - OPENS when piston is 3/32" to 5/32" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center
INTAKE VALVE - OPENS when piston is ll/64" to 19/64" before top dead center
CLOSES when piston is 9/16" to 13/16" after bottom dead center EXHAUST VALVE- OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 3/32" to 5/32" after top dead center
EXHAUST VALVE - OPENS when piston is 9/16" to 13/16" before bottom dead center
CLOSES when piston is 11/64" to 19/64" after top dead center IGNITION -- OCCURS when piston is 11/32" to 13/32" before top dead center on compression
stroke.
IGNITION - OCCURS when piston is l/4" to 5/16" before top dead center on compression stroke.

1936 AND LATER 61 CU. IN OVERHEAD VALVE TWIN MODELS TAPPET CLEARANCES
INTAKE VALVE - OPENS when piston is 5/16" to 3/8" before top dead center
CLOSES when piston is 15/16" to 1-l/16" after bottom dead center NOTE: When checking valve timing according to piston position, bear in mind that
tappets must first be adjusted to the correct clearances.
EXHAUST VALVE- OPENS when piston is 3/4" to 7/8" before bottom dead center
CLOSES when piston is 5/16" to 3/8" after top dead center. ALL SIDE BY SIDE VALVE MODELS (SINGLES AND TWINS)
IGNITION- OCCURS when piston is 7/16" before top dead center on compression stroke. INTAKE -- .004" to .005"
EXHAUST- .006" to .008"
74 CU. IN OVERHEAD VALVE TWIN MODELS
INTAKE VALVE- OPENS when piston is 3/8" to 7/16" before top dead center OVERHEAD VALVE SINGLE -- INTAKE AND EXHAUST - .002" to .003"
CLOSES when piston is l-3/64" to l-ll/64" after bottom dead center
OVERHEAD VALVE TWINS -- INTAKE AND EXHAUST - Correctly adjusted when tappet has just
EXHAUST VALVE- OPENS when piston is 27/32" to 31/32" before bottom dead center noticeable play or shake, and can be turned freely with finger
CLOSES when piston is 3/8" to 7/16" after top dead center. tips, completely around, without any trace of bind.
IGNITION- OCCURS when piston is 7/16" before top dead center on compression stroke.
CIRCUIT BREAKER OPENING
45 CU. IN. TWIN (ALL MODELS EXCEPT WLDR & WR)
All models -- .020" to .024"
INTAKE VALVE- OPENS when piston is 5/32" to 7/32" before top dead center
CLOSES when piston is 37/64" to 45/64" after bottom dead center
EXHAUST VALVE- OPENS when piston is 37/64" to 45/64" before bottom dead center
CLOSES when piston is 5/32" to 7/32" after ~op dead center.
IGNITION -- OCCURS when piston is 1/4" to 9/32" before top dead center on compression
stroke.
 to switch according to diagram. Extra wire in kit (attached to switch) replac.es original
wire connectin6 switch terminal No. 4, and signal light terminal No. 10. Original wire
connecting these therminals is needed as an extension for black wire to switch terminal
No. 6, which will be found too short to reach new switch. Connect extension wire with
small bolt and tape connection thoroughly so there will be no chance of shorting. Op-
erate switch and note that all wires are arranged so there is no interference.
No. 222 (U.S. Army) June 25, 1941
IGNITION-LIGHT SWITCH REPLACEMENT Adapter ring is furnished to reduce size of opening in panel cover to fit Harley-Davidson
switch. Insert ring into panel opening from top side, and peen the underside of ring
The fi-rst Harley-Davidson motorcycles with factory-equipped "blackout lights" furnished as necessary at four or more Points to secure it in cover. Cover can then be fitted to
the u.s. Army were 1941 WLA models bearing U.S.A. numbers W-64291 to W6~939 inclusive, base.
and W-65448 to W65747 inclusive. These motorcycles were fitted with "Mico" ignition-
light switch operated with only a key and lockout button. REPLACING "REMY" SWITCH
Later "blackout light" equipped 1941 WLA models furnished the Army were fitted with Remove switch panel cover, disconnect wires, remove and discard switch and mounting
"Remy 11 switch YJith a key for ignition only, and a lever and lockout button to operate spacers. Mount new switch with 23/32" long spacers underneath and secure with four 8-
lights. U.S.A. numbers-of motorcycle fitted with this switch are W-65748 to W66647 32 x 1" long fillister head screws and lock washers. Connect wires to switch according
inclusive, and H-67848 to W68012 inclusive. to diagram. Extra wire in kit (attached to switch) replaces original wire connecting
switch terminal No. 4 and signal light wire No. 10. Original wire connecting these
Latest "blackout light" equipped WLA models starting with W68013 are fitted with a terminals can be discarded. Operate switch and note that all wires are arranged so
Harley-Davidson switch the same as found in this replacement kit. This switch has a there is no interference. Assemble switch panel cover.
winged knob for turning ON and OFF both ignition and lights. It also has a service
light lockout button. Switch is provided with lock and key to permit locking, if Bear in mind that the above installation instructions apply when an earlier type "black-
desired, when motorcycle is not in use. Hhen switch is unlocked and motorcycle is out" switch is replaced with a Harley-Davidson "blackout" switch.
in use, key should be removed from lock. Only this Harley-Davidson switch (Part No.
4527-l,lM) is now supplied for replacement requirements applying to all "Blackout When a motorcycle already equipped with a Harley-Davidson switch requires a replacement
light" equipped motorcycle. Switch positions: - Turn LEFT all the way for OFF (This switch, all extra fittings furnished with new switch can be discarded as they will not
is the only position in which switch can be locked); turn to first right position be needed. In making this installation the wiring will of course be connected to re-
for ignition only; turn to second right position for ignition and "blackout lights"; placement switch exactly the same as it is found connected to s;;itch being replaced.
press lockout button and turn to third right position for ignition and service lights.

Har:ey-Davidson replacement switch kit contains the following parts: One complete switch;
Two spacers 19/32" long; One submounting plate; Two countersunk head screws 8-32 x 7/8"
long; Twi 8-32 x 3/8" long screws; Four 118 lock washers; One wire with terminals (attached
to switch); One 6-32 x 3/16" long bolt and nut; One piece of tape; One adapter ring 1-
61/64" inside diameter; Four spacers 23/32" long; Four fillister head screws 8-32 x 1" long.
When replacing a nMico" switch the following parts are not needed, and should be discarded:
Four 23/32" long spacers; Four fillister head screws 8-32 x 1: long; Two 118 lock washers.
lfuen replacing "Remy" switch discard the following: Two spacers 19/32" long; One sub-
mounting plate; Two countersunk head screws 8-32 x 7/8"; Two 8-32 x 3/8" long screws; One
6-32 x 3/16" bolt and nut; One piece of tape; One adapter ring.

Study wiring diagrams and determine type of switch being replaced. Note that while switches
differ as concerns location of terminals and order of numbering, wiring connections ac-
cording to terminal numbers are the same to Harley-Davidson switch as to the switch it re-
places. In other words, wires from earlier type switch transfer to terminals with same
numbers on Harley-Davidson switch.
REPLACING "MICO" SWITCH
Remove switch panel cover, disconnect wires, remove and discard switch and mounting spacers.
Mount new sub-plate on switch panel base, using 19/32" long spacers underneath, and secure
with two countersunk head screws. To properly locate switch in relation to opening in
panel cover, end of sub-plate with widest spacing between screw holes must be assembled to
left side. Place switch on sub-plate with lockout button forward and attach ;;ith two 8-32
x 3/8" long screws and lock washers. Tail and stop light wire cable will be found entering
switch panel on left side of switch. Transfer this cable to right side and connect wire~
SUPPLEMENT TO SWITCH REPLACEMENT DOPE SHEET NO. ,222
DATED JUNE 25, 1941

.......
c:O-
_,na
,....
..... ,..:z:
~C.-f
c:
...

Wiring Connections to "Remy" Switch

,--,
UGHT \
Wiring Connections to "Mico" Switch LOCK-OUT I
1
BUTTON

,--,,
UGHT \ 0

~;~T \
.

Wiring Connections When Replacing "Remy" Switch With Harley-Davidson Switch

HARLEY-DAVIDSON MOTOR CO.

Wiring Connections When Replacing "Mice" Switch With Harley-Davidson Switch Milwaukee, Wis., U. S. A.
No. 224 August 15, 1941
No. 225 August 15, 1941
REBUILDING WHEELS

OVERSIZE WHEEL MOUNTING SOCKET SCREW

In rebuilding wheels it is general practice to simply true up and tighten
spokes about as tight as they can be tightened with spoke wrench.
An oversize wheel mounting socket screw is ava~lable under
Part No. 43531-35, for all 1935 and later 45" reai wheels,
Ouite a number of rebuilt wheels do not run very far until the spokes, or
all 1936 and later 61" O.H.V. and all 1937 and later 74's''
at least part of them, are found loosened-up to some extent.
and 80'' front, rear and sidecar wheels.

The following suggestions will help you build a wheel in which the spokes
If the threads become stripped in the brake shell hub on any
will stay tight much longer.
of these models, it is a simple matter to make a satisfactory
repair job. Since the standard wheel mounting socket screw
After all nipples have been pulled up until spokes are normally tight and
is 3/8" - 20 U.S.F. thread and the oversize socket screw is
wheel is true, or nearly so, seat each spoke head into hub flange with a
7/16" - 20 U.S.F. thread, it is not necessary to drill out
sharp blow; using a flat nose punch and hammer. Then, re-tighten all
stock before re~threading hub for the oversize screw. It is
nipples and finish truing wheel. This method allows spokes to be drawn
only necessary to re-thread the stripped hole with a 7/16" -
tighter at the start and prevents possibility of spokes loosening, due
20 U.S.F. tap.
to spoke heads seating into flange, after wheel is put into service.

The standard wheel socket screw wrench fits the oversize screw.

HARLEY-DAVIDSON MOTOR CO.

Milwaukee, Wis., U.S.A.
 No. 227 January 15, 1942

No. 2 26 December 22, 1941

NEW CLUTCH GEAR OIL SEAL

/7EHNO. NAME
1 KVBBE~ SEAL
z ~IN/1116 t:'l/1' 7035-41 UPPEI!. .TAW
..,.
.!1 :SI'K.ING
ST£EL WASNE~
S" 1CVI18EIC SEAL
tG STEEL 611/PE

4 3 2 1
24GI-4/D
SET CL.VrcH G£A!i! OIL 5£AL. FA}!T.S
(.4.5FITTEP Tl'LATE!i! /942-45HOP£LS ATFWC~ICY;
At$0 US£P As A Ct?HPI.£7F .SET TV li!&Pk~CE tx/6/NAJ..
C/L SEAt.. PAICTS t:>N l!ihl/ AA1P£A.ct.Y 1!142-46"Ht:>PEL.S)

A new clutch gear oil seal has been used in production on all 1942 - 45 cu. in. model
motorcycles (including Serv.i-Cars), shipped after about November 1, 1941.

This is an improved seal that will do a better job of keeping clutch disc dry and free
of oil than the one it replaces. It can be fitted to all 1941 and earlier 1942 - 45 7034-4/ LOWE/e ..TAW
cu. in. and Servi-Car motorcycles provided it is used as a complete unit. Individual
parts will not be supplied. Order 2461-41D, Set Clutch Gear Oil Seal Parts - Price At the start of the 1942 season the Servi-Car jaw clamp was redesigned to permit wider
75c, list. jaw clamp opening to accomodate increased width of some of the 1942 auto bumpers. Upper
jaw screw pilot and lower jaw screw guide were each made 1/2" longer. Hand wheel screw
was also lengthened proportionately. After this change had gone into production some
further bumper changes were made with the result that the first 1942 jaw clamp would not
fit some 1942 model bumpers properly. Thus, additional clamp jaw changes were necessary.
Upper jaw outer notch lip is now ground off and end reinforcing rib is _eliminated. This
is to adapt jaw to 1942 Nash series bumpers. Lower jaw has an extended lip or notch for
use on 1942 Nash Deluxe bumpers.
The new .. clamp is to be used in the conventional way on most bumpers, including 1942
Standard Series Nash models. However, the 1942 Deluxe Nash bumper and stone shield
construction is such that there is no part of bumper extended above shield. To fasten
a clamp to it at all, the latest 1942 lower jaw with its long, thin hook or jaw must be
used as the upper jaw; the upper jaw as the lower, and the hand wheel upside down.
No. 228 January 30, 1942 No. 229 February 20, 1942
SERVICE NOTES FOR ALL MODEL "M" LINKERT CARBURETORS ON HARLEY-DAVIDSONS
WAR TIME BAN ON OHV ROCKER ARM HOUSING SYNTHETIC OIL SEALS
These notes apply to carburetors which have been in service for some time and have become
dirty, full of "crust" in the throttle barrel and are found to be difficult to get ad-
Due to gover.1ment restrictions on the· use of rubber and synthetic rubber compounds,
justed properly. Usually the effect of excessive dirt or "crust" formation in the carbur-
we will have to discontinue immediately the use of synthetic seals for OHV rocker
etor throttle barret, around the throttle di{>c and in the fuel mixture passageways is to
arm enclosures.
cause the carburetor to have a lean spot off idle. This crust should be removed, pa~ticu­

Until such time n.s we may .be able to. find a satisfactory substitute, we will not
larly when a lean spot comes in at speeds off idel up to 30 m.p.h. ,with the low speed
be able to furnish the following seals on parts orders: (idle) adjustment set properly for idling. The idle adjustment should not be set to the
very lean side when checking this point, but to a point about five to ten notches rich
from the setting where the engine dies from leanness.
120-38 Oil Seals 1!:;"
120,38A Oil Seals 1-15/32"
120~38B Oil Seals 1-33/64"
HOW TO·K~MOVE THE CRUST
1. Back off the throttle lever stop screw so the throttle disc closes tightly. With a
The only seal of which there is a small quantity available for shipment is 120-35 sharp pointed tool like_a sharp pen knife, scratch a line deeply on the closed throttle
Housing Rubber Packing Washer. disc and a1so on the throttle barrel so that the lines on the disc and on the barrel meet.
These lines should "jibe up" again when you replace the disc. Remove the throttle lever,
Shipping records show that a large quantity of these synthetic seals have been throttle disc and shaft, the idle hole body plug next to the idle holes in the throttle
supplied on parts orders in the past. This is obviously because most dealers make barrel, the body plugs in the carburetor flange and carburetor body idle channels and
it a practice when working on OHV motors to renew all oil seals, even though the old the low speed (idle) lift lever and needle valve assembly. Also remove the venturi and
ones may not be in bad shape. From now on, it will be necessary for you to re-use nozzle.
old seals; ·in that way making your present stock of new seals last as long as possible.
2. Scrape out the caking or crust in the throttle barrel with a scraper or knife, being
sure not to cut into the metal.

3. Clean up the throttle disc by rubbing it on both sides on emery cloth on a flat plate
HARLEY-DAVIDSON MOTOR CO • and clean the edge of the disc all around, being careful not to round the corners or cut
Milwaukee~ Wisconsin U.S.A. into the metal.

4. Clean out the idle holes in the throttle barrel next to the disc with the proper size
drills of clean up tool set described at end of this bulletin. See following list for
proper sizes for both holes for all models of carburetors.

MODELS Garb. Venturi Small idle hole Idle hole farthest Slot
(Stamped in top Size Size nearest maflifold from manifold flange Width
of carb. body) flange (drill size) (dri] 1 size)
M-4/11/16 1" 7 /8" 1170 1154 .009"
M-2 ll,;" 1-1/16" 1170 1155 .009"
M-5-5F ll,;" 1-1/16" 1170 1153 .009"
M-21 ll,;" 1-1/16" 1170 1155 .009"
M-25 1!:;" 1-5/16" 1172 1/55 .009"
M-31-31F ll,;" 1-1/16" 1170 1155 .009"
M-31FL 1!-z;" 1-l/8" 1170 1155 .009"
M-35-35F-35S-36 1~" 1-1/8" 1172 1155 .0155"
M-41-41F ll,;" 1-1/16" 1170 1155 .009"
M-41L-41LF 1~" 1-1/8" 1170 1155 .009"
M-45 1!:;" 1-5/16" 1172 1155 .020"
M51-51F 1~" 1-1/16" 1170 1155 .009"
M-51L-51LF I!.z" 1-1/8" 1170 1155 .009"
M75-75F 1~" 1-5/16" 1172 1155 .020"
 No. 229 -2- February 20, 1942 229 -3- February 20, 1942
(Model numbers folo...,ed by letter "F" of FL" or "LF" apply only to carburetors used on
California Highway Patrol motors.) 13. The bowl drain plug now being used in Model "M" carbuetors can be removed .for a
quick flushing of the bowl. Before removing this plug turn off the gasoline at the
5. Clean out the slot of al 1" and 1!,;" carburetors by inserting the tool with the .009" tanks. Be sure to pull up this screw tight when replacing.
blade (this tool has plain handle) through the slot between the two idle holes. Use the
tool with .0155" blade (this tool has two rings around handle) to clean out the slot in 14. In adjusting the carburetor, set the low speed needle for smooth idllng, and set
M25, M35, M35F, and M35S 1\i" carburetors. Use the tool with .020" blade (this tool has throttle lever stop screw for desired idling speed.
3 rings around handle) to clean the slot in M75 and M75F llj" carburetors.
6. Clean out the idle channels with #42 drill. When cleaning vertical idle channel do Starting and all-around carburetion are better with low speed adjustment slightly rich
not completely bottom drill as doing so may damage the low speed needle seat. rather than as lean as it can be made, and with throttle stop set for reasonably fast
idling.
7. Clean out the low speed (idle) needle valve seat hole with the proper drill size. All
earlier 1~" and l~" "M" carburetors are cleaned with the /1531 drill. Later M-35, M-35S, Average high speed needle adjustment for best engine performance is as follows: All
M-75 and M-75F, 1\;" carburetors, have a smaller channel above the seat hole and for these Side by Side Valve engine carburetors - about llj turns open; all OHV engine carburetors-
use the #53L #2 drill which has a smaller handle, (this tool has two rings around handle). Model M-25 about 1~ turns open; Model M-35 and M-36 about 1-1/8 turns open; Models M-45
All model 1" carburetors are cleaned with I/56L drill. and M-75 about 1-3/4 turns open. It is advisable to set high speed adjustment slightly
8. Blow out ail channels and holes with compressed air and wash parts in gasoline. rich rather than as lean as possible as a lean high speed mixture Causes overheating.
9. Re-assemble parts, being sure the lift lever spring seat or washer is between the
spring and carburetor when assembling the low speed lift lever and needle valve assembly CARBURETOR CLEAN-UP TOOLS
back into place. This spring seat or washer limits the air bleed to the idle system and
must be in place, otherwise carburetor cannot be adjusted for satisfactory engine idling. These tools are for hand cleaning only. Do not use in power or hand drill. A complete
Be sure throttle disc is assembled in barrel properly and closes off tight. Have the kit including 12 tools is·covered by Part No. 12012-38, list price $6.00. If you already
correct side of disc up or toward the flange and with the lines you scratched lining up have a set of clean-up tools that originally included ten tools, you will need only
with each other exactly. Push up shaft collar on throttle shaft firmly against body be- two extra tools to make your kit complete, part No. 12012-38L and 12012-38M. If you
fore tightening throttle disc screws. The throttle lever should be clamped to shaft have an earlier kit that originally included only eight tools, you will need to complete
with disc wide open and with the throttle lever wide-open stop against the body lug and it with the two extra tools just mention and also two additional tools, part No. 12012-
with wear take-up spring between throttle lever and bearing. 38J and 12012-38K. Extra tools are 50¢ list, each.
10. If the carburetor bowl continually leaks or runs over, remove it from the carburetor
body and first remove all dirt by cleaning it out with gasoline and compressed air. Hold
bowl up-side-down so the float valve closes and suck on the bottom of the float valve seat.
The valve and seat should hold this suction. If the valve and seat leak after repeated
testing, replace with new float valve and float valve seat.
11. If the float is damaged or "logged" replace with new float. Remove old float by cut-
ting thP seal around float screw which fastens float to float lever. The seal can be
cut '·lith a pocket knife. Remove float screw and assemble new float to lever. This should
be done with the float valve, float valve lever, float hinge pin and screws, float valve
seat and gasket assembled in the bowl. Before tightening float screw securely, adjust as
follows: looking down on bowl with gasoline inlet side away from you, pull float toward
you to the limit of slot in float lever and·about 1/16" to left of center line of bowl.
This provides necessary body clearance. Tighten the float screw and cement top of the
float screw to float with Dupont Household Cement or with a mixture of colluloid dis-
solved in acetone or with thick shellac. When cement has dried thoroughly check the float
height and adjust as explained in 12.
12. Check float lever, and if necessary, re-set to!,;". Measure directly opposite float
lever with bowl held u-side-down(top of float to top of bowl.) When re-adjusting Linkert
carburetor float, do not attempt to do so by bending float lever upward to some manne~,
without disassembling from bowl. Re-adjusting in this manner bends and spreads the fingers
between which the head of float needle fits, and thus develops lost motion between float
and needle. Float and lever assembly should be removed from bowl, and then lever bent.
Before re-assembling, see that needle head is a good free fit between lever fingers with
not more than approximately .003" play. This clearance can also be checked after lever
is assembled in bowl, by carefully placing a small screw driver or small rod against
valve head in such a position that it will hold the valve firmly against seat and yet not
bind lever. Moving lever up and down will then show the amount of actual clearnace be-
t\veen valve head and fingers. If this clearance is excessive the float mechanism will
not feed properly. After assembling, note float is approximately square with top of bowl.
SPECIAL No. 231 October 23, 1944
XA MODEL - ENGINE FITTING SPECIFICATIONS BIG TWIN TRANSMISSION STARTER CLUTCH AND ~~INSHAFT BAIL BEARING PULLER
CYLINDER- Standard bore- 3.062" to 3.063" PART NUMBER 12737-43
PISTON CLE/\.RANCE IN CYLINDER: .002" to .003" measuring piston at bottom of skirt, at right
angles to pin (across thrust faces). WARNING: This fitting clearance applies only to man-
ufacturer's taper - cam ground piston, which is .002 11 smaller at top of skirt underneath
lower ring, than at bottom of skirt. This clearance (.002 11 to .003 11 ) is not sufficient This puller applies to 1936 61" OHV and all 1937 and later Big Twin transmissions. One
for straight cam ground piston obtained from some other source. end of puller has full engaging lip; this end pulls the starter clutch. The other end
has four, lipped prongs; this end pulls mainshaft bearing.
PISTON - CYLINDER HEAD CLEARANCE: 1/16" to 3/32"
PISTON PIN IN PISTON: Light hand press fit. CAUTION: This toll is intended to be used only for removing starter clutch and a worn
out or damaged ball bearing from a complete transmission assembly, in the chassis when
PISTON PIN IN UPPER CONNECTING ROD BUSHING: .0008" to .0013" clearance; .001" pr<>ferred. there is no reason to disassemble transmission further than actually required to permit
PISTON RING GAP: .007" to .017" replacement of starter mainshaft parts and/or bearing. When for one reason or another
transmission must be completely disassembled, but ball bearing is still in good condition
PISTON RING SIDE CLEARANCE IN GROOVES: . 004" and usable, it is not necessary to use this tool for bearing removal, and it should not
CONNECTING ROD LOWER END BEARING: . 0007 5" to . 0025" clearance; . 001" preferred be used for this purpose as engaging it will damage bearing. When this applies, us_e___
tool for removal of only the starter clutch.
CONNECTING ROD LOWER END SIDE PLAY: .005" to .011". Retainer must be narrower, but not
more than .014" narrower than connecting rod. DISASSEMBLING PREPARATORY TO REMOVING STARTER CLUTCH AND MAINSHAFT BALL BEARING
CAM SHAFT: .0005" to .0015" clearance; .001" preferred (front and rear bearings)
1. If motorcycle is equipped with sidecar, remove sidecar first.
OIL PUMP DRIVE GEAR: .0005" to .0015" clearance .001" preferred
IDLER GEAR: .001" to .002" clearance; .0015" preferred 2. Remove muffler and rear cylinder exhaust pipe.
VALVE STEM - VALVE GUIDE CLEARANCE: .0035" to .0055" 3. Remove clutch release lever. Use an all-purpose claw ?uller to pull release lever
TAPPET GUIDES: Slip fit to .001" loose in crankcase from shaft.
VALVE TAPPET-TAPPET GUIDE CLEARANCE: .0005" to .0015"; .001" preferred 4. Place oil drain pan under transmission and remove starter cover nuts and plain washers.
TAPPET CcEARANCES: Engine cold. Intake, .004" to .006"; Exhaust, .012" to .014" Pull off starter cover assembly.
CIRCUIT BREAKER POINTS: .022" tap with breaker lever on highest point of cam 5. Remove clutch push rod from mainshaft.
SPARK TIMING: 1/64" before top center on compression stroke with automatic spark advance
in retarded position. 6. Wash starter compartment and parts with solvent, kerosene or gasoline.
CRANKCASE BREATHER TIMING: Engage in narrow slot(identified with yellow paint) of breather REMOVING STARTER CLUTCH
sleeve with pin on cam gear.
VALVE TIMING: Time according to mark on crankcase gear and mark on cam shaft gear. In- 1. Bend edge of starter clutch nut lock washer away from side of starter clut~h nut.
take opens 15/32" to 9/16" before top center; Intake closes 1-11/32" to 1-15/32" after
bottom center; Exhaust open 1-1/4 11 to 1-3/8'' before bottom center; Exhaust closes 31/64" 2. Remove starter clutch nut and lock washer.
to 37/64" after top center.
3. Insert puller center adapter into end of mainshaft. Push mainshaft gear inward as
CAUTION: Both intake and exhaust tappets must be adjusted to .005" while checking valve far as possible and insert puller halves between ratchet teeth on starter clutch
timing according to piston position. After checking valve timing, exhaust tappets must be and starter mainshaft gear.
readjusted .012" to .014" for normal operation
ASSEMBLED BALL BEARINGS: All bearings in case or on shaft, slip fit to light press fit. Hold puller body halves in place and slide sleeve over them. Push sleeve on until
When bearing is worn to extent of appreciable shake or pl~y, it should be renewed. it is·flush with inner end of puller halves.
CLUTCH SPRINGS: Must be of equal length. Engage puller screw and block in bayonet slots in puller halves. Hold screw block
REAR WHEEL SPRING SUSPENSION GUIDE BEARINGS: .001" to .002" clearance on vertical guide in position, with screw centered in adapter in shaft end, and tighten screw. If
post; .0015" preferred. When pressing new bushing in guides, bushing must be inserted starter clutch does not come off shaft by exerting hand pressure on screw, strike
with chamfered end outHard. Peen metal of guide into chamfer of bushing at three equi- end of screw sharp blows with a light hammer.
distant points to securely hold bushing in place.
No. 231 -2- October 23, 1944

4. Remove the two starter clutch keys from keyways in mains haft. Also ..:emove starter
mainshaft gear and spring from mainshaft.

REMOVING MAINSHAFT BALL BEARING

1. Remove the four bearing housing retaining plate screws and bearing housing retaining
plate. Note that starter gear oil deflector is held in place by the upper front
screw, and that V-notch in bearing housing retaining plate is upward and toward the
front.

2. Bend ear of lock washer away from bearing lock nut.

3. Remove bearing lock nut using Harley-Davidson special wrench #12733-41. Also remove
lock washer.

4. If transmission has late style shielded bearing, drill or punch a hole in shield
plate and pry shield out of bearing assembly.

5. Insert puller center adapter in end of mainshaft.

Insert the lipped prongs of puller body into inner ball race. I f ball retainer interferes
with hooking the prongs of puller in inner race, use a small-blunt punch and light hammer
to flatten four points of ball retainer to permit prongs-of puller to seat fully in ball
path.

Hold puller halves in place and push sleeve over them. Be sure inner end of sleeve is
pushed in against bearing to prevent springing or breaking puller prongs.

Engage puller screw and block in bayonet slots in puller halves. Hols screw block in
position with screw centered in adapter in shaft end and turn screw to right. Continue
to turn until bearing is removed.

NOTE: If bearing housing comes out of case with ball bearing, remove old bearing from
housing and replace housing in case before installing new bearing.

REASSEMBLY TIPS

Use a light hammer and block of hard wood or brass drift to drive bearing into place.

Be sure ball bearing nut and starter clutch nut are tightened securely and lock washers
are bent up against one flat side of each nut.

If a 1939 or later transmission, or if an earlier model transmission in which the late

type push rod thrust bearing has been installed (large bearing that fits over starter
clutch). next install thrust bearing on starter clutch and s-e that is slides freely,
back and forth. This ls essential for normal clutch operation. After this check, remove
thrust bearing and in~ert it into cover, with slot in outer bearing race engaging clutch
release finger. Insert push rod small diameter end into thrust bearing and insert the
other end of push rod into mainshaft. With push rod serving as a pilot, move the cover
assembly into place, observing at the same time that groove in thrust bearing inner race
and ball punger in starter clutch align so they will be engaged when assembly is completed.
 No. 233 November 16, 1944
OPERATION/MAINTENANCE MANUALS - PARTS LIST FOR MOTORCYCLES SOLD THROUGH ARMY SURPLUS
No. 232 October 30, 1944
During the past three or four months, the Government has sold a large number - 3,000 to
SERVIC IllG i-!A.'iDLE.BARS \I'ITH WORll SLOTS 5,000 Army suplus, used Harley-Davidson military model motorcycles. There is still a
large surplus accumulation of motorcycles yet tobe so1d. Included in the motorcycles
already sold are 800 to 900 XZ shaft-drive models. The others sold and the balance yet
File ends of slot as shown to be sold are principally 1940, 1941 and 1942 WLA models. The l-ILA model is basically
our standard 45 cu. in. Twin model with various changes and additions to adapt it to

( L.A --~-J :1; 1/

military service. The XA model is strictly a special motorcycle built entirely to Army
specification. This model has a 180 degree twin-opposed engine set· transversely in frame
and is shaft driven.
~.:=.;_---'--'-~::....:.=.:.c--+--=·-~~-J..- - . - ..iJ II•
F. ile slc t to width of block :· ·-
A portion of both types of these motorcycles have been purchased by Harley-Davidson dealers
the remainder have been purchased by used-car dealers. Many of the machines of both models
Guide Block 3321-}lA have already been resold to individuals, and we are receiving numerous letters from these
individuals regarding questions they have about their motorcycles. Since all Army motor-

~ cycles originally carried an information plate advising the numbers of the Spare Parts
List and Operation and Maintenance Manual supplied with these machines, the inquiries we
receive request principally these publications or information as to how to obtain them.
There is also much question about obtaining spare parts for both models. The purpose of
There now is available a:o oversize plunger guide block with which to service this bulletin is to information you in the future individuals making inquiry will be re-
all 1931 and later handlebars tl~it become worn in the plunger control slot to ferred back to their nearest Harley-Davidson dealer for any desired information - parts,
manuals, etc.
the extent of unsatisfactory grip operation. Repair is accomplished by the
use cf a new oversize plunger guide block which replaces the original block.
WLA Operation and Maintenance Manual No. TM-10-1175 is availab.e The price is $1.25 net
$2.00 list. Order under Part #13862-42. WLA Spare Parts List No. TM-10-1482 is not now
This new block is 1/2 inch long and 7/16 inch wide and slot can be widened for
available and is not likely to become available later.
either dimension. First, file slot to meet the 7/16 inch dimension, and i f it
does not smooth up at this width, use the l/2 inch dimension. Fiie same anount Spare parts for l-ILA model motorcycles are available. Standard 45 cu. in. twin model parts
of metal from both sides of sl~t. which was originally about 3/S inch wide. Ob- apply as a general thing to the l-ILA model and you should order from regular catalog. Some
serve that top of guide block does not protrude above sides of slot; if it does, of the exceptions are mudguards, oil bath air cleaner, carburetor (which is adapted to oil
it will be necessary to deepen recess in plunger. bath air cleaner), blackout lighting system, ignition and light switch, cylinder heads,
and other strictly Army fittings such as skid plate, gun scabbard and ammunition box
~ith a smooth file, file slot as square as possible in relation to the bearing brackets, saddlebags, etc. l-lhen ordering painted parts be sure to specify whether original
surfaces of the new block, as ~rp edges and uneveness in the slot will cause Olive Drab color or some other color is desired. l-ihen ordering parts applying to any of
plunger guide block to hang and prevent free movement. the equipment exceptions listed, give a clear description of item or items desired and
mention year and model.
Avoid filing slot wider th!ln necessary. The new block can be used as a gauge
by inserting it into the nearly finished slot and filing away only therections AX Model Operation and Maintenance Manusl No. TM-10-1293 is available. XA Model Spare
of the slot thD.t do not allow free movement. Parts list is not available now, but may be later.
File slot ends square, as shown in sk~tch above, so t!~t plunger guide block Spare parts and service tools for the XA model are not available. If and when Spare Parts
has the required amount of movement to fully operate throttle or spark lever. List, spare parts and service tools become available you will be notified. In the mean-
time, it will be of no avail to attempt to obtain parts by ordering according to the many
Part No. 3321-31A - - - - List Price $ .10 part and tool numbers shown in the Operation and Maintenance Manual.

li.'J'.LEY -DAVIDS::lll l·:O:CO?. CO.

l•:ilwaukee, Wis., U.S.A.
 No. 236
No. 235 December 23, 1944 BIG TWIN TRANSMISSION SHIFTER FORK GAUGE, PART NO. 12074-39
This tool applies to 1936 61 OHV and all 1937 and later big twin transmissions. The pur-
REPLACING WORN THROTTLE SHAFT AND SHAFT BUSHINGS IN HARLEY-DAVIDSON pose of this tool is to locate and hold transmission shifter fork fingers in the exact
CARBURETOR WITH TOOL SET NO. 12012-44D, FEDERAL STOCK NO. 41-K-144-10 positions they will have when transmission cover assembly is installed. Tool allows un-
obstructed view of interior of transmission so that 11 enutral1f side clearance of shifting
1. Remove throttle disc and worn throttle shaft. members (shifter clutch or gear) from gears with which they engage can be gauged.
Note that each end.fitting of tool has a hole on one side and dowel pin on the other side.
2. Oil tap and turn it into either bushing at least four or five threads; then The dowel pins are for locating on cover; the holes for locating on transmission case.
back it out about 1/2 turn so it will be loose and easily removed from
bushing after driving out. Applying to 1939 and later transmissions, shifter fingers (. 287" dia•.) require a roller
(.370" dia.). Be sure this roller is in place on each finger when using tool and also when
3. Drive out tap and bushing with drift. transmission cover is finally installed. 1938 and earlier transmissions were originally
assembled with solid type fingers (.370" dia.); however, in connection with service re-
4. Repeat operations 1, 2 and 3 to remove opposite bushing. quired in the meantime, the roller type finger which, with roller, is interchangeable with
the solid type, may have been installed. Watch This. Tool is to be used as follows:
5. Drive in new bushings with line drift. Bushing is in place when drift
bottoms on carburetor body. 1. Place tool on cover.
2. With the aid of 3/8" gauge rod furnished with tool, set first on gauge block and
6. Line ream one bushing and then the other. then the other in perfrect alignment with straight section of their respective
cam slots. Tighten lock screws securely.
7. Insert new throttle shaft and install disc. Disc renewal is not usually
necessary. If found worn or damaged to the extent of requiring renewal, 3. Remove tool from cover, turn it over, place it on transmission case with shifter
be sure to install a new one with the same identification number stamped fingers engaged.
in face of disc. With disc correctly installed and in closed position 4. With suitable thickness gauges, check clearance of shifting members.
number will be seen through manifold end of carburetor and will be on ~he
opposite side of carburetor from small idle holes. Shift disc to best All shifter clutches must be centered. When centered, 1938 and later mainshaft shifter
position for close fitting all around its edge, Press collar on lower clutch should have about .100" clearance, both sides. 1936-37 mainshaft shifter clutch
end of throttle shaft against carburetor body. Hold throttle shaft and should have about .075" clearance, both sides. 1936 and later counter~haft shifter clutch
disc snugly in these positions while tightening disc screws. should have about .075" clearance, both sides.
Where shifter clutch engagement is with dogs protruding from face of gear, turn gear so
dogs on gear are fully facing each other before checking clearance. Exception-dogs on 1938
and later main drive gear and mainshaft shifter clutch are bevel faced, so clearance must
1 be checked with only their highest points facing each other.
1. Drive~out tap Space sliding gear about .055" from mainshaft gear with which it engages. Have highest
2. Handle for 1 & 4 points of rounded ends of gear teeth exactly in alignment with ~ach other when checking
-3 -1 3. Drift this clearance.
~
4. Line Reamer
Shifting members are readjusted to correct side clearance by increasing or decreasing the
number of shims between shifter fork and shifter finger. To make this readjustment requires
removing shifter fork shaft and shifter fork assemblies from transmission. Shims are avail-
able .007" and .014" thick. After adding or taking out shims, be usre fork assembly lock
nut is firmly tightened, and secured with lock washer. Caution: while this nut must be very
tight so that fork is held firmly, don't over-do it. Overtightening may close up the hole
in bushing· so it is no longer a free sliding fit on shaft. In this case, lap out as nece-
ssary or install new bushing. Fork assembly must slide freely.
Tool must J>e reset for each transmission to which it is applied, as no two transmissions
are likely to have exactly the same relation between cover and case.
 5
CONCERNING SYNTHETIC CASINGS AND TUBES February 1, 1945
No. 234-A
For several months new motorcycles and sidecars have been shipped with synthetic rubber COLD-PATCHING SYNTHETIC TUBES
casings and tubes exclusively. Up to now, all synthetic casings and tubes have been made
of Buna-S. These casings have been marked S-3 and tubes are identified by a continuous red Col-patching sy~thetic rubber tubes is not recommended as a permanent repair.
band. Later ,.;re may get s.ome Butyl tubes which will be marked with a continuous blue band. It should be considered only as an emergency roadside repair when hot-patching
equipment is not available. Where this temporary repair method is necessary,
Synthetic tires have gen·erally given satisfactory service. Only an occasional tube failure
carefully observe these directions for best r.esults.
for other rea~on than puncture has been reported. Investigation of such failures has proven
that in nearly every ca~e failure was the result of tube having been installed by procedure
Nail holes that have not started any appreciable tear need not be trimmed.
long recognized os'OK for natural rubber tubes, but ~ood enough for synthetic tubes.
Synthetic tubes do not have the same stretching qualities natural rubber tubes have. They
If possible, tube injuries other than nail holes should be rounded at the ends
are more in6.lined ·to split and tear; therefore, synthetic tubes must be free from all
and trimmed with scissors or knife to prevent tearing.
strains and stress:es after installing and :f...nflating. To get the best service from synthetic
casings and tubes, ~hese things are vitally important:
Buff tube corss-sectionally for one inch from all edges of injury. Do not buff
L Install correctly. circumferential.ly. Reason is that tube will tear much more readily lengthwise
~z. Maintain correct air pressure of tube than crosswise. Buff THOROUGHLY to remove ALL glaze from buffed area.
3. Do not overload Adequate buffing is extremely important. Buff until tube shows even, blackish
4. Avoid high speeds. color with no streaks of surface glaze showing. Buffed area should have appear-
ance· and feel of suede leather i f buffing job has been done correctly. Use sand
Before installing tube in casing all dust and dirt, particularly hard particles which might
paper, emery cloth, or top of repair kit can. Be careful not to start deep
chafe an inflated tube, must be carefully removed. Wipe tube and inside of casing- thoroughly
scratches, Firm, steady pressure will get the job done right.
with clean, dry cloth. If rim is· dirty or rusty, it will take a good cleaning with stiff
wire brush. Be sure td examine used casing carefully for fabric injuries which, if neg-
Blow dust from buffed area. Don't touch with fingers. Apply one coat of cold-
lected, will damage tube.
patching cement. Cemented area should be about 1/4" larger is all directions
Dust tube, inside of casing and rim strip that covers spoke end liberally with soap-stone than patch to be used, Scrape off excess cement with dull knife blade.
powder. Insert tube in casing and apply soap solution. If no vegetable soap is available,
use soapstone powder more freely. Be careful not to use so much that it piles up in casing Cut required size patch from patch stock. Patch should overlap injury about one
It is desireable to use vegetable oil soap solution for lubricating tube and side of casing inch in all directions. Remove protective cloth covering, place patch over
about a third of the way up from bead toe, also face of rim strip that covers spoke ends, injury a,nd .roll or "stitch down" thoroughly with edge of repair kit can.
rather than to depend .en~irely upon soapstone powder as soap suds lubricate more effectively
and better assure tube pro,perly shaping iteself to rim well without adhesion, stretch or Never run a cold-patched synthetic tube farther than absolutely necessary because
strain. Do not use so much soap solution it runs into crown of casing. We recommend this type of repair is not dependable for synthetic rubber. When i t lets down,
Murphy's Vegetable Oil Soap mixed with just enough water to form a bubbly, sudy, slippery tube injury ma.y be found torn to point where tube is damaged beyond further
solution. That's what it takes to do the job. practicable ~epair. As soon as possible, cold patch should be removed, injury
Synthetic rubber tires generate niore heat from flexing under road contact then natural rub- xepaired by hot~patching or vulcanizing, and tube re-installed according to
reco~ended procedure,
ber tires. Therefore, maintenance of correct inflation and avoiding high speeds are "musts"
if dependable performance is to be gotten from them.
Tube injuries in synthetic tubes can pe satisfactorly repaired, but the job requires a diff-
erent repair technique than used for nature rubber and it must be done just right. Cold
patching synthetic. tubes is not recommeded except for emergency road service repair. Motor-
cycles should not be run farther than absolutely necessary with a cold-atch synthetic tube.
Pre-war hot patches designed for natural rubber tubes are not satisfactory for synthetic
tubes. Synthetic rubber requires a different hot-patch material and longer, hotter curing.
The patches developed for synthetic tubes are, however, OK for both natural rubber and
synthetic tubes. We are now in a position to supply synthetic hot-patchir.g equipment for
repairing _small tube injuries. You may order under the following part numbers:
11585-45 Camel Vulcanizing clamp and 3 partches .75 list
11586-45 Box ·of 10 round ?atches .60
11587.:.'45 Box of 10 oblong patches .60
No. 234B February 1, 1945 ----,---,"BIG THIN" TRANSMISSION MAIN DRIVE GEAR OIL
HOT-PATCHING SYNTHETIC TUBES SEAL TOOL
This tool applies to 1936-61 OHV and all 1937 and
Nail-hole injuries that have not started any appreciable tear need not be trimmed. later Big Twin transmissions. It enables removing
For all other tube injuries, trim edges of injury and round out of "buttonhole" ends worn-out or damaged oil seal and installing a new
to prevent splitting or tearing. Use scissors or leather punch. Injuries larger seal without removing transmission from motorcycle
than 1/2" trimmed length, should be vulcanized. chassis. It also works equally well with trans-
mission out of chassis. Transmission must be
Buff tube cross-sectionally ln from all edges of 1n]ury. Do not buff circumferentially.
Reason is that tube will tear much more readily lengthwise of tube than crosswise.
Also buff edges of injury. J J Je assembled, except clutch and countershaft sprocket,
in order to use tool.
DISASSEMBLING PREPARATORY TO REPLACING OIL SEAL
WITH TRANSMISSION IN MOTORCYCLE CHASSIS
Buff THOROUGHLY TO REMOVE ALL GALZE from buffed area. Adequate buffing is extremely
important. Buff until tube shows even blackish color with no streaks of surface glaze Shift transmission into low gear and lock rear
shawing. Puffed area should have appearance and feel of suede leather if buffing job wheel brake to prevent parts from turning while
has been done properly. Use "handee 11 type electric hand grinder and emery drum if disassembling. Remove outer front chain guard,
available, otherwise ·emery cloth, sand paper, or top of repair kit can. In buffing, engine sprocket, front chain, clutch assembly,
be careful not to start deep scratches. Firm, steady pressure will get the job done inner chain guard, countershaft Sprocket and rear
right. chain. (Note: Clutch hub nut and countershaft
L __ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ _ __ J sprocket nut are left thread).
Blow dust from buffed area; don't touch with fingers.
REMOVING OIL SEAL
l.Jhile the use of cement is not a "must" it is advisable in shop practice to apply one Place Sleeve ucu on end of main drive gear and against transmission case or mounting plate and
coat of vulcanizing cement over entire buffed area, including edges of injury. Hole while holding body in this position, insert center punch "E" through each of the three holes
in tube should be filled in with piece of patch, cut to fit. If area to be filled in in body and center punch oil seal. Remove body and drill a 3/32" hole through metal face of
is small, cut piece from patch you intend using for repair of tube; if larger area, cut oil seal, at each punch mark. Replace body and insert the three self-tapping screws "D"
up another patch. through body into holes drilled in oil seal. Tighten screws until body is snug against oil
seal. Turn actuating screw "A" into body and continue turning until oil seal is free from
Remove protective cloth covering from patch and center patch over tube injury. Place transmission case. Remove tool and discard old oil seal. Remove and discard cork gasket
paEch in clamp over tube. Turn clamp screw down as tight as possible without crushing found behind oil seal.
edges of patch pan. Light fuel cookie wick with match and let it set until it can be INSTALLING NEW OIL SEAL
handled comfortably with bare fingers (About 10 minutes or more)
Before installing new seal, remove burrs with scrapper from outer edge of oil seal recess in
Re-install tube in casing according to recommended procedure. transmission case~ particularly where aluminum was staked to secure seal just removed. Place
new cork gasket into oil seal recess in transmission case. Apply oil or grease to lip of oil
Tube injuries larger than 1/2" (trimmed size) should be repaired by vulcanizing. Any seal to prevent turning member from burning and damaging new seal when first put into service.
reliable tire repair shop should be able to do this work for you. Insert sleeve "C" into oil seal. Place sleeve and seal on main drive gear with lip side of
seal toward transmission case and move both sleeve and seal inward as far as they will go.
Observe location of staking notches in outer face of seal and turn seal so it will not stake
at the same points old seal was staked.
Place body on sleeve, against oil seal, and turn actuating screw into body as far as it will
go without pulling body away from seal. Install mainshaft clutch hub nut and turn in against
actuating screw. Back out actuating screw until body has pushed oil seal into. place and body
is tight agaillst end of gear box. Remove mainshaft nut and tool. Using small, blunt chisel
or punch, stake aluminum of transmission case into the three notches in seal outer face. This
prevents oil seal from turning or working out.
REASSEMBLING TIPS
Applying to 1938 or later transmission, be sure small "L" shaped key is installed between
spline of main drive gear and notch in outer end of main gear spacer. Securely tighten engine
sprocket nut, countershaft sprocket nut and clutch hub nut. Be sure to lock countershaft
sprocket nut and clutch hub nut by bending up lip of lock washer.
 November 15, 1945 No. 240E December 10, 1945
No. 240
NEW MOTORCYCLES EQUIPPED WITH DRY CHARGED BATTERY
NEW MOTORCYCLES EQUIPPED WITH DRY BATTERY
Since our supply of regular dry (moist uncharged) batteries is temporarily shut
off, all motorcycles regularly equipped with this type of battery are now being
Since our source of supply of regular wet batteries is temporarily shut off because shipped with a dry battery of a somewhat different type know as a "dry charged
of labor problems, we are forced to ship, equipped with dry battery, all motorcycles battery." The two types of batteries look exactly alike but the dry charged
that would regularly be equipped with wet battery. This applies to all motorcycles battery has a gray paint mark on the negative terminal and carries with it a
shipped from the factory since about November 12. Machines so fitted have a small white instruction tag imprinted in red entitled, "This battery is dry charged".
manila tag attached to the battery marked "dry battery" and also have a large while
In preparing a dry charged battery for service the instructions given on the
tag captioned "THIS BATTERY IS DRY CHARGED" covering instructions for preparing the
battery for service, attached to the frame tube next to battery. tag should be followed very carefully with the exceptions noted in the following
parpagraph. Battery solution of 1.285 gravity (tropical countries 1.225) required
In preparing dry battery for service, the instructions given on the tag should be for filling can be purchased from any recognized battery shop. About one-fifth
followed very carefully with exceptions noted below .. Battery solution of 1.285 U.S. gallon is the average amount of solution required for one battery.
gravity required for filling can be purchased locally from any recognized battery
shop. About one-fifth gallon is the average amount of solution required for one EXCEPTIONS: - Paragraph 4 of instructions and the footnote indicating date before
battery. which battery may be placed in service without charging apply to military emergency
use only. For your purpose this information should be disregarded. All batteries
should be fully prepared according to paragraphs 1, 2, 3, 5, and 6.
EXCEPTIONS; Paragraph 4 of instructions and the footnote indicating date before
which battery may be placed in service without charing apply to military emergency We have been using the dry charged battery in new motorcycles only since about
use only, For your purpose this information should be disregarded. All batteries November 21, 1945. Consequently if you have any motorcycles enroute to you some
should be fully prepared according to paragraphs 1, 2, 3, 5, and 6. of them may still be fitted with the regular dry (moist uncharged) battery, the
same as you have been getting right along. This battery carries a yellow in-
struction tag imprinted in black and the instructions on that tag must be fol-
lowed carefully without exception when placing this type of battery in service.
No. 241 February 10, 1946
No. 242
FACTORY REPAIR
ROLLER BEARING ROLLER GUIDE
We are now in a position to again accept some material for repair. However, our
Here is a handy chart, giving information on roller bearing rollers. It is suggested
capacity for repairing is still very limited. It therefore is essential that you
that this be kept in a prominen- place so it can be referred to on a moment's notice.
repair in your own shop and avoid factory repair as far as possible, especially as
concerns frames and forks. Unless this is done, we are very likely to again find
Rollers .250" and .1875" are used in retainers. Needle rollers .152", .125", .114" and
the Factory Repair Department hopelessly swamped with returned material and the
.0625" are used without retainers.
time required for repair again a matter of weeks or possibly months.
Rollers .zson, .1875" and .152" are furnished from .001" undersize to .001 11 oversize in
Here are some things to bear in mind in connection with the matter if factory steps of .0002"
repair jobs:
Rollers .125" and .ll4" are furnished only .0004" and .0008" oversize.
To facilitate repair at this end, it is necessary that all frames and forks be re-
Rollers .0625" are furnished only .0008" oversize.
turned thoroughly cleaned. We do not have the facilities for cleaning frames and
forks individually as, in their turn, they come up for repair. Dirty frames and PART NO. STD.
forks must be set aside until enough have been accumulated to warrant diverting new NO. WHERE USED USED LENGTH DIA.
production cleaning equipment for the necessary time to this job which of course
304-15 Forked End connecting rod (1915-1939 61", 74" & 80" Twins) 24 .360" .250"
means considerable delay as well as added repair cost.
Left Crankcase (1929 & earlier 61" & 74" Twins) 24
Left Crankcase (1929 & later 45" Twins) 24
Frames to be returned should be completely stripped, that is no assembled fittings
Front Brake Hub (1930-36 74" & 80" Twins) 24
should be left attached; neither should assembled forks be returned.
Sidecar Brake Hub (1930-36) except LE Model) 28
We are not in a position to repaint any frames or forks.
304-40 Forked End Connecting Rod (1940 & later 61" 74" & 80" Twins) 36 .344" .1875"
It is not economical to repair a frame if the total repair cost amounts to more than
305-15 Single End Connecting Rod (1915-3-9 61" 74" & 80" Twins) 12 .726" .250"
approximately $15.00 net. Therefore, it is hardly worthwhile to return for repair a
Connecting Rod (30.50" Single) i2
badly mangled frame, possibly with broken tubes or fittings, which pretty obviously
is going to run into higher repair cost.
Clutch Sprocket (1921-36 61", 74" & 80" except 61" OHV) 12

305-40 Single End Connecting Rod (1940 & later 61", 74" & 80" Twins) 18 .694" .1875"
We are again in a position to accept connecting rods in exchange for rebuilt com-
binations. In this connection remember that the rods returned for exchange must be
305-29 Single End Connecting Rod (1929 & later 45" Twins) 12 .550" .250"
in perfect condition aside from requiring new bushings. Rods that are badly bent or
Right Crankcase (1937 & later 45" Twins) 12
twisted or are damaged otherwise, or rods that have been plated or have been ground
down or polished to a point of weakening them will not be accepted for exchange;
305-26 Right Crankcase (1936 61"; 1937 & later 61", 74" & 80" Twins) 12 .600" .250"
neither are we in a position to recondition such rods individually. Bear in mind
Connecting Rod (21" Single) 12
also that we cannot exchange or repair connecting rods for 1934 or earlier single
Left Crankcase (21" & 30. 50" Single) 12
models: 1931 or earlier 45 cubic inch twin models; 1929 or earlier 61 and 74 cubic
inch twin models.
2289-17 Forked End Connecting Rod (1929 & later 45" Twins) 24 .270" .250"
As concerns assemblies such as engine, transmission and generator, or other odd parts Clutch Sprocket (1926-34 Singles and 45" Twins) 16
that you may wish to send to the factory for repair, please do not return any such Countershaft Gear-Std. Transmission (1931 & earlier 61" & 74")24
Main Drive Gear (1924 & earlier 61" & 74") 20
items without first writing us for approval because we may not be able to make desired
repair within reasonable time. This also applies to a complete motorcycle that you
2289-25 Left Crankcase (1930 & later 61" 74" & 80" Twins 24 .490" .250"
might be considering driving or sending in to the factory for some reapir or adjustmen-t
work. Rear Wheel Hub (1923-29 61" & 74" Twins) 32
Main Drive Gear (1925-36 61", 74" & 80" Twins except 61 OHV) 20
Clutch Gear (1934 & earlier 45" & Single Std. transmission) 16
Mainshaft (1934 & earlier 45" & Single Std. transmission) 12
Interchangeable Wheel Hub (1930-36 74" & 80" Twins) 28
Countershaft Gear-right side-(1931 Reverse-1932-36 Reverse &
Std. Transmission 74" & 80" Twins) 12
 No. 242 -2- February 10, 1946

PART NO. STD.

NO WHERE USED USED LENGTH DIA.

2289-25 Servi-Car Axle Outer Ends (1932 & later) 24 .490" .250"
Wheel Hubs (1935 & later 45" Rear Wheel and 1941 Servi-
Car front wheel, 1936 61", 1937 & later 61", 74" & 80"-
both wheel, "LE" Model Sidecar wheel) 26

2306-32 Countershaft gear - left side (1931-74" reverse, 1932-36

74'' Std. & reverse transmission) 21 5/8" .152"
Clutch Gear - left side - (1933-34 45" twin & single
reverse, 1935-40 45" std. & reverse transmission) 31
Mainshaft-right side - (1933-34 45" twin & single reverse,
1935 & later 45" std & reverse transmission) 21
Countershaft Gear-left side (1933-34 45" twin & single
reverse, 1935 & later 45" std. & reverse transmission) 19

2289-36 Countershaft Gear (1936 61", 1937 & later 61", 74" & 80") 44 .615" .125"
Main prive Gear (1936 61", 1937 & later 61", and 80" twins) 44
Clutch Gear (1941 45") 40

2289-39 Countershaft Gear - right side (1939 & later 45") 24 3/4" .114"

2289-36A Countershaft Gear (1936 74" & 80" - 4 speed) 78 39/64" .0625"

When assembling needle rollers in outer race preparatory to final assembly, apply a small
amount of grease to hold rollers in place. Assemble specified number of rollers and
observe that the last roller goes all the way into place freely and without requiring any
effort to force it. If it doesn't go into place freely, leave it out. This is sometimes
necessary when fitting oversize rollers, because they not only take up radial clearance,
but also take up circumferential clearance. Rollers must not be crowded.
 No. 242A March 4, 1946

PART NO.
NO WHERE USED USED A B c D E

417-30 Left Crankcase(l930 & later Big

No. 242A March 4, 1946
twin models} 2 1-29/64" .581" .502" 12 .260"
GUIDE FOR QUICK IDENTIFICATION OF ROLLER RETAINERS
Servi-Car axle outer ends (1932
and later) 2
Wheel hub-1935 & later 45" rear
wheel; 1941 & later Servi-Car
front wheel; 1937 & later Big
twins, also 1936 OHV front &
rear wheel "LE" sidecar wheel 2

3993-23 Rear wheel Hub (1934-39 Big

f·HOLf .Sl'Z£ Twin models) 2 1-53/64" .581" .502" 16 .260"
Clutch Gear(l934 & earlier
single & 45" models) 1

2286-25 Main Drive Gear(l925-36 Big

PART NO. Twins except 61" OHV) 1 2.580" .612" .502" 20 .260"
NO WHERE USED USED A B c D E
2538-26 Clutch Sprocket (1926-34 Single
301-15 Front & rear Connecting rod lower and 45") 1 1-53/64" .341" .292" 16 .260"
end (1921-36 Big Twins) 4 1-29/64" .434" .370" 12 .260"
2291-26 Transmission mainshaft (1929-34
Left Crankcase (1929 & earlier single and 45" 2 1-21/64" .303" .252" 12 .260"
61 & 74")
Transmission countershaft gear
Front Brake Hub(l930-36 Big Twins) 2 right side (1932-36 Reverse & 3
Connecting Rod 30.50"-Single 2 speed Big Twins except 6l"OHV) 2

Clutch Sprocket (1921-36 Big Twins 3922-30 Wheel Hub (1930-36 Big Twins
Except 61" OHV) 2 except 61" OHV) 1 1-37/64" .581" .502" 14 .260"
301-36 Front & rear connecting rod lower 6171-30 Sidecar Brake Shell Hub (1930-
end (1936 61", 1937-39 Big Twins) 4 1-37 /64" .434" .370" 14 .260" 36 Big Twins) 1-45/64" .434" .377" 14 .260"
301-29 Front & rear connecting rod lower 3967-35 Wheel Hub(l935 & later 45" rear
end (1929 & later 45" models) 4 1-29/64" .341" .282" 12 .260" wheel; 1941 & later Servi-Car
front wheel; 1937 & later Big
301-40 Front & rear connecting rod lower Twins, also 1936 OHV front &
end (1940 & later big twins) 4 1-19/32" .434" .354" 18 .1935" rear wheel; "LE" sidecar wheel 1 1-45/64" .573 .502" 14 .260"
301-26 Connecting Rod(21" single) 2 1-21/64" .370" .309" 12 .260"
Left crankcase (21"&30.50 single) 2

415-36 Right crankcase(l936 61", 1937 &

later Big Twins) 1-29/64" .370" .321" 12 .260"

415-37 Right Crankcase (1937 & later 45") 2 1-21/64" .341" .282" 12 .260"

417-29 Left Crankcase (1929 & later 45") 2 1-21/64" .444" .377" 12 .260"
 May 22, 1946 No. 250 May 27, 1946
No. 24 7
USE CORRECT TYPE CRANK PIN IN 45 CU. IN. ENGINE
CONNECTING ROD IDENTIFICATION GUIDE
In a letter dated April 2, 1946, sent out by the Parts Department dealers
Connecting rods can be identified by numbers forged in web or rod (disregard any letters
were offered numerous Army Surplus Parts at special reduced prices. Among
following number). the items offered was:

289-32 :- Set Connecting Rods Cpt. "These new rods, fitted with bearings and
45" MODELS (EXCEPT WLDR AND WR)
crankpin. They fit 1937 to 1946 - 45" Twins. They cannot be used in models
forging No. Part No. older than 1937"
Year Model
This connecting rod and bearing assembly can be used only in 1937 and later
1932 and later 45 cu. in, twin engines, because the crank pin fitted to the assembly is of
Forked End Rod UA 705 283-32
284-32 the type ordinarily used only in new engine production. It has only one oil
Single End rod UA 706
hole which registeres with the oil passage in right side flywheel of the 1937
and later engine but does not register with oil passages in right side of
74 11 and son Side Valve Models
1936 and earlier engine.
1930 to 1936 Connecting rod set with rollers and crank pin shipped on parts order since
Forked End Rod SA 705 285-30
1937 to other than the Army, formerly under catalog number 289-32 and now
Single End Rod SA 706 286-30
under catalog number 289-32A is fitted with crank pin formerly catalog number
348-29 and now catalog number 248-29B which has two oil holes in it making
1937 and later it apply to either 1936 and earlier or 1937 and later engines.
Forked End Rod ZA 705 285-37
Single End Rod ZA 706 286-37
Although most dealers and their mec·hanics are familiar with the fact that only
the two-hole type crank pin supplied individually and with rod sets on parts
61" and 74" O.H.V. Models
order as described above, is interchangeable in 1932 to 1946 engines and that
the single-hole type crank pin as used in new engine production can be applied
1936 and later
XA 705 or 40A 705 285-36 only to engines from 1937 to date; it will do no harm to again remind your
Forked end rod
mechanics and your parts man regarding this point. This caution will be es-
Single End Rod XA 706 or 40A 706 286-36
pecially timely, not only in connection with the use of the surplus connecting
Connecting rods with letters DA, MA, OA, OM, RA, or TA preceding forging number are obsolete. rod sets we're offering for sale, but also because many Army Surplus Parts
are showing up from other sources and you might run on to some of the indivi-
They can no longer be obtained new, nor will they be repaired at the factory.
dual crank pins with one oil hole. If these are used in earlier than 1937
Some rods require lfl outside diameter piston pin bushing; other 57/64" outside diameter
engines,. lubrication will be shut off.
bushing. Some forked rods have more lower end enclosure than others. Rods that differ
in any of these respects, but have same forging numbers, are considered interchangeable.
No. 251 July 1, 1946 252 November l, 1946
CARE OF TIRES AND WHEELS
NEW MOTORCYCLE PREVENTIVE MAINTENANCE OF FIRST IMPORTANCE When a racing motorcycle or car is being groomed for an event on road or track, as close
When you deliver a new motorcycle have a definite understanding with the purchaser that attention is given to perfect condition of wheels and tires as to engine tuning. Wheel
it is to be brought back to you after it has been operated its first 250 to 500 miles bearings are checked, wheels and tires are checked for out-of-true sideways, eccentricity,
so you can give it the following attention: out-of-round, and out-of-balance. Careful attention is given to everything. If a tire
tread is found worn irregular, tires are transposed or new tire installed. Inflation
SECURELY RE-TIGHTEN - Cylinder bas nuts, Cylinder head bolts or nuts, pressure is carefully adjusted to the poundage know to be right for weight of vehicle.
Intake manifold nuts.
RE-ADJUST, IF NECESSARY - Front drive chain oiler adjusting screw In other words, engine RPM and horsepower don't mean anything unless vehicle being driven
can be guided with ease and safety at top speed. Stock model motorcycles today are approach-
No matter how securely nuts, bolts, and screws may be tightened in original assembly, ing the speed of racing model motorcycles. Therefore, due attention to wheels and tires
initial seating of gaskets, joint surfaces, and bolts and screw heads after motorcycle of stock motorcycles driven solo at high speed is just as essential as a racing motorcycle.
is put in use, tends to develop looseness. It may not be much, but just enough so · Riders as a general thing do their own tire inflating and a wide variable is found in the
parts are no longer held together firmly. Vibration, wear and very often breakage are pressures to which they inflate. This probably is mainly becuase no one has taken the time
the results of this loosene~s. to impress them with the importance of correct inflation pressures according to load and
tire size, and to enlighten them as to the influence this has on good or bad high speed
Long established new motorcycle serv1c1ng calls for a complete checkup, tune-up, and re- handling.
tightening ~f all nuts, bolts and scr~ws at 1000 to 1500 miles. This also includes re-
tightening engine mounting bolts, cylinder head frame brace, transmission mounting, etc. Here and there a rider transposes his fires to avoid excessive irregular wear of front
However, this interval is too long for the items listed above. THEY MUST BE GIVEN ATTEN- tire tread and to equalize ~ire wear, but most riders don't make this a practice because
TION at 250 to 500 MILES, and should be checked again at 1000 to 1500 miles. they don't realize it is a must. A tire kep in continuous front end service long enough
to allow tread to wear noticeably irregular and peaked, is very likely to handle poorly
It is especially important that cylinder base nuts be securely retightened. If a cylinder at high speeds especially if over-inflated. When a rider complains of bad handling at
is even very slightly loose, the high frequency vibration and impact set up at cylinder higher speeds, check as follows:
basP. flange by the engine power impulses will in short time fatigue and crack cylinder 1. Loose wheel axle nuts
around its base. When a cylinder lets go, the rest of engine is usually pretty much 2. Excessive wheel hub bearing play
wrecked, and repair is an expensive job. 3. Loosened spokes
4. Rear wheel alignment in frame and with front wheel
As nearly everyone knows, the good performance and life of a front chain depends entirely 5. Rims and tires too much out-of~true sidesways (should not be more than 3/64")
upon its ample lubrication. The quantity of oil required for ample lubrication is very 6. Rims and tires too much out-of-round or eccentric with hub(not more than 3/32")
slight. However, oiling must be constant. If oiling fails for a period of only a few 7. IRREGULAR OR PEAKED FRONT TIRE TREAD WEAR: ALSO DETERMINE MILEAGE SINCE TIRES
hours or few hundred miles, especially when operating at high spped, chain is likely to WERE LAST TRANSPOSED. IF MILEAGE IS 2500 OR·MORE, TRASPOSE TIRES EVEN THOUGH
be ruined. Initial oiling adjustment is set at the factory as closely as possible to IRREGULAR WEAR OR PEAKING OF FRONT TREAD IS NOT VERY NOTICEABLE.
normal service requirements, however, the quantity of oil involved is so small, initial 8. Tire inflation as per inlation pressure chart. DO NOT OVER-INFLATE.
adjustment cannot always be trusted as final. At 250 to 500 miles, remove inspection 9. Tire and wheel balance. Static balancing is satisfactory.
hole cover and make close inspection of chain. If chain appearance raises the least
10. Correct adjustment of steering head bearings and indication of pitted ball races.
doubt as to its getting ample lubrication add one or two more .002" washers under head
9
11. Normal functioning of hydraulic forks, rear fork and shock absorbers.
of chain oiler adjusting screw. A well lubricated chain not only has an oily surface~ 12. Good working order and adjustment of steering damper so it can be applied easily
but is also clean and free of discoloration. If chain has a brownish hue, and rusty
and gradually to any desired steering friction.
appearance at side and center plates, it is under-lubricated even though the surface may
be oily. With attention given as outlined you will find any high speed handling faulst corrected.
The possible exception will be the case where there is serious frame or fork misalignment
Since the quantity of oil involved is small, the opening through which oil bleeds to or mayble a tire in extremely bad condition which should be replaced. REMEMBER, TRANS-
chain is regulated by adjusting screw to a very small orifice. Sediment and gummy matter POSING TIRES AND INFLATING NO HIGHER THAN THE RECOMMENDED PRESSURE ARE OF FIRST IMPORTANCE.
accumulated in oil supply deposits in and around this orifice and gradually decreases the IN MANY CASES YOU WILL FIND THAT THIS ATTENTION ALONE APPLIED TO A MOTORCYCLE THAT DEVELOPS
oil supplied to chain. In other words, a chain that lubricated perfectly the first 2000 FAULTY HANDLING AT HIGHER SPEEDS, WILL GAIN THE DESIRED RESULT.
miles, may run short of oil the second 2000 miles. You ~ill go a long way toward elimi-
nating chain failure by following the 250 to 500 mile recommendation and training your The advisable thing to do is to offer your riders this chassis tuneup as preventive maint-
riders as follows: At intervals of 1000 to 1500 miles. lGosen the chain oiler adjusting enance to be repeated at about 3000 mile intervals. If you sell this plan you can be sure
screw~ and back it up about two turns. Operate this way a few miles and then turn screw. you will hear little about faulty handling.
back dm•n lightly against its adjusting washers. This procedure flushes away accumulated
sediment and restores oil orifice to its original size.
 No. 253 December 23, 1946

CYLINDER REBORING AND PISTON FITTING INFORMATION

No. 252-A November 1, 1946 Supersedes'Shop Dope Sheet No. ZlZ
Straight Bore Cylinder And Slotted Type Piston
TIRE INFLATION PRESSURES (Note: Dimensions given are standard size.)
BIG TWIN - SOLO RIDER ONLY TOP

4.00" Tire - Front 14 1bs, Rear - 16 1bs.

5.00" Tire- Front 12 1bs., Rear- 14 1bs

SOLO - RIDER AND ONE PASSENGER Standard bore

dimension of
4.00" tire- Front 18 1bs., Rear 26 1bs. straight bore
5.00" tire- Front 12 1bs., Rear 16 1bs. cylinder for
slotted piston
SIDECAR - RIDER AND ONE SIDECAR PASSENGER OR 150 LB. SIDECAR LOAD 45" (1935 and later) Z.745"
74" ( 1935 and 19J6, and all 80") 3.4ZZ"
4.00" tire- Front 20 1bs., Rear 24 1bs., Sidecar 14 1bs.
74" Side Valve (1937 and later) 3.31Z5"
5.00" the - Front 14 1bs., Rear 16 1bs., Sidecar 14 lbs.
61" Overhead Valve (1936 and later) 3.31Z5"
74" Overhead Valve (1941 and later) 3.4375"
PACKAGE TRUCK- RIDER AND 150 1bs. TRUCK LOAD

4.00" tire- Front 22 1bs., Rear 30 1bs., Package Truck 16 lbs.

5.00" tire- Front 14 1bs., Rear 20 1bs., Package Truck 14 1bs.

45" MODEL - SOLOR RIDER ONLY

4.00" tire ,... Front 12 1bs., Rear 14 1bs.

5.00" tire ~ Front 12 1bs., Rear 12 1bs.

SOLO - RIDER AND ONE PASSENGER

4,00" tire ... Front 14 lbs., Rear 22 1bs.

5.00" tire - Front 12 1bs., Rear 14 lbs

The above tire inflation pressures are based on rider and passenger weight of approxi-
mately 150 lbs, each; Package Truck load 150 1bs.

When these loads are exceeded by 50 lbs or more, increase tire pressure as follows:
For each SO lbs of overload, increase pressure of rear tire, 2 lbs.; front tire, 1
lb.; sidecar or package truck tire, 1 lb.
0 Slotted piston should be fitted
.001" to .OOZ" clearance in
straight bore cylinder, check-
ing fit at bottom of skirt, front
to rear.

HARLEY-DAVIDSON MOTOR CO.

Milwaukee, Wisconsin
U.S.A.
 February 25, 1947 April 10, 1947
No. 255 No. 256
HARLEY-DAVIDSON FACTORY MECHANICS' SCHOOL REOPENS!
WIRING DIAGRAMS APPLYING TO 1947 MOTORCYCLES
Now we can make the announcement of the opening of the factory training school for
Harley-Davidson dealers and their mechanics. On Monday, March 17, 1947, the doors
will open on a new and completely modern classroom for the first three-week course
in a series that will last as long as the demand for mechanics' training exists.

A word about the school. Harley-Davidson has invested thousands of dollars in building
and furnishing a 2100 square foot, permanent Mechanics' School. No expense has been
spared in making this a strictly modern school for the instruction of Harley-Davidson
mechanics. All the very latest tool and service equipment has been installed.

Requests for attendance at the Mechanics' School are bound to be many. Selection of
students will be made in the following manner:
(a) All applicants considered must be authorized Harley-Davidson dealers, or
their mechanics who are occupied FULL TIME with the servicing of Harley-
Davidson motorcycles.
(b) All applicants must be approved by the Harley-Davidson traveling repre-
sentative for the territory.
(c) Enrollment will be determined on the basis of order in which applications
are received and how urgently the dealer is in need of aid to bring his
service up to approved standards.
...
Until such time as all dealers urgently in need of service aid have had the opportunity
to enroll themselves or a mechanic, only one enrollment per dealer will be accepted.
.
Wiring Diagram: Generator - Battery; Ignition· Horn· Generator
It is not advisable for a dealer to enroll a mechanic with very little or no experience and Oiling System Signal Lights and Stop Lam~- 1;47 Models
at all anticipating developing him into a full-fledged mechanic in the school. A man A. THREE WIRE CABLE-Green wire; red wire· black wire 14 TAIL AND
doesn't need to be a thoroughly experienced mechanic to be enrolled, but unless he has B. THREE WIRE CABLE--Green wire; red black wire; Wire: · (lZ). STOP LAMP-Red wire hom atop lamp switch
had enough practical experience to have a dealer's shop picture and knows something of C. THREE WIRE ?ABLE-Green. wire; red wire; black wire. 15. JUNCJ10N TERMINAL {in right aide of motor e
frame
the service problems, he will not hand on to enough information to make it worth while. D. LOOM (four wuea)-Black '!'ue ~th
red tracer; red wire ~der
saddle)-CabJe "A" red wire hom ~tchter-
"'!th yellow tracer; red wue Wlth black tracer; black mtnal { J ); red wire from battery positive terminal (9).
The school schedule is laid out for a three-week course, the first class to start on I. ;~CH TERMINAL-Cable "A" d . IT 19. HORN SWITCH-Loom "D"' black wire from hom (20).
March 17, and finish April 4th. The second class is scheduled to begin April 7th and terminal (15); cable "B"" red -w:e~ro';,"~ela~m(fa)C::=. 20
· ~r;'~'f ~D" bl~k wire from h""' switch (19);
minal marked '"BAT"). ac 'Wlle uom Junc:tion termmal (6}.
finish April 25th. The third class will being April 28th and finish May 16th. New 22· GENERATOR .C"SWITCH'") TERMINAL-Cable "B" green
2. SWITCH TERMINAL-Cable "B'"· een wire
classes, to be announced later, will be starting about every three weeks. Subjects erotor "awitc:h" terminal (22). gr from gen- wne from switch termmal (2).
covered include all phases of modern motorcycle service work on all Harley-Davidson 5. r:rCH TERMINAL-Black wire from junction terminal 23 · ~~~T?R C"RE!.AY"") TERMINAL-Green wire from
models. Shop equipment and efficient shop operation will also be gone into thoroughly.
Tuition is free - the only expense encountered in attending school will be transportation, 6. JUNCTION TERMINAL-Cable "C" black wire from horn 24. IGNITION-UGHT SWITCH (top view)-Switch t. OfT
(20); black wire from oil signal light (29); black wire when swttch lock cover hinge is directly forward. Tum
room, board and necessary personal expenses. from generator signal llght (28); hJacl: wire from switch to first ~ght position for ignition only. Switch is pto--
te~inal (5); cable ..A.. blac:l wire from c:oU front ter· Tided wtth lock and key to permit lochng if desired
Room and board or rooms only in sufficent number are not available near the factory, so mmal. when motorcycl~ .is nol in use. It can be Joci.ed in orf
arrangements have been made for room accomodations downtown at ''770 Marshall" Hotel, just 7. JUNCTION ~MINAJ.,.....Cable "B" blocl. 'Wire from relay and PARK positions only. When switch ta unlocked
(13); green WUe from generator signal light (28). and motorcycle is in use. key should be removed from
one and one-half blocks from the Chicago and Northwestern Depot. This is an apartme~t 9. BA11'ERY POSITIVE TERMINAL (left •lde)-Red wire lock.
hotel. Each apartment has one double and one single bed for accomodating up to three from junction terminal (15). 25. IGNITION CO~Je "A" block wiie from junction
men. Each apartment has a private bath. Applying only to those enrolled in our school, 10. B~TTERY NE~ATI.V£ TERMINAL (right aide)_ Black terminal. (6); green .wire _from stop lamp switch (12);
wtre from ground:termina1 on frame. black wue Oow tens1on wue) from circuit breaker (26).
those Stl,l0ents willing to put up three n;en in an apartment can get accomodations at $1.33
II. o.,.~aii'REI.~hStURE( _siGNAL SWITCH-Green wire from oil
per man, per day, or $9.31, per man, per week. Food costs will, of course, depend upon ".. 1 .. 291 26. IGNITION CIRCUIT BREAKI:R-Biack wire (low tension
wue) from cot! rear terminal.
where and how a man eats. A minimum estimate would be approximately $2.00 per day or 12. f[.~P~:::r~--~Ud ~~:,:::;~~and •top lamp 28. GENERATOR SIGNAL UGHT (marked "GEN"J-Biock
$14.00 per week, and this would have to be added to room cost. 13 RELAY-Cable ..B.. red wire from switch terminal (}) to ;:n~tr;:~~~~etic7}. terminal (6); green wire from junc-
f:Jay. lerm.inal ma:ked ""BAT..; cable ""B" black wire 29. 0~ PRESSlJ!U: SIGNAL UGHT (marked "'Oll."}-Green
··r:icr}·'!-~~~~n:J"fzJ)~ (7); green wire from generator wue _from. otl pressure signal switch (11); black. wire
from Junctton terminal (6}.
 r .
W.256 l- 0- l· Li PAGE 2 NO. 256
[_.
[.- !
L PAGE 3

r
.
.r -=-=~··-*"IIEO

Wiring Diagram: Lighting System and Horn - 1947 Models

~- THREE WIRE CABLE--Green wire; red wire; black wire. lamp bracket)-Cable "C" green wire from switch
.... THREE WIRE CABLE_:Green wire; red wire; black wire. terminal (2); loom "0" red wire with black tracer from
). LOOM (four wires)-Black wire with red tracer; red wire handlebar toggle switch (18).
with yellow tracer; red wire with black tracer; black 18. HANDLEBAR TOGGLE SWJTCH-Loom "D" black wire Wiring Diagram: Lighting System Accessory Lamps (does not
wire. with red tracer from headlamp large terminal screw;
1. SWITCH TERMINAL-Cable "A'' red wire from junction loom "D'' red wire with yellow tracer from headlamp apply to Police Pursuit Lamps)- 1947 Models
terminal ( 15); cable "C" red wire from junction terminal small terminal screw; loom "D" red wire with black
(30). tracer from junction terminal (17).
2. SWITCH TERMINAL-Cable "C" green wire from junc- 19. HORN SWITCH-Loom "D" black wire from horn (20). Note: With this method of wiring, when spotlamps are turned ON. headlamp is automatically turned OFF
tion terminal (17); green wire from speedometer light 20. HORN-Cable "C" black wire from junction terminal cmd vice-versa.
(8). (6); loom "D" black wire from hom switch (19).
3. SWITCH TERMINAL-Black. wire £rom mudguard lamp 21. HEADLAMP-Loom "D" black wire with red tracer from
(36). handlebar toggle switch (18) to large terminal screw; C. THREE WIRE CABLE-Green wire; red wire; black wire. lamp bracket)-Cable "E'. red wue from toggle switch
4. SWITCH TERMINAL-Cable "A" green wire from junc- loom "D" red wire with yellow tracer from handlebar (38); loom "D" red wire with black tracer.
tion terminal 06). toggle switch (18) to small terminal screw. Note: Head· D. LOOM (four wires)-Black wire with red tracer; red wire
lamp is shown in upside down position. w~th yellow tracer; red wire with black tracer; black 32. JUNCTION TErlMINAL (aide terminal-right side, in
6. JUNCTION TERMINAL-Cable "C" black wire -from headlamp bracket)-Biack wires from spotlamps (35)
horn (20:. 24. IGNITION-LIGHT SWJTCH (top view)--Switch is OFF and (37); cable "E" b1ack wire from toggle switch (38).
8. SPEEDOMETER LIGHT-Green wire from switch terminal when switch lock cover hinge is directly forward. Turn E. THREE WIRE CABLE (damped on outside of right
(2). left for parking lights-first right position tor ignition handlebar}-Green wire; red wire; black wire. 35. SPOTLAMP-Black wire from junction terminal (32).
only-second right position for ignition and running 36. MUDGUARD LAMP-Black wire from switch terminal
9. BATTERY POSITIVE TERMINAL (left side )-Red wire lights. Bear in mind that lighting headlamp when 2. SWITCH TERMINAL-Green wire from junction terminal
from junction terminal {l5). (3).
engine is dead also turns ignition ON. Switch is pro-- (39).
10. BATTERY NEGATIVE TERMINAL (right oide)- Black vided with lock and key to permit locking, if desired, 37. SPOTLAMP-Black wire from junction terminal (32).
wire from ground terminal on 1rame. 3. SWITCH TERMINAL-Black wire from mudguard lamp
when motorcycle is not in use. It can be locked in (36). 38. HANDLEBAR TOGGLE SWITCH (clamped to right barl
14. TAIL AND STO? LAMP-Black wire 1rom junction ter· OFF and PARK positions only. When switch is un· -Cable "E" red wire from junction terminal (31 ); cable
roinal (16). locked and motorcycle is in use, key should be re- 17. JUNCTION TERMINAL (hont !erminol-left side, in head· "E" green wire from junction terininal (17); cable "E"
15. JUNCfiON TERMINAL (in right side of motorcycle frame moved from lock. lamp bracket)-Cable "C'' green wire; cable "E" green block wire from junction terminal (32).
under saddle)-Cable "A" red wire from switch ter· 30. JUNCTION TERMINAL--(hont terminal-right side, in wire from handlebar toggle switch (38). Note: Loom
minal 0 ); red wire from battery positive terminal (9). "D" red wire ·with black tracer is connected to this 39. JUNCTION TERMINAL (in saddle bar-right side)-
headlamp brad:ef)-Cable "C" red wire from switch Green wire from switch terminal (2); bl~ck wires from
i6. JUNCTION TERMINAL (in left side of motorcycle frame terminal (1). This is a live terminal and can be used terminal lor Standard Equipment Lighting System, but
when installing spotlamps, it is disconnected from this saddle lamps (40) and (41)
under saddle)-Cable "A" green wire from swilch ter· for accessory lamps independent of ignilion·light switch.
mino:l (4); black wire hom tail and stop lamp 04). terminal and reco,,nected to junchon terminal (31). 40, SADDLE LAMP-Black wire from junction terminal {39).
36. MUDGUARD LAMP-Black wire from switch terminal
17. JUNCTION TERMINAL (hont terminal-leh side, in head· (3). 3l. JUNCTION TERMINAL (aide lerminal-lelt side, in head· 41. SADDLE LAMP-Black wire from junction terminal (39).
No. 260 July l, 1947 No. 260B July l, 1947

74 CU. IN. O.H.V. ENGINE FITTING SPECIFICATIONS (1941 TO AND INCLUDING 1947 MODELS) 74 AND 80 CU. IN. SIDE VALVE ENGINE FITTING SPECIFICATIONS (1937 AND LATER MODELS)
(NOTE: These supersed previous specifications dated June 6, 1941)
PISTON CLEARANCE - ALUMINUM PISTON -- Slotted, cam ground type - new piston fitted
in cylinder .001" to .002" clearance. Piston shapes to cylinder and acquires more PISTON CLEARANCE -- ALUMINUM PISTON - Slotted, cam ground type - New piston fitted in
clearance after short time in service. straight bore cylinder, .001" to .002" clearance. Piston shapes to cylinder and ac-
Measure piston at bottom of skirt, front to rear. quires more clearance after short time in service.
Measure cylinder about l/2u from top of bore, front to rear. Measure piston at bottom of skirt, front to rear.
PISTON PIN IN PISTON -- Light hand press fit. Measure cylinder about l/2" from top of bore, front to rear.

P~STON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose PISTON-CYLINDER HEAD CLEARANCE -- l/16" to 3/32" with piston at top center.

PISTON RING GAP AND GROOVE CLEARANCE -- .010" to .020" gap, l/2" from top of cylinder. PISTON PIN IN PISTON -- Lig~t hand press fit
Rings should be .004 11 loose in grooves.
PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose.
LOWER CONNeCTING ROD BEARING -- .001" to .0012" loose
PISTON RING GAP AND GROOVE CLEARANCE -- .010" to .020" gap, l/2" from top of cylinder.
CONNECTING RODS -- .006" to .010" end play between flywheels -- roller and retainer Rings should be .004" loose in grooves.
assembly should be narrower, but not more than .010" narrower than forked rod.
LOWER CONNECTING ROD BEARING -- .001" to .0012" loose.
SPROCKET SHAFT -- .0005" to .001" loose in roller bearing - .007" to .009" loose in
oil retaining bushing. CONNECTING RODS .006" to .010" clearance between flywheels - roller and retainer
assembly should be narrower, but not more than .010" narrower than forked rod.
PINION GEAR SHAFT -- .0008" to .0012" loose in roller bearing -- .0005" to .0012" loose
in cover bushing.· Oil slot in cover bushing is centered with drilled feed oil PINION GEAR SHAFT -- .0008'' to .0012" loose in roller bearing, and .0005" to .0012"
channel in cover. loose in cover bushing. Oil hole in cover bushing is 30 ahead of top center, and in
line (on opposite side) with drilled feed oil channel in cover .
FLYEHEEL ASSEMBLY . 012" to .014" end play in crank case.
SPROCKET SHAFT -- .0005" to .001" loose in roller bearing - .007" to .009" loose in
CAM GEAR -- .001" to .0015" loose in crank case and cover bushings . . . free to .005n end oil retaining bushing.
play.
FLYWHEEL ASSEMBLY -- .012" to .014" end play in crank case.
INTERMEDIATE GEARS -- .001" to .0015" loose on studs
CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .007"
TAPPET GUIDES .0005" to .001" press fit in crank case end play.
VALVE TAPPETS .0008" to .00175" loose in tappet guides INTERMEDIATE GEAR -- .001" to .0015" loose on stud.
ROCKER ARM FIT ON SHAFT ,0005" to .0015" loose - .007" to .016" end play TAPPET GUIDES .0005" to .001" press fit in crank case.
OIL PUMP DRIVE SHAFT-- .0008" to .0012" loose in crank case bushing VALVE TAPPETS .0005" to .001" loose in tappet guides
CRANK CASE BREATHER -- Timed with front cylinder - opens l/8" before top center to CRANK CASE BREATHER - Which is part of, and drives scavenger pump, is timed according
1/8" after top center, and closes 13/16'' to 1-5/16" after bottom center. to instructions in Riders Instruction Folder.
No. 260C July 1, 1947 No. 260D Jul./ 1, 1947
74 & 80 CU. IN. SIDE VALVE ENGINE FITTING SPECIFICATIONS
(1930 TO AND INCLUDING 1936 MODELS) 45 CU. IN. SIDE VALVE ENGINE FITTING SPECIFICATION (1937 AND LATER MODELS)
PISTON CLEARANCE -- IRON ALLOY PISTONS -- Used in 1930-34 engines fitted with taper bore EXCEPT WLDR AND WR MODELS
cylinders -- .004fl to .005 11 clearance.
ALl~INUM AND DOW METAL PISTONS -- Solid skirt type -- used in 1930-34 engines fitted with PISTON CLEARANCE -- ALUMINUM PISTON - Slooted, cam ground type - new piston fitted in
taper bore cylinders -- .016" to .018" clearance. straight bore cylinder, .001" to .002" clearance. Piston shapes to cylinder and ac-
ALUMINUM PISTON -- Slotted, cam ground type -- New piston fitted in straight bore cylinder; quires more clearance after short time in service.
.001" to .002" clearance. Piston shapes to cylinder and acquires more clearance after Measure piston at bottom of skirt, front to rear
short time in service.
When fitting oversize piston which has vertical slot in addition to horizontal slots,
Measure solid skirt piston just below the top group of rings. fit with vertical slot forward.
Measure slotted piston at bottom of skirt, front to rear. Measure cylinder about 1/2" from top of bore, front to rear.
Measure cylinder about 1/2" from top of bore, front to rear.
PISTON CYLINDER HEAD CLEARANCE -- l/16" to 3/32" with piston at top center
PISTON-CYLINDER HEAD CLEARANCE --All models except VC Commercial, 1/16" to 3/32"; VC
Conunercial, discontinued after 1933 7/64" to 9/64" - with piston at top center PISTON PIN IN PISTON-- Light hand press fit.
PISTON PIN IN IRON ALLOY PISTON -- .0005" to .001" press fit in lock pin side - plug or PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose
slip fit in opposite side.
PISTON PIN IN DOW METAL AND ALUMINUM PISTONS - Solid skirt type .0005" to .001" P"ess fit PISTON RING GAP AND GROOVE CLEARANCE - Straight bore cylinder - .010" to .020" gap,
in piston. l/2" from top of cylinder. Rings should be .004" loose in grooves.
PISTON PIN IN ALUMINUM PISTON-- Slotted type- light hand press fit. LOWER CONNECTING ROD BEARING-- .0007" to .001" loose.
PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose
CONNECTING RODS -- .006" to .010" end play between flywheels - roller and retainer
PISTON RING GAP AND GROOVE CLEARANCE - Taper bore cylinder, .006" gap, 1/2" from top of assembly should be narrower, but not more than .010" narrower than forked rod.
cylinder. Straight. bore cylinder, . 010" to . 020" gap, 1/2" from top of cylinder. Rings
should be .004' 1 loose in Dow metal and Aluminum piston grooves and just free in Iron PINION GEAR SHAFT - .0008" to .0012" loose in roller bea!Jing, and .0005" to .0012"
piston grooves. loose in cover bushing. Oil slot in cover bushing is 30 ahead of top center and
LOWER CONNECTING ROD BEARING -- .001" to .0012" loose in line (on opposite side) with drilled feed oil channel in cover.
CONNECTING RODS - .006" to .OJO" clearance between flywheels - roller and retainer assembly SPROCKET SHAFT - .0005" to .001" loose in roller bearing - .006" to .007" loose in
should be narrower~ but not more than .010" narrower than forked rod. oil retaining bushing.
PINION GEAR SHAFT - .0045" loose at inner end of bushing --.002" loose at outer end of
bushing. Bushing is taper reamed with special reamer. FLYWHEEL ASSEMBLY - .009" to .Oll" end play in crank case
SPROCKET SHAFT - .0005" to .001" loose in roller beadng - .006" to .007" loose in oil CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .007"
retair.ing bushing. end play.
FLYWHEEL ASSEMBLY - .006" to .010" end play in crank case.
INTERMEDIATE GEAR -- .001" to .0015" loose on stud.
CAM GEARS - .0005" to .001" loose in crank case and cover bushings - free to .005" end play
INTERMEDIATE GEAR- .001" to .0015" loose on stud. TAPPET GUJDES - .0005" to .001" press fit in crank case.
TAPPET GUIDES - .0005" to .001" press fit in crank case. VALVE TAPPETS -- .0005" to .001" loose in tappet guides
VALVE TAPPETS -- .0005" to .001" loose in tappet guides.
CRANK CASE BREATHER - Which is a part of, and drives scavenger pump, is timed ac-
cording to instructions in Riders Instruction Folder.
 No. 260G July 1, 1947
No. 260E July 1, 1947
TIMING SPECIFICATIONS
45 CU. IN. SIDE VALVE ENGINE FITTING SPECIFICATIONS
(1930 TO AND INCLUDING 1936) EXCEPT WLDR MODEL 74 & 80 CU. IN. SIDE VALVE ENGINE (1930 AND LATER MODELS EXCEPT 1930 AND 1931 V & VC)
PISTON CLEARANCE -- ALUMINUM AND DOW METAL PISTONS - Solid skirt type used in 1934 and INTAKE VALVE - OPENS when piston is 9/32" to 13/32" before top dead center
earlier engines fitted with taper bore cylinders - .014" to .016" clearance. CLOSES when piston is 7/8" to 1-1/8" after bottom dead center
ALUMINUM PISTON - Slotted, cam ground type - new piston fitted in straight bore cylinder,
. 001 1 ' to . 002 11 clearance. Piston shapes to cylinder and acquires more clearance after EXHAUST VALVE- OPENS when piston is 5/8" to 7/8" before bottom dead center
short time in service. CLOSES when piston is 1/4" to 3/8" after top dead center
Measure solid skirt piston just below the top group of rings. IGNITION -- OCCURS when piston is 5/16" to 11/32" before top dead center on compression
Measure slotted piston at bottom of skirt~ front to rear. stroke.
When fitting oversize piston which has vertical slot in addition to horizontal slots, fit 11/32" timing (Flywheel mark slightly forward of center of crank case inspection hole)
with vertical slot forward. applies to moderate compression engines in solo service. High compression solo engine
(8.2 heads) also all engines in sidecar service should be timed 5/16".
Measure cylinder about "l/2" from top of bore, front to rear.
PISTON-CYLINDER HEAD CLEARANCE -- 3/64" to 5/64" with piston at top center 74 CU. IN. SIDE VALVE ENGINE (1930 AND 1931 V AND VC MODELS)
PISTON PIN I!'l ALUMINUM AND DOW METAL PISTONS -- Solid skirt type - .0005" to .001" press INTAKE VALVE - OPENS when piston is 11/64" to 19/64" before top de.ad center
fit in piston CLOSES when piston is 9/16" to 13/16" after bottom dead center
PISTON PIN IN ALUMINUM PISTON -- Slotted type - light hand press fit. EXHAUST VALVE - OPENS when piston is 9/16" to 13/16" before bottom dead center
PISTON PIN IN UPPER END OF CONNECTING ROD -- .0008" to .0012" loose CLOSES when piston is 11/64" to 19/64" after top dead center
PISTON RING GAP AND GROOVE CLEARANCE - Taper bore cylinder, .006" gap, 1/2" from top of IGNITION - OCCURS when piston is 1/4" to 5/16" before top dead center on compression
cylinder. Straight bore cylinder, .010" to .020" gap, 1/2" from top of cylinder. Rings stroke.
should be .004" loose in grooves.
LOWER CONNECTING ROD BEARING -- .0007" to .001" loose 61 CU. IN, OHV ENGINE (1936 AND LATER MODELS)
CONNECTING RODS--.006" to .010" end play between flywheels - roller and retainer assembly INTAKE VALVE ~ OPENS when piston is 19/64" to 25/64" before top dead center
should be narrower, but not more than .010" narrower than forked rod. CLOSES wehn piston is 29/32" to 1-3/32" after bottom dead center
PINION GEAR SHAFT -- .0045" loose at inner end of bushing - .002" at outer end of bushing. EXHAUST VALVE - OPENS when piston is 23/32" to 29/32" before bottom dead center
Bushing is taper reamed with special reamer. CLOSES when piston is 19/64" to 25/64" after top dead center
SPROCKET SHAFT -- .0005" to .001" loose in roller bearing - .006" to .007" loose in oil
retaining bushing. IGNITION- OCCURS when piston is 7/16" before top dead center on compression stroke.
FLYWHEEL ASSEMBLY - .004" to .008" end play in crank case. 74 CU. IN. O.H.V. ENGINE (1941 AND LATER MODELS)
CAM GEARS -- .0005" to .001" loose in crank case and cover bushings - free to .005" end INTAKE VALVE - OPENS when piston is 23/64" to 29/64" before top dead center
play. CLOSES when piston is 1-1/64" to 1-13/64" after bottom dead center
GENERATOR DRIVE GEARS AND SHAFT (1931 and earlier models) -- Shaft must be free running fit;
have .002" to 004" end play, and .001" to .0015" clearance in bearings. Small bevel gear EXHAUST VALVE - OPENS WHEN PISTON IS 13/16" to 1" before bottom dead center
should be .002" to .003" loose in bushing assembly, and shinuned to allow .002" to .004" CLOSES when piston is 23/64" to 29/64" after top dead center
clearance between bevel gears.
IGNITION- OCCURS when piston is 7/16" before top dead center on compression stroke .
TAPPET GUIDES . 0005" to .001" press fit in crank case
45 CU. IN. SIDE VALVE ENGINE (ALL MODELS EXCEPT WLDR & WR)
VALVE TAPPETS .0005" to .001" loose in tappet guides.
INTAKE VALVE- OPENS when piston is 5/32" to 7/32" before top dead center
CLOSES when piston is 37/64" to 45/64" after bottom dead center
No. 260G -2- July 1, 1947

EXHAUST VALVE- OPENS when piston is 37/64" to 45/64" before bottom dead center
CLOSES when piston is 5/32" to 7/32" after top dead center
IGNITION - OCCURS when piston is 1/4" to 9/32" before top dead center on compression
stroke.

30.50 CU. IN. SIDE VALVE SINGLE ENGINE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 5/16" to 9/16" before top dead center
CLOSES when piston is 11/16" to 15/16" after bottom dead center
EXHAUST VALVE - OPENS when piston is 1/2" to 3/4" before bottom dead center
CLOSES when piston is 1/4" to 1/2" after top dead center
IGNITION - OCCURS when piston is 1/4" to 5/16" before top dead center on compression
3troke.

21 CU. IN SIDE VALVE SINGLE ENGINE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 1/8" to 3/16" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center
EXHAUST VALVE- OPENS when piston is 7/16" to 9/16" before bottom dead center
. CLOSES when piston is 1/8" to 3/16" after top dead center
IGNITION- OCCURS when piston is 7/32" to 9/32" before top dead center on compression
stroke.

21 CU. IN O.H.V. SINGLE ENGINE (ALL MODELS)

INTAKE VALVE - OPENS when piston is 3/32" to 5/32" before top dead center
CLOSES when piston is 7/16" to 9/16" after bottom dead center

EXHAUST VALVE- OPENS when piston is 7/16" to 9/16" before bottom dead center
CLOSES when piston is 3/32" to 5/32" after top dead center
IGNITION - OCCURS WHEN piston is 11/32" to 13/32" before top dead center on compression
stroke.
TAPPET CLEARANCES
45" AND SINGLE SIDE VALVE ENGINES -- INTAKE - .004" to .005"
EXHAUST - .006" to .007"
74" & 80" SIDE VALVE ENGINES -- INTAKE - .004" to .005"
EXHAUST - .007" to .008"
O.H.V. SINGLE ENGINE-- INTAKE AND EXHAUST- .002" to .003"
O.H.V. TWIN ENGINE -- INTAKE AND EXHAUST - Correctly adjusted when tappet has just
noticeable play or shake, and can be turned freely with finger tips, completely around,
without any trace of bind.
NOTE: ALL SIDE VALVE ENGINES AND O.H.V. SINGLE ENGINE -When checking valve timing
according to piston position, first make sure tappets are adjusted to the correct
clearance as given above.
O.H.V. TWIN ENGINE -When checking valve timing according to piston position, first ad-
just all valve tappets temporarily to .004 11 clearance. Turn engine in direction it runs
until valve being checked is open .001" before measuring piston position. After timing
has been checked valve tappets must be readjusted to the correct clearance as given
above.
CIRCUIT BREAKER OPENING
ALL MODELS -- .022"
 No. 263 Page 2
There are two principal parts of the hydraulic unit. These
are the plunger #3 and the cylinder #7. The plunger con-
tains the check valve assembly, which is held in position
by the plunger spring #6. It is recommended that only one
unit at a time be taken apart for service and that it be
reassembled before working on another un~t, as plunger and
cylinder are selectively fitted by manufacturer to clear-
No. 263 November 21, 1947 ance required to allow definite leakage rate between plunger
SERVICE INFORMATION ON HYDRAULIC TYPE PUSH RODS ON 1948 OVERHEAD VALVE ENGINES and cylinder. Plunger or cylinder of one unit MUST NOT BE
INTERCHANGED with plunger or cylinder of another unit.
PUSH RODS AND VALVE TAPPETS (RIDER INFORMATION) ·--o As the hydraulic unit cylinder is a press fit into push rod,
·~
Push rods are self-adjusting, hydraulic type. They automatically adjust their length it will be necessary to service unit without removing from
to compensate for hot engine expansion and valve mechanism wear, and thus keep the valve push rod. Where a complete unit must be replaced, cylinder
mechanism free of lash when engine is running. Tappet adjustment is required only in new
engine assembly, and when engine is reassembled after reapir, to compress the push rod
hydraulic units to the length specified for normal functioning.
'--8 can be forced out of push rod and new unit pressed or diven
in.
In disassembling hydraulic unit, first remove snap ring #1,
On starting an @ngine, which has been shut off even for a few minutes, the valve mechanism which is located at top of cylinder; 'then remove plunger
may tend to be slightly noisy till the hydraulic push rods completely refill with oil. from cylinder. In case plunger does not pull out of cylinder
If at any time, other than a short period immediately after engine is started, valve mech- easily, grip top of plunger with pair of pliers wrapped with
anism becomes abnormally noisy, it is an indication that one or more of the hydraulic push tape and pull with twisting motion.
rod units may not be functioning properly. Always check lubricating oil supply in oil
tank first, if the valve mechanism becomes noisy, since normal circulation of oil through During the disassembly operation, it is advisable to hold
engine is necessary for proper operation of hydraulic units. If there is oil in tank, the hydraulic unit over pan of clean solvent in which parts
the push rod units may not be function properly due to contamination in oil supply Drive are to be washed, or at least over a bench, so check valve
at moderate speed to nearest Harley-Davidson dealer for further attention. parts will not become lost. After removing plunger, dis-
assemble check valve parts 4 and 5 and wash all thoroughly.
ADJUSTING TAPPETS OF 1948 OVERHEAD VALVE ENGINES (MECHANIC INFORMATION)
fter parts have been thoroughly washed, test hydraulic unjt

~
Engine must be cold. o detemine if check valve is holding, and also whether
Remove push rod cover keepers and telescope covers to expose tappets eakage past plunger is still normal. Thic can be done as
follows: (DO NOT OIL ANY PARTS WHEN MAKING THIS TEST)
Before readjusting a tappet, make sure it is at its lowest position. You can make sure PUSH ROD
of this by turning engine in direction in which it runs until the like tappet (intake or HYDRAULIC UNIT Assemble ball 4, retainer 5 and spring 6 back into plunger
exhaust) in the other cylinder is at its highest position (Valve fully open). then, holding plunger in upside-down position so ball falls
1. Plunger retaining
into its seat, start cylinder onto plunger. Quickly push
loosen tappet adjusting screw lock nut and turn tappet screw down until push rod is free cylinder down over plunger and immediately releast it. If
and has noticeable shake. When checking for push rod shake, grasp push rod with finger snap ring
unit is in good order and check valve is holding, cylinder
tips just below cylinder head, and shake toward front and rear of engine. should bounce back.
Slowly turn tappet screw upward just far enough to take up all push rod shake. Now, mark
z. Oil inlet hole
If when cylinder is quickly pushed down and immediately re-
tappet screw with chalk or some other manner, so its turns can be accurately counted, and 3. Plunger leased, it stays down, either the check valve is leaking, or
then continue turning it upward exactly three full additional turns. cylinder and plunger are worn to extent there is excessive
Adjust the other three tappets the same way. 4. Ball check-valve leakage past plunger. In order to determine whether check
valve is leaking, place finger over hole 2 at end of plunger
With tappets accurately adjusted, according to above, hydraulic units will be compressed 5. Ball retainer and repeat the test operation. If cylinder now bounces back
3/32" which is the specified setting for normal functioning. as it should, it is an indication that check valve is leaking
If after readjusting tappets, engine does not start readily because of loss of compression 6. Plunger spring possibly due to parts still being dirty. Rewash parts
in one or both cylinders, allow engine to stand a few minutes before further attempt to thoroughly and repeat test operation. If cylinder still does
start. This standing time is required to allow the newly adjusted hydraulic units time 7. Cylinder not bounce back, the complete hydraulic unit should be re-
to leak-down until valves are fully seated. placed with a new one.
Bear in mind that after initial tappet adjustment as described above, hydraulic type push If above described test shows unit functioning normally,
rods are self-adjusting to compensate for hot engine expansion and valve mechanism wear. complete reassembly by installing snap ring l making sure
Therefore, tappet adjustment is normally required only in new engine assembly and when it seats in its groove near top of cylinder.
engine is reassembled after having been taken apart for repair. If a serviced push rod is to be used immediately, it is not necessary to re-oil the hydraulic
SERVICING HYDRAULIC PUSH ROD (DEALER AND MECHANIC INFORMATION) unit before assembling push rod in engine. The engine oiling system will re-oil the unit as
soon as engine is started. After reassembling push rod in engine, be sure tappet is ~ccurately
Servicing push rod consists only of removing it from engine, disassembling hydraulic unit, readjusted according to tappet adjusting instructions in this bulletin. A newly serv1ce~
washing the parts thoroughly, and reassembling. hydraulic may be noisy for several minutes after engine is started, as some time is requ1red
to work out all the air and fill unit with oil.
 No. 268 February 24, 1948
No. 267 February 19, 1948
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 No. 278 October 14, 1948
SERVICING 1948 OVERHEAD VALVE ENGINES FOR BEST OIL CONTROL
No. 271 March 25, 1948
Anything above 250 miles per quart of oil is considered normal oil mileage. Where oil
mileage may be reported considerably below 250 miles per quart don't jump to the conclusion
that piston rings or cylinder bores or both are in bad order. There are other reasons for
abnormal oil consumption.
GREASE 125 MODEL WHEEL HUB BEARINGS
Before taking any action get a complete case history. If the report claims heavy exhaust
smoke and possibly repeated plug fouling, and your observations and tests confirm this,
In factocy assembly the wheel hub bearings of 125 model motorcycles there is no futher question but what, excessive oil is passing through one or both com-
below No. 48S2800 were only lightly greased. Because of insufficient bustion chambers, and an engine top end job will have to be done to determine why. If
grease to adequately lubricate bearings and protect them from moisture there is no evidence of heavy exhaust smoke of plug fouling, but you confirm the report
entering hubs, a number of bearings have been found unduly worn and of oil mileage below normal, it may be due to one or more of the conditions described
badly rusted. below, in which case engine probably will not need to be opened up for internal inspection.

Starting with No. 48S2800 wheel bearings (not wheel hubs) have been Maybe front chain oiler is adjusted to feed an excessive amount of oil, and possibly motor-
packed full of grease. cycle has been equipped with a rear chain oiler as supplied by various accessory producers.
A combination like this, set for heavy feed, can account for as much as 50% of oil used.
Avoid trouble with bearing failures by immediately regressing the Possibly oil pump check valve ball is-not seating perfectly, and oil is being lost to the
wheel hub bearings of all 125's below 48S2800. Use Harley-Davidson outside through breather when motorcycle is standing for any length of time. Possibly
or other equally good wheel bearing grease, and pack bearings full. considerable oil is being waster due to a leak somewhere about engine as a result of a
sandhole in one of the castings, a broken or damaged gasket or push rod cover seal, or
loosened fittings.

HARLEY-DAVIDSON MOTOR CO. Where investigation proves that low oil mileage is due to excessive amount of oil passing
through combusion chambers and out with exhuast, proceed as follows with upper end job;
Milwaukee 1, Wis., U.S.A.
1. When removing cylinder heads, carefully inspect head gaskets around the holes that
match oil passages that feed oil to overhead fittings, and drain back the discharged oil.
If you find a break or furrow between one of these holes and the inside diameter of gasket,
this alone is enough to account for excessive oil consumption, plug fouling, and heavy
exhaust smoke. Unless gaskets are in perfect condition and form a perfect seal around
these holes, the combustion chamber of cylinder involved will be flooded with oil. Also
examine cylinder head joint face around these holes. If the joint face between one of
these holes and combustion chamber has been nicked or deeply scratched, the result will
be the same as with gasket damaged as described above.

Also examine cylinder base gaskets as cylinders are removed. Observe whether or not gas-
kets are in good order around the hole punched for oil passage up the right side of cy-
linders. A break in base gasket from this hole inward is likely to result in the oiling
system running lower than normal pressure and an over supply of oil in crankcase.

2. Remove cylinder head covers and make close inspection of rocker arms. Observe parti-
cularly that welch plugs (one in each end or arm) are securely in place. If an arm is
found with welch plug out, be sure to find the plug. as it may be lodged somewhere in the
oil return channel down the left side of head and cylinder. Unless found and removed. it
will probably eventually shift into a position where it completely blocks the return chanc
nel. In this case, the cylinder head will be flooded with oil, and the job of removing
cylinder will have to done over in order to remove obstruction. Where a welch plug has
come out of place, it can be re-installed by soldering or brazing. A welch plug that
appears to be even slightly loose should be treated in the same manner; as a missing or
 No. 278 -3- October 14, 1948
NL). 278 -2- IJctober 14, 1948

5. The new piston ring combination to be used on each piston is two No. 2b5-3B c0mpres~ion
badly leaking \Velclt plug will drop overhead oil pressure so low, especially when oil is rings for the 61 OHV or two 265-41 compression rings for the 74 OHV. A new type vent"J
hot, that pushrod hydraulic units will become noisy. (Latest rocker arms which went into oil ring is to be used for the 61 OHV, part No. 22374-49 or part no. 22364-49 for later
new assembly near the end of the 1948 season have no welch plugs. Only one end of the 1948 74 OHV. Since the new type oil ring is 3/16" wide it cannot be used on the earlier
arm require~ plug~ing, and a solid, drive fit plug is installed. Only rocker arms of l948"'74"0HV piston, because that piston had an oil ring groove only 1/8" wide. Later 1948
this construction are now supplied on parts order.) 74" OHV pistons have oil ring groove 3/16" wide. This change went into production with
engine No. 48FL 10184. When servicing an early 1948 74 OHV equipped with pistons with
Also inspect rocker arms for loosened or broken pushrod ball socket. A ball socket in l/8" oil ring groove, which are still in condition for further use, use vented oil ring
bad order may also bleed away enough oil so pushrod hydraulic units do not get the oil 266-41A which is 1/8" wide. All the piston ring numbers above cover standard size rings.
required for normal quietness of operation. (The pushrod ball socket has been so changed In the future when pistons or rings are ordered, covering pistons and rings for 1948 OHV
and strengthened that there will probably be litted if any breakage in the future. models, instead of furnishing four rings, all alike, per piston, the new combination of
two compression rings ~nd one 3/16" wide vented oil ring per piston will be furnished.
The next step is checking cylinder heads for possible oil leak from top of head into
the intake port. There is considerable oil discharged from overhead fittings onto top of For sometime the 3/32" wide compression rings furnished for 1948 overhead engines (also
head, and if there is a leak through the head into the intake port, due to a loose valve apply to earlier than 1948 74 OHV) have been bevel backed rings. One side of ring has
guide or sand hole, some of this oil will be sucked through into inlet port and combustion inner edge beveled. This side of ring is or should be marked "TOP". This type of ring
chamber. Enough will be sucked through .to cause plug fouling, heavy exhaust smoke, and must be installed in piston with beveled edge upward, whether or not that side is marked
to drop oil mileage way below normal. In other words, the result will be the same as if TOP". If installed with beveled edge down, this type of ring becomes an oil pumper.
rings and cylinder bores were in bad order. This check should be made by applying air
pressure to intake port and at the same time applying gasoline or solvent to top of head 6. The next step is to conver the oil pump as follows: It is not necessary to remove
around valve gu1de and the surrounding area above inlet port. If there is a leak around complete oil pump from engine in order to make these changes. Remove pump cover and gover-
valve guide or elsewhere it will be indicated by bubbles. Even the slightest leak found nOr rotor, and also remove cover plate. Discard governor rotor and cover plate. Install
must be corrected. If there should be a leak around inlet valve guide, due simply to new cover plate 683-49. You will note that new cover plate blocks off the holes in pump
guide fitting loosely in head, it probably can be serviced satisfactorily with an over- body and cover that formerly passed oil to and from governor. (If new cover plate is not
size guide. If, however, it is found that guide hole in head is out of round, there is available when it is desired to make this pump change, use original plate after securely
no satisfactory repair. When a new oversize guide is installed to replace one found with plugging these holes.) After plate and gasket are installed, replace pump cover. Remove
a leak by it, repeat the air test after new guide is installed, even though it does seem and discard· pump check valve spring 703-48 and replace it with check valve spring 703-36,
to drive in with a normally tight fit. If hole in head is out of round, guide may drive which is a much ligh~er spring. 703-36 is the same check valve spring used in 1947 and
in ti~ht, but still have a leak by it. A sand hole through head into intake port can earlier oil pumps. With the above changeds made in oil pump, oil pressure builds up much
usually be repaired with low temperature welding material. faster from low speed, and considerable more oil is circulated through engine while idling
and operating in the low speed range. This explains the ring change from a moderate to
A set of fittings with which a dealer can make a quick air pressure check for inlet port a venter oil control ring.
leaKage is in the making, but not yet available. As soon as these fittings are available,
you will be advised. In the meantime you can devise a temporary means of making this 7. When servicing an engine as above, if piston rings were found badly worn and scuffed,
check. All you need is a plug or cork of a size to fit cylinder head inlet nipple. The and cylinder walls scratched and scuffed, don't fail to thoroughly flush out engine base,
plug must have a small pipe installed through it, so air pressure can be applied. \Vith timing gear case, and oil tank before reassembling and putting engine back in service.
inlet valve assembled and plug pushed tight into inlet nipple, apply air pressure and at Where these is undue piston and cylinder wear, engine oil becomes contaminated with fine
the same time apply gasoline or solvent to top of head around valve guide. The exhaust particles of metal. Unless a newly serviced engine is put back in use with clean, fresh
valve guide should also be tight in head. However, i f there happened to be a minor leak oil, free of metal particles and other contamination, undue wear is again likely to be
by it, there would be little if any effect on oil consumption. • experienced, Even an engine that appears clean, and with little i f any ring and cylinder
bore wear, should at least have the oil tank drained, flushed and refilled with fresh oil
4. Next check cylinder bores and pistons for size and condition. If it is found that before putting back in use.
cylinder bores are not enlarged enough, due to wear, to require refinishing oversize, make
another extremely close inspection of the bore of each cylinder to be sure that the ring 8. When reassembling cylinders and heads, apply gasket sealer to all gaskets. If the
path is smooth and polished as it should be, with only minor up and down scratches where head cover gaskets you have available are only 1/32" thick, use two per head, if approxi-
the piston thrust faces take hearing against cylinder bore. If the ring path in one or mately 3/64" thick use only one gasket. Only the later 3/64" thick cover gasket is now
both cylinders has dull, lapped appearance, this indicates there are probably a multitude used in new production and supplied on parts orders.
of fine scratches the length of ring path, all around the bore, as a result of ring scuf-
fing. lf this condition exists, bore should be refinished oversize. Simply re-ringing a 9. Install spark plugs with latest 7 /8" outside diamter plug gasket, especially i f there
scratched bore, even though a the new ring set includes the most effective type of oil has been seepage of oil between cylinder head and spark plug insert. The new larger
ring, is not likely to effect a satisfactory oil seal. Bear in mind that there is a dif- gasket will seal any leakage at this point as it is large enough to overlap the insert
ference between scored cylinder bores and scratched bores. Scoring, which results from and seal against head surface.
high speed or overheated operation, is damage that can't be overlooked and leaves no
choice about refinishing. Bore scratching to the extent .of excessive oil passing, even If you still have some new 1948 OHV motorcycles in stock, make the above described oil
with new rings, is not so readily observed. Take no chances on cylinder bore condition. pump converstion before delivering. These engines are fitted with the four rings per pis-
Unless the bore is unquestionably smooth and shiny, except for minor streaks or scratches ton combination applying to all late 1948 overheads. However, it will be o.k. to make the
where piston takes bearing against cylinder bore, refinish. pump change without going into engines to fit the later vented oil ring. It is also per-
missible in the case of any 1948 OHV engine that is running normal or above normal oil
mileage to convert oil pump.
No. 287 April 15, 1949 No. 291 October 20, 1949
NEW HANDLEBAR REINFORCING LINK VENTED FORK CAP SCREWS FOR HYDRA-GLIDE FORKS
Since about the middle of May, 1949, all Hydra-Glide Harley-Davidsons have had vented
fork cap screws to relieve air pressure which, in earlier unvented forks, sometimes
All Hydra-Glide OHV model motor- caused oil leakage past the fork slider seals.
cycles with rubber-mounted handle-
bars shipped on and after April 7, It has been decided to supply fork vents for all Hydra-Glides that left the factory with
1949 are fitted with a new metal forks not vented. The service vent being furnished idffers somewhat from the production
(chrome plated) handlebar reinforc- type vent, although they both work on the same principle. Both types of vents incorporate
ing link. Does not apply to Hydra- a natural rubber valve that allows air to escape, but no air to enter forks. The service
Glide models with solid -mounted type vents can be installed without disassembling fork further than simply removing
handlebars. original cap screws. (Forks already fitted with production type vents can be distinguished
from others by a 3/32" air escape hole leading from one face of hexagaon headed fork cap
We consider it advisable to install screws to center of screw.)
this link on all 1949 OHV Hydra "Clide
motorcycles with rubber mounted These fork vents are being supplied without charge, Since the job of installing the vents
handlebars that were shipped without is a minor one, you should install them in the motorcycles for which they are intended
it. This applies to all such motor- promptly and without charge to the owners. Getting these vents installed without delay
cycles that you have delivered as will put an end to complaints about foPk oil leakage. Although a fork may be leaking oil
well as to any you might still have at the top of slider at the time vented cap screws are installed, it ordinarily is not
in stock. necessary to renew or give any attention to slider seals. Simply installing vented cap
screws stops the leak.
Prompt action is suggested Parts
needed will be supplied on no charge CAUTION: Be sure to follow instruction of installation carefuuly. After draining oil from
terms. Just tell us on enclosed post fork sides, measure closely the quantity of oil put back in - Don't overfill - use only
card how many sets of parts you Harley-Davidson fork oil. Extreme care must be used in handling rubber valves to be sure
need for motorcycles you have sold they are not punctured. If they are damaged, they cannot perform their intended function
and whrch are still serviced by you. of allowing air to escape without permitting air to enter forks.
Required parts will be sent just as
soon as possible. Don't put off re- After fork, fitted with standard solo springs and originally unvented, has had vents in-
turning the card with full informa- stalled and air pressure no longer builds up, the fork will be noticeably softer, and will
tion - Do it today! "bottom" more readily, on rough roads and when front brake is applied. If after fork
venting, futher useage of motorcycle proves forks are too soft, spring spacer can be
installed underneath each spring, or heavy duty springs can be installed. Unless a motor-
cycle carries an extremely heavy load, installing spring spacers underneath original solo
springs usually effect the best riding combination. New motorcycle forks assembled with
standard solo springs have included this same spacer for some time.
INSTALLATION INSTRUCTIONS
It will be noted that spring spacer has one end counterbored and other end shouldered.
Replace original 4 riser cap screws with the 4 double-end studs furnished, long It is to be assembled underneath springs with shouldered end upward.
end downward. Tighten securely. Place link over upper ends of studs, install and
tighten acorn nuts. How to distinguish between standard and heavy duty fork springs:
STANDARD SPRING - WIRE SIZE 3/16"
HARLEY-DAVIDSON MOTOR CO. HEAVY DUTY SPRING - WIRE SIZE .200" (APPROX. 13/64")
MILWAUKEE 1, W!S., U.S.A. STANDARD SPRING IS LONGER THAN HEAVY DUTY SPRING

~OTE: This b1.llletin being sent to direct dealers only. Be sure to include rnotor-
.::yr:les sold by associate dealers when orderi.ng reinforcing links needed.
No. 292 November 15, 1949 NO. 294 NOVEMBF..R 30, 1949
125 MODEL FITTING SPECIFICATIONS 1949-1950 WIRING DIAGRAM FOR 61 AND 74
PISTON CLEARANCE - ALUMINUt~ PISTON - Taper ground - new piston fitted in cylinder .003" to HYDP~GLIDE MODELS
.004" clearance, measuring piston at extreme bottom of skirt and cylinder 1/2" from top of
bore. front to rear. Before installing cylinder, locate piston rings so ends register with
R• R•o R-B•Rac wtT>< B~.AocK 'JlitAci:Jt.
retaining pins in ring grooves. • lit N R• !h...&.C'K W!TW ~ACe"
B • B\..AC.K R.Y• Ftto WtT"W Yci.LOwT!ItACU
PISTON PIN IN PISTON -.0003"tight at room temperature. Apply a thin coat of engine oil on Y• YaLLow
piston pin. Heat piston just enough so pin can be pushed into piston bosses by hand and
install piston with arrow stamped on head pointing to front.
PISTON PIN IN UPPER END OF CONNECTING ROO - .0008" to .0012" loose
PISTON RING GAP AND GROOVE CLEARANCE - .012" to .020" gap, 1/2" from top of cylinder. Rings
should be .004" loose in grooves.
LOWER CONNECTING ROD BEARING - .0008" to .001" loose. Apply thin coat of engine oil on
rollers.
CONNECT! NG ROD - . 011" to . 01"7" endp 1ay between fl ywhee 1s.
FLYWHEEL ASSEMBLY - Bearing fit on sprocket shaft and armature shaft- size to size to
light press fit.
In order to disassembly and reassemble flywheels the set of Flywheel/Connect-
ing Rod Assembly Tools is necessary. Sprocket shaft, armature shaft and
crank pin are press fit in flywheels (apply thin coat of engine oil to shafts
and crank pin before pressing them into wheels). The sprocket shaft and
armature shaft must be pressed into wheels to correct depth and armature shaft
must be located in flywheel so keyway in shaft in in correct relation to crank
pin for ignition timing after armature and circuit breaker cam have been in-
stalled. Above tools serve this purpose and maintain close alignment of shafts
v1hen reassembling wheels. Sprocket shaft and armature shaft must run true
within .001" with flywheel assembly installed in flywheel truing device.
CRANKCASE ASSEMBLY -Good crankcase compression is essential to proper function of the 125
engine Scrape all gasket cement or sealer from crankcase joint faces, clean faces and
then before installi.ng flywheels in crankcase apply thin coat of gasket cement or sealer
to crankcase joint face- also apply thin coat of engine oil to all bearings -DO NOT POUR
ANY OIL INTO FLYWHEEL COMPARTMENT. Apply thin coat of gasket cement to all gasketed sur-
faces. Bearing fit in crankcase size to size to light press fit.
GENERATOR ARMATURE AND CIRCUIT BREAKER CAM - After armature has been installed and tightened
commutator run-out must not exceed .002". Circuit breaker cam runout must not exceed .003"
checking at concentric section of cam next to commutator. Check with d·ial indicator.
CIRCUIT BREAKER POINT GAP - .020"
SPARK PLUG GAP - .025" to .030"
IGNITION TIMING - Time so ignition occurs when piston is 7/32" before top dead center.
TRANSMISSION BEARING - Bearing fit on mainshaft - size to size to light press fit. Bearing
fit in transmission case size to size to light press fit . .Countershaft in countershaft
bushings .0005" to .0015" loose. Before reassembling apply a thin coat of engine oil to
all bearings, gears and shafts. After engine and transmission have been completely re-
assembled POUR 20 OZ. HARLEY-DAVIDON "MEDIUM HEAVY" OIL INTO CLUTCH COMPARTMENT before
putting in service.
 No. 294 WIRING DIAGRAM KEY ll/30/49 No. 294 -3- 11/30/49
A. FOUR WIRE CABLE - Red, green, black and yellow wires from switch and instrument 18. HANDLEBAR HEAD LAMP SWITCH-Black wire with red tracer through cable D to terminal
panel base, terminals #1, 4, 6 and 7. Right front cable in panel base to terminal 21; red wire with yellow tracer through cableD to terminal 22; red wire with black
box behind ignition coil. tracer through cable D to terminal 9.
B. THREE WIRE CABLE - Red, green and black wires from switch and instrument panel base 19. HORN SWITCH - Black wire to terminal 25.
terminals #l, 2 and 44. Left cable in panel base to generator and cut-out relay.
20. TERMINAL-Yellow wire through cable C to switch terminal 3. Used only with parking
C. FOUR WIRE CABLE - Red, green, yell ow and black w.i res from switch and instrument panel
base terminals #1, 2, 3 and 6. Right rear cable in panel base to terminal plate on lamps.
fork. 21. TERMINAL-Black wire with red tracer through cableD to headlamp switch 18; black wire
D. THREE WIRE CABLE - Red wire with black tracer; Black wire with red tracer and Red through loom H to headlamp 31.
wire with yellow tracer from headlamp switch on handlebar to terminal plate terminals 22. TERMINAL - Red 1vire with yellow tracer through cableD to headlamp switch 18; red
#9, 21 and 22. Black wire with white tracer from horn switch to terminal plate termi- wire through loom H to headlamp 31.
nal #25. 23. TERMINAL-Not used with standard wiring.
E. THO WIRE CABLE - Red and green wires from terminal plate terminals 24 & 25 to horn. 24. TERMINAL - Black wire through cable C to junction terminal 6; .red wire through cable
F. THREE inRE CABLE - Black, green & red wires from terminal box, terminals 41, 42 and E to horn 30.
43 oil pressure switch and stop lamp switch. 25. TERMINAL- Green wire through cable E to horn 30; black wire to. horn switch.
G. LOOM - (three wires)-Red, green & red wires from terminal box terminals 39, 40 & 43. 26. IGNITION CIRCUIT BREAKER- Black wire to coil 35 rear terminal.
H. LOOM - (Two wires)- Black & red wires from terminal plate terminals 21 & 22 to headlamp. 27. STOP LAMP SWITCH- Red wire through cable F to terminal 43; black wire through cable
J. LOOM - (two wires)-Red & green 1vires, continuation from 3 wire loom(G) to tail lamp. F to terminal 41.
28. GENERATOR SIGNAL LIGHT (GEN) Black wire (under panel base)to junction terminal 6;
l. SWITCH TERMINAL-Red wire through cable A to terminal 39; red wire through cable A to green wire (under panel base) to junction terminal 44.
relay 13; red wire through cable C to terminal 10.
29. OIL PRESSURE SIGNAL LIGHT(OIL)-Black wire(under panel base) to junction terminal 6;
2. SWITCH TERMINAL-Green wire through cable C to terminal 9; green wire through cable B green wire(under panel base) to junction terminal 7.
to generator switch terminal 32; green wire to speedometer light 8.
30. HORN-Red wire through cable E to terminal 24; green wire through cable E to terminal 25.
3. SWITCH TERMINAL - Yellow w·ire through cable C to terminal 20.
31. HEADLAMP-Red wire through loom H to terminal 22; black wire through loom H to terminal
4. SWITCH TERMINAL - Green wire through cable A to terminal 40
21.
5. SWITCH TERMINAL - Black wire to junction terminal 6. 32. GENERATOR SWITCH TERMINAL-Green wire through cable B to switch terminal 2.
6. JUNCTION TERMINAL-Black wire through cable C to terminal 24; black wire to oil press- 33. GENERATOR RELAY TERMINAL-Green wire through cable B to relay 13.
ure signal light 29; black wire to generator light 28; black wire to switch terminal
5; black wire through cable A to terminal 41. 34. IGNITION-LIGHT SWITCH(Top view) Switch position for off, ignition only, ignition and
running light and parking lights are shown. Switch can be locked in off and park only.
7. JUNCTION TERMINAL-Yellow wire through cable A to terminal 42; green wire to oil signal
light 29. 35. IGNITION COIL- Black wire to terminal 41; black wire to circuit breaker 26.
8. SPEEDOMETER LIGHT - Green v1ire to switch terminal 2. 36. TERMINAL PLATE - Mounted on fork.
9. TERMINAL - Green wire through cable C to switch terminal 2; red wire with black tracer 38. TERMINAL BOX- Mounted on frame behind ignition coil.
through cable D to head lamp toggle switch 18. 39. TERMINAL(Upper left terminal of terminals box)-Red wire through cable A to switch
10. TERMINAL-Red wire through cable C to switch terminal l. This is a light terminal and termi na 1 1 ; red wire through 1oom G to battery positive termi na 1 15.
can be used for accessory lamps independent of ignition-light switch. 40. TERMINAL(Upper right terminal of terminal box)-Green wire through cable A to switch
12. TERMINAL-Not used with standard wiring. terminal 4; green wire through loom G to tail and stop lamp 14.
13. CUT OUT RELAY-Red wire from relay terminal marked BAT through cable B to switch term- 41. TERMINAL-Center left terminal of terminal box-Black wire through cable A to junction
inal l; black wire from junction terminal 44 through cable B to relay; green wire terminal 6; black wire through cable F to stop lamp switch 27; black wire to front
from generator relay terminal 33 through cable B to relay. coil terminal.
14. TAIL AND STOP LAMP - Red wire through loom J & loom G to terminal 43; green wire 42. TERMINAL-Lower right Terminal of terminal box-yellow wire through cable A to junction
through looms J & G to terminal 40. terminal 7; green wire through cable F to oil pressure signal switch 17.
15. BATTERY POSITIVE TERf1INAL(LEFT SIDE) Red wire through Loom G to terminal 39. 43. TERMINAL-Lower left terminal box-Red wire through loom G and J to tail & stop lamp 14;
16. BATTERY NEGATIVE TERMINAL(RIGHT SIDE) Black wire to ground terminal on frame. red wire through cable F to stop lamp switch 27.
17. OIL PRESSURE SIGNAL SWITCH-green wire through cable F to terminal 42. 44. JUNCTION TERMINAL-Green wire(under panel base) to generator signal light 28; black wire
through cable B to relay 13.
NOTE: Sidecar tail & stop lamps. If sidecar or package truck is equipped with tail &
stop lamp, green wire of lamp cable is connected to terminal 40 & red wire to terminal
43 on terminal plate 38 behind ignition coil.
 SHOP DOPE
No. 295 Page 2.

Because shafts in Model 125 flywheel assembly are a straight press fit in the
flywheels, and main shafts must be pressed into wheels to a specified depth to cor-
rectly position generator armature and engine sprocket, jig and fittings described
are necessary for accurate assembly. With this jig shafts can be started and press-
ed in, in perfect alignment with flywheel holes.
NO. 295 NOVEMBER l, 1949 If directions are followed closely, completed assembly will require little, if
any, further truing between centers as shown in Illus. 12.
MODEL 125 FLYWHEEL and CONNECTING ROD ASSEMBLY TOOL SET
These are precision tools; they can be easily damaged through rough usage;
handle with care.
7
00L NO.!!.
Note: When removing armature shaft
B c D E bearing, insert a nut about l/2" hex be-
I
I
tween end of shaft and puller screw, to
prevent puller screw from damaging end
I I of shaft.

\ \ '.

~
h_ ~1r' \
.. ~G) ~
-'

\J
ILLUS. l
\j ''? \ \ ,.-- ILLUS. 2
';)
...
T
'\\ ~\--
' /
!
REMOVING SHAFT BEARINGS

\
i REMOVING COMPRESSION PLATES
I I
Make a puller bar attachment for
F G H J K L
Harley-Davidson wedge puller, Part No. When wedge puller is used to remove
12738-48 as shown in lllus. l. Puller bar sprocket and armature shaft bearings as
can be made out of a piece of flat stock shown in Illus. l, compression plates may
about l/2" thick, 1-l/2" wide, and 4" long. come out of their recesses as bearings
ASSEMBLY PART NO. 96125-49 Puller screw from one of several Harley- are removed. However, if they do not,
Davidson pullers can be used, size & thread remove the plates in following manner.
Part No. Qescription Part No. l/2"- 18. Two cap screws, 3/8" - 1 6
Description
thread, about 3-l/2" long are required to Drill a small hole at edge of com-
A. 96138-49 Flywheel Tapered Spacer. G. attach bar to wedge. Ends of puller bar pression plate just deep enough to per-
96134-49 Crank Pin Pilot Alignmg
Armature Shaft Installing must be slotted, 7/16" wide and about 1" mit using a sharp pointed pry below edge
Sleeve.
B. 96126-49 Plate. H. deep to a !low for variable wedge width. of plate as shown in lllus .. 2. The plate
96136-49 Crank Pin Aligning Pilot.
C. } { Sprocket Shaft Installing I. With described puller available, secure will readily break through the staking
96132-49 Shaft Locating Press Block.
Plate. J. 96130-49 Drift and Pilot Pin. flywheel shaft in a vise fitted with copper which over 1 a p s edge of plate at eight
D. 96202-49 Recess Clean-up Tool. K. 96135-49 Crank Pin Press Cap. jaw caps and pull bearing; turn assembly equally spaced locations. Flywheels are
E. 96207-49 Staking Punch. L. 96137-49 Flywheel Support Plate. over and pull the other bearing. now ready for disassembly as in Illus. 4.
F. 96133-49 Press Block.
 SHOP DOPE
SHOP DOPE No. 295 Page 4
No. 295 Page 3

DISASSEMBLING FLY WHEELS

Slide "Flywheel Support Plate" (L),

between flywheels and place on two blocks
as shown in !!!us. 4.

Blocks must be over 5" high so end

of main shaft will not come in contact with
bench before flywheels are fully separat-
ed. Then, using "Drift and Pilot Pin" (J),
tapered end against crank pin, press out
crank pin with connecting rod and lower
flywheel attached.

Follow same procedure to remove

crank pin from other flywheel.

ILLUS. 3

COMPRESSION PLATE RECESS

CLEAN-UP TOOL

Alter compression plates have been

removed as shown in lllus. 2, c I e an up ILLUS. 5
compression plate recess in each flywheel,
using "Recess Clean-up Tool." (D).
PRESSING OUT MAIN SHAFTS ginally assembled, are hammering shafts
First put a thin film of oil on shaft when removing engine sprocket or gen-
and slide tool onto it. Hold tool down (Note: In most instances when fly- erator armature, or hammering shafts or
firmly with one hand, and with other hand wheel assembly requires repair, only crankcases, when disassembling wheels
turn clockwise as shown in Illus. 3. The crank pin, connecting rod and rod bear- from or into crankcases. Even though
cutter will remove old staking from re- ings need be removed. shafts are a real tight press fit in wheels,
cess. Caution: Do not pull tool counter- the impact of a moderate hammer blow is
clockwise, or a broken cutting edge will Main shafts (armature and sprocket) sufficient to move them.)
result. are seldom found worn or damaged to such
extent that replacement is required. How- With flywheels separated as de-
Cutter is adjustable to compensate ever, in any instance when flywheel as- scribed under "Disassembling Flywheels"
for wear and sharpening. Adjust cutter sembly is removed from engine and taken and shown in !!Ius. 4, the sprocket shaft,
so it completely cleans up staking aroun:l apart, if there is the slightest possibility armature shaft, or both, can be removed
recess. that main shafts have shifted from origi- for replacement, if necessary. See Illus. 5.
nal specified qepth, to which they were
pressed into flywheels, they should be par- Placeflywheelwithshaft in it, on two
tially pressed out of wheels, then pressed blocks, shaft downward between blocks.
back to specified depth, with jig fittings Bring the two blocks as close to shaft as
provided for that operation. possible. Again use the Drift and Pilot
Pin( with tapered end against end of shaft),
ILLUS. 4 The thmgs most likely to cause main and press out shaft.
shafts to shift from their locations as or1-
SHOP DOPE SHOP DOPE
No. 295 Page 5 No. 295

Illus. 7 shows the Cra0k Fw V'ot

being secured while being hf: lrl ir, ,llign-
ment with the Crank Pin Align-!n6 Sleeve.
Ill us. 8 shows Aligning Sleevt:: removed
after Crank Pin Pilot has been secured .

•
ILLUS. 7

INSTALLING CRANK PIN PILOT

Attach "Crank Pin Aligning Pilot"

(H) to crank pin as shown in Illus. 7. Hold
small tapered end against one end of crank
pin, then pass screw through crank pin
from opposite end. Do not tighten as yet.

Next slide "Crank Pin Pilot Aligning

ILLUS. 6 Sleeve" (G) over Crank Pin Aligning Pilot
and crank pin, (heavily chamfered end to-
REASSEMBLY ward connecting rod). Tighten aligning
Illus. 6. Be sure that Press Block is
pressed down tight against Installing Plate pilot screw securely and remove sleeve.
After flywheels have been disas- (B). This procedure presses shaft the cor-
sembled, thoroughly cleaned, faulty parts rect depth into flywheel and locates arma-
discarded, and connecting rod serviced as ture shaft keyway in relation with crank- ILLUS. 9
necessary, oil shafts and holes in fly- pin hole so that correct ignition timing
wheels and proceed to assemble flywheels can be attained, after armature and cir- PRESSING CRANK PIN INTO
in following manner. cuit breaker cam are installed. FLYWHEEL
After end of crank pin has been coat-
ed with a thin film of engine oil, place fly-
INSTALLING MAIN SHAFTS Shafts must be a very tight press fit wheel in which armature shaft is installed
in flywheels. When a shaft has only a very on two blocks and insert Crank Pin Pilot
First install key in armature shaft. light press fit in flywheel it is probably into crank pin hole as shown in Illus 9.
Place tapered end of shaft in "Shaft Lo- because flywheel hole has become enlarg- Place "Press Cap" (K) on end of pin and
cating Press Block" (I). Insert straight ed. Wheel in this condition should be dis- press pin into flywheel until it bottoms.
end of shaft through "Shaft Installing Plate" carded and new one used.
(B) into flywheel. Insert "Pilot Pin" (J) Remove Press Block, also Crank
through hole in Press Block, hole in In- Follow this sa rn e procedure when Pin Pilot, and install Pilot on opposite end
stalling Plate and crank pin hole in .fly- installing sprocket shaft, using "Sprocket of crank pin in same manner as shown in
wheel. Support wheel with a block placed Shaft Installing Plate" (C); however, key ILLUS. 8 Illus. 7 and explained under "Installing
directly underneath flywheel center hole way location in relation to crank pin can Crank Pin Pilot."
and press shaft into flywheel as shown in be disregarded. CRANK PIN PILOT ALIGNING SLEEVE
SHOP DOPE SHOP DOPE
No. 295 Page 7 No. 295 Page 8

flywheel. Push upper plate downward "by

hand" until upper flywheel contacts end of . Note: Shaft bearings have only a
crank pin. Using "Press Block" (F) over ltght press fit, therefore, there is little
protruding enq...of Crank Pm Aligning Pi- danger of moving shafts in flywheels when
lot, press down until upper flywheel bot- pressing bearings on.
toms against connecting rod thrust washer.
Caution: When installing bearings
do not drive on with a hammer.

REINSTALLING COMPRESSION PLATES

,,
Support flywheels as shown in Illus.
ll and install compression plates, pre-
ferably new plates if old plates are in the
least damaged or out of shape.

Using Compression Plate Recess

Clean-up Tool as a guide, stake compres-
sion plates in place by upsetung edge of
ILLU.S. 12
flywheel recess with "Staking Punch" {E).
Note that end of this punch is angled, and
TRUING FLYWHEELS
is to be used with longer tip outward.
Using "Flywheel Truing Device"
Make sure compression plates are
Part No. 11962-X check armature and
well secured. Plates have a tendency to
sprocket shaft run-out as shown in !!!us.
spring, and if not securely installed may
12. Shafts must run true within .001".
bre-ak away from staking. A loose plate
This is one half graduation on indicator
is not only noisy but also lowers engine
scale. If armature and sprocket shafts
performance due to below normal crank-
run high near the crank pin, install a ''C ..
case compression.
clamp above crank pin and apply light
pressure. With clamp in place strike fly-
ILLTTS. I 0 wheels very lightly above crank pin. Take
another reading, if shafts still do not run
PRESSING FLYWHEELS TOGETHER true repeat operation again. Shafts must
be within specification, so arn1ature will
Flywheels can now be pressed to- run true, otherwise there will be exces-
gether in the following manner. See Illus. sive ubrush hop" and arcing.
!0.

Place flywheel that has crank pin and INSTALLING ARMATURE SHAFT
connecting rod installed on "Armature BEARING
Shaft Installing Plate" {B). Place flywheel
in which sprocket shaft is installed on Again using two blocks and Flywheel
Sprocket Shaft Installing Plate. Support Plate as shown in Illus. !3, press
armature shaft bearing and sprocket shaft ILLUS. \ :l
Note that Sprocket Shaft Installing inner bearing on their respective shafts.
Plate is marked on one side "This side
up. Flywheel must be held against op- Place bearing on shaft. Use a sleeve
posite side. or a piece of 3/4" pipe no less than 3"
long, over sha..{t against ball bearing inner
Holding flywheel against plate, start race. Press bearing on shaft until it bot-
plate onto guide pins attached to Armature toms.
Shaft Installing Plate. At the same time
guide Crank Pin Pilot through flywheel,
then through hole in upper installing plate
which corresponds with crank pin hole in ILLUS. !!
SHOP DOPE
No. 295 Page 9

Next heat right crdnkcase around

bearing bore and apply heat around open
dowel pin holes. Apply sealer to joint
faces of both cases.

Install right crankcase. Insert and

securely tighten all crankcase clamp
screws.

The next assembly operation is in-

stalling sprocket shaft outer beanng.
How~?ver, before thts can be done, it must
be determined how many shims are re-
quired behind bearing to obtatn correct
clearance between bearing inner race and
back face of engine sprocket.

The destred clearance is .003" to

ILLUS. 14 .012''. To attain this clearance, s h 1m s
are provided .007" thick. To determine
INSTALLING FLYWHEEL ASSEMBLY how many shims are needed, temporarily
IN CRANKCASES insert, mstead of bearing, a 45" model
reverse gear spacing collar, part No.
Prepare crankcases I or assembly: 2296-33A. Spacing collar is approximat-
See that transmisston and shifter parts ely the same width as bearing No. 9008.
are correctly ass em b 1 e d in left case. Insert this collar with large diameter In-
Thoroughly clean·crankcase joint faces. ward ag 1.inst oil seal.

Insert "Flywheel Tapered Spacer" Install sprocket and securely hghten

(A) between the two flywheels o p posit e sprocket nut. Use feeler gauge to deter-
crank pin, upper end of connecting rod mine total clearance between back face of
between the two prongs of spacer as shown sprocket and collar. It can now be calcu-
in Ulus. 14. The purpose of this spacer lated how many . 007" thick shtms are re-
is to prevent closing up flywheels and thus quired to reduce the total clearance to
throwing whee 1 shafts out of alignment approximately .01 0". Sprocket and gaug-
when installing flywheel assembly in ing collar can now be removed and cor-
crankcases. Do not force spacer between rect number of shims inserted. Heat case
flywheels, just snug is all that is necess- around bearing hole and press bearing in-
ary. to place.

Using a torch, heat left crankcase

around bearing bore enough so bearing
will slide easily into crankcase as fly-
wheel assembly is installed in left case.
Do not apply f 1 am e directly agamst oil
seal. NOTE: At this point, observe that
oil seal is snug agatnst 1ts retaining ring.

Insert flywheel assembly tn left case.

It ts seated i;l left case when sprocket HARLEY-DAVIDSON MOTOR CO.
shaft beanng :~;,ats against oil seal re-
taining ring. Milwaukee l, Wis., U.S.A.
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