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Routine maintenance
Periodic routine maintenance is a continuous process that too low, pump up the tyre with the pump or a garage air line
commences immediately the machine is used. It must be the correct pressure. If the pressure is too high, push the valvj
carried out at specified mileage recordings or on a calendar centre to release the air until the correct pressure is reached
basis if the machine is not used frequently, whichever is sooner. Replace the dust cap because it is a second seal.
Maintenance should be regarded as an insurance policy, to help
keep the machine in the peak of condition and to ensure long, 2 Checking the oil tank level. t
troublefree service. It has the additional benefit of giving early The oil tank capacity is 1-4 litres (2-4 pints) and a sell
warning of any faults that may develop and will act as a safety mixing two-stroke oil should be used.
check, to the obvious advantage of both rider and machine The level can be checked either by looking through tfi
alike. window on the frame or by lifting the seat, pushing the oil tani
The various maintenance tasks are described below, under lighting switch, and reading the level gauge. Refill the tank,!
their respective mileage and calendar headings. Accompanying required.
diagrams are provided, where necessaiy. It should be remem¬ On no account run the engine when the oil tank is empty ai
bered that the interval between the various maintenance tasks engine seizure will result.
serves only as a guide. As the machine gets older or is used
under particularly adverse conditions, it would be advisable to 3 OH and adjust the brake cable and rod
reduce the period between each check. The standard brake cables should be lubricated with a lig|
No special tools are required for the normal routine machine oil, but if a nylon lined cable has been fitted on nt
maintenance tasks. The tools contained in the toolkit supplied account use oil on it.
with every new machine are limited, but will suffice if the owner Similarly, the cable nipples and pivot points should be oilel
wishes to carry out only minor maintenance tasks. including those of the brake rod. Normally, rain and the washing
When buying tools, it is worth spending a little more than of the machine will provide sufficient lubrication for the nylo|
the minimum to ensure that good quality tools are obtained. and plastic parts. Before the winter sets in each year, it is advis-
Some of the cheaper tools are too soft or flimsy to do an ade¬ able to remove the cables completely and thoroughly lubricatf
quate job. It is infuriating to have to stop part way through a job them as shown in the accompanying sketch, to ensuri
because a spanner has splayed open or broken, and a replace¬ troublefree riding during the more arduous conditions to bt
ment must be found. found in winter.
A deep rooted knowledge of engineering principle is by no The brakes need adjusting when there is too much move¬
means necessary before the owner undertakes his or her own ment on the lever or the pedal ie; when the brake lever come!
maintenance tasks but familiarity with a few of the more com¬ close to the handlebar when the brake is applied or if there il
monly used terms and a basic knowledge of how to use tools too much movement of the brake pedal. To adjust either brakt
will help. turn the adjusting nut until the brake just starts to rub when thf
The following list of tools will suffice to undertake the wheel is spun. Slacken back the adjusting nut until the brakt
routine maintenance tasks described in the Section, but where just stops rubbing. Ensure that the adjusting nut cut-outs art
reference is made to another Chapter for the dismantling proce¬ seating correctly on the brake operating arm on the rear brake
dure, additional tools may be required. and that the locknut is fully tightened on the front brake.
A tyre pressure gauge
A tyre pump 4
Tth,.
Check, adjust andlubricate the final drive chain:
. 1
A pair of pliers.
Place the machine on its centre stand on level ground
Two cross head screwdrivers, size 2 and 3. Check the up and down movement of the chain, midwai
A small electrical screwdriver between the two sprockets. Rotate the back wheel until the up
A set of feeler gauges. and down movement is at the minimum. This is the 'tight spot1
A 14 mm spark plug spanner. on the chain and the up and down movement here should b<l
A set of metric open-ended spanners between 10 mm (0-40 inch) and 20 mm (0-79 inch).
Box spanners to include 12 mm, 2 1 mm and 23 mm sizes. If the play is greater than 20 mm (0-79 inch) the chajgi
An adjustable spanner (this tool to be used only as a last should be adjusted as follows:
resort).
Slacken the wheel spindle nuts so that they are finger tight
Make sure that each adjusting nut is turned the same amount
Weekly or every 300 miles (500 km) to keep the wheels in line, until the play is reduced to within thp
limits. Tighten the wheel spindle nuts and recheck the amounll;
of play on the chain. . ‘j;|
1 Check the tyre pressures When the wheels are properly aligned both the adjusters
The tyre pressure should be 20 psi for the front tyre and 28 should match the swinging arm markings.
psi for the rear tyre measured when the tyres are cold. An SAE 90 oil or a chain lubricant should be spread on the
Remove the dust cap, flick the valve centre to blow out any chain for lubrication. The latter is applied from an aerosol pack.
dirt or water and push on the pressure gauge. If the pressure is to make application easier.
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Adjust the back brake with the special nut Check the chain through the inspection hole
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The adjusters should match the frame markings on each side Lubrication is easier from on aerosol can
10 Routine maintenance

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Check the oil level, using the dipstick provided
Oiling a control cable 1 i

5 Check the lights andhdrn & I

Check that all the lights are working properly. Renew any
defective bulbs and if any lights are dim, clean the connections Wj A i
and earthing points, to restore the lights to their original bright¬
ness.
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Check that the horn works, again checking the connection if
the performance is poor. u r
6 Visual inspection
Give the whole machine a close visual inspection, checking
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for loose nuts and fittings, frayed control cables or missing parts DIPSTICK
which may have fallen off. it
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7 Check the battery

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Remove the side panel, release the battery and slide it out.
Remove the top cover, if fitted, and unscrew the vent plugs on
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4 Minimum oil level
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top of the plates. On translucent batteries, the level of the liquid
is marked on the outside of the battery. If the liquid level is low,
the separate cells in the battery should be topped up to the
correct level with distilled water. Tap water should not be used i
as the impurities in the water will have an adverse effect on the Crankcase dipstick i
battery life.
Replace the plugs and the cover and refit the battery to the
machine, finally replacing the side panel. 2 Check the spark plug •I
If any liquid is spilt out of the battery this should be washed An NGK type B-7HS is fitted as standard equipment to the
off immediately with plenty of water as it will corrode any metal Yamaha V50, 75 and 90 models. The recommended gap of the
parts and burn the skin if left unattended. plug is 0-5 mm - 0-6 mm (0-020in - 0-024 in).
Pull off the spark plug gap and unscrew the plug. Clean the
electrodes to remove any oil or carbon. Check that gap between
Monthly or every 1000 miles (1600 km) the electrodes with a set of feeler gauges. If the gap needs
resetting, bend the outer electrode to bring it closer to the
Check the tyres, brakes, lights and horn as described in the central electrode. Do not try to move the centre electrode as the
weekly/300 miles service and then carry out the following
additional tasks:
insulation will break and ruin the plug.
Refit the spark plug and push on the plug cap. Do not over¬
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tighten the spark plug as this can cause the thread to strip in the
1 Check the gearbox oil level cylinder head. A normal plug spanner has the correct lengtlj
The gearbox capacity is 650 cc (1 -14 pints), and an SAE tommy bar or handle to make overtightening impossible.
20W/50 oil is recommended. A new spark plug should be fitted every 5000 miles (8000 ’
Place the machine on its centre stand on level ground. If the km), or if it is damaged or excessively worn.
machine has just been run, allow the oil to settle for 5 minutes
before checking the level. Remove the plastic filler cap with its 3 Check and adjust the throttle cable 1
integral dipstick. Wipe the oil off the dipstick. Replace the The throttle should have about 1 mm - 2 mm (0-04 in -1
dipstick without screwing it in, remove it and check that the oil 0-08 in) free play movement.
level is between the upper and lower limit marks on the dipstick. To adjust the amount of free play, slide the rubber sleeve up the
Add oil if necessary, to bring the oil to the correct level, and cable to reveal the adjusting nut. The adjusting nut is turned to
•
replace the filler cap dipstick after ensuring that the sealing 0
ring is in good condition.
provide the correct play and locked in position with the locknut.
Slide the rubber sleeve back down the cable to exclude the dirt. 1 *
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 Routine maintenance 11

Check and adjust the carburettor slow running 1 Change the gearbox oil
adjustment As stated previously the gearbox capacity is 650 cc (1-14
Any checks or adjustments that are made on the car- pints) of SAE20W/50 oil.
burettor should be undertaken only when the engine has Place the machine on its centre stand on level ground. Run
reached its normal working temperature and not when the the engine for a few minutes to warm up the oil so that it will
'engine is cold. run out easier. Place a container under the engine and remove
„ The engine should continue to run slowly when the throttle the drain plug, which is situated on the underside of the engine.
is closed. If the engine stops every time the throttle is closed, When all the oil has drained, replace and tighten the drain plug,
adjustment is necessary. As the machine has an automatic ensuring that the sealing washer is in good condition.
clutch, if the engine runs too fast, the machine will tend to creep the engine with oil of the correct viscosity, checking
forward when it is in gear unless the brakes are applied to stop the level as described in the weekly check.
it. 2 Clean the air filter
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Slacken the throttle cable to ensure that there is plenty of The air filter is located under the main frame tube,
slack so that cable tension does not give false adjustment on immediately behind the; steering head, clearly visible when the
the carburettor. legshields have been removed.
I! On the side of the carburettor are two screws, the upper To clean the air filter, remove the legshields to gain access
one is the throttle stop screw, the lower the air mixture screw. to the air filter box. Remove the centre nut and bolt from the air
To adjust the sldw- running of the engine, turn the throttle box and pull off the end plates. The filter element can then be
stop screw until the engine is running at approximately 1300 pulled clear of the rubber intake hose and slid out of the air box.
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'rpm. Turn the air mixture screw until the highest engine speed is Accumulated dust can be removed from the element either by
obtained. If the engine speed is then too fast, unscrew the tapping it lightly and brushing with a soft brush or by using a
throttle stop screw to reduce it, then turn the air mixture screw vacuum cleaner on the outside taking care not to damage the
to find the Highest engine speed again. This process is repeated element as it is only made of paper. If it is torn, disintegrating or
until the engine runs slowly and evenly. Readjust the-throttle oiled up, fit a replacement.
cable slack to the limit as set out under the previouslieading. Oil or water will reduce the efficiency of the filter element
5 Check the tyre condition and may upset the carburation.
-

By law a motorcycle must have a minimum depth of tread It is advisable to replace the element at less than the
of 1 mm (0-04 inch) for at least 75% of the tyre width all the recommended 6000 miles if the machine is used in very dusty
way round the circumference of the tyre. In the interest of safety conditions. The usual signs of a filter element in need of
it is better to renew the tyre long before the legal minimum is replacement are reduced performance, misfiring and a tendency
reached. for the carburation to run rich.
When checking the tyre condition, remove any stones in the On no account should the machine be run without the filter
tread, check for any bulges, splits or bald spots and renew the element in place because this will have an adverse effect on
tyre if any doubt exists by following the procedure given in carburation. Reassembly of the air filter is the reverse of the
Chapter 6, Section 1 7. dismantling procedure.
6 Check the Autolube pump adjustment 3 Clean the carburettor
When the throttle cable has its correct free play of 1 mm - Over a period of time sediment and water will collect in the
2 mm (0 04 in - 0 08 in) turn the twistgrip to take up the slack carburettor. A drain screw on the carburettor enables the float
and the oil pump guide pin should line up with the mark on the chamber to be flushed out with petrol to remove nearly all of the
oil pump pulley. The cable adjuster and locknut are situated just dirt but Chapter 3 Sections 8 to 10 will describe how the car¬
above the oil pump but the legshields need removing if adjust¬ burettor itself is removed, stripped, cleaned and reassembled, if
ment is necessary. any trouble still persists.

—
; 4 Clean the fuel tap filter
The fuel tap filter should stop any dirt, rust or water from
Six monthly or every 3000 miles (5000 km) getting into the carburettor from the petrol tank.
Unscrew the small bowl on the bottom of the tap and lift
Complete all the checks under the weekly and monthly out the gauze filter. Clean the filter and the sediment bowl and
headings taking into acpount the additional work required by refit to the tap ensuring that the sealing ring is in good condi¬
the following items. tion.
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12 Routine maintenance

5 Remove, dean and lubricate the final drive chain timing. The flywheel inspection cover should be removed so
Although the final drive chain is fully enclosed, the oil and that the contact breaker can be viewed through one of this;
grease lubricant on the chain will tend to pick up dust and grit, apertures in the flywheel. When the line marked on the flywheel
so every six months it is advisable to remove the chain from the lines up with the timing plate the contact breaker should just: i
machine for thorough cleaning. start to open. If adjustment is necessary, the fixed contact can !
To remove the chain, place the machine on its centre stand be moved by slackening the clamping screw and using e
on level ground, remove the four bolts and the two chaincase screwdriver in the slot provided. Retighten the clamping screw
halves. and check the adjustment again, to ensure that it has not
It may be necessary to release the bottom of the rear altered.
suspension unit to enable the top half of the chaincase to be When the ignition timing is correct, rotate the flywheel to
removed without being scratched. determine the position at which the contact breaker points are
Rotate the rear wheel until the spring link is in a convenient fully open. When fully open the contact breaker gap should be i
position, preferably on the rear wheel sprocket. Use a pair of between 0-3 mm and 0-4 mm (0-012 and 0-016 in). I|
pliers to remove the spring clip and then remove the side plate If the gap is too small, the contact breaker points need
and the linkplate, thus disconnecting the chain. Connect to one renewing, as described in Chapter 4, Section 6.
end of the chain a second chain, either an old worn out one or a Refit the flywheel cover and the spark plug and plug cover,! ,
brand new one which is kept in readiness for fitting to the if these have been removed.
machine. Pull the first chain off the machine, feeding the second After checking the timing, rotate the engine and check
chain on, until the first chain can be disconnected from the again before replacing the covers. The accuracy of the ignition
second chain. If the second chain is usable, reconnect it, ensur¬ timing is critical in terms of both engine performance and petrol
ing that the closed end of the spring clip is facing the direction consumption. Even a small error in setting can have a notice¬
of travel of the chain. Adjust the chain as described in the able effect on both.
weekly maintenance section and refit the chaincase.
The chain which has just been removed should be washed
thoroughly in petrol or paraffin to remove all the dirt and grease. I
To check whether the chain is due for renewal, lay it
lengthwise in a straight line and compress it so that all play is
taken up. Anchor one end and then pull on the other end to take
s
up the play in the opposite direction. If the chain extends by n
more than the distance between two adjacent links, it should be •<-
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renewed in conjunction with the sprockets. ;/ ii

The chain should be lubricated by immersing it in a molten
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lubricant such as Linklyfe or Chainguard and then hanging it up !
to drain. This will ensure good penetration of lubricant between
the pins and rollers, which is less likely to be thrown off when
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the chain is in motion.
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To refit the chain to the machine, connect it to the second i
chain, pull the second chain and feed the first chain back onto f
the machine. Reconnect the chain, ensuring the spring clip is
correctly fitted as stated before. It is easier to reconnect the ill
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chain if the ends are fitted onto the rear wheel sprocket whilst
the connecting link is inserted. Adjust the chain, following the
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weekly maintenance procedure, and refit the chaincase.
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6 Check and adjust the ignition timing C )

The ignition timing is determined by when the contact Use a screwdriver through the flywheel aperture ... 1
breaker points open. The flywheel operates the contact breaker
and the heel of the contact arm will wear, altering the ignitidn
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Routine maintenance 13

7 Decoke the engine and exhaust system. oil, should be put on the wick to reduce wear on the heel of the
This task although not too difficult is very messy. Chapters contact arm. Do not over oil. If oil finds its way on to the contact
breaker points it will act as an insulator and prevent electrical
I and 3 fully describe the necessary procedures required to
contact from being made.
amove and replace the cylinder head and cylinder barrel and
he exhaust system.
2 Check the condition of the sprockets
j Grease the leading link forks When the final drive chain is cleaned and checked, ensure
Apply a grease gun to the nipples on the leading links and that the sprockets are not badly worn, before replacing the
he fork blades. Pump grease into the bearings until clean chain. If the sprocket teeth are badly worn, they will probably
jrease emerges from the joints. Wipe away any excess grease have a hooked appearance and should be renewed as described . -ft-,
is this will collect dirt and make the machine look unsightly. in Chapter 1, Sections 9 and 6 and Chapter 6, Section 12.
) Grease the throttle twist grip and oil the throttle r
table 3 Adjust and lubricate the steering head bearings
Remove the two screws and the indicator switch from the Dismantling and reassembly of the steering head is a task
that should be undertaken only if the problems involved are
landlebar. This releases the twisting sleeve which slides off the understood. Chapter 5, Sections 2 and 4, fully describe the
landlebar with an anti-clockwise twist. The sliding block can necessary procedures.
IOW be lifted out of the handlebar and the inner cable
jnhooked. The outer cable stop can then be removed from the
landlebar and unhooked from the cable. 4 Examine andlubricate the wheel bearings
.Dismantling and reassembly of the wheel bearings is also a
tO Check the centre andprop stand springs tapfc to be undertaken only if an understanding of the problems
Check the condition of the centre and prop stand springs involved is realised. Chapter 6 fully describes the necessary
md renew them if they are worn or heavily corroded. If the procedure.
stand drops when the machine is moving, it may catch in some
jbstacle in the road and unseat the rider. Grease the springs 5 Examine both front andrear brake assemblies
and the stand pivot points. The brake assemblies should be cleaned to remove any dust
11 Grease the speedometer cable and checked to ensure that the brake linings are not wearing
v Once the headlamp lens has been removed, the too thin. This task is fully described in Chapter 6.
speedometer cable can be unscrewed from the speedometer
head and pulled clear. The inner cable can then be pulled out. I—es.
Clean off the old grease by washing in petrol or paraffin. Spread wm
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jiaw grease along the length of the cable except for the top 15
cm (6 inch) and feed the cable back into the outer casing. *
Reconnect the cable to the speedometer head.
If the top of the cable is greased, the grease will work its
way into the speedometer head and stop it functioning, thus m :
necessitating a replacement as the speedometer head cannot
be stripped for cleaning. $

yearly or every 5000 miles{8000 km)

Complete all the checks listed under the weekly, monthly

and six monthly headings, then complete the following
additional tasks: £

1 Lubricate the felt wick of the contact breaker cam

When the ignition timing is checked, the felt wick of the
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contact breaker cam can be seen. A few drops of light machine i
Grease the leading
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Lubricate the felt wick for the contact cam

'ftai Greasing the speedometer cable