16-22 ELECTRICAL SYSTEM

Precautions
There are a number of important precautions that are
musts when servicing electrical systems. Learn and ob-
serve all the rules below.
○Do not reverse the battery cable connections. This will
burn out the diodes on the electrical parts.
○Always check battery condition before condemning other
parts of an electrical system A fully charged battery is a
must for conducting accurate electrical system tests.
○The electrical parts should never be struck sharply, as
with a hammer, or allowed to fall on a hard surface. Such
a shock to the parts can damage them.
○To prevent damage to electrical parts, do not disconnect
the battery cables or any other electrical connections
when the ignition switch is on, or while the engine is
running.
○Because of the large amount of current, never keep the
starter button pushed when the starter motor will not turn
over, or the current may burn out the starter motor wind-
ings.
○Do not use a meter illumination bulb rated for other than
voltage or wattage specified in the wiring diagram, as the
meter or gauge panel could be warped by excessive heat
radiated from the bulb.
○Take care not to short the leads that are directly con-
nected to the battery positive (+) terminal to the chassis
ground.
○Troubles may involve one or in some cases all items.
Never replace a defective part without determining what
CAUSED the failure. If the failure was caused by some
other item or items, they must be repaired or replaced, or
the new replacement will soon fail again.
○Make sure all connectors in the circuit are clean and tight,
and examine wires for signs of burning, fraying, etc. Poor
wires and bad connections will affect electrical system op-
eration.
○Measure coil and winding resistance when the part is cold
(at room temperature).
○Color Codes:
BK Black G Green P Pink
BL Blue GY Gray PU Purple
BR Brown LB Light blue R Red
CH Chocolate LG Light green W White
DG Dark green O Orange Y Yellow

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 ELECTRICAL SYSTEM 16-23
Precautions

○Electrical Connectors
Female Connectors [A]

Male Connectors [B]

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 16-24 ELECTRICAL SYSTEM
Electrical Wiring
Wiring Inspection
• Visually
etc.
inspect the wiring for signs of burning, fraying,

If any wiring is poor, replace the damaged wiring.

•Pull each connector [A] apart and inspect it for corrosion,
dirt, and damage.
If the connector is corroded or dirty, clean it carefully. If it
is damaged, replace it.
•Check the wiring for continuity.
○Use the wiring diagram to find the ends of the lead which
is suspected of being a problem.
○Connect the hand tester between the ends of the leads.
Special Tool - Hand Tester: 57001-1394
○Set the tester to the × 1 Ω range, and read the tester.
If the tester does not read 0 Ω, the lead is defective. Re-
place the lead or the wiring harness [B] if necessary.

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 ELECTRICAL SYSTEM 16-25
Battery
Battery Removal
• Remove:
Tool Box (see Tool Box Removal in the Frame chapter)
• Slide out thethe
Disconnect negative (–) cable [A].
• nect the positive (+) cable.
positive (+) terminal cap [B] and then discon-

CAUTION
Be sure to disconnect the negative (–) cable first.

• Remove the battery.

Battery Installation
• Put the battery into the battery case.
• corrosion.
Apply a light coat of grease on the terminals to prevent

• Install the positive (+) cable [A] first.

• Cover the positive (+) terminal with the cap [B].
• Install the negative (–) cable [C].

Battery Activation
Electrolyte Filling
• Make sure that the model name [A] of the electrolyte con-
tainer matches the model name [B] of the battery. These
names must be the same.
Battery Model Name for VN900B/D: YTX12-BS

CAUTION
Be sure to use the electrolyte container with the
same model name as the battery since the elec-
trolyte volume and specific gravity vary with the
battery type. This is to prevent overfilling of the
electrolyte, shorting the battery life, and deteriora-
tion of the battery performance.

CAUTION
Do not remove the aluminum sealing sheet [A] from
the filler ports [B] until just prior to use. Be sure to
use the dedicated electrolyte container for correct
electrolyte volume.

• Place the battery on a level surface.

• or holestoinseeit. that the sealing sheet has no peeling, tears,
Check

• Remove the sealing sheet.

NOTE
○The battery is vacuum sealed. If the sealing sheet has
leaked air into the battery, it may require a longer initial
charge.

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 16-26 ELECTRICAL SYSTEM
Battery

• Remove the electrolyte container from the vinyl bag.

• aside, thesestrip
Detach the of caps [A] from the container and set
will be used later to seal the battery.
NOTE
○Do not pierce or otherwise open the sealed cells [B] of
the electrolyte container. Do not attempt to separate
individual cells.

• Place the electrolyte container upside down with the six

sealed cells into the filler ports of the battery. Hold the
container level, push down to break the seals of all six
cells. You will see air bubbles rising into each cell as the
ports fill.
NOTE
○Do not tilt the electrolyte container.

• Check the electrolyte flow.

If no air bubbles [A] are coming up from the filler ports, or
if the container cells have not emptied completely, tap the
container [B] a few times.
• Keep the container in place for 20 minutes or more. Don’t
remove the container from the battery until it’s empty, the
battery requires all the electrolyte from the container for
proper operation.
CAUTION
Removal of the container before it is completely
empty can shorten the service life of the battery. Do
not remove the electrolyte container until it is com-
pletely empty and 20 minutes have elapsed.

• Gently remove the container from the battery.

• the electrolyte
Let the battery sit for 30 minutes prior to charging to allow
to permeate into the plates for optimum
performance.
NOTE
○Charging the battery immediately after filling can
shorten service life. Let the battery sit for at least 30
minutes after filling.

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 ELECTRICAL SYSTEM 16-27
Battery
Initial Charge
• Place the strip [A] of caps loosely over the filler ports.
• Newly activated sealed batteries require an initial charge.
Standard Charge: 1.2 A × 5 ∼ 10 hours
If using a recommended battery charger, follow the
charger’s instructions for newly activated sealed battery.
Kawasaki-recommended chargers
Optimate III
Yuasa 1.5 Amp Automatic Charger
Battery Mate 150-9
If the above chargers are not available, use equivalent
one.
NOTE
○Charging rates will vary depending on how long the
battery has been stored, temperature, and the type of
charger used. Let battery sit 30 minutes after initial
charge, then check voltage using a voltmeter. If it is
not at least 12.8 V, repeat charging cycle.

• After charging is completed, press down firmly with both

hands to seat the strip of caps [A] into the battery (don’t
pound or hammer.). When properly installed, the strip of
the caps will be level with the top of the battery.
CAUTION
Once the strip of the caps [A] is installed onto the
battery, never remove the caps, nor add water or
electrolyte to the battery.

NOTE
○To ensure maximum battery life and customer satisfac-
tion, it is recommended the battery be load tested at
three times its amp-hour rating for 15 seconds.
Re-check voltage and if less than 12.8 V repeat the
charging cycle and load test. If still below 12.8 V the
battery is defective.

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 16-28 ELECTRICAL SYSTEM
Battery
Precautions
1) No need of topping-up
No topping-up is necessary in this battery until it ends its life under normal use. Forcibly prying
off the seal cap to add water is very dangerous. Never do that.
2) Refreshing charge.
If an engine will not start, a horn sounds weak, or lamps are dim, it indicates the battery has been
discharged. Give refresh charge for 5 to 10 hours with charge current shown in the specification
(see Specifications section).
When a fast charge is inevitably required, do it following precisely the maximum charge current
and time conditions indicated on the battery.
CAUTION
This battery is designed to sustain no unusual deterioration if refresh-charged according
to the method specified above. However, the battery’s performance may be reduced no-
ticeably if charged under conditions other than given above. Never remove the seal cap
during refresh charge.
If by chance an excessive amount of gas is generated due to overcharging, the relief valve
releases the gas to keep the battery normal.
3) When you do not use the motorcycle for months.
Give a refresh charge before you store the motorcycle and store it with the negative cable re-
moved. Give a refresh charge once a month during storage.
4) Battery life.
If the battery will not start the engine even after several refresh charges, the battery has ex-
ceeded its useful life. Replace it (Provided, however, the vehicle’s starting system has no prob-
lem).
WARNING
Keep the battery away from sparks and open flames during charging, since the battery
gives off an explosive gas mixture of hydrogen and oxygen. When using a battery charger,
connect the battery to the charger before turning on the charger.
This procedure prevents sparks at the battery terminals which could ignite any battery
gases.
No fire should be drawn near the battery, or no terminals should have the tightening loos-
ened.
The electrolyte contains sulfuric acid. Be careful not to have it touch your skin or eyes. If
touched, wash it off with liberal amount of water. Get medial attention if severe.

Interchange
A sealed battery can fully display its performance only when combined with a proper vehicle electric
system. Therefore, replace a sealed battery only on a motorcycle which was originally equipped with
a sealed battery.
Be careful, if a sealed battery is installed on a motorcycle which had an ordinary battery as original
equipment, the sealed battery’s life will be shortened.

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 ELECTRICAL SYSTEM 16-29
Battery
Charging Condition Inspection
○Battery charging condition can be checked by measuring
battery terminal voltage with a digital voltmeter [A].
• Remove:
Seat (see Seat Removal in the Frame chapter)
Battery Cable Cap (see Battery Removal)
• Disconnect the battery terminals.
CAUTION
Be sure to disconnect the negative (–) cable first.

• Measure the battery terminal voltage.

NOTE
○Measure with a digital voltmeter which can be read one
decimal place voltage.
If the reading is 12.8 V or more, no refresh charge is re-
quired, however, if the read is below the specified, refresh
charge is required.
Battery Terminal Voltage
Standard: 12.8 V or more
Terminal Voltage (V) [A]
Battery Charge Rate (%) [B]
Good [C]
Refresh charge is required [D]

Refreshing Charge
• Remove the battery [A] (see Battery Removal).
• battery terminal
Do refresh charge by following method according to the
voltage.
WARNING
This battery is sealed type. Never remove sealing
cap [B] even at charging. Never add water. Charge
with current and time as stated below.

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 16-30 ELECTRICAL SYSTEM
Battery
Terminal Voltage: 11.5 ∼ less than 12.8 V
Standard Charge 1.2 A × 5 ∼ 10 h (see following chart)
Quick Charge 5A×1h

CAUTION
If possible, do not quick charge. If quick charge is
done unavoidably, do standard charge later on.

Terminal Voltage: less than 11.5 V

Charging Method 1.2 A × 20 h

NOTE
○Increase the charging voltage to a maximum voltage of
25 V if the battery will not accept current initially. Charge
for no more than 5 minutes at the increased voltage then
check if the battery is drawing current. If the battery
will accept current decrease the voltage and charge by
the standard charging method described on the battery
case. If the battery will not accept current after 5 min-
utes, replace the battery.
Battery [A]
Battery Charger [B]
Standard Value [C]
Current starts to flow [D]

•○Determine the battery condition after refresh charge.

Determine the condition of the battery left for 30 minutes
after completion of the charge by measuring the terminal
voltage according to the table below.
Criteria Judgement
12.8 V or higher Good
12.0 ∼ lower than 12.8 V Charge insufficient → Recharge
lower than 12.0 V Unserviceable → Replace

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 ELECTRICAL SYSTEM 16-31
Charging System
Alternator Outer Cover Removal
• Remove:
Bolts [A]
Alternator Outer Cover [B]

Alternator Outer Cover Installation

• Install the alternator outer cover.
• Tighten:
Torque - Alternator Outer Cover Bolts: 9.8 N·m (1.0 kgf·m,
87 in·lb)

Alternator Cover Removal

• Drain the engine oil (see Engine Oil Change in the Peri-
odic Maintenance chapter).
• Remove:
Bolt [A]
Bolts [B]
Footboard [C] and Shift Pedal as a set

• Remove:
Alternator Outer Cover (see Alternator Outer Cover Re-
moval)
Engine Pulley Cover (see Engine Pulley Cover Removal
in the Final Drive chapter)
Crankshaft Sensor Lead Connector [A]

• Remove:
Left Side Cover (see Left Side Cover Removal in the
Frame chapter)
Tool Box (see Tool Box Removal in the Frame chapter)
Plug [A] and Bolt
Ignition Switch [B]
Alternator Lead Connector [C]

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 16-32 ELECTRICAL SYSTEM
Charging System

• Remove:
Bolts [A]
Alternator Cover [B]

Alternator Cover Installation

• Replace the alternator cover gasket with a new one.
• Tighten: see that the knock pins [A] are in place.
Check to
•
Torque - Alternator Cover Bolts: 9.8 N·m (1.0 kgf·m, 87
in·lb)
• Install the shift lever, shift pedal and footboard as a set.
Torque - Rear Shift Lever Clamp Bolt: 12 N·m (1.2 kgf·m,
106 in·lb)
Footboard Bracket Bolts: 34 N·m (3.5 kgf·m, 25
ft·lb)
• Make sure shift rod nuts outside length is 149 ±1 mm (5.87
±0.04 in.).
Stator Coil Removal
• Remove:
Alternator Cover (see Alternator Cover Removal)
Bolts [A]
Alternator Lead Holder Plate [B]
Bolts [C]
Crankshaft Sensor [D]
Crankshaft Sensor and Alternator Lead Grommets [E]
Stator Coil Bolts [F]
• Remove the stator coil [G] from the alternator cover.
Stator Coil Installation
• Apply a non-permanent locking agent to the threads of
the stator coil bolts.
• Tighten:
Torque - Stator Coil Bolts: 12 N·m (1.2 kgf·m, 106 in·lb)
• Apply silicone sealant to the circumference of the alterna-
tor lead and crankshaft sensor lead grommets, and fit the
grommets into the notch of the cover securely.
Sealant - Kawasaki Bond (Silicone Sealant): 92104-0004
○First install the alternator lead grommet and then crank-
shaft sensor lead grommets.
• Secure the alternator lead and crankshaft sensor lead
with clamps, and tighten the bolts.
Torque - Alternator Lead Holder Plate Bolts: 5.9 N·m (0.60
kgf·m, 52 in·lb)
• Install
tion).
the alternator cover (see Alternator Cover Installa-

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 ELECTRICAL SYSTEM 16-33
Charging System
Alternator Rotor Removal
• Remove:
Alternator Cover (see Alternator Cover Removal).
• Hold the
Wipe oil off the outer circumference of the rotor.
• and removealternator rotor steady with the rotor holder [A],
the rotor bolt [B].
Special Tools - Rotor Holder: 57001-1674
Grip [C]: 57001-1591
○The rotor holder is prevented from turning by using the
suitable M10 bolt [D] and footboard bracket bolt hole.

• Using the rotor puller [A], remove the alternator rotor from
the crankshaft.
Special Tool - Rotor Puller, M16/M18/M20/M22 × 1.5: 57001
-1216

NOTE
○Screw in the puller while tapping the head [B] of the
puller with a hammer.

CAUTION
Do not attempt to strike the alternator rotor itself.
Striking the rotor can cause the magnets to lose
their magnetism.

Alternator Rotor Installation

• Using a cleaning fluid, clean off any oil or dirt on the fol-
lowing portions and dry them with a clean cloth.
[A] Crankshaft Tapered Portion
[B] Alternator Rotor Tapered Portion
• Fit the woodruff key securely in the slot [C] in the crank-
shaft before installing the alternator rotor.

• Align the left balancer mark [A] with the left crankcase
projection [B].

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 16-34 ELECTRICAL SYSTEM
Charging System

• When installing the alternator rotor, align the rotor mark

[A] with the left crankcase projection [B].
• Apply molybdenum disulfide oil solution to the threads
and seating surface of the alternator rotor bolt.

• Install the washer.

NOTE
○Confirm the alternator rotor fit or not to the crankshaft
before tightening it with specified torque.

• Install the rotor bolt and tighten it with 69 N·m (7.0 kgf·m,
52 ft·lb) of torque.
• Remove the rotor bolt and washer.
• wheel pullertightening
Check the
assembly.
torque with M20 bolt [A] in the fly-

Special Tool - Flywheel Puller Assembly, M38 × 1.5/M35 ×

1.5: 57001-1405
If the rotor is not pulled out with 20 N·m (2.0 kgf·m, 15
ft·lb) of drawing torque, it is installed correctly.
If the rotor is pulled out with under 20 N·m (2.0 kgf·m, 15
ft·lb) of drawing torque, clean off any oil dirt or flaw of the
crankshaft and rotor tapered portion, and dry them with
a clean cloth. Then, confirm that it is not pulled out with
above torque.

• Tighten the alternator rotor bolt [A] while holding the alter-
nator rotor steady with the rotor holder [B].
Special Tools - Rotor Holder: 57001-1674
Grip [C]: 57001-1591
○The rotor holder is prevented from turning by using the
suitable M10 bolt [D] and footboard bracket bolt hole.
Torque - Alternator Rotor Bolt: 160 N·m (16.3 kgf·m, 118
ft·lb)
• Install
tion).
the alternator cover (see Alternator Cover Installa-

Alternator Inspection
There are three types of alternator failures: short, open
(lead burned out), or loss in rotor magnetism. A short or
open in one of the stator coil lead will result in either a low
output, or no output at all. A loss in rotor magnetism, which
may be caused by dropping or hitting the alternator, by leav-
ing it near an electromagnetic field, or just by aging, will re-
sult in low output.

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 ELECTRICAL SYSTEM 16-35
Charging System

• To check the alternator output voltage, do the following

procedures.
○Remove the regulator/rectifier and disconnect the con-
nector [A].
○Connect the hand tester to the connector as shown.
Special Tool - Hand Tester: 57001-1394
○Start the engine.
○Run it at 4 000 rpm of the engine speed.
○Note the voltage readings.

Alternator Output Voltage

Tester Connections Reading
Range Tester (+) to Tester (–) to @3 000 rpm
54 V or
250 V AC One white lead Another white lead
more
If the output voltage shows the value in the table, the alter-
nator operates properly and the regulator/rectifier is dam-
aged. A much lower reading than the value in the table
indicates that the alternator is defective.
○Repeat the test for the other white leads.
Hand Tester [A]

•○Check the stator coil resistance as follows:

Turn off the ignition switch.
○Connect the hand tester [A] to the connector as shown in
the table.
○Note the resistance readings.
Stator Coil Resistance
Tester Connections
Reading
Range Tester (+) to Tester (–) to
×1 Ω One white lead Another white lead 0.11 ∼ 0.17 Ω
If there is more resistance than shown in the table, or no
hand tester reading (infinity), the stator has an open wire
and must be replaced. Much less than this resistance
means the stator is shorted, and must be replaced.
•Using the highest resistance range of the hand tester,
measure the resistance between each of the white leads
and chassis ground.
Any hand tester reading less than infinity (∞) indicates a
short, necessitating stator replacement.
If the stator coil has normal resistance, but the voltage
check showed the alternator to be defective, then the rotor
magnets have probably weakened, and the rotor must be
replaced.
○Repeat the test for the other white leads.

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 16-36 ELECTRICAL SYSTEM
Charging System
Regulator/Rectifier Removal
• Remove:
Bolts [A]
Regulator/Rectifier Cover [B]

• Remove:
Bolts [A]
Regulator/Rectifier [B]
Connector [C] (disconnect)

Regulator/Rectifier Inspection
Rectifier Circuit Check
•Remove the regulator/rectifier (see Regulator/Rectifier
Removal).
•Check conductivity of the following pair of terminals.
Rectifier Circuit Inspection
R-W1, R-W2, R-W3
Tester connection
BK-W1, BK-W2, BK-W3
The resistance should be low in one direction and more
than ten times as much in the other direction. If any two
leads are low or high in both directions, the rectifier is
defective and the regulator/rectifier must be replaced.
NOTE
○The actual meter reading varies with the meter used
and the individual rectifier, but, generally speaking the
lower reading should be from zero to one half the scale.
Regulator Circuit Check
To test the regulator out of circuit, use three 12 V batteries
and a test light (12 V 3 ∼ 6 W bulb in a socket with leads).
CAUTION
The test light works as an indicator and also a cur-
rent limiter to protect the regulator/rectifier from ex-
cessive current. Do not use an ammeter instead of
a test light.

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 ELECTRICAL SYSTEM 16-37
Charging System

•○Do the 1st step regulator circuit test.

Connect the test light and the 12 V battery to the regula-
tor/rectifier as shown.
○Check W1, W2 and W3 terminal respectively.
If the test light turns on, the regulator/rectifier is defective.
Replace it.
If the test light does not turn on, continue the test.

•○Do the 2nd step regulator circuit test.

Connect the test light and the 12 V battery in the same
manner as specified in the "1st step regulator circuit test".
○Apply 12 V to the BR terminal.
○Check W1, W2 and W3 terminal respectively.
If the test light turns on, the regulator/rectifier is defective.
Replace it.
If the test light does not turn on, continue the test.

•○Do the 3rd step regulator circuit test.

Connect the test light and the 12 V battery in the same
manner as specified in the "1st step regulator circuit test".
○Momentarily apply 24 V to the BR terminal by adding a 12
V battery.
○Check W1, W2, and W3 terminals respectively.
CAUTION
Do not apply more than 24 V to the regulator/recti-
fier and do not leave the 24 V applied for more than
a few seconds, or the unit will be damaged.
If the test light did not light when the 24 V was applied
momentarily to the BR terminal, the regulator/rectifier is
defective. Replace it. .
If the regulator/rectifier passes all of the tests described,
it may still be defective. If the charging system still does
not work properly after checking all of the components
and the battery, test the regulator/rectifier by replacing it
with a known good unit.

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 16-38 ELECTRICAL SYSTEM
Charging System
Charging Voltage Inspection
• Check the battery condition (see Charging Condition In-
spection).
• Warm up the engine to obtain actual alternator operating
conditions.
• Remove:
Seat (see Seat Removal in the Frame chapter)
Tool Box (see Tool Box Removal in the Frame chapter)
• Check that the ignition switch is turned off, and connect
the hand tester [A] to the battery terminals [B].
Special Tool - Hand Tester: 57001-1394
• Start the engine, and note the voltage readings at var-
ious engine speeds with the headlight turned on and
then turned off (To turn off the headlight, disconnect
the headlight connector on the headlight unit.). The
readings should show nearly battery voltage when the
engine speed is low, and, as the engine speed rises, the
readings should also rise. But they must be kept under
the specified voltage.
Charging Voltage
Connections
Tester Range Reading
Tester (+) to Tester (–) to
25 V DC Battery (+) Battery (–) 14.2 ∼ 15.2 V

• Turn off the ignition switch to stop the engine, and discon-
nect the hand tester.
If the charging voltage is kept between the values given in
the table, the charging system is considered to be working
normally.
If the charging voltage is much higher than the values
specified in the table, the regulator/rectifier is defective
or the regulator/rectifier leads are loose or open.
If the charging voltage does not rise as the engine speed
increases, then the regulator/rectifier is defective or the
alternator output is insufficient for the loads. Check the
alternator and regulator/rectifier to determine which part
is defective.

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 ELECTRICAL SYSTEM 16-39
Charging System
Charging System Circuit

1. Ignition Switch
2. Regulator/Rectifier
3. Alternator
4. Frame Ground
5. Battery
6. Main Fuse 30 A
7. Load

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