YAMAHA YZF-R125 2008 Repair Manual

PERIODIC MAINTENANCE AND MINOR REPAIR
6-29
6
EAU23310
Battery A poorly maintained battery will corrode
and discharge quickly. The electrolyte
level, battery lead connections and
breather hose routing should be
checked before each ride and at the in-
tervals specified in the periodic mainte-
nance and lubrication chart.
To check the electrolyte level
1. Place the vehicle on a level sur-
face and hold it in an upright posi-
tion.NOTE:Make sure that the vehicle is positioned
straight up when checking the electro-lyte level.
2. Check the electrolyte level in the
battery.NOTE:The electrolyte should be between theminimum and maximum level marks.3. If the electrolyte is at or below the
minimum level mark, add distilled
water to raise it to the maximum
level mark.
WARNING
EWA10770


Electrolyte is poisonous and
dangerous since it contains sul-
furic acid, which causes severe
burns. Avoid any contact with
skin, eyes or clothing and al-
ways shield your eyes when
working near batteries. In case
of contact, administer the fol-
lowing FIRST AID.
EXTERNAL: Flush with plenty
of water.INTERNAL: Drink large quan-
tities of water or milk and im-
mediately call a physician.
EYES: Flush with water for 15
minutes and seek prompt
medical attention.


Batteries produce explosive hy-
drogen gas. Therefore, keep
sparks, flames, cigarettes, etc.,
away from the battery and pro-
vide sufficient ventilation when
charging it in an enclosed
space.


Take care not to spill electrolyte
on the drive chain, as this may
weaken it, shorten chain life and
possibly result in an accident.


KEEP THIS AND ALL BATTER-
IES OUT OF THE REACH OFCHILDREN.
CAUTION:
ECA10610
Use only distilled water, as tap water
contains minerals that are harmfulto the battery.
4. Check and, if necessary, tighten
the battery lead connections and
correct the breather hose routing.
1. Maximum level mark
2. Minimum level mark1
2
+
UPPER
LOWER
ZAUM0106
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-30
6To store the battery
1. If the motorcycle will not be used
for more than one month, remove
the battery, fully charge it, and then
place it in a cool, dry place.
2. If the battery will be stored for more
than two months, check the specif-
ic gravity of the electrolyte at least
once a month and fully charge the
battery whenever necessary.
3. Fully charge the battery before in-
stallation.
4. After installation, make sure that
the battery leads are properly con-
nected to the battery terminals and
that the breather hose is properly
routed, in good condition, and not
obstructed.
CAUTION:
ECA10600
If the breather hose is positioned in
such a way that the frame is ex-
posed to electrolyte or gas expelled
from the battery, the frame could
suffer structural and external dam-ages.
EAUM2410
Replacing the fuses The fuse box is located under the rider
seat. (See page 3-9.)
If a fuse is blown, replace it as follows.
1. Turn the key to “OFF” and turn off
the electrical circuit in question.
2. Remove the blown fuse, and then
install a new fuse of the specified
amperage.
CAUTION:
ECA10640
Do not use a fuse of a higher amper-
age rating than recommended to
avoid causing extensive damage to
the electrical system and possibly afire.
3. Turn the key to “ON” and turn on
the electrical circuit in question to
check if the device operates.
4. If the fuse immediately blows
again, have a Yamaha dealer
check the electrical system.
1. Fuse box
2. Spare fuse
3. Headlight fuse
4. Signaling system fuse
5. Ignition fuse
6. Radiator fan fuse
7. Main fuse
Specified fuses:
Main fuse:
20.0 A
Ignition fuse:
7.5 A
Signaling system fuse:
7.5 A
Headlight fuse:
15.0 A
Radiator fan fuse:
5.0 A
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-31
6
EAU34240
Replacing a headlight bulb This model is equipped with quartz bulb
headlights. If a headlight bulb burns
out, have a Yamaha dealer replace it
and, if necessary, adjust the headlight
beam.
EAU24181
Tail/brake light This model is equipped with an LED-
type tail/brake light.
If the tail/brake light does not come on,
have a Yamaha dealer check it.
EAU24202
Replacing a turn signal light
bulb 1. Remove the turn signal light lens
by removing the screw.
2. Remove the defective bulb by
pushing it in and turning it counter-
clockwise.
3. Insert a new bulb into the socket,
push it in, and then turn it clock-
wise until it stops.
4. Install the lens by installing the
screw.CAUTION:
ECA11190
Do not overtighten the screw, other-wise the lens may break.1. Screw
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PERIODIC MAINTENANCE AND MINOR REPAIR
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6
EAUM2200
Replacing the license plate
light bulb 1. Remove the socket (together with
the bulb) by pulling it out.
2. Remove the defective bulb by pull-
ing it out.
3. Insert a new bulb into the socket.
4. Install the socket (together with the
bulb) by pushing it in.
EAU43230
Replacing an auxiliary light
bulb This model is equipped with two auxil-
iary lights. If an auxiliary light bulb burns
out, replace it as follows.
1. Remove the socket (together with
the bulb) by pulling it out.
2. Remove the defective bulb by pull-
ing it out.
3. Insert a new bulb into the socket.
4. Install the socket (together with the
bulb) by pushing it in.
EAU24350
Supporting the motorcycle Since this model is not equipped with a
centerstand, follow these precautions
when removing the front and rear
wheel or performing other maintenance
requiring the motorcycle to stand up-
right. Check that the motorcycle is in a
stable and level position before starting
any maintenance. A strong wooden
box can be placed under the engine for
added stability.
To service the front wheel
1. Stabilize the rear of the motorcycle
by using a motorcycle stand or, if
an additional motorcycle stand is
not available, by placing a jack un-
der the frame in front of the rear
wheel.
2. Raise the front wheel off the
ground by using a motorcycle
stand.
To service the rear wheel
Raise the rear wheel off the ground by
using a motorcycle stand or, if a motor-
cycle stand is not available, by placing
1. License plate light bulb
1. Auxiliary light bulb
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-33
6 a jack either under each side of the
frame in front of the rear wheel or under
each side of the swingarm.
EAU24360
Front wheel
EAUM2420
To remove the front wheel
WARNING
EWA10820


It is advisable to have a Yamaha
dealer service the wheel.


Securely support the motor-
cycle so that there is no dangerof it falling over.
1. Loosen the front wheel axle pinch
bolt, then the wheel axle and the
brake caliper bolts.
2. Lift the front wheel off the ground
according to the procedure on
page 6-32.3. Remove the speed sensor lead
holder by removing the bolt.
4. Remove the brake hose holder by
removing the bolt.
5. Remove the brake caliper by re-
moving the bolts.
1. Front wheel axle pinch bolt
1. Speed sensor cable holder
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-34
66. Pull the wheel axle out, remove the
speed sensor by pulling it out, and
then remove the wheel.
CAUTION:
ECA11050
Do not apply the brake after the
brake calipers have been removed,
otherwise the brake pads will beforced shut.
EAUM2430
To install the front wheel
1. Lift the wheel up between the fork
legs.
2. Install the speed sensor at the
wheel hub.NOTE:Make sure that the projections on the
speed sensor rotor are aligned with the
notches in the wheel hub and that the
slot in the speed sensor fits over the re-tainer on the fork leg.
3. Insert the wheel axle.
4. Lower the front wheel so that it is
on the ground.
5. Push down hard on the handlebar
several times to check for proper
fork operation.
6. Install the brake caliper by install-
ing the bolts.
NOTE:Make sure that there is enough space
between the brake pads before install-
ing the brake caliper onto the brakedisc.
7. Install the brake hose holder by in-
stalling the bolt.
8. Install the speed sensor lead hold-
er by installing the bolt.
9. Tighten the wheel axle, front wheel
axle pinch bolt and brake caliper
bolts to the specified torques.
1. Brake hose holder
2. Brake caliper bolt
3. Brake caliper
4. Axle bolt
1. Speedometer gear unit
Tightening torques:
Wheel axle:
59 Nm (5.9 m·kgf, 43 ft·lbf)
Front wheel axle pinch bolt:
14 Nm (1.4 m·kgf, 10 ft·lbf)
Brake caliper bolt:
30 Nm (3.0 m·kgf, 22 ft·lbf)
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-35
6
EAU25080
Rear wheel
EAU25311
To remove the rear wheel
WARNING
EWA10820


It is advisable to have a Yamaha
dealer service the wheel.


Securely support the motor-
cycle so that there is no dangerof it falling over.
1. Loosen the axle nut.
2. Lift the rear wheel off the ground
according to the procedure on
page 6-32.3. Remove the axle nut.
4. Loosen the locknut on each side of
the swingarm.
5. Turn the drive chain slack adjust-
ing bolts fully in direction (a) and
push the wheel forward.
6. Remove the drive chain from the
rear sprocket.
NOTE:

If the drive chain is difficult to re-
move, remove the wheel axle first,
and then lift the wheel upward
enough to remove the drive chain
from the rear sprocket.


The drive chain cannot be disas-sembled.7. While supporting the brake caliper
bracket, pull the wheel axle out,
and then remove the wheel.
CAUTION:
ECA11070
Do not apply the brake after the
wheel has been removed together
with the brake disc, otherwise thebrake pads will be forced shut.
EAU39411
To install the rear wheel
1. Install the wheel and the brake cal-
iper bracket by inserting the wheel
axle from the left-hand side.NOTE:

Make sure that the slot in the brake
caliper bracket is fit over the retain-
er on the swingarm.


Make sure that there is enough
space between the brake pads be-fore installing the wheel.
1. Axle nut
2. Drive chain slack adjusting bolt
3. Locknut
4. Brake caliper
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-36
62. Install the drive chain onto the rear
sprocket.
3. Install the axle nut, and then lower
the rear wheel so that it is on the
ground.
4. Adjust the drive chain slack. (See
page 6-22.)
5. Tighten the axle nut to the speci-
fied torque.
EAU25870
Troubleshooting Although Yamaha motorcycles receive
a thorough inspection before shipment
from the factory, trouble may occur dur-
ing operation. Any problem in the fuel,
compression, or ignition systems, for
example, can cause poor starting and
loss of power.
The following troubleshooting charts
represent quick and easy procedures
for checking these vital systems your-
self. However, should your motorcycle
require any repair, take it to a Yamaha
dealer, whose skilled technicians have
the necessary tools, experience, and
know-how to service the motorcycle
properly.
Use only genuine Yamaha replace-
ment parts. Imitation parts may look like
Yamaha parts, but they are often inferi-
or, have a shorter service life and can
lead to expensive repair bills.
1. Retainer
2. SlotTightening torque:
Axle nut:
85 Nm (8.5 m·kgf, 61 ft·lbf)
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-37
6
EAUM2440
Troubleshooting charts Starting problems or poor engine performance
WARNING
EWA10840
Keep away open flames and do not smoke while checking or working on the fuel system.
Check the fuel level in
the fuel tank.1. Fuel
There is enough fuel.
There is no fuel.
Check the compression.
Supply fuel.
Operate the electric starter.2. Compression
There is compression.
There is no compression.
Check the ignition.
Have a Yamaha dealer
check the vehicle.
Remove the spark plug
and check the electrodes.3. Ignition
Wet
Dry
Wipe off with a dry cloth and correct the
spark plug gap, or replace the spark plug.
Have a Yamaha dealer check the vehicle.The engine does not start.
Check the battery.
Operate the electric starter.
Operate the electric starter.4. Battery
The engine turns over
quickly.
The engine turns over
slowly.The battery is good.
Check the electrolyte and battery
lead connections, and charge the
battery if necessary.The engine does not start.
Have a Yamaha dealer
check the vehicle.
The engine does not start.
Check the compression.
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PERIODIC MAINTENANCE AND MINOR REPAIR
6-38
6Engine overheating
WARNING
EWA10400


Do not remove the radiator cap when the engine and radiator are hot. Scalding hot fluid and steam may be
blown out under pressure, which could cause serious injury. Be sure to wait until the engine has cooled.


After removing the radiator cap retaining bolt, place a thick rag, like a towel, over the radiator cap, and then
slowly rotate the cap counterclockwise to the detent to allow any residual pressure to escape. When the hissingsound has stopped, press down on the cap while turning it counterclockwise, and then remove the cap.
NOTE:If coolant is not available, tap water can be temporarily used instead, provided that it is changed to the recommended coolantas soon as possible.
Wait until the
engine has cooled.
Check the coolant level in the
reservoir and radiator.
The coolant level
is OK.The coolant level is low.
Check the cooling system
for leakage.
Have a Yamaha dealer checkand repair the cooling system.Add coolant. (See NOTE.)
Start the engine. If the engine overheats again,
have a
Yamaha dealer check
and repair the cooling system.
There is
leakage.
There is
no leakage.
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