YAMAHA YBR125 2003 Repair Manual

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Rear brake adjustment
A
a. Free play: 20 ~ 30 mm (0.8 ~ 1.2 in)
Check the free play the rear brake pedal free play should
be adjusted to 20 ~ 30 mm (0.8 ~ 1.2 in) at the brake pedal
end.
Turn the adjusting nut in direction  to increase free play
and in direction  to decrease free play.
Press the brake pedal several times and check if the wheel
turns free when the pedal is released.
For brake pedal adjustment, be sure to proceed as
follows (it is advisable to have a Yamaha dealer make
this adjustment.)
Check the operation of the brake light after adjusting
the rear brake.
1. Adjusting nut
CAUTION:
!!
Rear brake adjustment
A
a. Free play: 20 ~ 30 mm (0.8 ~ 1.2 in)
Check the free play the rear brake pedal free play should
be adjusted to 20 ~ 30 mm (0.8 ~ 1.2 in) at the brake pedal
end.
Turn the adjusting nut in direction  to increase free play
and in direction  to decrease free play.
Press the brake pedal several times and check if the wheel
turns free when the pedal is released.
For brake pedal adjustment, be sure to proceed as
follows (it is advisable to have a Yamaha dealer make
this adjustment.)
Check the operation of the brake light after adjusting
the rear brake.
1. Adjusting nut
CAUTION:

6-17
Brake light switch adjustment
The rear brake light switch is activated by the brake pedal
and is properly adjusted when the brake light comes on just
before braking takes effect. To adjust the rear brake light
switch, hold the switchbody so it does not rotate while turning
the adjusting nut.
Turn the adjusting nut in direction a to make the brake
light come on earlier.
Turn the adjusting nut in direction b to make the brake
light come on later.
1. Brake light switch 2. Adjusting nut
Checking the front brake pads and rear brake shoes
A wear indicator is provided on each brake. This indicator
allows checking of brake pad/shoe wear without
disassembling the brake.
6-17
Brake light switch adjustment
The rear brake light switch is activated by the brake pedal
and is properly adjusted when the brake light comes on just
before braking takes effect. To adjust the rear brake light
switch, hold the switchbody so it does not rotate while turning
the adjusting nut.
Turn the adjusting nut in direction a to make the brake
light come on earlier.
Turn the adjusting nut in direction b to make the brake
light come on later.
1. Brake light switch 2. Adjusting nut
Checking the front brake pads and rear brake shoes
A wear indicator is provided on each brake. This indicator
allows checking of brake pad/shoe wear without
disassembling the brake.

FRONT BRAKE
Apply the brake and inspect the wear indicator. If the wear
indicator is almost in contact with the disc plate, ask a
Yamaha dealer to replace the pads.!#REAR BRAKE
Apply the brake and inspect the wear indicator. If the
indicator reaches the wear limit line, ask a Yamaha dealer
to replace the shoes.
1. Wear indicator 2. Wear limit
1. Wear limit line 2. Wear indicator
FRONT BRAKE
Apply the brake and inspect the wear indicator. If the wear
indicator is almost in contact with the disc plate, ask a
Yamaha dealer to replace the pads.
!#REAR BRAKE
Apply the brake and inspect the wear indicator. If the
indicator reaches the wear limit line, ask a Yamaha dealer
to replace the shoes.
1. Wear indicator 2. Wear limit
1. Wear limit line 2. Wear indicator

!$
Inspecting the brake fluid level
Insufficient brake fluid may let air enter the brake system,
possibly causing the brakes to become ineffective. Before
riding, check that the brake fluid is above the lower level
and replenish when necessary. Observe these precautions:
1. When checking the fluid level, make sure the top of the
master cylinder is level by turning the handlebars.
2. Use only the designated quality brake fluid. Otherwise,
the rubber seals may deteriorate, causing leakage and
poor brake performance.
Recommended brake fluid:
DOT #4
NOTE:
If DOT #4 is not available, #3 can be used.
1. Lower level
3. Refill with the same type of brake fluid. Mixing fluids
may result in a harmful reaction and lead to poor brake
performance.
4. Be careful that water does not enter the master cylinder
when refilling. Water will significantly lower the boiling
point of the fluid and may result in vapor lock.
5. Brake fluid may deteriorate painted surfaces or plastic
parts. Always clean up spilled fluid immediately.
6. Have a Yamaha dealer check the cause if the brake
fluid level goes down.
!$
Inspecting the brake fluid level
Insufficient brake fluid may let air enter the brake system,
possibly causing the brakes to become ineffective. Before
riding, check that the brake fluid is above the lower level
and replenish when necessary. Observe these precautions:
1. When checking the fluid level, make sure the top of the
master cylinder is level by turning the handlebars.
2. Use only the designated quality brake fluid. Otherwise,
the rubber seals may deteriorate, causing leakage and
poor brake performance.
Recommended brake fluid:
DOT #4
NOTE:
If DOT #4 is not available, #3 can be used.
1. Lower level
3. Refill with the same type of brake fluid. Mixing fluids
may result in a harmful reaction and lead to poor brake
performance.
4. Be careful that water does not enter the master cylinder
when refilling. Water will significantly lower the boiling
point of the fluid and may result in vapor lock.
5. Brake fluid may deteriorate painted surfaces or plastic
parts. Always clean up spilled fluid immediately.
6. Have a Yamaha dealer check the cause if the brake
fluid level goes down.

Brake fluid replacement
1. Complete fluid replacement should be done only bytrained service personnel.
2. Have a Yamaha dealer replace the following components during periodic maintenance or when they
are damaged or leaking.
a. Replace all rubber seals every two years.
b. Replace all hoses every four years.
!%Clutch adjustment
The clutch lever free play should be adjusted to 10 ~ 15
mm (0.4 ~ 0.6 in) at the clutch lever end. If the free play is
incorrect, adjust as follows.
1. Loosen the locknut at the handlebar.
2. Turn the adjuster in or out until proper lever free play is
obtained.
3. Tighten the locknut.
4. If the free play is still incorrect, make an adjustment at the crankcase side.
NOTE:
If proper adjustment cannot be obtained or the clutch does
not work correctly, ask a Yamaha dealer to inspect the
internal clutch mechanism.
1. Locknut 2. Adjuster a. 10 ~ 15 mm (0.4 ~ 0.6 in)
Brake fluid replacement
1. Complete fluid replacement should be done only by trained service personnel.
2. Have a Yamaha dealer replace the following components during periodic maintenance or when they
are damaged or leaking.
a. Replace all rubber seals every two years.
b. Replace all hoses every four years.
!%Clutch adjustment
The clutch lever free play should be adjusted to 10 ~ 15
mm (0.4 ~ 0.6 in) at the clutch lever end. If the free play is
incorrect, adjust as follows.
1. Loosen the locknut at the handlebar.
2. Turn the adjuster in or out until proper lever free play is
obtained.
3. Tighten the locknut.
4. If the free play is still incorrect, make an adjustment at the crankcase side.
NOTE:
If proper adjustment cannot be obtained or the clutch does
not work correctly, ask a Yamaha dealer to inspect the
internal clutch mechanism.
1. Locknut 2. Adjuster a. 10 ~ 15 mm (0.4 ~ 0.6 in)

!


Drive chain slack check NOTE:
Spin the wheel several times and find the tightest position
of the chain. Check and/or adjust the chain slack while it is
in this tightest position.
To check the chain slack the motorcycle must be held
straight up with both wheels on the ground and without rider.
Check the slack at the position shown in the illustration.
Normal slack is approximately 20 ~ 30 mm ( 0.8 ~ 1.2
in). If the slack exceeds 30 mm ( 1.2 in), adjust.
a. 20 ~ 30 mm (0.8 ~ 1.2 in)
!


Drive chain slack check NOTE:
Spin the wheel several times and find the tightest position
of the chain. Check and/or adjust the chain slack while it is
in this tightest position.
To check the chain slack the motorcycle must be held
straight up with both wheels on the ground and without rider.
Check the slack at the position shown in the illustration.
Normal slack is approximately 20 ~ 30 mm ( 0.8 ~ 1.2
in). If the slack exceeds 30 mm ( 1.2 in), adjust.
a. 20 ~ 30 mm (0.8 ~ 1.2 in)

!
Drive chain slack adjustment
1. Locknut 2. Adjusting bolt
1. Loosen the rear brake pedal free play adjusting nut.
2. Loosen the axle nut.
3. Loosen the chain adjusting locknuts on each chainpuller. To tighten the chain, turn the chain adjusting nuts
in direction  .To loosen the chain turn the chain
adjusting nuts in direction  and push the wheel
forward. Turn each chain adjusting nut exactly the same
amount to maintain correct axle alignment. There are
marks on each chain puller. Use these marks to align
the rear wheel. Too little chain slack will overload the engine and other vital
parts. Keep the slack within the specified limits.
To maintain correct axle alignment, Ensure the notch on
the adjuster is on the same mark on left and right side
4. After adjusting, be sure to tighten each chain adjusting
locknut. The tighten the axle nut to the specified torque
Axle nut torque: 91 N.m (9.1 Kgf.m, 66 lbf.ft)
Locknut torque: 15 N.m (1.5 Kgf.m, 11 lbf.ft)
5. Adjust the free play in the brake pedal.
Check the operation of the brake light after adjusting
the rear brake.
CAUTION:
CAUTION:
!
Drive chain slack adjustment
1. Locknut 2. Adjusting bolt
1. Loosen the rear brake pedal free play adjusting nut.
2. Loosen the axle nut.
3. Loosen the chain adjusting locknuts on each chain puller. To tighten the chain, turn the chain adjusting nuts
in direction  .To loosen the chain turn the chain
adjusting nuts in direction  and push the wheel
forward. Turn each chain adjusting nut exactly the same
amount to maintain correct axle alignment. There are
marks on each chain puller. Use these marks to align
the rear wheel. Too little chain slack will overload the engine and other vital
parts. Keep the slack within the specified limits.
To maintain correct axle alignment, Ensure the notch on
the adjuster is on the same mark on left and right side
4. After adjusting, be sure to tighten each chain adjusting
locknut. The tighten the axle nut to the specified torque
Axle nut torque: 91 N.m (9.1 Kgf.m, 66 lbf.ft)
Locknut torque: 15 N.m (1.5 Kgf.m, 11 lbf.ft)
5. Adjust the free play in the brake pedal.
Check the operation of the brake light after adjusting
the rear brake.
CAUTION:
CAUTION:

6-23 Drive chain lubrication
The chain consists of many parts which work with each
other. If the chain is not maintained properly, it will wear out
quickly. Therefore, the chain must be serviced regularly.
This service is especially necessary when riding in dusty
areas.
1. Use Yamaha Chain and Cable Lube or any
brands of spray-type chain lubricant. First,
remove all dirt and mud from the chain with a
brush or cloth, then spray lubricant between both
rows of side plates and on all center rollers. The
chain should be lubricated every 500 km (300 mi).
2. To clean the chain, remove it from the machine,
dip it in solvent, and clean out as much dirt as
possible. Take the chain out of the solvent and
dry it. Immediately lubricate the chain to prevent
it from rusting.Cable inspection and lubrication
Damage to the outer housing of cables may allow
internal rusting and cause interfere with cable
movement. Replace damaged cables as soon as
possible to prevent unsafe conditions.
Lubricate the inner cable and the cable end. If it does not
operate smoothly, ask a Yamaha dealer to replace them.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50
WARNING:
6-23 Drive chain lubrication
The chain consists of many parts which work with each
other. If the chain is not maintained properly, it will wear out
quickly. Therefore, the chain must be serviced regularly.
This service is especially necessary when riding in dusty
areas.
1. Use Yamaha Chain and Cable Lube or any
brands of spray-type chain lubricant. First,
remove all dirt and mud from the chain with a
brush or cloth, then spray lubricant between both
rows of side plates and on all center rollers. The
chain should be lubricated every 500 km (300 mi).
2. To clean the chain, remove it from the machine,
dip it in solvent, and clean out as much dirt as
possible. Take the chain out of the solvent and
dry it. Immediately lubricate the chain to prevent
it from rusting.Cable inspection and lubrication
Damage to the outer housing of cables may allow
internal rusting and cause interfere with cable
movement. Replace damaged cables as soon as
possible to prevent unsafe conditions.
Lubricate the inner cable and the cable end. If it does not
operate smoothly, ask a Yamaha dealer to replace them.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50
WARNING:

6-24
Throttle cable and grip lubrication
The throttle twist grip assembly should be greased at the
time the cable is lubricated, since the grip must be removed
to get at the end of the throttle cable.
After removing the screws, hold the end of the cable up in
the air and put in several drops of lubricant. With the throttle
grip disassembled, coat the metal surface of the grip
assembly with a suitable all-purpose grease.Brake and shift pedals
Lubricate the pivoting parts.
RECOMMENDED LUBRICANT: Engine oil SAE 20W50
Brake and clutch levers
Lubricate the pivoting parts. RECOMMENDED LUBRICANT: Engine oil SAE 20W50
Sidestand
Lubricate the pivoting parts. Check to see that the sidestand
moves up and down smoothly. RECOMMENDED LUBRICANT: Engine oil SAE 20W50
WARNING:
If the sidestand does not move smoothly, consult a
Yamaha dealer.
CAUTION:
6-24
Throttle cable and grip lubrication
The throttle twist grip assembly should be greased at the
time the cable is lubricated, since the grip must be removed
to get at the end of the throttle cable.
After removing the screws, hold the end of the cable up in
the air and put in several drops of lubricant. With the throttle
grip disassembled, coat the metal surface of the grip
assembly with a suitable all-purpose grease. Brake and shift pedals
Lubricate the pivoting parts.
RECOMMENDED LUBRICANT: Engine oil SAE 20W50
Brake and clutch levers
Lubricate the pivoting parts. RECOMMENDED LUBRICANT: Engine oil SAE 20W50
Sidestand
Lubricate the pivoting parts. Check to see that the sidestand
moves up and down smoothly. RECOMMENDED LUBRICANT: Engine oil SAE 20W50
WARNING:
If the sidestand does not move smoothly, consult a
Yamaha dealer.
CAUTION:

6-25
1. Visual check
Check for scratches or damage on the inner tube and
excessive oil leakage from the front fork.
2. Operation check
Place the motorcycle on a level place.
a. Hold the motorcycle in an upright position and apply
the front brake.
b. Push down hard several times and check if the fork
rebounds smoothly.
If any damage or unsmooth movement is found with
the front fork, consult a Yamaha dealer. Front fork inspection
Securely support the motorcycle so there is no danger
of it falling over.
CAUTION:
WARNING:
6-25
1. Visual check
Check for scratches or damage on the inner tube and
excessive oil leakage from the front fork.
2. Operation check
Place the motorcycle on a level place.
a. Hold the motorcycle in an upright position and apply
the front brake.
b. Push down hard several times and check if the fork
rebounds smoothly.
If any damage or unsmooth movement is found with
the front fork, consult a Yamaha dealer. Front fork inspection
Securely support the motorcycle so there is no danger
of it falling over.
CAUTION:
WARNING: