2003 YAMAHA YBR125 check engine

CONTENTS
DESCRIPTION............................................................. 1-1
MACHINE IDENTIFICATION ....................................... 2-1
Vehicle identification number ................................. 2-1
Engine serial number ............................................ 2-1
CONTROL FUNCTIONS .............................................. 3-1
Main switch ............................................................ 3-1
Indicator lights ........................................................ 3-2
Speedometer .......................................................... 3-3
Fuel gauge ............................................................. 3-3
Handlebar switches over left .................................. 3-4
Handlebar switches over right .............................. 3-5
Clutch lever .......................... .................................. 3-6
Shift pedal ............................................................. 3-6
Front brake lever ................................................... 3-7
Rear brake pedal ................................................... 3-7
Fuel tank cap ......................................................... 3-8
Fuel cock ............................................................... 3-9
Starter lever ......................................................... 3-10
Steering lock ....................... ................................ 3-11
Seat ...................................................................... 3-12
Side covers ......................................................... 3-13
Rear shock absorber adjustment........................ 3-14
Clutch switch operation check ............................ 3-15
XIPRE-OPERATION
CHECKS........................................ 4-1
Brakes ................................................................... 4-3
Brake fluid leakage ................................................ 4-4
Engine oil ................................................................ 4-4
Tires ........................................................................\
4-5
Clutch ..................................................................... 4-8
Throttle grip ............................ ................................ 4-8
Fitting/Fasteners .................................................... 4-8
Switches ................................................................ 4-8
Wheels ......................................................... 4-8
Fuel ........................................................... 4-9
OPERATION AND IMPORT ANT RIDING POINTS....... 5-1
Starting a cold engine .................................................. 5-2
Starting a warm engine ................................................ 5-4
Warming up the engine ................................................ 5-4
Shifting ........................................................................\
.. 5-5
Engine Break-in ............................................................ 5-6
Parking ........................................................................\
.. 5-7
CONTENTS
DESCRIPTION ............................................................. 1-1
MACHINE IDENTIFICATION ....................................... 2-1
Vehicle identification number ................................. 2-1
Engine serial number ............................................ 2-1
CONTROL FUNCTIONS .............................................. 3-1
Main switch ............................................................ 3-1
Indicator lights ........................................................ 3-2
Speedometer .......................................................... 3-3
Fuel gauge ............................................................. 3-3
Handlebar switches over left .................................. 3-4
Handlebar switches over right .............................. 3-5
Clutch lever .......................... .................................. 3-6
Shift pedal ............................................................. 3-6
Front brake lever ................................................... 3-7
Rear brake pedal ................................................... 3-7
Fuel tank cap ......................................................... 3-8
Fuel cock ............................................................... 3-9
Starter lever ......................................................... 3-10
Steering lock ....................... ................................ 3-11
Seat ...................................................................... 3-12
Side covers ......................................................... 3-13
Rear shock absorber adjustment........................ 3-14
Clutch switch operation check ............................ 3-15
XIPRE-OPERATION
CHECKS........................................ 4-1
Brakes ................................................................... 4-3
Brake fluid leakage ................................................ 4-4
Engine oil ................................................................ 4-4
Tires ........................................................................\
4-5
Clutch ..................................................................... 4-8
Throttle grip ............................ ................................ 4-8
Fitting/Fasteners .................................................... 4-8
Switches ................................................................ 4-8
Wheels ......................................................... 4-8
Fuel ........................................................... 4-9
OPERATION AND IMPORT ANT RIDING POINTS....... 5-1
Starting a cold engine .................................................. 5-2
Starting a warm engine ................................................ 5-4
Warming up the engine ................................................ 5-4
Shifting ........................................................................\
.. 5-5
Engine Break-in ............................................................ 5-6
Parking ........................................................................\
.. 5-7

PERIODIC MAINTENANCE AND MINOR REPAIRS..... 6-1
Tool kit..................................................................... 6-2
PERIODIC MAINTENANCE/LUBRICATION......... 6-3
Torque specifications............................................. 6-5
Engine oil................................................................ 6-6
Oil pressure ............................................................ 6-9
Air filter .................................................................6-10
Carburetor adjustment ......................................... 6-12
Valve clearance adjustment.................................6-12
Idle speed adjustment..........................................6-13
Throttle cable adjustment....................................6-14
Spark plug inspection...........................................6-15
Rear brake adjustment ......................................... 6-16
Brake light switch adjustment ..............................6-17
Checking the front brake pads and rear brake
shoes.................................................................... 6-17
Front brake...........................................................6-18
Rear brake ............................................................ 6-18
Inspecting the brake fluid level ............................6-19
Brake fluid replacement.......................................6-20
Clutch adjustment................................................6-20
Drive chain slack check .......................................6-21
Drive chain slack adjustment...............................6-22
Drive chain lubrication..........................................6-23
Cable inspection and lubrication..........................6-23
Throttle cable and grip lubrication.......................6-24Brake and shift pedals ......................................... 6-24
Brake and clutch levers ....................................... 6-24
Sidestand ............................................................. 6-24
Front fork inspection ............................................ 6-25
Steering inspection.............................................. 6-26
Wheel bearings.................................................... 6-26
Battery.................................................................. 6-27
Replenishing the battery fluid .............................. 6-28
Fuse replacement................................................ 6-29
Headlight bulb replacement................................. 6-30
Turn signal bulb replacement.............................. 6-32
Taillight bulb replacement.................................... 6-32
Front wheel removal............................................. 6-33
Front wheel installation........................................ 6-34
Rear wheel removal............................................. 6-35
Rear wheel installation ......................................... 6-36
Troubleshooting.................................................... 6-36
Troubleshooting chart.......................................... 6-37
CLEANING AND STORAGE....................................... 7-1
CLEANING............................................................. 7-1
STORAGE.............................................................. 7-2
SPECIFICATIONS ........................................................ 8-1
XII
PERIODIC MAINTENANCE AND MINOR REPAIRS..... 6-1
Tool kit..................................................................... 6-2
PERIODIC MAINTENANCE/LUBRICATION......... 6-3
Torque specifications............................................. 6-5
Engine oil................................................................ 6-6
Oil pressure ............................................................ 6-9
Air filter .................................................................6-10
Carburetor adjustment ......................................... 6-12
Valve clearance adjustment.................................6-12
Idle speed adjustment..........................................6-13
Throttle cable adjustment....................................6-14
Spark plug inspection...........................................6-15
Rear brake adjustment ......................................... 6-16
Brake light switch adjustment ..............................6-17
Checking the front brake pads and rear brake
shoes.................................................................... 6-17
Front brake...........................................................6-18
Rear brake ............................................................ 6-18
Inspecting the brake fluid level ............................6-19
Brake fluid replacement.......................................6-20
Clutch adjustment................................................6-20
Drive chain slack check .......................................6-21
Drive chain slack adjustment...............................6-22
Drive chain lubrication..........................................6-23
Cable inspection and lubrication..........................6-23
Throttle cable and grip lubrication.......................6-24Brake and shift pedals ......................................... 6-24
Brake and clutch levers ....................................... 6-24
Sidestand ............................................................. 6-24
Front fork inspection ............................................ 6-25
Steering inspection.............................................. 6-26
Wheel bearings.................................................... 6-26
Battery.................................................................. 6-27
Replenishing the battery fluid .............................. 6-28
Fuse replacement................................................ 6-29
Headlight bulb replacement................................. 6-30
Turn signal bulb replacement.............................. 6-32
Taillight bulb replacement.................................... 6-32
Front wheel removal............................................. 6-33
Front wheel installation........................................ 6-34
Rear wheel removal............................................. 6-35
Rear wheel installation ......................................... 6-36
Troubleshooting.................................................... 6-36
Troubleshooting chart.......................................... 6-37
CLEANING AND STORAGE....................................... 7-1
CLEANING............................................................. 7-1
STORAGE.............................................................. 7-2
SPECIFICATIONS ........................................................ 8-1
XII

 If improper operation is noted, consult a Yamaha dealer
or other qualified mechanic immediately.
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Clutch switch operation check
Check the operation of the clutch switch against the
information below.
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↓ ↓
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TURN MAIN SWITCH TO “ON” AND
ENGINE STOP SWITCH TO “ ”.
TRANSMISSION IS IN GEAR.
PULL IN CLUTCH LEVER AND PUSH STARTER SWITCH.
ENGINE WILL START
CLUTCH SWITCH IS OK
WARNING:

 If improper operation is noted, consult a Yamaha dealer
or other qualified mechanic immediately.
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Clutch switch operation check
Check the operation of the clutch switch against the
information below.
↓
↓ ↓
↓
↓
TURN MAIN SWITCH TO “ON” AND
ENGINE STOP SWITCH TO “ ”.
TRANSMISSION IS IN GEAR.
PULL IN CLUTCH LEVER AND PUSH STARTER SWITCH.
ENGINE WILL START
CLUTCH SWITCH IS OK
WARNING:

PRE-OPERATION CHECKS
Before using this motorcycle, check the following points:
ITEM ROUTINE
PAGE
Front brake
Check operation, condition and free play.
Adjust if necessary
Clutch
Throttle grip / cableCheck for smooth operation.
Lubricate / Adjust if necessary
Check oil level / add oil as necessary
Engine oil
Drive chainCheck chain slack and condition. Lubricate if necessary
Adjust if necessary.
Air filter
Control and meter cableCheck tire pressure, wear, damage and spoke tightness
Check for smooth operation.
Lubricate if necessary4-3 ~ 4-4
6-16 ~ 6-20
4-8 , 6-14 , 6-24
4-4 , 6-6 , 6-9
6-21 ~ 6-23
6-10 ~ 6-11
4-5 ~ 4-8 , 6-26
6-23 Check operation, condition and free play.
Adjust if necessary
Wheels / Tires
Clean and oil it frequently.4-8 , 6-20 Rear brakeCheck operation, free play, fluid level and fluid leakage.
Top-up with DOT #4 (or DOT #3) brake fluid if necessary.

PRE-OPERATION CHECKS
Before using this motorcycle, check the following points:
ITEM ROUTINE
PAGE
Front brake
Check operation, condition and free play.
Adjust if necessary
Clutch
Throttle grip / cableCheck for smooth operation.
Lubricate / Adjust if necessary
Check oil level / add oil as necessary
Engine oil
Drive chainCheck chain slack and condition. Lubricate if necessary
Adjust if necessary.
Air filter
Control and meter cableCheck tire pressure, wear, damage and spoke tightness
Check for smooth operation.
Lubricate if necessary4-3 ~ 4-4
6-16 ~ 6-20
4-8 , 6-14 , 6-24
4-4 , 6-6 , 6-9
6-21 ~ 6-23
6-10 ~ 6-11
4-5 ~ 4-8 , 6-26
6-23 Check operation, condition and free play.
Adjust if necessary
Wheels / Tires
Clean and oil it frequently.4-8 , 6-20 Rear brakeCheck operation, free play, fluid level and fluid leakage.
Top-up with DOT #4 (or DOT #3) brake fluid if necessary.



NOTE:
Pre-operation checks should be made each time the motorcycle is used. Su\
ch an inspection can be thoroughly accomplished
in a very short time; and the added safety it assures is more than worth\
the time involved. If any maintenance service or
adjustment is needed, consult the chart above to refer to the pages in w\
hich the service or adjustment is described.
1. The engine, exhaust pipe, and muffler will be very hot after the engine \
has been run.
Be careful not to touch them or to allow any clothing item to contact th\
em during inspection or repair.
2. If any item is not working properly, have it inspected and repaired before operating the motorcycle.
ITEM ROUTINE
PAGE
Sidestand
Fittings / Fasteners Check all chassi fittings and fasteners.
Tighten / Adjust, if necessary
Check fuel level / top up as required.
Fuel tank
Lights, signals and switches
Battery Check electrolyte level.
Replenish with “distilled water” if necessary. 6-24
4-8 , 6-5
4-8 , 6-30 ~ 6-32 6-27 ~ 6-296-24
4-9 ~ 4-10
Check for proper operation
Front brake and clutch lever pivots Check for smooth operation.
Lubricate if necessary
Check for smooth operation.
Lubricate if necessary
6-24
Check for smooth operation.
Lubricate if necessary
Rear brake and shift pedal
shafts
WARNING:

NOTE:
Pre-operation checks should be made each time the motorcycle is used. Su\
ch an inspection can be thoroughly accomplished
in a very short time; and the added safety it assures is more than worth\
the time involved. If any maintenance service or
adjustment is needed, consult the chart above to refer to the pages in w\
hich the service or adjustment is described.
1. The engine, exhaust pipe, and muffler will be very hot after the engine \
has been run.
Be careful not to touch them or to allow any clothing item to contact th\
em during inspection or repair.
2. If any item is not working properly, have it inspected and repaired before operating the motorcycle.
ITEM ROUTINE
PAGE
Sidestand
Fittings / Fasteners Check all chassi fittings and fasteners.
Tighten / Adjust, if necessary
Check fuel level / top up as required.
Fuel tank
Lights, signals and switches
Battery Check electrolyte level.
Replenish with “distilled water” if necessary. 6-24
4-8 , 6-5
4-8 , 6-30 ~ 6-32 6-27 ~ 6-296-24
4-9 ~ 4-10
Check for proper operation
Front brake and clutch lever pivots Check for smooth operation.
Lubricate if necessary
Check for smooth operation.
Lubricate if necessary
6-24
Check for smooth operation.
Lubricate if necessary
Rear brake and shift pedal
shafts
WARNING:

4-4
Brake fluid leakage
Apply the brake for several seconds. Check to see if any
brake fluid leaks out from the pipe joints or the master
cylinder.
Brake fluid may deteriorate painted surfaces or plastic parts.
Never spill any fluid. If spilled, clean it up immediately.
If brake fluid leakage is found, ask a Yamaha dealer or
other qualified mechanic for immediate repairs. Such
leakage could indicate a hazardous condition.
OIL QUANTITY:
Total amount:
1.2 L ( 0.264 Imp gal, 0.317 US gal)
Periodic oil change:
1.0 L ( 0.220 Imp gal, 0.264 US gal)
Engine oil
(See page 6-6 for details)
Make sure the engine oil is at the specified level. Add oil as
necessary.
Check the oil level in a daily manner and top it up if
necessary.
CAUTION:
WARNING:
CAUTION:
4-4
Brake fluid leakage
Apply the brake for several seconds. Check to see if any
brake fluid leaks out from the pipe joints or the master
cylinder.
Brake fluid may deteriorate painted surfaces or plastic parts.
Never spill any fluid. If spilled, clean it up immediately.
If brake fluid leakage is found, ask a Yamaha dealer or
other qualified mechanic for immediate repairs. Such
leakage could indicate a hazardous condition.
OIL QUANTITY:
Total amount:
1.2 L ( 0.264 Imp gal, 0.317 US gal)
Periodic oil change:
1.0 L ( 0.220 Imp gal, 0.264 US gal)
Engine oil
(See page 6-6 for details)
Make sure the engine oil is at the specified level. Add oil as
necessary.
Check the oil level in a daily manner and top it up if
necessary.
WARNING:
CAUTION:
CAUTION:

4-8Wheels
To ensure maximum performance, long service, and safe
operation, note the following:
1. Always inspect the wheels before a ride. Check for
cracks, bends, or warpage of the wheel; be sure the
spokes are tight and undamaged. If any abnormal
condition exists in a wheel, consult a Yamaha dealer or
other qualified mechanic. Do not attempt even small
repairs to the wheel. If a wheel is deformed or cracked,
it must be replaced.
2. Tires and wheels should be balanced whenever either one is changed or replaced. Failure to have a wheel
balanced can result in poor performance, adverse
handling characteristics, and shortened tire life.
3. After installing a tire, ride conservatively to allow the tire to seat itself on the rim properly. Failure to allow
proper seating may cause tire failure, resulting in
damage to the motorcycle and injury to the rider.
Clutch
( See page 6-20 for details)
Check the free play in the clutch lever, and make sure the
lever operates properly. If the free play is incorrect, adjust
it.
Throttle grip (See page 6-24 for details)
Turn the throttle grip to see if it operates properly, and check
the free play.
Make sure the grip returns by spring force when released.
Ask a Yamaha dealer or other qualified mechanic to make
any necessary adjustments.
Fitting/Fasteners
Alway check the tightness of chassis fittings and fasteners
before a ride. Use the chart on page 6-5 to find the correct
torque.
Switches
Check the operation of the starter switch, main switch, “
Engine Stop” switch.
4-8Wheels
To ensure maximum performance, long service, and safe
operation, note the following:
1. Always inspect the wheels before a ride. Check for
cracks, bends, or warpage of the wheel; be sure the
spokes are tight and undamaged. If any abnormal
condition exists in a wheel, consult a Yamaha dealer or
other qualified mechanic. Do not attempt even small
repairs to the wheel. If a wheel is deformed or cracked,
it must be replaced.
2. Tires and wheels should be balanced whenever either one is changed or replaced. Failure to have a wheel
balanced can result in poor performance, adverse
handling characteristics, and shortened tire life.
3. After installing a tire, ride conservatively to allow the tire to seat itself on the rim properly. Failure to allow
proper seating may cause tire failure, resulting in
damage to the motorcycle and injury to the rider.
Clutch
( See page 6-20 for details)
Check the free play in the clutch lever, and make sure the
lever operates properly. If the free play is incorrect, adjust
it.
Throttle grip (See page 6-24 for details)
Turn the throttle grip to see if it operates properly, and check
the free play.
Make sure the grip returns by spring force when released.
Ask a Yamaha dealer or other qualified mechanic to make
any necessary adjustments.
Fitting/Fasteners
Alway check the tightness of chassis fittings and fasteners
before a ride. Use the chart on page 6-5 to find the correct
torque.
Switches
Check the operation of the starter switch, main switch, “
Engine Stop” switch.

TURN THE MAIN SWITCH TO “ON” AND ENGINE STOP SWITCH TO “ ”
5-3
Before going through the following steps, check the
function of the clutch switch (See page 3-15)
ADVERTENCIA:
IF TRANSMISSION IS IN GEARPULL IN CLUTCH LEVER
AND PUSH STARTER SWITCH; ENGINE WILL START
MOTORCYCLE CAN BE RIDDEN
IF TRANSMISSION IS IN NEUTRAL
PUSH STARTER SWITCH; ENGINE WILL START
PUT TRANSMISSION IN GEAR
MOTORCYCLE CAN BE RIDDEN
WARNING:
TURN THE MAIN SWITCH TO “ON” AND ENGINE STOP SWITCH TO “ ”
5-3
Before going through the following steps, check the
function of the clutch switch (See page 3-15)
ADVERTENCIA:
IF TRANSMISSION IS IN GEARPULL IN CLUTCH LEVER
AND PUSH STARTER SWITCH; ENGINE WILL START
MOTORCYCLE CAN BE RIDDEN
IF TRANSMISSION IS IN NEUTRAL
PUSH STARTER SWITCH; ENGINE WILL START PUT TRANSMISSION IN GEAR
MOTORCYCLE CAN BE RIDDEN
WARNING: