engine YAMAHA YBR125 2004 Owners Manual

2. ENGINE SERIAL NUMBER: IDENTIFICATION NUMBERS RECORD
Record the frame serial number and engine serial number in the spaces provided for assistance when
ordering spare parts from a Yamaha dealer or reference in case the vehicle is stolen.
1. FRAME SERIAL NUMBER:
II
2. ENGINE SERIAL NUMBER: IDENTIFICATION NUMBERS RECORD
Record the frame serial number and engine serial number in the spaces provided for assistance when
ordering spare parts from a Yamaha dealer or reference in case the vehicle is stolen.
1. FRAME SERIAL NUMBER:
II

VIII
PROTECTIVE APPAREL
The majority of fatalities from machine accidents are the result of head injuries. The use of a safety helmet is the single
most critical factor in the prevention or reduction of head injuries.
1. Always wear an approved helmet.
2. Wear a face shield or goggles. Wind on your unprotected eyes could contribute to an impairment of vision which could
delay seeing a hazard.
3. The use of heavy boots, jacket, trousers, gloves, etc. is effective in preventing or reducing abrasions or lacerations.
4. Never wear loose fitting clothing. It could catch on the control levers, footrests, or wheels and cause injury or accident.
5. Never touch the engine or exhaust system during or after operation. They become very hot and can cause burns.
Always wear protective clothing that covers your legs, ankles and feet.
6. Always use clear clothes to make your visualization easier.
7. Items above must also be followed by pillion rider.
MODIFICATION
Modifications made to the machine not approved by Yamaha, or the removal of original equipment, may render your
machine unsafe for use and may cause severe personal injury. Modifications may also make your machine illegal to use.
VIII
PROTECTIVE APPAREL
The majority of fatalities from machine accidents are the result of head injuries. The use of a safety helmet is the single
most critical factor in the prevention or reduction of head injuries.
1. Always wear an approved helmet.
2. Wear a face shield or goggles. Wind on your unprotected eyes could contribute to an impairment of vision which could
delay seeing a hazard.
3. The use of heavy boots, jacket, trousers, gloves, etc. is effective in preventing or reducing abrasions or lacerations.
4. Never wear loose fitting clothing. It could catch on the control levers, footrests, or wheels and cause injury or accident.
5. Never touch the engine or exhaust system during or after operation. They become very hot and can cause burns.
Always wear protective clothing that covers your legs, ankles and feet.
6. Always use clear clothes to make your visualization easier.
7. Items above must also be followed by pillion rider.
MODIFICATION
Modifications made to the machine not approved by Yamaha, or the removal of original equipment, may render your
machine unsafe for use and may cause severe personal injury. Modifications may also make your machine illegal to use.

IX
ACCESSORIES AND LOADING
Adding accessories or cargo to your machine can adversely affect stability and handling if the weight distribution of the machine
is changed. To avoid the possibility of an accident, extreme caution should be used if adding cargo or accessories to your
machine.
Use extra care if riding a machine which has added cargo or acessories. Genuine Yamaha accessories have been specifically
designed for use on this machine. Since Yamaha cannot test all other accessories which may be available, you must personally
be responsible for the proper selection, installation and use of non-Yamaha accessories.
You should use extreme caution when selecting and installing any accessories. Keep in mind these guidelines for mounting
accessories in addition to those provided under ìLOADINGî.
1. Never install accessories or carry cargo that would impair the performance of your machine. Carefully inspect the accessory
before using it to make sure it does not in any way reduce ground clearance or cornering clearance, limit suspension travel,
steering travel or control operation, or obscure lights or reflectors.
a. Accessories fitted to the handlebar or the front fork area can create instability due to improper weight distribution or aerodynamic
changes. If accessories are added to the handlebar or front fork area, they must be as lightweight as possible and should be kept
to a minimum.
b. Bulky or large accessories may seriously affect the stability of the machine due to aerodynamic effects. Wind may
attempt to lift the machine, or the machine may become unstable in cross winds. These accessories may also cause instability
when being passed by or passing large vehicles.
c. Certain accessories can displace the operator from his or her normal riding position. This improper position limits the
freedom of movement of the operator and may limit control ability. Therefore such accessories are not recommended.
2. Caution must be used if adding electrical accessories. If these accessories exceed the capacity of the machineís electrical
system, an electric failure could result, which could cause a dangerous loss of lights or engine power.
IX
ACCESSORIES AND LOADING
Adding accessories or cargo to your machine can adversely affect stability and handling if the weight distribution of the machine
is changed. To avoid the possibility of an accident, extreme caution should be used if adding cargo or accessories to your
machine.
Use extra care if riding a machine which has added cargo or acessories. Genuine Yamaha accessories have been specifically
designed for use on this machine. Since Yamaha cannot test all other accessories which may be available, you must personally
be responsible for the proper selection, installation and use of non-Yamaha accessories.
You should use extreme caution when selecting and installing any accessories. Keep in mind these guidelines for mounting
accessories in addition to those provided under ìLOADINGî.
1. Never install accessories or carry cargo that would impair the performance of your machine. Carefully inspect the accessory
before using it to make sure it does not in any way reduce ground clearance or cornering clearance, limit suspension travel,
steering travel or control operation, or obscure lights or reflectors.
a. Accessories fitted to the handlebar or the front fork area can create instability due to improper weight distribution or aerodynamic
changes. If accessories are added to the handlebar or front fork area, they must be as lightweight as possible and should be kept
to a minimum.
b. Bulky or large accessories may seriously affect the stability of the machine due to aerodynamic effects. Wind may
attempt to lift the machine, or the machine may become unstable in cross winds. These accessories may also cause instability
when being passed by or passing large vehicles.
c. Certain accessories can displace the operator from his or her normal riding position. This improper position limits the
freedom of movement of the operator and may limit control ability. Therefore such accessories are not recommended.
2. Caution must be used if adding electrical accessories. If these accessories exceed the capacity of the machineís electrical
system, an electric failure could result, which could cause a dangerous loss of lights or engine power.

X
GASOLINE AND EXHAUST GAS
1. GASOLINE IS HIGHLY FLAMMABLE:
a. Always turn off the engine when refueling.
b. Take care not to spill any gasoline on the engine or exhaust system when refueling.
c. Never refuel while smoking or in the vicinity of an open flame.
2. Never start the engine or let it run for any length of time in a closed area. The exhaust fumes are poisonous and may cause
loss of consciousness and death within a short time. Always operate your motorcycle in an area that has adequate ventilation.
3. Always turn off the engine before leaving the machine unattended and remove the ignition key. When parking the machine,
note the following:
a. The engine and exhaust system may be hot. Park the machine in a place where pedestrians or children are not likely to
touch these hot areas.
b. Do not park the machine on a slope or soft ground; the machine may fall over.
c. Do not park the machine near a flammable source, e. g. a kerosene heater, or near an open flame. The machine could
catch fire.
4. When transporting the machine in another vehicle, be sure it is kept upright and that the fuel cock is turned to ìONî or ìRESî
(for vacuum type) / ìOFFî (for manual type).
If it should lean over, gasoline may leak out of the carburetor or fuel tank.
5. If you should swallow any gasoline, inhale a lot of gasoline vapor, or allow gasoline to get in your eyes, see your doctor
immediately. If any gasoline spills on your skin or clothing, immediately wash it off with soap and water and change your
clothes.
X
GASOLINE AND EXHAUST GAS
1. GASOLINE IS HIGHLY FLAMMABLE:
a. Always turn off the engine when refueling.
b. Take care not to spill any gasoline on the engine or exhaust system when refueling.
c. Never refuel while smoking or in the vicinity of an open flame.
2. Never start the engine or let it run for any length of time in a closed area. The exhaust fumes are poisonous and may cause
loss of consciousness and death within a short time. Always operate your motorcycle in an area that has adequate ventilation.
3. Always turn off the engine before leaving the machine unattended and remove the ignition key. When parking the machine,
note the following:
a. The engine and exhaust system may be hot. Park the machine in a place where pedestrians or children are not likely to
touch these hot areas.
b. Do not park the machine on a slope or soft ground; the machine may fall over.
c. Do not park the machine near a flammable source, e. g. a kerosene heater, or near an open flame. The machine could
catch fire.
4. When transporting the machine in another vehicle, be sure it is kept upright and that the fuel cock is turned to ìONî or ìRESî
(for vacuum type) / ìOFFî (for manual type).
If it should lean over, gasoline may leak out of the carburetor or fuel tank.
5. If you should swallow any gasoline, inhale a lot of gasoline vapor, or allow gasoline to get in your eyes, see your doctor
immediately. If any gasoline spills on your skin or clothing, immediately wash it off with soap and water and change your
clothes.

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
Kick starter .......................................................... 3-10
Steering lock....................................................... 3-11
Seat......................................................................3-12
Side covers......................................................... 3-13
Rear shock absorber adjustment ....................... 3-14
XIPRE-OPERATION CHECKS........................................ 4-1
Engine oil................................................................ 4-3
Tires........................................................................4-3
Fitting/Fasteners....................................................4-6
Switches................................................................ 4-6
Wheels ......................................................... 4-6
Fuel ........................................................... 4-7
OPERATION AND IMPORTANT RIDING POINTS....... 5-1
Starting a cold engine........................................... 5-2
Starting a warm engine .......................................... 5-2
Warming up the engine .......................................... 5-2
Shifting ................................................................... 5-3
Tips for reduccing fuel consumption...................... 5-4
Engine Break-in...................................................... 5-4
Parking ................................................................... 5-5
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
Kick starter .......................................................... 3-10
Steering lock....................................................... 3-11
Seat......................................................................3-12
Side covers......................................................... 3-13
Rear shock absorber adjustment ....................... 3-14
XIPRE-OPERATION CHECKS........................................ 4-1
Engine oil................................................................ 4-3
Tires........................................................................4-3
Fitting/Fasteners....................................................4-6
Switches................................................................ 4-6
Wheels ......................................................... 4-6
Fuel ........................................................... 4-7
OPERATION AND IMPORTANT RIDING POINTS....... 5-1
Starting a cold engine........................................... 5-2
Starting a warm engine .......................................... 5-2
Warming up the engine .......................................... 5-2
Shifting ................................................................... 5-3
Tips for reduccing fuel consumption...................... 5-4
Engine Break-in...................................................... 5-4
Parking ................................................................... 5-5

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
Front brake adjustment........................................6-16
Checking the brake shoes ...................................6-16
Rear brake adjustment.........................................6-17
Brake light switch adjustment ..............................6-18
Clutch adjustment................................................ 6-18
Drive chain slack check.......................................6-19
Drive chain slack adjustment...............................6-20
Drive chain lubrication..........................................6-21
Cable inspection and lubrication.......................... 6-21
Throttle cable and grip lubrication .......................6-22
Brake and shift pedals .........................................6-22
Brake and clutch levers .......................................6-22
Sidestand.............................................................6-22
Front fork inspection............................................6-23Steering inspection.............................................. 6-24
Wheel bearings.................................................... 6-24
Battery.................................................................. 6-25
Replenishing the battery fluid .............................. 6-26
Storage the battery.............................................. 6-27
Fuse replacement................................................ 6-27
Headlight bulb replacement................................. 6-28
Turn signal bulb replacement.............................. 6-30
Taillight bulb replacement.................................... 6-30
Front wheel removal............................................. 6-31
Front wheel installation........................................ 6-32
Rear wheel removal............................................. 6-32
Rear wheel installation......................................... 6-33
Troubleshooting.................................................... 6-34
Troubleshooting chart.......................................... 6-35
CLEANING AND STORAGE....................................... 7-1
CLEANING............................................................. 7-1
STORAGE.............................................................. 7-2
SPECIFICATIONS ........................................................ 8-1
XII
CONTENTS
DESCRIPTION............................................................. 1-1
MACHINE IDENTIFICATION....................................... 2-1
Vehicle identikfication 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
Kick starter .......................................................... 3-10
Steering lock....................................................... 3-11
Seat......................................................................3-12
Side covers......................................................... 3-13
Rear shock absorber adjustment ....................... 3-14
XIPRE-OPERATION CHECKS........................................ 4-1
Engine oil................................................................ 4-3
Tires........................................................................4-3
Fitting/Fasteners....................................................4-6
Switches................................................................ 4-6
Wheels ......................................................... 4-6
Fuel ........................................................... 4-7
OPERATION AND IMPORTANT RIDING POINTS....... 5-1
Starting a cold engine........................................... 5-2
Starting a warm engine .......................................... 5-2
Warming up the engine .......................................... 5-2
Shifting ................................................................... 5-3
Tips for reduccing fuel consumption...................... 5-4
Engine Break-in...................................................... 5-4
Parking ................................................................... 5-5

2-1 Vehicle identification number
The vehicle identification number is stamped into the
steering head pipe.Record this number in the space
provided.
1. Frame number 2. Production year
Engine serial number
The engine serial number is stamped on right-hand engine
crankcase.
1. Engine serial number
NOTE:
Model code is indicated by 4th to 8th A digits and serial
number is indicated by 12th to 17th digits B. Record these
numbers for reference in case of ordering parts from a
Yamaha dealer.
MACHINE IDENTIFICATION
AB
2-1 Vehicle identification number
The vehicle identification number is stamped into the
steering head pipe.Record this number in the space
provided.
1. Frame number 2. Production year
Engine serial number
The engine serial number is stamped on right-hand engine
crankcase.
1. Engine serial number
NOTE:
Model code is indicated by 4th to 8th A digits and serial
number is indicated by 12th to 17th digits B. Record these
numbers for reference in case of ordering parts from a
Yamaha dealer.
MACHINE IDENTIFICATION
AB

3-1
CONTROL FUNCTIONS
Main switch
The main switch controls the ignition and the electrical
system. Itís operation is described below.
ON:
Electrical circuits are switched on. Engine can be started.
The key cannot be removed.
OFF:
All electrical circuits are switched off. The key can be
removed.
LOCK:
The steering is locked and all electrical circuits are switched
off. The key can be removed. Refer to page (3-11) ìSteering
lockî for instructions.
NOTE:
Always turn the main switch to ìOFFî or ìLOCKî and remove
the key when the motorcycle is unattended.
3-1
CONTROL FUNCTIONS
Main switch
The main switch controls the ignition and the electrical
system. Itís operation is described below.
ON:
Electrical circuits are switched on. Engine can be started.
The key cannot be removed.
OFF:
All electrical circuits are switched off. The key can be
removed.
LOCK:
The steering is locked and all electrical circuits are switched
off. The key can be removed. Refer to page (3-11) ìSteering
lockî for instructions.
NOTE:
Always turn the main switch to ìOFFî or ìLOCKî and remove
the key when the motorcycle is unattended.

Handlebar switches over rigt
1. ìENGINE STOPî switch, shuts the engine off
3-5“ENGINE STOP” switch
The engine stop switch is a safety device for use in an
emergency such as when the motorcycle overturns or if
trouble occurs in the throttle system. Turn the switch to
ì î to start the engine, and turn the switch to ì î to
stop the engine.
Handlebar switches over rigt
1. ìENGINE STOPî switch, shuts the engine off
3-5“ENGINE STOP” switch
The engine stop switch is a safety device for use in an
emergency such as when the motorcycle overturns or if
trouble occurs in the throttle system. Turn the switch to
ì î to start the engine, and turn the switch to ì î to
stop the engine.

The clutch lever is located on the left handlebar. Pull the
clutch lever to the handlebar to disengage the clutch, and
release the lever to engage the clutch. The lever should be
pulled rapidly and released slowly for smooth clutch
operation.
3-6This motorcycle is equipped with a constant-mesh 5-speed
transmission.
The shift pedal is located on the left side of the engine and
is used in combination with the clutch when shifting.
Clutch lever
Shift pedal
1. Clutch lever1. Shift pedal
The clutch lever is located on the left handlebar. Pull the
clutch lever to the handlebar to disengage the clutch, and
release the lever to engage the clutch. The lever should be
pulled rapidly and released slowly for smooth clutch
operation.
3-6This motorcycle is equipped with a constant-mesh 5-speed
transmission.
The shift pedal is located on the left side of the engine and
is used in combination with the clutch when shifting.
Clutch lever
Shift pedal
1. Clutch lever1. Shift pedal