2003 YAMAHA YBR125 engine

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.

$Always wipe off spilled fuel immediately with a dry and clean
soft cloth. Fuel may deteriorate painted surfaces or plastic
parts. Fuel
1. Fuel level 2. Filler tube
Make sure there is sufficient fuel in the tank.
Do not overfill the fuel tank. Avoid spilling fuel on the
hot engine. Do not fill the fuel tank above the bottom of
the filler tube as shown in the illustration or it may
overflow when the fuel heats up later and expands.
Recommended fuel:
UNLEADED FUEL
Fuel tank capacity:
Total:
13.0 L ( 2.860 Imp gal, 3.434 US gal)
Reserve:
1.7 L ( 0.374 Imp gal, 0.450 Us gal)
WARNING:
CAUTION:
Your Yamaha engine has been designed to use regular
unleaded gasoline with a pump octane number ([R+m]/2)
of 86 or higher, or research octane number of 91 or higher.
If knocking or pinging occurs, use a different brand of
gasoline or premium unleaded fuel. Unleaded fuel will give
you longer spark plug life and reduced maintenance cost.
If unleaded gasoline is not available, then leaded regular
gasoline can be used.
Gasohol
There are two types of gasohol; gasohol containing ethanol
and that containing methanol. Gasohol containing ethanol
can be used if ethanol content does not exceed 10%.
Gasohol containing methanol is not recommended by
Yamaha because it can cause fuel system damage or
vehicle performance problems.
$Always wipe off spilled fuel immediately with a dry and clean
soft cloth. Fuel may deteriorate painted surfaces or plastic
parts. Fuel
1. Fuel level 2. Filler tube
Make sure there is sufficient fuel in the tank.
Do not overfill the fuel tank. Avoid spilling fuel on the
hot engine. Do not fill the fuel tank above the bottom of
the filler tube as shown in the illustration or it may
overflow when the fuel heats up later and expands.
Recommended fuel:
UNLEADED FUEL
Fuel tank capacity:
Total:
13.0 L ( 2.860 Imp gal, 3.434 US gal)
Reserve:
1.7 L ( 0.374 Imp gal, 0.450 Us gal)
WARNING:
CAUTION:
Your Yamaha engine has been designed to use regular
unleaded gasoline with a pump octane number ([R+m]/2)
of 86 or higher, or research octane number of 91 or higher.
If knocking or pinging occurs, use a different brand of
gasoline or premium unleaded fuel. Unleaded fuel will give
you longer spark plug life and reduced maintenance cost.
If unleaded gasoline is not available, then leaded regular
gasoline can be used.
Gasohol
There are two types of gasohol; gasohol containing ethanol
and that containing methanol. Gasohol containing ethanol
can be used if ethanol content does not exceed 10%.
Gasohol containing methanol is not recommended by
Yamaha because it can cause fuel system damage or
vehicle performance problems.

1. Be very careful if you are carrying object while riding
the motorcycle
2. Be vareful not to put any object near battery terminals.
Electrical failure or acid corrosion may occur.
OPERATION AND IMPORTANT RIDING POINTS
Before riding this motorcycle, become thoroughly
familiar with all operating controls and their functions.
Consult a Yamaha dealer regarding any control or
function that you do not thoroughly understand.
Never start your engine or let it run for any
length of time in a closed area.
The exhaust fumes are poisonous and can cause loss
of consciousness and death within a short time. Always
operate your machine in an area with adequate
ventilation.
Before starting out, always be sure the sidestand is up.
Failure to retract the sidestand completely can result
in a serious accident when you try to turn a corner.
CAUTION:
CAUTION:
 1. Be very careful if you are carrying object while riding
the motorcycle
2. Be vareful not to put any object near battery terminals.
Electrical failure or acid corrosion may occur.
OPERATION AND IMPORTANT RIDING POINTS
Before riding this motorcycle, become thoroughly
familiar with all operating controls and their functions.
Consult a Yamaha dealer regarding any control or
function that you do not thoroughly understand.
Never start your engine or let it run for any
length of time in a closed area.
The exhaust fumes are poisonous and can cause loss
of consciousness and death within a short time. Always
operate your machine in an area with adequate
ventilation.
Before starting out, always be sure the sidestand is up.
Failure to retract the sidestand completely can result
in a serious accident when you try to turn a corner.
CAUTION:
CAUTION:

5-2
Starting a cold engine
1. Turn the fuel cock to “ON”.
2. Turn the main switch to “ON” and the engine stop switch
to “ “.
3. Shift transmission into neutral.
NOTE:
When the transmission is in neutral, the neutral indicator
light should be on. If the light does not come on, ask a
Yamaha dealer to inspect it.
4. Fully open the starter (CHOKE) and completely close the throttle grip.
5. Start the engine by pushing the starter switch.
NOTE:
This motorcycle is equipped with a starting and an ignition
circuit cut-off switch.
1. The engine can be started only under the following conditions:
a. The transmission is in neutral.
b. The transmission is in gear and the clutch is disengaged.
2. The motorcycle must not be ridden when the sidestand is down. NOTE:
If the engine fails to start, release the starter switch, wait a
few seconds, then try again. Each attempt should be as
short as possible to preseve the battery. Do not crank the
engine more than 10 seconds on any one attempt.
6. After starting the engine, turn back the starter to an
intermediate position.
NOTE:
To obtain maximum engine life and service, do not ever
thoroughly accelerate it while the engine is cold.
7. After warming up the engine, turn back the starter (CHOKE) completely.
NOTE:
The engine is warm when it responds normally to the throttle
with the starter turned off.
5-2
Starting a cold engine
1. Turn the fuel cock to “ON”.
2. Turn the main switch to “ON” and the engine stop switch
to “ “.
3. Shift transmission into neutral.
NOTE:
When the transmission is in neutral, the neutral indicator
light should be on. If the light does not come on, ask a
Yamaha dealer to inspect it.
4. Fully open the starter (CHOKE) and completely close the throttle grip.
5. Start the engine by pushing the starter switch.
NOTE:
This motorcycle is equipped with a starting and an ignition
circuit cut-off switch.
1. The engine can be started only under the following conditions:
a. The transmission is in neutral.
b. The transmission is in gear and the clutch is disengaged.
2. The motorcycle must not be ridden when the sidestand is down. NOTE:
If the engine fails to start, release the starter switch, wait a
few seconds, then try again. Each attempt should be as
short as possible to preseve the battery. Do not crank the
engine more than 10 seconds on any one attempt.
6. After starting the engine, turn back the starter to an
intermediate position.
NOTE:
To obtain maximum engine life and service, do not ever
thoroughly accelerate it while the engine is cold.
7. After warming up the engine, turn back the starter (CHOKE) completely.
NOTE:
The engine is warm when it responds normally to the throttle
with the starter turned off.

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:

 Starting a warm engine
The starter lever is not required when the engine is warm.
If the engine fail to start with the procedures above, try to
start it again with the throttle grip opened 1/4 to 1/2.Warming up the engine
For an extended engine life always warm the engine up
never accelerate hard while the engine is cold.
To check if engine temperature is normal, rev the engine
with the choke closed and check to see if it responds
normally.
See the “Break-in section” prior to operating the
motorcycle for the first time.
CAUTION:
CAUTION:
 Starting a warm engine
The starter lever is not required when the engine is warm.
If the engine fail to start with the procedures above, try to
start it again with the throttle grip opened 1/4 to 1/2.Warming up the engine
For an extended engine life always warm the engine up
never accelerate hard while the engine is cold.
To check if engine temperature is normal, rev the engine
with the choke closed and check to see if it responds
normally.
See the “Break-in section” prior to operating the
motorcycle for the first time.
CAUTION:
CAUTION:

1. Do not coast for long periods with the engine off,and do not tow the motorcycle a long distance. Even
with gears in neutral, the transmission is only
properly lubricated when the engine is running.
Inadequate lubrication may damage the
transmission.
2. Always use the clutch when changing gears. The engine, transmission, and driveline are not
designed to withstand the shock of forced shifting
and can be damaged by shifting without using the
clutch.

Shifting
The transmission lets you control the amount of power you
have available at a given speed for starting, accelerating,
climbing hills, etc. The use of shift pedal is sho
wn in the
illustration (page 3-6).
To shift into NEUTRAL, depress the shift pedal repeatedly
until it reaches the end of its travel (you will feel a stop
when you are in first gear), then raise the pedal slightly.
CAUTION:
1. Do not coast for long periods with the engine off,
and do not tow the motorcycle a long distance. Even
with gears in neutral, the transmission is only
properly lubricated when the engine is running.
Inadequate lubrication may damage the
transmission.
2. Always use the clutch when changing gears. The engine, transmission, and driveline are not
designed to withstand the shock of forced shifting
and can be damaged by shifting without using the
clutch.

Shifting
The transmission lets you control the amount of power you
have available at a given speed for starting, accelerating,
climbing hills, etc. The use of shift pedal is sho
wn in the
illustration (page 3-6).
To shift into NEUTRAL, depress the shift pedal repeatedly
until it reaches the end of its travel (you will feel a stop
when you are in first gear), then raise the pedal slightly.
CAUTION:

5-6
Tips for reducing fuel consumption
Your motorcycle’s fuel consumption depends to a large
extent on your riding style. The following tips can help reduce
fuel consumption.
1. Warm up the engine before riding.
2. Turn off the starter lever as soon as possible.
3. Shift up swiftly and avoid high engine speeds during
acceleration.
4. Do not double-clutch or rev the engine while shifting down and avoid high engine speeds with no load engine.
5. Turn off the engine instead of letting it idle for an extended lenght of time, i.e. in traffic jams, at traffic lights or railroad
crossings. Engine Break-in
There is never a more important period in the life of your
motorcycle than the period 1.000Km. For this reason we
ask that you carefully read the following material. Because
the engine is brand new, you must not put an excessive
load on it for the first several hours of running.
During this period, prolonged full throttle operation, or any
condition which might result in excessive heating of the
engine must be avoided.
1. 0 ~ 150 Km:
Avoid operation above 1/3 throttle. Stop the engine and
let it cool for 5 to 10 minutes after every hour of
operation. Vary the speed of the motorcycle from time
to time. Do not operate it at one set throttle position.
5-6
Tips for reducing fuel consumption
Your motorcycle’s fuel consumption depends to a large
extent on your riding style. The following tips can help reduce
fuel consumption.
1. Warm up the engine before riding.
2. Turn off the starter lever as soon as possible.
3. Shift up swiftly and avoid high engine speeds during
acceleration.
4. Do not double-clutch or rev the engine while shifting down and avoid high engine speeds with no load engine.
5. Turn off the engine instead of letting it idle for an extended lenght of time, i.e. in traffic jams, at traffic lights or railroad
crossings. Engine Break-in
There is never a more important period in the life of your
motorcycle than the period 1.000Km. For this reason we
ask that you carefully read the following material. Because
the engine is brand new, you must not put an excessive
load on it for the first several hours of running.
During this period, prolonged full throttle operation, or any
condition which might result in excessive heating of the
engine must be avoided.
1. 0 ~ 150 Km:
Avoid operation above 1/3 throttle. Stop the engine and
let it cool for 5 to 10 minutes after every hour of
operation. Vary the speed of the motorcycle from time
to time. Do not operate it at one set throttle position.