engine YAMAHA XTZ125 2003 User Guide

3-9
3-9
Fuel cockThe fuel cock supplies fuel from the tank to the carburetor
while filtering it also.
The fuel cock has three positions:
OFF:
With the fuel cock in this position, fuel will not flow. Always
set the fuel cock to this position when the engine is not
running.
ON:
With the fuel cock in this position, fuel flows to the
carburetor. Set the fuel cock to this position when starting
the engine and while riding.
RES:
This indicates reserve. If you run out of fuel while riding,
set the fuel cock to this position.
Fill the tank at the first opportunity. Be sure to set fuel cock
back to “ON” after refueling!
Fuel cockThe fuel cock supplies fuel from the tank to the carburetor
while filtering it also.
The fuel cock has three positions:
OFF:
With the fuel cock in this position, fuel will not flow. Always
set the fuel cock to this position when the engine is not
running.
ON:
With the fuel cock in this position, fuel flows to the
carburetor. Set the fuel cock to this position when starting
the engine and while riding.
RES:
This indicates reserve. If you run out of fuel while riding,
set the fuel cock to this position.
Fill the tank at the first opportunity. Be sure to set fuel cock
back to “ON” after refueling!

3-10
3-10
Starting a cold engine requires a richer air-fuel mixture. A
separate starter circuit supplies the mixture.
Pull the starter knob up to open the circuit for starting. When
the engine has warmed up, push the knob down to close
the circuit.Starter lever

2

5
-./
%50
Rotate the kick starter away from the engine. Push the
starter down lighty with your foot until the gears engage,
then kick smoothly and forcefully to start the engine.
Shift to neutral before starting. Kick starter
Starting a cold engine requires a richer air-fuel mixture. A
separate starter circuit supplies the mixture.
Pull the starter knob up to open the circuit for starting. When
the engine has warmed up, push the knob down to close
the circuit.Starter lever

2

5
-./
%50
Rotate the kick starter away from the engine. Push the
starter down lighty with your foot until the gears engage,
then kick smoothly and forcefully to start the engine.
Shift to neutral before starting. Kick starter

3-15
3-15
If improper operation is noted, consult a Yamaha
dealer or other qualified mechanic immediately.
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 operation check
↓ ↓↓ ↓
↓
CLUTCH SWITCH IS OK
WARNING:
* Obs.: XTZ 125E
If improper operation is noted, consult a Yamaha
dealer or other qualified mechanic immediately.
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 operation check
↓ ↓↓ ↓
↓
CLUTCH SWITCH IS OK
WARNING:
* Obs.: XTZ 125E

4-1
4-1
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
6-17 ~ 6-23
4-8 , 6-14 , 6-27
4-4 , 6-6 , 6-9
6-24 ~ 6-26
6-10 ~ 6-11
4-5 ~ 4-8
6-26 Check operation, condition and free play.
Adjust if necessary
Wheels / Tires
Clean and oil it frequently.4-8 , 6-16 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
6-17 ~ 6-23
4-8 , 6-14 , 6-27
4-4 , 6-6 , 6-9
6-24 ~ 6-26
6-10 ~ 6-11
4-5 ~ 4-8
6-26 Check operation, condition and free play.
Adjust if necessary
Wheels / Tires
Clean and oil it frequently.4-8 , 6-16 Rear brakeCheck operation, free play, fluid level and fluid leakage.
Top-up with DOT #4 (or DOT #3) brake fluid if necessary.

4-2
4-2 NOTE:
Pre-operation checks should be made each time the motorcycle is used. Such 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 which 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 them during inspection or repair.
2. If any item is not working properly, have it inspected and repaired before operating the motorcycle.
ITEMROUTINE
PAGE
Sidestand
Fittings / FastenersCheck all chassi fittings and fasteners.
Tighten / Adjust, if necessary
Check fuel level / top up as required.
Fuel tank
Lights, signals and switches
BatteryCheck electrolyte level.
Replenish with “distilled water” if necessary.6-27
4-8 , 6-5
4-8 , 6-35 ~ 6-36
6-32 ~ 6-346-28
4-9
Check for proper operation
Front brake and clutch
lever pivotsCheck for smooth operation.
Lubricate if necessary
Check for smooth operation.
Lubricate if necessary
6-27 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. Such 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 which 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 them during inspection or repair.
2. If any item is not working properly, have it inspected and repaired before operating the motorcycle.
ITEMROUTINE
PAGE
Sidestand
Fittings / FastenersCheck all chassi fittings and fasteners.
Tighten / Adjust, if necessary
Check fuel level / top up as required.
Fuel tank
Lights, signals and switches
BatteryCheck electrolyte level.
Replenish with “distilled water” if necessary.6-27
4-8 , 6-5
4-8 , 6-35 ~ 6-36
6-32 ~ 6-346-28
4-9
Check for proper operation
Front brake and clutch
lever pivotsCheck for smooth operation.
Lubricate if necessary
Check for smooth operation.
Lubricate if necessary
6-27 Check for smooth operation.
Lubricate if necessary Rear brake and shift pedal
shafts
WARNING:

4-4
4-4 If brake fluid leakage is found, ask a Yamaha dealer or
other qualified mechanic for immediate repairs. Such
leakage could indicate a hazardous condition.
CAUTION:
Brake fluid may deteriorate painted surfaces or plastic
parts. Never spill any fluid. If spilled, clean it up
immediately.
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.
WARNING:
CAUTION:
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.
If brake fluid leakage is found, ask a Yamaha dealer or
other qualified mechanic for immediate repairs. Such
leakage could indicate a hazardous condition.
CAUTION:
Brake fluid may deteriorate painted surfaces or plastic
parts. Never spill any fluid. If spilled, clean it up
immediately.
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.
WARNING:
CAUTION:
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.

4-8
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 6-16 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 6-14 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.
Wheels
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 6-16 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 6-14 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.

4-9
4-9
CAUTION:
Always wipe off spilled fuel immediately with a dry and
clean soft cloth. Fuel may deteriorate painted surfaces
or plastic parts.
Fuel
-./ - .0
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:
10.6 l ( 2.33 Imp gal, 2.80 US gal)
Reserve:
1.0 l ( 0.220 Imp gal, 0.264 Us gal)
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.
WARNING:
CAUTION:
Always wipe off spilled fuel immediately with a dry and
clean soft cloth. Fuel may deteriorate painted surfaces
or plastic parts.
Fuel
-./ - .0
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:
10.6 l ( 2.33 Imp gal, 2.80 US gal)
Reserve:
1.0 l ( 0.220 Imp gal, 0.264 Us gal)
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.
WARNING:

5-1
5-1
OPERATION AND IMPORTANT RIDING POINTS
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.
CAUTION:
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.
OPERATION AND IMPORTANT RIDING POINTS
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.
CAUTION:
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.

5-2
5-2 Starting a cold engine
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.
XTZ 125K
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.
XTZ 125E
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.
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.
4. Fully open the starter (CHOKE) and completely close
the throttle grip.
5. Kick the kick start to start the engine.
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.
Starting a cold engine
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.
XTZ 125K
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.
XTZ 125E
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.
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.
4. Fully open the starter (CHOKE) and completely close
the throttle grip.
5. Kick the kick start to start the engine.
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.