2003 YAMAHA YBR125 engine

Handlebar switches over rigt
1. “ENGINE STOP” switch, shuts the engine off 2. Starter switch
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
“
” to start the engine, and turn the switch to “ ” to
stop the engine.
Starter switch “ ”
The starter motor cranks the engine when pushing the
starter switch.
See starting instructions prior to starting the
engine.
CAUTION:
Handlebar switches over rigt
1. “ENGINE STOP” switch, shuts the engine off 2. Starter switch
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
“
” to start the engine, and turn the switch to “ ” to
stop the engine.
Starter switch “ ”
The starter motor cranks the engine when pushing the
starter switch.
See starting instructions prior to starting the
engine.
CAUTION:

The clutch lever is located on the left handlebar, and the
starting circuit cut off switch is incorporated in the clutch
lever holder. 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.

!This 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
15
4
3
2
N
1
The clutch lever is located on the left handlebar, and the
starting circuit cut off switch is incorporated in the clutch
lever holder. 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.

!This 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
15
4
3
2
N
1

Fuel cock

$
ON
OFF
RES
FUEL
The 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 cock

$
ON
OFF
RES
FUEL
The 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!

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
1. Starter lever
1
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
1. Starter lever
1

 If improper operation is noted, consult a Yamaha dealer
or other qualified mechanic immediately.
↓
↓ ↓
↓
↓
↓
↓ ↓
↓
↓↓
↓ ↓
↓
↓
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:

 If improper operation is noted, consult a Yamaha dealer
or other qualified mechanic immediately.
↓
↓ ↓
↓
↓
↓
↓ ↓
↓
↓↓
↓ ↓
↓
↓
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: