fuel YAMAHA YBR125 2003 User Guide

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.

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.

5-7
2. 150 ~ 500 Km:
Avoid prolonged operation above 1/2 throttle. Allow the
machine to rev freely through the gears, but do not use
full throttle at any time.
3. 500 ~ 1,000 Km: Avoid cruising speeds in excess of 3/4 throttle.
After 1,000Km of operation, be sure to replace the engine
oil.
4. After 1,000 Km: Avoid prolonged full throttle operation. Vary speeds
occasionally.
If any engine trouble should occur during the break-in
period, consult a Yamaha dealer immediately. Parking
When parking the motorcycle, stop the engine and remove
the ignition key. Turn the fuel cock to “OFF” whenever
stopping the engine.
The muffler and exhaust pipe are hot. Park the
motorcycle in a place where pedestrians or children
are not likely to touch the motorcycle. Do not park the
motorcycle on a slope or soft ground; the motorcycle
may fall over.
CAUTION:
CAUTION:
WARNING:
5-7
2. 150 ~ 500 Km:
Avoid prolonged operation above 1/2 throttle. Allow the
machine to rev freely through the gears, but do not use
full throttle at any time.
3. 500 ~ 1,000 Km: Avoid cruising speeds in excess of 3/4 throttle.
After 1,000Km of operation, be sure to replace the engine
oil.
4. After 1,000 Km: Avoid prolonged full throttle operation. Vary speeds
occasionally.
If any engine trouble should occur during the break-in
period, consult a Yamaha dealer immediately. Parking
When parking the motorcycle, stop the engine and remove
the ignition key. Turn the fuel cock to “OFF” whenever
stopping the engine.
The muffler and exhaust pipe are hot. Park the
motorcycle in a place where pedestrians or children
are not likely to touch the motorcycle. Do not park the
motorcycle on a slope or soft ground; the motorcycle
may fall over.
CAUTION:
CAUTION:
WARNING:

6-3
PERIODIC MAINTENANCE / LUBRICATION
Wheel bearings* Battery*
Check looseness and damage.
Check electrolyte level, routing breather pipe.
ITEM
How it sounds
/ Adjust if necessary.
REMARKS 1,000KM
Fuel line
Air filter
Carburetor* Valves*
Muffler
Brakes* Engine oil
Steering bearings* Rear arm pivot* Check fuel hose, for cracks or damage.
Clean or replace if necessary.
Adjust
Check damage, Retighten.
Check operation, adjust.
Grease the brake cam. Replace / Check level
Check loosenes.
Repack every 12,000 km or 12 month.** Check rear arm assembly for looseness.
Moderately repack.***
EVERY
3,000KM
OR ERERY
6 MONTHS
Wheels* and tires Check tire pressure, runout and spoke tightness.
Spark plug Check condition and clean if necessary.
Replace if necessary every 12,000 Km.
3,000KM
6-3
PERIODIC MAINTENANCE / LUBRICATION
Wheel bearings* Battery*
Check looseness and damage.
Check electrolyte level, routing breather pipe.
ITEM
How it sounds
/ Adjust if necessary.
REMARKS 1,000KM
Fuel line
Air filter
Carburetor* Valves*
Muffler
Brakes* Engine oil
Steering bearings* Rear arm pivot* Check fuel hose, for cracks or damage.
Clean or replace if necessary.
Adjust
Check damage, Retighten.
Check operation, adjust.
Grease the brake cam. Replace / Check level
Check loosenes.
Repack every 12,000 km or 12 month.** Check rear arm assembly for looseness.
Moderately repack.***
EVERY
3,000KM
OR ERERY
6 MONTHS
Wheels* and tires Check tire pressure, runout and spoke tightness.
Spark plug Check condition and clean if necessary.
Replace if necessary every 12,000 Km.
3,000KM

Valve clearance adjustment
The correct valve clearance changes with use, resulting in
improper fuel/air supply or engine noise. To prevent this,
valve clearance must be adjusted regularly. This adjustment,
however, should be left to a professional Yamaha service
technician.
Carburetor adjustment
The carburetor is a vital part of the engine. Adjusting should
be left to a Yamaha dealer who has the professional
knowledge, specialized data, and equipment to do so
properly. However, the following may be serviced by the
owner as part of routine maintenance.
The carburetor was set at Yamaha factory after many
tests. If the settings are changed, poor engine
performance and damage may result.
!
CAUTION:
Valve clearance adjustment
The correct valve clearance changes with use, resulting in
improper fuel/air supply or engine noise. To prevent this,
valve clearance must be adjusted regularly. This adjustment,
however, should be left to a professional Yamaha service
technician.
Carburetor adjustment
The carburetor is a vital part of the engine. Adjusting should
be left to a Yamaha dealer who has the professional
knowledge, specialized data, and equipment to do so
properly. However, the following may be serviced by the
owner as part of routine maintenance.
The carburetor was set at Yamaha factory after many
tests. If the settings are changed, poor engine
performance and damage may result.
!
CAUTION:

6-36
Rear wheel installation
When installing the rear wheel, reverse the removal
procedures. Pay attention to the following points:
1. Adjust the drive chain.
2. Tighten the axle nut and the tension bar nut to the
specified tightening torque.
Axle nut torque: 91 N.m ( 9.1 Kgf.m, 66 lbf.ft)
Tension bar nut: 19 N.m (1.9 Kgf.m, 14 lbf.ft)
3. Adjust the rear brake.
Check the operation of the brake light after adjusting the
rear brake Troubleshooting
Although Yamaha motorcycles receive a rigid inspection
before shipment from the factory, trouble may occur during
operation. Any problem in the fuel, compression, or ignition
systems can cause poor starting and loss of power. The
troubleshooting chart describes a quick, easy, procedure
for making checks. If your motorcycle requires any repair,
bring it to a Yamaha dealer. The skilled technicians at a
Yamaha dealership have the tools, experience, and know-
how to properly service your motorcycle. Use only genuine
Yamaha parts on your motorcycle. Imitation parts may look
like Yamaha parts, but they are often inferior. Consequently,
they have a shorter service life and can lead to expensive
repair bills.
CAUTION:
6-36
Rear wheel installation
When installing the rear wheel, reverse the removal
procedures. Pay attention to the following points:
1. Adjust the drive chain.
2. Tighten the axle nut and the tension bar nut to the
specified tightening torque.
Axle nut torque: 91 N.m ( 9.1 Kgf.m, 66 lbf.ft)
Tension bar nut:
19 N.m (1.9 Kgf.m, 14 lbf.ft)
3. Adjust the rear brake.
Check the operation of the brake light after adjusting the
rear brake Troubleshooting
Although Yamaha motorcycles receive a rigid inspection
before shipment from the factory, trouble may occur during
operation. Any problem in the fuel, compression, or ignition
systems can cause poor starting and loss of power. The
troubleshooting chart describes a quick, easy, procedure
for making checks. If your motorcycle requires any repair,
bring it to a Yamaha dealer. The skilled technicians at a
Yamaha dealership have the tools, experience, and know-
how to properly service your motorcycle. Use only genuine
Yamaha parts on your motorcycle. Imitation parts may look
like Yamaha parts, but they are often inferior. Consequently,
they have a shorter service life and can lead to expensive
repair bills.
CAUTION:

6-37Never check the fuel system while smoking or in the
vicinity of an open flame.
Check if there is
fuel in the fuel tank
Use electric
starter
Remove spark
plug and check
electrode
Use electric starter 1. Fuel
2. Compression
3. Ignition
4. BatteryEnough fuel
No fuel
There is compression
No compression
Wet
Dry
Engine turns
over quickly
Engine turns
over slowlySupply fuel
Go to ignition check
Ask Yamaha dealer to inspect
Wipe clean with dry cloth and correct
spark plug gap or replace spark plugs
Ask Yamaha dealer to inspect
Battery good
Check fluid,
recharge and check
connections
Troubleshooting chart
Go to compression
check
Engine doesn’t start, go
to compression check
Open the throttle hal-way
and start the engine
Engine doesn’t start, ask
Yamaha dealer to inspect.Engine doesn’t start,
go to battery check
WARNING:
6-37Never check the fuel system while smoking or in the
vicinity of an open flame.
Check if there is
fuel in the fuel tank
Use electric
starter
Remove spark
plug and check
electrode
Use electric starter 1. Fuel
2. Compression
3. Ignition
4. BatteryEnough fuel
No fuel
There is compression
No compression
Wet
Dry
Engine turns
over quickly
Engine turns
over slowlySupply fuel
Go to ignition check
Ask Yamaha dealer to inspect
Wipe clean with dry cloth and correct
spark plug gap or replace spark plugs
Ask Yamaha dealer to inspect
Battery good
Check fluid,
recharge and check
connections
Troubleshooting chart
Go to compression
check
Engine doesn’t start, go
to compression check
Open the throttle hal-way
and start the engine
Engine doesn’t start, ask
Yamaha dealer to inspect.Engine doesn’t start,
go to battery check
WARNING:

7-2 B. STORAGE
Long term storage (30 days or more) of your machine will
require some preventive procedures to guard against
deterioration. After thoroughly cleaning the machine,
prepare for storage as follows:
1. Drain the fuel tank, fuel lines, and carburetor float
bowl(s).
2. Remove the spark plug(s), pour about one tablespoon
of SAE 20W50 motor oil in the spark plug hole(s) and
reinstall the spark plug(s).
Crank the engine over several times (with the
ignition off) to coat the cylinder walls with oil.
3. Remove the drive chain. Clean it thoroughly with
solvent and lubricate it.
Reinstall the chain or store it in a plastic bag
(tied to frame for safe-keeping).
4. Lubricate all control cables.
5. Block up the frame to raise both wheels off the
ground.
6. Tie a plastic bag over the exhaust pipe outlet to
prevent moisture from entering.7. If storing in a humid or salt-air atmosphere, coat
all exposed metal surfaces with a light film of
oil. Do not apply oil to any rubber parts or the
seat cover.
8. Remove the battery and charge it. Store it in a dry place
and recharge it once a month. Do not store the battery
in an excessively warm or cold place (less than 0ºC
(30ºF) or more than 30ºC (90ºF).
NOTE:
Make any necessary repairs before storing the machine.
7-2 B. STORAGE
Long term storage (30 days or more) of your machine will
require some preventive procedures to guard against
deterioration. After thoroughly cleaning the machine,
prepare for storage as follows:
1. Drain the fuel tank, fuel lines, and carburetor float
bowl(s).
2. Remove the spark plug(s), pour about one tablespoon
of SAE 20W50 motor oil in the spark plug hole(s) and
reinstall the spark plug(s).
Crank the engine over several times (with the
ignition off) to coat the cylinder walls with oil.
3. Remove the drive chain. Clean it thoroughly with
solvent and lubricate it.
Reinstall the chain or store it in a plastic bag
(tied to frame for safe-keeping).
4. Lubricate all control cables.
5. Block up the frame to raise both wheels off the
ground.
6. Tie a plastic bag over the exhaust pipe outlet to
prevent moisture from entering.7. If storing in a humid or salt-air atmosphere, coat
all exposed metal surfaces with a light film of
oil. Do not apply oil to any rubber parts or the
seat cover.
8. Remove the battery and charge it. Store it in a dry place
and recharge it once a month. Do not store the battery
in an excessively warm or cold place (less than 0ºC
(30ºF) or more than 30ºC (90ºF).
NOTE:
Make any necessary repairs before storing the machine.

8-1
SPECIFICATIONS
MODEL YBR 125 ED
Dimension: Overall length 1,980 mm ( 78 in)
Overall width 745 mm ( 29 in)
Overall height 1,050 mm ( 41 in)
Seat height 780 mm ( 31 in)
Wheel base 1,290 mm ( 51 in)
Minimum ground clearance 175 mm ( 7 in)
Basic weight: 108 Kg ( 238 lb)
With oil and without fuel: 119 Kg ( 262 lb)
Minimum turning radius: 1,750 mm ( 70 in)
Engine: Type Air cooled, 4-stroke gasoline, SOHC
Cylinder arrangement Single cylinder, Forward inclined
Displacement 123.7 cm
3
Bore x Stroke 54 x 54 mm ( 2.13 x 2.13 in)
Compression rate 10.0 : 1
Starting system Electric starter
Lubrication system Wet sump
8-1
SPECIFICATIONS
MODEL YBR 125 ED
Dimension: Overall length 1,980 mm ( 78 in)
Overall width 745 mm ( 29 in)
Overall height 1,050 mm ( 41 in)
Seat height 780 mm ( 31 in)
Wheel base 1,290 mm ( 51 in)
Minimum ground clearance 175 mm ( 7 in)
Basic weight: 108 Kg ( 238 lb)
With oil and without fuel: 119 Kg ( 262 lb)
Minimum turning radius: 1,750 mm ( 70 in)
Engine: Type Air cooled, 4-stroke gasoline, SOHC
Cylinder arrangement Single cylinder, Forward inclined
Displacement 123.7 cm
3
Bore x Stroke 54 x 54 mm ( 2.13 x 2.13 in)
Compression rate 10.0 : 1
Starting system Electric starter
Lubrication system Wet sump

MODEL YBR 125ED
Engine oil: Type Yamalube 4 or SAE 20W50 type SH
Capacity: Periodic oil change 1.0 L ( 0.220 Imp galt, 0.264 US gal)
Total amount 1.2 L ( 0.264 Imp gal, 0.317 US gal)
Air filter: Wet type element
Fuel: Type Regular unleaded gasoline
Tank capacity 13 L ( 2.860 Imp gal, 3.434 US gal)
Reserve amount 1.7 L ( 0.374 Imp gal, 0.450 US gal)
Carburetor: Type/manufacturer VM 20 / MIKUNI
Spark plug: Type/manufacturer CR7HSA / NGK or U22FSR-U / DENSO
Gap 0.7 mm (0.028 in)
Clutch type: Wet, multi-disc
8-2
MODEL YBR 125ED
Engine oil: Type Yamalube 4 or SAE 20W50 type SH
Capacity: Periodic oil change 1.0 L ( 0.220 Imp galt, 0.264 US gal)
Total amount 1.2 L ( 0.264 Imp gal, 0.317 US gal)
Air filter: Wet type element
Fuel: Type Regular unleaded gasoline
Tank capacity 13 L ( 2.860 Imp gal, 3.434 US gal)
Reserve amount 1.7 L ( 0.374 Imp gal, 0.450 US gal)
Carburetor: Type/manufacturer VM 20 / MIKUNI
Spark plug: Type/manufacturer CR7HSA / NGK or U22FSR-U / DENSO
Gap 0.7 mm (0.028 in)
Clutch type: Wet, multi-disc
8-2