2006 YAMAHA XTZ125 engine

6-11
6-11
CAUTION:
Make sure the element is properly seated in the air filter
case.
CAUTION:
The engine should never be run without the air filter
element installed; excessive piston and/or cylinder wear
may result.
Recommended oil:
Engine oil 20W50 4. Remove the air filter element from the guide and clean
it with solvent. After cleaning, remove the remaining
solvent by squeezing the air filter
5. Apply recommended oil to the entire surface of the filter
and squeeze out the excess oil. The air filter should be
wet but not dripping.
6. Reinstall the air filter in its case.
7. Install the air filter case cover and the right side cover.
CAUTION:
Make sure the element is properly seated in the air filter
case.
CAUTION:
The engine should never be run without the air filter
element installed; excessive piston and/or cylinder wear
may result.
Recommended oil:
Engine oil 20W50 4. Remove the air filter element from the guide and clean
it with solvent. After cleaning, remove the remaining
solvent by squeezing the air filter
5. Apply recommended oil to the entire surface of the filter
and squeeze out the excess oil. The air filter should be
wet but not dripping.
6. Reinstall the air filter in its case.
7. Install the air filter case cover and the right side cover.

6-12
6-12Valve 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.
CAUTION:
The carburetor was set at Yamaha factory after many
tests. If the settings are changed, poor engine
performance and damage may result.
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.
CAUTION:
The carburetor was set at Yamaha factory after many
tests. If the settings are changed, poor engine
performance and damage may result.

6-13
6-13
1
NOTE:
A diagnostic tachometer must be used for this
procedure.
Standard idle speed:1400
± 100 rpm NOTE:
If the specified idle speed cannot be obtained by performing
the above adjustment, consult a Yamaha dealer.
1. Throttle stop screw
Idle speed adjustment
1. Attach the tachometer. Start the engine and warm it upfor a few minutes (normally, 1 or 2 minutes) at
approximately 1,000 to 2,000 r/min. Occasionally rev
the engine to 4,000 to 5,000 r/min. The engine is warm
when it quickly responds to the throttle.
2. Set the idle to the specified engine speed by adjusting the throttle stop screw; turn the screw in to increase
engine speed and out to decrease engine speed.
1
NOTE:
A diagnostic tachometer must be used for this
procedure.
Standard idle speed: 1400
± 100 rpm NOTE:
If the specified idle speed cannot be obtained by performing
the above adjustment, consult a Yamaha dealer.
1. Throttle stop screw
Idle speed adjustment
1. Attach the tachometer. Start the engine and warm it upfor a few minutes (normally, 1 or 2 minutes) at
approximately 1,000 to 2,000 r/min. Occasionally rev
the engine to 4,000 to 5,000 r/min. The engine is warm
when it quickly responds to the throttle.
2. Set the idle to the specified engine speed by adjusting the throttle stop screw; turn the screw in to increase
engine speed and out to decrease engine speed.

6-14
6-14
NOTE:
Before checking the throttle cable free play, the engine
idling speed should be adjusted.
Free play:
3 ~ 5 mm (0.12 ~ 0.19 in) Throttle cable adjustment
The throttle cable should have an specified free play in the
turning direction at the grip flange. If the free play is incorrect,

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NOTE:
Before checking the throttle cable free play, the engine
idling speed should be adjusted.
Free play:
3 ~ 5 mm (0.12 ~ 0.19 in) Throttle cable adjustment
The throttle cable should have an specified free play in the
turning direction at the grip flange. If the free play is incorrect,

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6-15
6-15Before installing the spark plug, measure the electrode gap
with a wire thickness gauge and adjust the gap to
specification as necessary.
Standard spark plug:
CR7HSA (NGK) and U22FSR-U (DENSO)


Spark plug gap:
0.7 mm ( 0.028 in) Spark plug inspection
The spark plug is an important engine component and is
easy to inspect. The condition of the spark plug can indicate
the condition of the engine.
The ideal color on the white porcelain insulator around the
center electrode is a medium to light tan color for a
motorcycle that is being ridden normally. Do not attempt to
diagnose any problems yourself. Instead, take the
motorcycle to a Yamaha dealer. You should periodically
remove and inspect the spark plug because heat and
deposits will cause the spark plug to slowly break down
and erode.
If electrode erosion becomes excessive, or if carbon and
other deposits are excessive, you should replace the spark
plug with the specified plug.NOTE:
If a torque wrench is not available when you are installing a
spark plug, a good estimate of the correct torque is 1/4 to
1/2 turn past finger tight. Have the spark plug torqued to
the correct value as soon as possible with a torque wrench.
When installing the plug, always clean the gasket surface
and use a new gasket. Wipe off any grime from the threads,
and torque the spark plug properly.
Spark plug torque:
12.5 N.m (1.25 Kgf.m, 9 lbf.ft)
Before installing the spark plug, measure the electrode gap
with a wire thickness gauge and adjust the gap to
specification as necessary.
Standard spark plug:
CR7HSA (NGK) and U22FSR-U (DENSO)


Spark plug gap:
0.7 mm ( 0.028 in) Spark plug inspection
The spark plug is an important engine component and is
easy to inspect. The condition of the spark plug can indicate
the condition of the engine.
The ideal color on the white porcelain insulator around the
center electrode is a medium to light tan color for a
motorcycle that is being ridden normally. Do not attempt to
diagnose any problems yourself. Instead, take the
motorcycle to a Yamaha dealer. You should periodically
remove and inspect the spark plug because heat and
deposits will cause the spark plug to slowly break down
and erode.
If electrode erosion becomes excessive, or if carbon and
other deposits are excessive, you should replace the spark
plug with the specified plug.NOTE:
If a torque wrench is not available when you are installing a
spark plug, a good estimate of the correct torque is 1/4 to
1/2 turn past finger tight. Have the spark plug torqued to
the correct value as soon as possible with a torque wrench.
When installing the plug, always clean the gasket surface
and use a new gasket. Wipe off any grime from the threads,
and torque the spark plug properly.
Spark plug torque:
12.5 N.m (1.25 Kgf.m, 9 lbf.ft)

6-25
6-25
CAUTION:
Too little chain slack will overload the engine and other
vital parts. Keep the slack within the specified limits.
Axle nut torque:
80 N.m (8.0 Kgf.m, 58 lbf.ft)
5. Adjust the free play in the brake pedal.
CAUTION:
Check the operation of the brake light after adjusting
the rear brake.1. Loosen the rear brake adjuster.
2. Loosen the axle nut.
3. Turn both left and right chain puller the same
amount.Make sure that they are in the same position
for proper wheel alignment. Drive chain slack adjustment

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4. After adjusting, be sure to tighten the axle nut.
CAUTION:
Too little chain slack will overload the engine and other
vital parts. Keep the slack within the specified limits.
Axle nut torque:
80 N.m (8.0 Kgf.m, 58 lbf.ft)
5. Adjust the free play in the brake pedal.
CAUTION:
Check the operation of the brake light after adjusting
the rear brake.1. Loosen the rear brake adjuster.
2. Loosen the axle nut.
3. Turn both left and right chain puller the same
amount.Make sure that they are in the same position
for proper wheel alignment. Drive chain slack adjustment

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 .!

4. After adjusting, be sure to tighten the axle nut.

6-26
6-26Cable inspection and lubrication Drive chain lubrication
The chain consists of many parts which work with each
other. If the chain is not maintained properly, it will wear out
quickly. Therefore, the chain must be serviced regularly.
This service is especially necessary when riding in dusty
areas.
1. Use Yamaha Chain and Cable Lube or any brands of
spray-type chain lubricant. First, remove all dirt and mud
from the chain with a brush or cloth, then spray lubricant
between both rows of side plates and on all center
rollers. The chain should be lubricated every 500 km
(300 mi).
2. To clean the chain, remove it from the machine, dip it
in solvent, and clean out as much dirt as possible. Take
the chain out of the solvent and dry it. Immediately
lubricate the chain to prevent it from rusting.Damage to the outer housing of cables may allow
internal rusting and cause interfere with cable
movement. Replace damaged cables as soon as
possible to prevent unsafe conditions.
Lubricate the inner cable and the cable end. If it does not
operate smoothly, ask a Yamaha dealer to replace them.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50
WARNING:
Cable inspection and lubrication Drive chain lubrication
The chain consists of many parts which work with each
other. If the chain is not maintained properly, it will wear out
quickly. Therefore, the chain must be serviced regularly.
This service is especially necessary when riding in dusty
areas.
1. Use Yamaha Chain and Cable Lube or any brands of
spray-type chain lubricant. First, remove all dirt and mud
from the chain with a brush or cloth, then spray lubricant
between both rows of side plates and on all center
rollers. The chain should be lubricated every 500 km
(300 mi).
2. To clean the chain, remove it from the machine, dip it
in solvent, and clean out as much dirt as possible. Take
the chain out of the solvent and dry it. Immediately
lubricate the chain to prevent it from rusting.Damage to the outer housing of cables may allow
internal rusting and cause interfere with cable
movement. Replace damaged cables as soon as
possible to prevent unsafe conditions.
Lubricate the inner cable and the cable end. If it does not
operate smoothly, ask a Yamaha dealer to replace them.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50
WARNING:

6-27
6-27Brake and clutch levers
Lubricate the pivoting parts.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50 Throttle cable and grip lubrication
The throttle twist grip assembly should be greased at the
time the cable is lubricated, since the grip must be removed
to get at the end of the throttle cable.
After removing the screws, hold the end of the cable up in
the air and put in several drops of lubricant. With the throttle
grip disassembled, coat the metal surface of the grip
assembly with a suitable all-purpose grease.Brake and shift pedals
Lubricate the pivoting parts.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50
Brake and clutch levers
Lubricate the pivoting parts.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50 Throttle cable and grip lubrication
The throttle twist grip assembly should be greased at the
time the cable is lubricated, since the grip must be removed
to get at the end of the throttle cable.
After removing the screws, hold the end of the cable up in
the air and put in several drops of lubricant. With the throttle
grip disassembled, coat the metal surface of the grip
assembly with a suitable all-purpose grease.Brake and shift pedals
Lubricate the pivoting parts.
RECOMMENDED LUBRICANT:
Engine oil SAE 20W50