2002 YAMAHA YZ250LC engine

INSP
ADJ
3-10
THROTTLE CABLE ADJUSTMENT/
THROTTLE LUBRICATION
EC35A001
THROTTLE CABLE ADJUSTMENT
1. Check:
9Throttle grip free play a
Out of specificationAdjust.
2. Adjust:
9Throttle grip free play
EC35S002
THROTTLE LUBRICATION
1. Remove:
9Cap cover 1
9Throttle cable cap 2
2. Apply:
9Lithium soap base grease
On the throttle cable end a, tube guide
cable winding portion band roller sliding
surface c.
Throttle grip free play adjustment steps:
9Loosen the locknut 1.
9Turn the adjuster 2until the specified free
play is obtained.
9Tighten the locknut.
NOTE:
Before adjusting the throttle cable free play,
the engine idle speed should be adjusted.
w
After adjusting, turn the handlebar to
right and left and make sure that the
engine idling does not run faster.
Throttle grip free play ?a:
3~5 mm (0.12~0.20 in)
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INSP
ADJ
3-11
AIR FILTER CLEANING
3. Install:
9Throttle cable cap
9Cap cover
EC35G040
AIR FILTER CLEANING
NOTE:
Proper air filter maintenance is the biggest key
to preventing premature engine wear and dam-
age.
cC
Never run the engine without the air filter
element in place; this would allow dirt and
dust to enter the engine and cause rapid
wear and possible engine damage.
1. Remove:
9Seat
9Fitting bolt 1
9Washer 2
9Air filter element 3
9Filter guide 4
2. Clean:
9Air filter element
Clean them with solvent.
NOTE:
After cleaning, remove the remaining solvent by
squeezing the element.
cC
Do not twist the element when squeezing
the element.
1 Nm (0.1 m•kg, 0.7 ft•lb)
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INSP
ADJ
3-12
TRANSMISSION OIL LEVEL CHECK
3. Inspect:
9Air filter element
DamageReplace.
4. Apply:
9Foam-air-filter oil or engine mixing oil
To the element.
NOTE:
Squeeze out the excess oil. Element should be
wet but not dripping.
5. Install:
9Filter guide 1
NOTE:
Align the projection aon filter guide with the
hole bin air filter element.
6. Apply:
9Lithium soap base grease
On the matching surface aon air filter ele-
ment.
7. Install:
9Air filter element 1
9Washer
9Fitting bolt
NOTE:
Align the projection aon filter guide with the
hole bin air filter case.
EC35H002
TRANSMISSION OIL LEVEL CHECK
1. Start the engine, warm it up for several min-
utes and wait for five minutes.
2. Place the machine on a level place and hold
it up on upright position by placing the suit-
able stand under the engine.
2 Nm (0.2 m•kg, 1.4 ft•lb)
5NX-9-30-3A 6/5/01 3:59 PM Page 32

INSP
ADJ
3-13
TRANSMISSION OIL REPLACEMENT
3. Check:
9Transmission oil level
EC35K002
TRANSMISSION OIL REPLACEMENT
1. Start the engine and warm it up for several
minutes and wait for five minute.
2. Place the machine on a level place and hold
it on upright position by placing the suitable
stand under the engine.
3. Place a suitable container under the engine.
Transmission oil level checking steps:
9Remove the oil check bolt 1.
9Inspect the oil level.
NOTE:
Be sure the machine is positioned straight
up when inspecting the oil level.
w
Never attempt to remove the oil check bolt
just after high speed operation. The heat-
ed oil could spout out, causing danger.
Wait until the oil cools down.
Oil flows outOil level is correct.
Oil does not flow outOil level is low.
Add transmission
oil until oil flows
out.
9Inspect the gasket (oil check bolt), replace if
damaged.
9Tighten the oil check bolt.
Recommended oil:
Yamalube 4 (10W-30) or SAE
10W-30 type SE motor oil
Oil check bolt:
10 Nm (1.0 m•kg, 7.2 ft•lb)
5NX-9-30-3A 6/5/01 3:59 PM Page 34

INSP
ADJ
3-15
IDLE SPEED ADJUSTMENT/MUFFLER INSPECTION/
SILENCER FIBER REPLACEMENT
EC35M001
IDLE SPEED ADJUSTMENT
1. Start the engine and thoroughly warm it up.
2. Adjust:
9Idle speed
EC35P030
MUFFLER INSPECTION
1. Inspect:
9O-ring 1
Damage Replace.
NOTE:
Install the O-rings with their depressed afacing
outward.
EC35R050
SILENCER FIBER REPLACEMENT
1. Remove:
9Side cover (right)
9Bolt (silencer) 1
9Silencer 2
9Bolt (fiber) 3 Adjustment steps:
Turn the throttle stop screw 1until the
engine runs at the lowest possible speed.
To increase idle speed Turn the throttle
stop screw 1 1
in.
To decrease idle speed Turn the throttle
stop screw 1 1
out.
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3-25
DRIVE CHAIN SLACK ADJUSTMENT
INSP
ADJ
EC36A060
DRIVE CHAIN SLACK ADJUSTMENT
1. Elevate the rear wheel by placing the suit-
able stand under the engine.
2. Check:
9Drive chain slack a
Above the seal guard installation bolt.
Out of specification Adjust
NOTE:
Before checking and/or adjusting, rotate the rear
wheel through several revolutions and check the
slack several times to find the tightest point. Check
and/or adjust chain slack with rear wheel in this
“tight chain” position.
Drive chain slack:
40~50 mm (1.6~2.0 in)
Drive chain lubricant:
SAE 10W-30 motor oil or suitable
chain lubricants
5. Install:
9Drive chain 1
9Joint 2
9Master link clip 3
cC
Be sure to install the master link clip to the
direction as shown.
aTurning direction
6. Lubricate:
9Drive chain
5NX-9-30-3B 6/5/01 4:06 PM Page 18

3-26
FRONT FORK INSPECTION
INSP
ADJ
3. Adjust:
9Drive chain slack
EC36C000
FRONT FORK INSPECTION
1. Inspect:
9Front fork smooth action
Operate the front brake and stroke the
front fork.
Unsmooth action/oil leakage Repair or
replace.
Drive chain slack adjustment steps:
9Loosen the axle nut 1and locknuts 2.
9Adjust chain slack by turning the
adjusters 3.
To tighten Turn adjuster 3 3
counter-
clockwise.
To loosen Turn adjuster 3 3
clockwise
and push wheel forward.
9Turn each adjuster exactly the same amount
to maintain correct axle alignment. (There are
marks aon each side of chain puller align-
ment.)
NOTE:
Turn the adjuster so that the chain is in line
with the sprocket, as viewed from the rear.
cC
Too small chain slack will overload the
engine and other vital parts; keep the
slack within the specified limits.
9Tighten the axle nut while pushing down the
drive chain.
9Tighten the locknuts.
Axle nut:
125 Nm (12.5 m•kg, 90 ft•lb)
5NX-9-30-3B 6/5/01 4:06 PM Page 20

3-27
FRONT FORK OIL SEAL AND DUST SEAL CLEANING/
FRONT FORK INTERNAL PRESSURE RELIEVING/
FRONT FORK REBOUND DAMPING FORCE ADJUSTMENT
INSP
ADJ
EC36D001
FRONT FORK OIL SEAL AND DUST SEAL
CLEANING
1. Remove:
9Protector
9Dust seal 1
NOTE:
Use a thin screw driver, and be careful not to
damage the inner fork tube and dust seal.
2. Clean:
9Dust seal a
9Oil seal b
NOTE:
9Clean the dust seal and oil seal after every
run.
9Apply the lithium soap base grease on the in-
ner tube.
EC36H002
FRONT FORK REBOUND DAMPING FORCE
ADJUSTMENT
1. Adjust:
9Rebound damping force
By turning the adjuster 1.
Stiffer a a
Increase the rebound damping
force. (Turn the adjuster 1 1
in.)
Softer b b
Decrease the rebound
damping force. (Turn the
adjuster 1 1
out.)
EC36f000
FRONT FORK INTERNAL PRESSURE
RELIEVING
NOTE:
If the front fork initial movement feels stiff during
a run, relieve the front fork internal pressure.
1. Elevate the front wheel by placing a suitable
stand under the engine.
2. Remove the air bleed screw 1and release
the internal pressure from the front fork.
3. Install:
9Air bleed screw
1 Nm (0.1 m•kg, 0.7 ft•lb)
5NX-9-30-3B 6/5/01 4:06 PM Page 22