2001 YAMAHA YZ250F engine oil

4 - 75
ENGKICK SHAFT AND SHIFT SHAFT
4. Install:
lBolt (shift guide) 1
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
Shift shaft
1. Install:
lRoller 1
lCollar 2
lTorsion spring 3
lShift shaft 4
NOTE:
Apply the engine oil on the roller and shift
shaft.
2. Install:
lShift pedal 1
lBolt (shift pedal) 2
NOTE:
When installing the shift pedal onto the shift
shaft, be sure that the center of the shift pedal
is about 2 mm a above the top of the footrest.
Kick shaft assembly
1. Install:
lKick gear 1
lWasher 2
lCirclip 3
lRatchet wheel 4
lSpring 5
lWasher 6
lCirclip 7
To kick shaft 8.
NOTE:
lApply the molybdenum disulfide oil on the
kick gear inner circumference.
lAlign the punch mark a on the ratchet wheel
with the punch mark b on the kick shaft.

4 - 76
ENGKICK SHAFT AND SHIFT SHAFT
2. Install:
lTorsion spring 1
To kick shaft 2.
NOTE:
Make sure the stopper a of the torsion spring
fits into the hole b on the kick shaft.
3. Install:
lSpring guide 1
NOTE:
Slide the spring guide into the kick shaft, make
sure the groove a in the spring guide fits on
the stopper of the torsion spring.
4. Install:
lKick shaft assembly 1
lWasher 2
NOTE:
lApply the engine oil on the kick shaft.
lSlide the kick shaft assembly into the crank-
case, make sure the kick shaft stopper a fit
into their home position 3.
5. Hook:
lTorsion spring 1
NOTE:
Turn the torsion spring clockwise and hook
into the proper hole a in the crankcase.
Kick idle gear
1. Install:
lKick idle gear 1
lWasher 2
lCirclip 3
NOTE:
lApply the engine oil on the kick idle gear
inner circumference.
lInstall the kick idle gear with its depressed
side a toward you.

4 - 81
ENGENGINE REMOVAL
EC4M0000
ENGINE REMOVAL
Extent of removal Order Part name Q’ty Remarks
ENGINE REMOVAL
Preparation for removal Hold the machine by placing the
suitable stand under the frame.
WARNING
Support the machine securely so there is nodanger of it falling over.
Seat and fuel tank Refer to “SEAT, FUEL TANK AND SIDE
COVERS” section.
Carburetor Refer to “CARBURETOR” section.
Exhaust pipe and silencer Refer to “EXHAUST PIPE AND
SILENCER” section.
Clutch cable Disconnect at engine side.
Decompression cable and guide Disconnect at engine side.
Radiator Refer to “RADIATOR” section.
Shift pedal Refer to “KICK SHAFT AND SHIFT
SHAFT” section.
Cylinder head breather hose and
oil tank breather hoseRefer to “CAMSHAFTS” section.
Drain the engine oil Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.

4 - 82
ENGENGINE REMOVAL
Extent of removal:1 Engine removal
Extent of removal Order Part name Q’ty Remarks
Spark plug cap
Disconnect the CDI magneto lead.
Right engine guard
1 Neutral switch 1
2 Bolt (oil hose) 2
3 Drive chain sprocket cover 1
4 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 5 Lock washer 1
6 Drive sprocket 1
7 Clip 1
8 Bolt (brake pedal) 1
9 Brake pedal 1
10 Upper engine bracket 2
11 Lower engine bracket 2
12 Engine mounting bolt 3
13 Pivot shaft 1
Refer to “REMOVAL POINTS”.
14Engine
1
1

4 - 85
ENGENGINE REMOVAL
2. Install:
lLock washer 1
lNut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
T R..75 Nm (7.5 m · kg, 54 ft · lb)
3. Bend the lock washer tab to lock the nut.
4. Install:
lDrive chain sprocket guide 1
lDrive chain sprocket cover 2
lScrew (drive chain sprocket cover) 3
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
Oil hose and neutral switch
1. Install:
lO-ring 1
lDowel pin 2
lOil hose 3
lBolt (oil hose) 4
NOTE:
Apply the lithium soap base grease on the O-
ring.
2. Install:
lSpring 1
lPin 2
lO-ring 3
lNeutral switch 4
lBolt (neutral switch) 5
NOTE:
Apply the lithium soap base grease on the O-
ring.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)

4 - 86
ENGCRANKCASE AND CRANKSHAFT
CRANKCASE AND CRANKSHAFT
Extent of removal:1 Crankcase separation2 Crankshaft removal
Extent of removal Order Part name Q’ty Remarks
CRANKCASE AND CRANK-
SHAFT REMOVAL
Preparation for removal Engine Refer to “ENGINE REMOVAL” section.
Piston Refer to “CYLINDER AND PISTON” sec-
tion.
Kick shaft assembly
Refer to “KICK SHAFT AND SHIFT
SHAFT” section.
Segment
Stator Refer to “CDI MAGNETO” section.
Balancer shaft Refer to “BALANCER” section.
1 Timing chain guide (intake side) 1
2 Timing chain 1
3Oil delivery pipe 2
1
21

4 - 90
ENGCRANKCASE AND CRANKSHAFT
Crankshaft
1. Remove:
lCrankshaft 1
Use the crankcase separating tool 2.
CAUTION:
Do not use a hammer to drive out the
crankshaft.
Crankcase bearing
1. Remove:
lBearing 1
NOTE:
lRemove the bearing from the crankcase by
pressing its inner race.
lDo not use the removed bearing.
Crankcase separating tool:
YU-1135-A/90890-01135
INSPECTION
Timing chain and timing chain guide
1. Inspect:
lTiming chain
Cracks/stiff ® Replace the timing chain
and camshaft sprocket as a set.
2. Inspect:
lTiming chain guide
Wear/damage ® Replace.
Crankcase
1. Inspect:
lContacting surface a
Scratches ® Replace.
lEngine mounting boss b, crankcase
Cracks/damage ® Replace.
2. Inspect:
lBearing
Rotate inner race with a finger.
Rough spot/seizure ® Replace.
3. Inspect:
lOil seal
Damage ® Replace.

4 - 94
ENGCRANKCASE AND CRANKSHAFT
6. Tighten:
lHose guide 1
lClutch cable holder 2
lBolt (crankcase) 3
NOTE:
Tighten the crankcase tightening bolts in
stage, using a crisscross pattern.
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
7. Install:
lOil delivery pipe 2 1
lO-ring 2
lBolt (oil delivery pipe 2) 3
NOTE:
Apply the lithium soap base grease on the O-
rings.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
8. Install:
lTiming chain 1
lTiming chain guide (intake side) 2
lBolt (timing chain guide) 3
9. Remove:
lSealant
Forced out on the cylinder mating sur-
face.
10. Apply:
lEngine oil
To the crank pin, bearing and oil deliv-
ery hole.
11. Check:
lCrankshaft and transmission operation.
Unsmooth operation ® Repair.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)