2001 YAMAHA YZ250F engine

4 - 52
ENGCLUTCH
EC4A5000
ASSEMBLY AND INSTALLATION
Push lever shaft
1. Install:
lPush lever shaft 1
lBolt (push lever shaft) 2
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lApply the engine oil on the push lever shaft.
lFit the seat plate 3 in the groove a of the
push lever shaft and tighten the bolt (seat
plate).
3
1
a2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
Clutch
1. Install:
lPrimary driven gear 1
lThrust washer 2
lClutch boss 3
NOTE:
Apply the engine oil on the primary driven gear
inner circumference.
2. Install:
lLock washer 1
lNut (clutch boss) 2
NOTE:
Use the clutch holding tool 3 to hold the clutch
boss.
For USA and CDN
õExcept for USA and CDN
Clutch holding tool:
YM-91042/90890-04086
T R..60 Nm (6.0 m · kg, 43 ft · lb)

õ

4 - 53
ENGCLUTCH
3. Bend the lock washer 1 tab.
4. Install:
lSeat plate 1
lCushion spring 2
NOTE:
lInstall the seat plate with its chamfered por-
tion a facing the clutch boss 3.
lInstall the cushion spring with the paint b
facing out.
1
2 1
2 3
a
b
5. Install:
lFriction plate 1 1
lClutch plate 1 2
lFriction plate 2 3
lClutch plate 2 4
NOTE:
lInstall the clutch plates and friction plates
alternately on the clutch boss, starting with a
friction plate and ending with a friction plate.
lUse the friction plates 1 for the first and final
while paying attention to the difference in
surface pattern.
lApply the engine oil on the friction plates and
clutch plates.
lUnlike the clutch plate 2, the clutch plate 1
has no surface gloss. Use the clutch plate 1
for the first while paying attenion to the differ-
ence in surface gloss.
1
2
6. Install:
lBearing 1
lWasher 2
lCirclip 3
To push rod 1 4.
NOTE:
Apply the engine oil on the bearing and
washer.

4 - 54
ENGCLUTCH
7. Install:
lPush rod 2 1
lBall 2
lPush rod 1 3
NOTE:
Apply the engine oil on the push rod 1, 2 and
ball.
8. Install:
lPressure plate 1
9. Install:
lClutch spring 1
lBolt (clutch spring) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
10. Install:
lDowel pin 1
lGasket (clutch cover) 2
11. Install:
lClutch cover 1
lBolt (clutch cover)
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 55
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Extent of removal:1 Oil filter element removal2 Water pump removal
3 Right crankcase cover removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER ELEMENT, WATER
PUMP AND RIGHT CRANK-
CASE COVER REMOVAL
Preparation for removal Drain the engine oil. Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
Drain the coolant. Refer to “COOLANT REPLACEMENT”
section in the CHAPTER 3.
Radiator hose 3 Disconnect at water pump side.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section.
Brake pedal Refer to “ENGINE REMOVAL” section.
Right engine guard
1 Oil filter element cover 1
2 Oil filter element 1
13

4 - 60
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
2. Install:
lRight crankcase cover 1
lBolt (right crankcase cover) 2
NOTE:
lApply the engine oil on the impeller shaft
end.
lMesh the impeller shaft gear 3 with primary
drive gear 4.
lTighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
Kickstarter crank
1. Install:
lKickstarter crank 1
lWasher 2
lBolt (kickstarter crank) 3
NOTE:
Install the kickstarter crank so that the kick-
starter crank is as vertical as possible with the
distance a between the kickstarter crank and
the frame being 8 mm (0.31 in) or more.
2. Install:
lOil hose 1
lBolt (oil hose) 2
T R..33 Nm (3.3 m · kg, 24 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
3. Install:
lCopper washer 1
lOil delivery pipe 2
lUnion bolt (M8) 3
lUnion bolt (M10) 4
T R..18 Nm (1.8 m · kg, 13 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)

4 - 64
ENGBALANCER
ASSEMBLY AND INSTALLATION
Balancer shaft, balancer shaft drive gear
and balancer shaft driven gear
1. Install:
lBalancer shaft 1
NOTE:
lApply the engine oil on the bearing.
lWhen installing the balancer shaft, align the
center a of the balancer shaft weight along
the line connecting the centers of the crank-
shaft and balancer shaft.
2. Install:
lBalancer shaft driven gear 1
NOTE:
Install the balancer shaft driven gear onto the
balancer shaft while aligning the punch mark
a on the balancer shaft driven gear with the
lower spline b on the balancer shaft end.
3. Install:
lBalancer shaft drive gear 1
NOTE:
lAlign the punched mark a on the balancer
shaft drive gear with the punched mark b on
the balancer shaft driven gear 2.
lAlign the punched mark c on the balancer
shaft drive gear with the lower spline d on
the crankshaft end.
4. Install:
lLock washer 1
lNut (balancer shaft driven gear) 2
lPrimary drive gear 3
lNut (primary drive gear) 4
NOTE:
lInstall the primary drive gear with its stepped
side a facing the engine.
lPlace an aluminum plate b between the
teeth of the balancer shaft drive gear 5 and
driven gear 6.
5. Bend the lock washer tab.
T R..50 Nm (5.0 m · kg, 3.6 ft · lb)
T R..75 Nm (7.5 m · kg, 54 ft · lb)

4 - 68
ENGOIL PUMP
ASSEMBLY AND INSTALLATION
Oil pump
1. Install:
lOil pump drive shaft 1
lWasher 2
lDowel pin 3
lInner rotor 1 4
NOTE:
lApply the engine oil on the oil pump drive
shaft and inner rotor 1.
lFit the dowel pin into the groove in the inner
rotor 1.
2. Install:
lOuter rotor 1 1
NOTE:
Apply the engine oil on the outer rotor 1.
3. Install:
lOil pump cover 1
lScrew (oil pump cover) 2
lDowel pin 3
lInner rotor 2 4
lCirclip 5
NOTE:
lApply the engine oil on the inner rotor 2.
lFit the dowel pin into the groove in the inner
rotor 2.
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)

4 - 69
ENG
4. Install:
lOuter rotor 2 1
lDowel pin 2
lOil pump assembly 3
lBolt (oil pump assembly)
[L = 25 mm (0.94 in)] 4
lBolt (oil pump assembly)
[L = 30 mm (1.18 in)] 5
NOTE:
Apply the engine oil on the outer rotor 2.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
5. Install:
lOil pump drive gear 1
lWasher 2
lCirclip 3
NOTE:
Apply the engine oil on the oil pump drive gear
inner circumference.
OIL PUMP