Oil YAMAHA YZ250F 2002 Repair Manual

4 - 55
ENGCLUTCH
7. Install:
Push rod 2 1
Ball 2
Push rod 1 3
NOTE:
Apply the engine oil on the push rod 1, 2 and
ball.
8. Install:
Pressure plate 1
9. Install:
Clutch spring 1
Bolt (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:
Dowel pin 1
Gasket (clutch cover) 2
11. Install:
Clutch cover 1
Bolt (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 - 56
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 - 57
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Extent of removal Order Part name Q’ty Remarks
3 Water pump housing 1
4 Oil delivery pipe 1
5 Bolt (oil hose) 1
6 Kickstarter crank 1
7 Right crankcase cover 1
8 Impeller 1
Refer to “REMOVAL POINTS”. 9 Washer 1
10 Impeller shaft 1
11 Oil seal 2
12Bearing
1
3
2

4 - 58
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
REMOVAL POINTS
Impeller shaft
1. Remove:
Impeller 1
Washer 2
Impeller shaft 3
NOTE:
Hold the impeller shaft on its width across the
flats a with spanners, etc. and remove the
impeller.
EC4G3210
Oil seal
NOTE:
It is not necessary to disassemble the water
pump, unless there is an abnormality such as
excessive change in coolant level, discolora-
tion of coolant, or milky transmission oil.
1. Remove:
Bearing 1
2. Remove:
Oil seal 1
INSPECTION
Oil delivery pipe
1. Inspect:
Oil delivery pipe 1
Bend/damage → Replace.
Clogged → Blow.

4 - 59
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
EC444200
Impeller shaft
1. Inspect:
Impeller shaft 1
Bend/wear/damage → Replace.
Fur deposits → Clean.
EC444300
Impeller shaft gear
1. Inspect:
Gear teeth a
Wear/damage → Replace.
EC4H4600
Bearing
1. Inspect:
Bearing
Rotate inner race with a finger.
Rough spot/seizure → Replace.
EC444400
Oil seal
1. Inspect:
Oil seal 1
Wear/damage → Replace.
ASSEMBLY AND INSTALLATION
Oil seal
1. Install:
Oil seal 1
NOTE:
Apply the lithium soap base grease on the oil
seal lip.
Install the oil seal with its manufacture’s
marks or numbers facing the right crankcase
cover 2.

4 - 60
ENG
OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
2. Install:
Bearing 1
NOTE:
Install the bearing by pressing its outer race
parallel.
Impeller shaft
1. Install:
Impeller shaft 1
Washer 2
Impeller 3
NOTE:
Take care so that the oil seal lip is not dam-
aged or the spring does not slip off its posi-
tion.
When installing the impeller shaft, apply the
lithium soap base grease on the oil seal lip
and impeller shaft. And install the shaft while
turning it.
Hold the impeller shaft on its width across
the flats a with spanners, etc. and install the
impeller.
T R..14 Nm (1.4 m · kg, 10 ft · lb)
Right crankcase cover
1. Install:
Dowel pin 1
O-ring 2
Collar 3
Gasket 4
NOTE:
Apply the lithium soap base grease on the O-
ring.

4 - 61
ENG

OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
2. Install:

Right crankcase cover
1


Bolt (right crankcase cover)
2

NOTE:


Apply the engine oil on the impeller shaft
end.

Mesh the impeller shaft gear
3
with primary
drive gear
4
.

Tighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

Kickstarter crank
1. Install:

Kickstarter crank
1


Washer
2


Bolt (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:

Oil hose
1


Bolt (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:

Copper washer
1


Oil delivery pipe
2


Union bolt (M8)
3


Union 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 - 62
ENG

OIL FILTER ELEMENT, WATER PUMP AND RIGHT
CRANKCASE COVER
Water pump housing
1. Install:

Dowel pin
1


O-ring
2

NOTE:

Apply the lithium soap base grease on the O-
ring.
2. Install:

Water pump housing
1


Bolt (water pump housing)
2

T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

Oil filter element
1. Install:

Oil filter element
1


O-ring
2


Oil filter element cover
3


Bolt (oil filter element cover)
NOTE:

Apply the lithium soap base grease on the O-
ring.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 63
ENG

BALANCER
BALANCER
Extent of removal:
1
Balancer shaft drive gear
2
Balancer shaft
Extent of removal Order Part name Q’ty Remarks
BALANCER REMOVAL
Preparation for removal Primary driven gear Refer to “CLUTCH” section.
Right crankcase cover Refer to “OIL FILTER ELEMENT,
WATER PUMP AND RIGHT CRANK-
CASE COVER” section.
Stator Refer to “CDI MAGNETO” section.
1 Nut (primary drive gear) 1
Refer to “REMOVAL POINTS”.
2 Nut (balancer shaft driven gear) 1
3 Lock washer 1
4 Primary drive gear 1
5 Balancer shaft drive gear 1
6 Lock washer 1
7 Balancer shaft driven gear 1
8 Balancer shaft 1 Refer to “REMOVAL POINTS”.
2
1
2

4 - 65
ENGBALANCER
ASSEMBLY AND INSTALLATION
Balancer shaft, balancer shaft drive gear
and balancer shaft driven gear
1. Install:
Balancer shaft 1
NOTE:
Apply the engine oil on the bearing.
When 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:
Balancer 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:
Balancer shaft drive gear 1
NOTE:
Align the punched mark a on the balancer
shaft drive gear with the punched mark b on
the balancer shaft driven gear 2.
Align the punched mark c on the balancer
shaft drive gear with the lower spline d on
the crankshaft end.
4. Install:
Lock washer 1
Nut (balancer shaft driven gear) 2
Primary drive gear 3
Nut (primary drive gear) 4
NOTE:
Install the primary drive gear with its stepped
side a facing the engine.
Place 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)