2003 YAMAHA YZ250F water pump

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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.

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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.

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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)

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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)

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ENGBALANCER
BALANCER
Extent of removal:1 Balancer shaft drive gear2 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

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ENGOIL PUMP
OIL PUMP
Extent of removal:1 Oil pump removal2 Oil pump disassembly
Extent of removal Order Part name Q’ty Remarks
OIL PUMP REMOVAL AND DIS-
ASSEMBLY
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.
1 Circlip 1
2 Washer 1
3 Oil pump drive gear 1
4 Oil pump assembly 1
5 Outer rotor 2 1
6 Circlip 1
7 Inner rotor 2 1
8 Dowel pin 1
9 Oil pump cover 1
10 Outer rotor 1 1
11Inner rotor 1
1
2
1