2000 YAMAHA YZ426F oil

4 - 50
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
EC4H4600
Bearing
1. Inspect:
lBearing
Rotate inner race with a finger.
Rough spot/seizure ® Replace.
EC444400
Oil seal
1. Inspect:
lOil seal
Wear/damage ® Replace.
EC4G5000
ASSEMBLY AND INSTALLATION
EC4G5110
Oil seal
1. Install:
lOil seal 1
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lInstall the oil seal with its manufacture’s
marks or numbers facing inward.
Bearing
1. Install:
lBearing 1
NOTE:
Install the bearing by pressing its outer race
parallel.
New

4 - 51
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
EC4G5220
Impeller shaft
1. Install:
lImpeller shaft 1
lPlain washer 2
lImpeller shaft 3
NOTE:
lTake care so that the oil seal lip is not dam-
aged or the spring does not slip off its posi-
tion.
lWhen installing the impeller shaft, apply the
engine oil on the oil seal lip and impeller
shaft. And install the shaft while turning it.
lHold the impeller shaft on its width across
the flats a with spanners, etc. and remove
the impeller.
Crankcase cover (right)
1. Install:
lDowel pin 1
lO-ring 2
lCollar 3
lGasket 4 New
2. Install:
lCrankcase cover (right) 1
lBolt
NOTE:
lWhen installing the crankcase cover onto the
crankcase, be sure that the impeller shaft
end 2 aligns with the balancer end slot 3.
lTighten the bolts in stage, using a crisscross
pattern.
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 52
ENG
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
Kick crank
1. Install:
lKick crank 1
NOTE:
Install the kick crank so that the kick crank is
as vertical as possible with the distance a
between the kick crank and the frame being
5 mm (0.20 in) or more.
T R..33 Nm (3.3 m · kg, 24 ft · lb)
2. Install:
lOil hose 1
lBolt (oil hose) 2
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)
Water pump housing
1. Install:
lPin 1
lO-ring 2 New
2. Install:
lWater pump housing 1
lBolt (water pump housing) 2
lPlain washer 3
lCoolant drain bolt 4
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

ENG
4 - 53
BALANCER
BALANCER
BALANCER
Extent of removal:1 Balancer drive gear2 Balancer
Extent of removal Order Part name Q’ty Remarks
BALANCER REMOVAL
Preparation for removal Clutch housing Refer to “CLUTCH” section.
Crankcase cover (right)Refer to “OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT)” section.
Stator Refer to “CDI MAGNETO” section.
1 Nut (primary drive gear) 1
Refer to “REMOVAL POINTS”. 2 Nut (balancer) 1
3 Lock washer 1
4 Primary drive gear 1
5 Balancer drive gear 1
6 Straight key 1
7 Lock washer 1
8 Balancer driven gear 1
9Balancer
1
2
1
2

ENG
4 - 56
OIL PUMP
OIL 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 Clutch housingRefer to “CLUTCH” section.
Crankcase cover (right)Refer to “OIL FILTER, WATER PUMP AND
CRANKCASE COVER (RIGHT)” section.
1 Circlip 1
2 Plate washer 1
3 Oil pump drive gear 1
4 Oil pump assembly 1
5 Dowel pin 1
6 Outer rotor 2 1
7 Circlip 1
8 Inner rotor 2 1
9 Pin 1
10 Oil pump cover 1
11 Outer rotor 1 1
12Inner rotor 1
1
2
1

ENG
4 - 57
OIL PUMP
Extent of removal Order Part name Q’ty Remarks
13 Pin 1
14 Washer 1
15 Oil pump drive shaft 1
16 Rotor housing 1
2

4 - 58
ENGOIL PUMP
INSPECTION
Oil pump
1. Inspect:
lOil pump drive gear
lOil pump driven gear
lRotor housing
lOil pump cover
Cracks/wear/damage ® Replace.
2. Measure:
lTip clearance a
Between the inner rotor 1 and the
outer rotor 2.
lSide clearance b
Between the outer rotor 2 and the rotor
housing 3.
Out of specification ® Replace the oil
pump.
Tip clearance a:
0.07 ~ 0.12 mm (0.0028 ~ 0.0047 in)
: 0.15 mm (0.006 in)
Side clearance b:
0.03 ~ 0.08 mm (0.0012 ~ 0.0031 in)
: 0.15 mm (0.006 in)
3. Check:
lUnsmooth ® Repeat steps #1 and #2
or replace the defective parts.
ASSEMBLY AND INSTALLATION
Oil pump
1. Install:
lOil pump drive shaft 1
lWasher 2
lPin 3
lInner rotor 1 4
NOTE:
Fit the pin into the groove in the inner rotor 1.

4 - 59
ENGOIL PUMP
2. Install:
lOuter rotor 1 1
NOTE:
Align the match mark a on the inner rotor 1
with the match mark b on the outer rotor 1.
3. Install:
lOil pump cover 1
lScrew (oil pump cover) 2
lPin 3
lInner rotor 2 4
lCirclip 5
NOTE:
Fit the pin into the groove in the inner rotor 2.
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)
New
4. Install:
lOuter rotor 2 1
lDowel pin 2
lOil pump assembly 3
lBolt (oil pump assembly) 4
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
5. Install:
lOil pump drive gear 1
lPlate washer 2
lCirclip 3 New