engine oil YAMAHA YZ426F 2000 Owner's Guide

ENG
4 - 47
OIL FILTER, WATER PUMP AND CRANKCASE COVER
(RIGHT)
OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)
OIL FILTER, WATER PUMP AND CRANKCASE COVER (RIGHT)
Extent of removal:1 Oil filter removal2 Water pump removal
3 Crankcase (right) removal
Extent of removal Order Part name Q’ty Remarks
OIL FILTER, WATER PUMP
AND CRANKCASE COVER
(RIGHT) 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.
Exhaust pipe Refer to “EXHAUST PIPE AND
SILENCER” section in the CHAPTER 3.
Brake pedal Refer to “ENGINE REMOVAL” section.
Clutch cover Refer to “CLUTCH” section.
1 Oil filter cover 1
Refer to “ENGINE OIL REPLACEMENT”
section in the CHAPTER 3.
2 Oil filter 1
3 Coolant pipe 2 1
4 Water pump housing 1
5 Pin 2
6 Oil delivery pipe 1
1
23

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)

ENG
4 - 60
KICK AXLE AND SHIFT SHAFT
KICK AXLE AND SHIFT SHAFT
KICK AXLE AND SHIFT SHAFT
Extent of removal:1 Kick axle removal2 Kick axle disassembly
3 Shift shaft4 Segment removal
Extent of removal Order Part name Q’ty Remarks
KICK AXLE AND SHIFT SHAFT
REMOVAL
Preparation for removal Shift pedalRefer to “ENGINE REMOVAL” section.
Oil pumpRefer to “OIL PUMP” section.
1 Kick idle gear 1
2 Kick axle assembly 1 Refer to “REMOVAL POINTS”.
3 Spring guide 1
4 Torsion spring 1
5 Ratchet wheel 1
6 Kick gear 1
7 Kick axle 1
8 Plain washer 1
9 Shift shaft 1
10Collar
1
3
2
1
4
1

4 - 64
ENGKICK AXLE AND SHIFT SHAFT
EC4C5202
Shift guide and shift lever assembly
1. Install:
lSpring 1
lPawl pin 2
lPawl 3
To shift lever 4.
2. Install:
lShift lever assembly 1
To shift guide 2.
3. Install:
lShift lever assembly 1
lShift guide 2
NOTE:
lThe shift lever assembly is installed at the
same time as the shift guide.
lApply the engine oil on the bolt (segment)
shaft.
4. Install:
lBolt (shift guide) 1
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
EC4C5301
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.

4 - 65
ENGKICK AXLE AND SHIFT SHAFT
EC4B5302
Kick axle assembly
1. Install:
lKick gear 1
lRatchet wheel 2
NOTE:
Align the punched mark a on the ratchet
wheel with the punched mark b on the kick
axle.
2. Install:
lTorsion spring 1
To kick axle 2.
NOTE:
Make sure the stopper a of the torsion spring
fits into the hole b on the kick axle.
3. Install:
lSpring guide 1
NOTE:
Slide the spring guide into the kick axle, make
sure the groove a in the spring guide fits on
the stopper of the torsion spring.
4. Install:
lKick axle assembly 1
lPlain washer 2
NOTE:
lApply the engine oil on the kick axle.
lSlide the kick axle assembly into the crank-
case, make sure the kick axle stopper a fit
into their home position b.
5. Hook:
lTorsion spring 1
NOTE:
Turn the torsion spring clockwise and hook
into the proper hole a in the crankcase.

4 - 66
ENGKICK AXLE AND SHIFT SHAFT
EC4C5412
Kick idle gear
1. Install:
lKick idle gear 1
lPlain washer 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.
New

ENG
4 - 71
ENGINE 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.
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 “CDI MAGNETO” 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.
Spark plug cap
Disconnect the CDI magneto lead.
WARNING
Support the machine securely so there is nodanger of it falling over.

ENG
4 - 72
ENGINE REMOVAL
Extent of removal:1 Engine removal
Extent of removal Order Part name Q’ty Remarks
1 Engine skidplate 1
2 Neutral switch 1
3 Engine oil hose 2
4 Chain cover 1
5 Nut (drive sprocket) 1
Refer to “REMOVAL POINTS”. 6 Lock washer 1
7 Drive sprocket 1
8 Clip 1
9 Bolt (brake pedal) 1
10 Brake pedal 1
11 Engine upper bracket (right) 1
12 Engine upper bracket (left) 1
13 Engine lower bracket 2
14 Engine mounting bolt 3
15 Pivot shaft 1
Refer to “REMOVAL POINTS”.
16 Engine 1
1

4 - 75
ENGENGINE REMOVAL
2. Install:
lLock washer 1
lNut (drive sprocket) 2
NOTE:
Tighten the nut while applying the rear brake.
New
T R..75 Nm (7.5 m · kg, 54 ft · lb)
3. Bend the lock washer tab to lock the nut.
4. Install:
lChain guide
lChain cover 1
lBolt (chain cover) 2
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
5. Install:
lEngine oil hose 1
lBolt (engine oil hose) 2
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
6. Install:
lSpring 1
lPin 2
lNeutral switch 3
lBolt (neutral switch) 4
T R..4 Nm (0.4 m · kg, 2.9 ft · lb)

4 - 81
ENG

CRANKCASE AND CRANKSHAFT
EC4N4101
Crankcase
1. Inspect:
l
Contacting surface
a

Scratches
®
Replace.
l
Engine mounting boss
b
, crankcase
Cracks/damage
®
Replace.
2. Inspect:
l
Bearing
Rotate inner race with a finger.
Rough spot/seizure
®
Replace.
3. Inspect:
l
Oil seal
Wear/damage
®
Replace.
EC4N4201
Crankshaft
1. Measure:
l
Runout limit
a

l
Small end free play limit
b

l
Connecting rod big end side clearance
c

l
Crank width
d

Out of specification
®
Replace.
Use the dial gauge and a thickness
gauge.
Dial gauge and stand:
YU-03097/90890-01252
Standard
Runout
limit:0.03 mm
(0.0012 in)0.05 mm
(0.002 in)
Small end
free play:0.4 ~ 1.0 mm
(0.016 ~ 0.039 in)2.0 mm
(0.08 in)
Side
clearance:0.15 ~ 0.45 mm
(0.0059 ~ 0.0177 in)—
Crack
width:61.95 ~ 62.00 mm
(2.439 ~ 2.441 in)—