bolt pattern YAMAHA YZ426F 2000 Betriebsanleitungen (in German)

3 - 20
INSP
ADJ
VALVE CLEARANCE ADJUSTMENT
6. Adjust:
lValve clearance
Adjustment steps:
lLoosen the timing chain tensioner cap
bolt.
lRemove the timing chain tensioner and
camshaft caps.
lRemove the camshaft (intake 1 and
exhaust 2).
lRemove the decompression cable 4,
guide 5, bolt 6 and decompression shaft
7.
lRemove the valve lifters 8 and the pads
9.
lSelect the proper pad using the pad
selecting table.
Pad rangePad Availability:
25 increments
No. 120
~
No. 2401.20 mm
~
2.40 mmPads are available in
0.05 mm increments
NOTE:
Remove the camshaft cap bolts in a criss-
cross pattern from the outside working
inwards.
NOTE:
Attach a wire 3 to the timing chain to pre-
vent it from falling into the crankcase.
NOTE:
lPlace a rag in the timing chain space to
prevent pads from falling into the crank-
case.
lIdentity each valve lifter and pad position
very carefully so that they can be rein-
stalled in their original place.
NOTE:
The thickness a of each pad is indicated in
hundreths of millimeters on the pad upper
surface.

4 - 19
ENGCAMSHAFTS
REMOVAL POINTS
Camshaft
1. Remove:
lTiming plug 1
lStraight plug 2
2. Align:
l“I” mark
With stationary pointer.
Checking steps:
lTurn the crankshaft counterclockwise with
a wrench.
lAlign the “I” mark a on the rotor with the
stationary pointer b on the crankcase
cover. When the “I” mark is aligned with
the stationary pointer, the piston is at the
Top Dead Center (T.D.C.).
NOTE:
lIn order to be sure that the piston is at Top
Dead Center, the punch mark c on the
exhaust camshaft and the punch mark d
on the intake camshaft must align with the
cylinder head surface, as shown in the
illustration.
lIf there is no clearance, rotate the crank-
shaft counterclockwise one turn.
3. Loosen:
lCamshaft sprocket bolts
lTensioner cap bolt 1
4. Remove:
lTiming chain tensioner 2
5. Remove:
lBolt (camshaft cap) 1
lCamshaft caps 2
NOTE:
Remove the bolts (camshaft cap) in a criss-
cross pattern, working from the inside out.
CAUTION:
The bolts (camshaft cap) must be removed
evenly to prevent damage to the cylinder
head, camshafts or camshaft caps.

4 - 21
ENG

CAMSHAFTS

Measurement steps:
l
Install the camshaft onto the cylinder
head.
l
Position a strip of Plastigauge
®


1
onto the
camshaft.
l
Install the circlip, dowel pins and camshaft
caps.
T R..

Bolt (camshaft cap):
10 Nm (1.0 m • kg, 7.2 ft • lb)
.
l
Remove the camshaft caps and measure
the width of the Plastigauge
®


1
.
NOTE:
lTighten the bolts (camshaft cap) in a
crisscross pattern from innermost to outer
caps.
lDo not turn the camshaft when measuring
clearance with the Plastigauge®.
5. Measure:

l
Bearing diameter (camshaft)
a

Out of specification
®
Replace the
camshaft.
Within specification
®
Replace camshaft
case and camshaft caps as a set.
Bearing diameter (camshaft):
0.020 ~ 0.054 mm
(0.0008 ~ 0.0021 in)
Camshaft sprocket
1. Inspect:
l
Camshaft sprocket
Wear/damage
®
Replace the camshaft
assembly and timing chain as a set.

4 - 23
ENG

CAMSHAFTS
2. Install:
l
Timing chain tensioner
3. Turn:
l
Crankshaft
Counterclockwise several turns
4. Check:
l
Rotor “I” mark
Align with the crankcase stationary
pointer.
l
Camshaft match marks
Align with the cylinder head surface.
Out of alignment
®
Adjust.
.
l
Install the dowel pins, clips and camshaft
caps
4
.
T R..

Bolt (camshaft cap):
10 Nm (1.0 m • kg, 7.2 ft • lb)
.
Installation steps:
l
While pressing the tensioner rod lightly with
fingers, use a thin screwdriver and wind the
tensioner rod up fully clockwise.
l
With the rod fully wound and the chain ten-
sioner UP mark
a
facing upward, install the
gasket
1
and the chain tensioner
2
, and
tighten the bolt
3
to the specified torque.
T R..

Bolt (timing chain tensioner):
10 Nm (1.0 m • kg, 7.2 ft • lb)
l
Release the screwdriver, check the ten-
sioner rod to come out and tighten the
gasket
4
and the cap bolt
5
to the speci-
fied torque.
T R..

Tensioner cap bolt:
7 Nm (0.7 m • kg, 5.1 ft • lb)
CAUTION:
Do not turn the crankshaft during the
camshaft installation. Damage or
improper valve timing will result.
NOTE:
Tighten the bolts (camshaft cap) 5 in a
crisscross pattern.
CAUTION:
The bolts (camshaft cap) must be tightened
evenly or damage to the cylinder head,
camshaft caps and camshaft will result.

4 - 26
ENG

CYLINDER HEAD
INSPECTION
Cylinder head
1. Eliminate:
l
Carbon deposits (from the combustion
chambers)
Use a rounded scraper.
NOTE:

Do not use a sharp instrument to avoid dam-
aging or scratching:
lSpark plug threads
lValve seats
2. Inspect:
lCylinder head
Scratches/damage ® Replace.
3. Measure:
lCylinder head warpage
Out of specification ® Resurface.
ASSEMBLY AND INSTALLATION
1. Install:
lCylinder head
lBolts (1 ~ 4)
lBolt (5)
lNuts (6, 7)
lNuts (8, 9)
NOTE:
Follow the numerical order shown in the illus-
tration. Tighten the bolts and nuts in two
stages.
Cylinder head warpage:
Less than 0.03 mm (0.002 in)
Warpage measurement and resurface-
ment steps:
lPlace a straightedge and a feeler gauge
across the cylinder head.
lUse a feeler gauge to measure the
warpage.
lIf the warpage is out of specification,
resurface the cylinder head.
lPlace a 400 ~ 600 grit wet sandpaper on
the surface plate, and resurface the head
using a figure-eight sanding pattern.
NOTE:
To ensure an even surface rotate the cylin-
der head several times.
T R..44 Nm (4.4 m · kg, 32 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)
T R..20 Nm (2.0 m · kg, 14 ft · lb)
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

4 - 46
ENGCLUTCH
5. Install:
lPush rod 2 1
lPush rod 1 2
NOTE:
Apply the engine oil on the push rod 1,2.
6. Install:
lPressure plate 1
7. Install:
lClutch spring
lBolt (clutch spring)
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
T R..8 Nm (0.8 m · kg, 5.8 ft · lb)
8. Install:
lGasket (clutch cover) 1
lDowel pin 2
New
9. 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 - 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 - 84
ENG

CRANKCASE AND CRANKSHAFT
5. Install:
l
Dowel pin
1

lO-ring 2
lCrankcase (right)
To crankcase (left).
NOTE:
lFit the crankcase (right) onto the crankcase
(left). Tap lightly on the case with soft ham-
mer.
lWhen installing the crankcase, the connect-
ing rod should be positioned at TDC (top
dead center).
6. Tighten:
lHose guide 1
lClutch cable holder 2
lBolt (crankcase)
NOTE:
Tighten the crankcase tightening bolts in
stage, using a crisscross pattern.
7. Install:
lOil delivery pipe
lO-ring
lBolt (oil delivery pipe)
8. Install:
lTiming chain
lTiming chain guide (rear)
lPlate washer
lBolt (timing chain guide)
9. Remove:
lSealant
Forced out on the cylinder mating sur-
face.
10. Apply:
lEngine oil
To the crank pin, bearing and oil deliv-
ery hole.
11. Check:
lCrankshaft and transmission operation.
Unsmooth operation ® Repair.
New
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
New
T R..10 Nm (1.0 m · kg, 7.2 ft · lb)

5 - 5
CHAS

FRONT WHEEL AND REAR WHEEL
EC595000
ASSEMBLY AND INSTALLATION
EC595100
Front wheel
1. Install:
l
Bearing (left)
1

l
Spacer
2

l
Bearing (right)
3

l
Oil seal
4

NOTE:

l
Apply the lithium soap base grease on the
bearing and oil seal lip when installing.
l
Use a socket that matches the outside diam-
eter of the race of the bearing.
l
Left side of bearing shall be installed first.
l
Install the oil seal with its manufacture’s
marks or numbers facing outward.
ACHTUNG:CAUTION:
Do not strike the inner race of the bearing.
Contact should be made only with the outer
race.
2. Install:
lBrake disc 1
lBolt (brake disc) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
New
T R..12 Nm (1.2 m · kg, 8.7 ft · lb)
3. Install:
lCollar 1
NOTE:
lApply the lithium soap base grease on the oil
seal lip.
lInstall the collars with their projections a
facing the wheel.
4. Install:
lWheel
NOTE:
Install the brake disc 1 between the brake
pads 2 correctly.

5 - 7
CHASFRONT WHEEL AND REAR WHEEL
9. Install:
lHose cover 1
lPlain washer 2
lBolt [hose cover (M8)] 3
lBolt [hose cover (M6)] 4
T R..16 Nm (1.6 m · kg, 11 ft · lb)
T R..7 Nm (0.7 m · kg, 5.1 ft · lb)
EC525112
Rear wheel
1. Install:
lBearing (right) 1
lCirclip 2
lSpacer 3
lBearing (left) 4
lOil seal 5
NOTE:
lApply the lithium soap base grease on the
bearing and oil seal lip when installing.
lInstall the bearing with seal facing outward.
lUse a socket that matches the outside diam-
eter of the race of the bearing.
lRight side of bearing shall be installed first.
lInstall the oil seal with its manufacture’s
marks or numbers facing outward.
ACHTUNG:CAUTION:
Do not strike the inner race of the bearing.
Contact should be made only with the outer
race.
New
New
2. Install:
lBrake disc 1
lBolt (brake disc) 2
NOTE:
Tighten the bolts in stage, using a crisscross
pattern.
1
1
1
1

2


1
3
5
2
4
6
T R..14 Nm (1.4 m · kg, 10 ft · lb)