2004 YAMAHA WR 450F valve

3 - 20
INSP
ADJ
VALVE CLEARANCE ADJUSTMENT
3. Remove:
Timing plug 1
Straight plug 2
O-ring1
2
4. Check:
Valve clearance
Out of specification → Adjust.
Valve clearance (cold):
Intake valve:
0.10 ~ 0.15 mm
(0.0039 ~ 0.0059 in)
Exhaust valve:
0.20 ~ 0.25 mm
(0.0079 ~ 0.0098 in)
Checking steps:
Turn the crankshaft counterclockwise with
a wrench.
Align the T.D.C. mark a on the rotor with
the align mark b on the crankcase cover
when piston is at T.D.C. on compression
stroke.
NOTE:
In 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 cyl-
inder head surface, as shown in the illustra-
tion.
Measure the valve clearance e using a
feeler gauge 1.
NOTE:
Record the measured reading if the clear-
ance is incorrect.
b
a

3 - 21
INSP
ADJ
VALVE CLEARANCE ADJUSTMENT
5. Adjust:
Valve clearance
Adjustment steps:
Loosen the timing chain tensioner cap
bolt.
Remove the timing chain tensioner and
camshaft caps.
NOTE:
Remove the camshaft cap bolts in a criss-
cross pattern from the outside working
inwards.
Remove the camshaft (exhaust 1 and
intake 2).
NOTE:
Attach a wire 3 to the timing chain to pre-
vent it from falling into the crankcase.
Remove the valve lifters 4 and the pads 5.
NOTE:
Place a rag in the timing chain space to
prevent pads from falling into the crank-
case.
Identity each valve lifter and pad position
very carefully so that they can be rein-
stalled in their original place.
Select 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:
The thickness a of each pad is indicated in
hundreths of millimeters on the pad upper
surface.
1
2
3

3 - 22
INSP
ADJ
Round off the last digit of the installed pad
number to the nearest increment.
Last digit of pad
numberRounded value
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
NOTE:
Pads can only be selected in 0.05 mm incre-
ments.
Locate the rounded-off value and the mea-
sured valve clearance in the chart “PAD
SELECTION TABLE”. The field where
these two coordinates intersect shows the
new pad number to use.
NOTE:
Use the new pad number only as a guide
when verifying the valve clearance adjust-
ment.
Install the new pads 6 and the valve lift-
ers 7.
NOTE:
Apply the engine oil on the valve lifters.
Apply the molybdenum disulfide oil on the
valve stem ends.
Valve lifter must turn smoothly when
rotated with a finger.
Be careful to reinstall valve lifters and
pads in their original place.
Install the camshafts (exhaust and intake),
the timing chain and the camshaft caps.
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
T R..
Bolt (camshaft cap):
10 Nm (1.0 m • kg, 7.2 ft • lb)
VALVE CLEARANCE ADJUSTMENT

3 - 23
INSP
ADJ
6. Install:
All removed parts
NOTE:
Install all removed parts in reversed order of
their removal.
Install the timing chain tensioner.
Refer to “CAMSHAFTS” section in the
CHAPTER 4.
NOTE:
Turn the crankshaft counterclockwise sev-
eral turns so that the installed parts settle
into the right position.
Recheck the valve clearance.
If the clearance is still incorrect, repeat all
the clearance adjustment steps until the
specified clearance is obtained.
VALVE CLEARANCE ADJUSTMENT

3 - 24
INSP
ADJ
VALVE CLEARANCE ADJUSTMENT
INTAKE
MEASURED
CLEARANCEINSTALLED PAD NUMBER
120 125 130 135 140 145 150 155 160 165 170
175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 ~ 0.04 120 125 130 135 140 145 150 155
160165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.05 ~ 0.09
120 125 130 135 140 145 150 155 160 165170 175 180 185 190 195 200 205 210 215 220 225 230 235
0.10 ~ 0.15
STANDARD CLEARANCE
0.16 ~ 0.20125130135140145150155160165170175180 185 190 195 200 205 210 215 220 225 230 235240
0.21 ~ 0.25130135140145150155160165170175180185 190 195 200 205 210 215 220 225 230 235240
0.26 ~ 0.30 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.31 ~ 0.35 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.36 ~ 0.40 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.41 ~ 0.45 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.46 ~ 0.50 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.51 ~ 0.55 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.56 ~ 0.60 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.61 ~ 0.65 170 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.66 ~ 0.70 175 180 185 190 195 200 205 210 215 220 225 230 235240
0.71 ~ 0.75 180 185 190 195 200 205 210 215 220 225 230 235240
0.76 ~ 0.80 185 190 195 200 205 210 215 220 225 230 235240VALVE CLEARANCE (cold):
0.10 ~ 0.15 mm
Example: Installed is 175
Measured clearance is 0.22 mm
Replace 175 pad with 185 pad
Pad number: (example)
Pad No. 175 = 1.75 mm
Pad No. 185 = 1.85 mm0.81 ~ 0.85 190 195 200 205 210 215 220 225 230 235240
0.86 ~ 0.90 195 200 205 210 215 220 225 230 235240
0.91 ~ 0.95 200 205 210 215 220 225 230 235240
0.96 ~ 1.00 205 210 215 220 225 230 235240
1.01 ~ 1.05 210 215 220 225 230 235240
1.06 ~ 1.10 215 220 225 230 235240
1.11 ~ 1.15 220 225 230 235240
1.16 ~ 1.20 225 230 235240
1.21 ~ 1.25 230 235240
1.26 ~ 1.30 235240
1.31 ~ 1.35 240
EXHAUST
MEASURED
CLEARANCEINSTALLED PAD NUMBER
120 125 130 135 140 145 150 155 160 165 170
175 180 185 190 195 200 205 210 215 220 225 230 235 240
0.00 ~ 0.04 120 125 130 135 140 145
150155 160 165 170 175 180 185 190 195 200 205 210 215 220
0.05 ~ 0.09
120 125 130 135 140 145 150 155160 165 170 175 180 185 190 195 200 205 210 215 220 225
0.10 ~ 0.14
120 125 130 135 140 145 150 155 160165 170 175 180 185 190 195 200 205 210 215 220 225 230
0.15 ~ 0.19120125130135140145150155160165170 175 180 185 190 195 200 205 210 215 220 225230235
0.20 ~ 0.25
STANDARD CLEARANCE
0.26 ~ 0.30 125 130 135 140 145 150 155 160 165 170 175180 185 190 195 200 205 210 215 220 225230235240
0.31 ~ 0.35130135140145150155160165170175180185 190 195 200 205 210 215 220 225230235240
0.36 ~ 0.40 135 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.41 ~ 0.45 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.46 ~ 0.50 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.51 ~ 0.55 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.56 ~ 0.60 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.61 ~ 0.65 160 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.66 ~ 0.70 165 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.71 ~ 0.75 170 175 180 185 190 195 200 205 210 215 220 225230235240
0.76 ~ 0.80 175 180 185 190 195 200 205 210 215 220 225230235240
0.81 ~ 0.85 180 185 190 195 200 205 210 215 220 225230235240
0.86 ~ 0.90 185 190 195 200 205 210 215 220 225230235240
VALVE CLEARANCE (cold):
0.20 ~ 0.25 mm
Example: Installed is 175
Measured clearance is 0.32 mm
Replace 175 pad with 185 pad
Pad number: (example)
Pad No. 175 = 1.75 mm
Pad No. 185 = 1.85 mm0.91 ~ 0.95 190 195 200 205 210 215 220 225230235240
0.96 ~ 1.00 195 200 205 210 215 220 225230235240
1.01 ~ 1.05 200 205 210 215 220 225230235240
1.06 ~ 1.10 205 210 215 220 225230235240
1.11 ~ 1.15 210 215 220 225230235240
1.16 ~ 1.20 215 220 225230235240
1.21 ~ 1.25 220 225230235240
1.26 ~ 1.30 225230235240
1.31 ~ 1.35 230235240
1.36 ~ 1.40 235240
1.41 ~ 1.45 240

3 - 44
INSP
ADJTIRE PRESSURE CHECK/SPOKES INSPECTION AND
TIGHTENING/WHEEL INSPECTION
EC36Q000
TIRE PRESSURE CHECK
1. Measure:
Tire pressure
Out of specification → Adjust.
NOTE:
Check the tire while it is cold.
Loose bead stoppers allow the tire to slip off
its position on the rim when the tire pressure
is low.
A tilted tire valve stem indicates that the tire
slips off its position on the rim.
If the tire valve stem is found tilted, the tire is
considered to be slipping off its position. Cor-
rect the tire position.
Standard tire pressure:
100 kPa (1.0 kgf/cm2, 15 psi)
EC36S002
SPOKES INSPECTION AND TIGHTENING
1. Inspect:
Spokes 1
Bend/damage → Replace.
Loose spoke → Retighten.
2. Tighten:
Spokes
NOTE:
Be sure to retighten these spokes before and
after break-in. After a practice or a race check
spokes for looseness.
T R..3 Nm (0.3 m · kg, 2.2 ft · lb)
EC36T000
WHEEL INSPECTION
1. Inspect:
Wheel runout
Elevate the wheel and turn it.
Abnormal runout → Replace.

4 - 9
ENGCARBURETOR
CARBURETOR DISASSEMBLY
Extent of removal:1 Carburetor disassembly
Extent of removal Order Part name Q’ty Remarks
CARBURETOR DISASSEMBLY
1Breather hose 4
2Valve lever housing cover 1
3Screw (throttle shaft) 1
4Throttle valve 1
5Needle holder 1
6Jet needle 1
7Cover 1
8Spring 1
9Diaphragm (accelerator pump) 1
0Air cut valve cover 1
ASpring (air cut valve) 1
BDiaphragm (air cut valve) 1
CFloat chamber 1
DLeak jet 1
EPilot screw 1 Refer to “REMOVAL POINTS”.
FFloat pin 1
GFloat 1
1

4 - 10
ENGCARBURETOR
Extent of removal Order Part name Q’ty Remarks
HNeedle valve 1
IMain jet 1
JNeedle jet 1
KSpacer 1
LPilot jet 1
MStarter jet 1
NPush rod 1 Pull the push rod.
OThrottle shaft assembly 1
PPush rod link lever assembly 1
QPilot air jet 1
RCold starter plunger 1
1