Yamaha WR450F Owner's Service Manual page 119

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1
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5. Adjust:
• Valve clearance
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a. Remove the camshaft (intake and exhaust).
Refer to "CAMSHAFT" on page 6-11.
b. Remove the valve lifter "2" and the adjusting
pad "3" with a valve lapper "1".
TIP
• Place a cloth in the timing chain space to pre-
vent adjusting pads from falling into the crank-
case.
• Identity each valve lifter and adjusting pad po-
sition very carefully so that they can be rein-
stalled in their original place.
Valve lapper
90890-04101
Valve lapping tool
YM-A8998
1
3
e
2
3-21
c. Check the number on the originally installed
adjusting pad.
TIP
• The adjusting pad number "a" is indicated on
the top of the adjusting pad.
• For the number on the originally installed ad-
justing pad, convert the last digit of adjusting
pad number as per the below table.
d. Select an adjusting pad with a proper valve
clearance from the adjusting pad selection
table.
TIP
• There are 25 types of adjusting pads, ranging
from 1.20 mm (0.0472 in) to 2.40 mm (0.0945
in), in increments of 0.05 mm (0.0020 in).
• The field where the number on the originally
installed adjusting pad and the measured
valve clearance intersect shows the adjusting
pad number to replace.
Last digit of pad
number
0, 1 or 2
4, 5 or 6
8 or 9
Example:
Pad number = 148
Rounded value = 150
ENGINE
Rounded valve
0
5
10