Yamaha WR450F(Y) 2009 Owner's Service Manual page 72

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5. Adjust:
• Valve clearance
Adjustment steps:
a. Remove the camshaft (intake and
exhaust).
Refer to "CAMSHAFTS" section
in the CHAPTER 5.
b. Remove the valve lifters "1" and
the pads "2".
• Place a rag in the timing chain
space to prevent pads from falling
into the crankcase.
• Identity each valve lifter and pad
position very carefully so that they
can be reinstalled in their original
place.
c. Select the proper pad using the
pad selecting table.
Pad Availabil-
Pad range
ity: 25 incre-
ments
No.
1.20
Pads are
120–
mm–
available in
No.
2.40
0.05 mm in-
240
mm
crements
The thickness "a" of each pad is indi-
cated in hundredths of millimeters on
the pad upper surface.
d. Round off the last digit of the in-
stalled pad number to the nearest
increment.
Last digit of pad
Rounded valve
number
0, 1 or 2
4, 5 or 6
8 or 9
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
Pads can only be selected in 0.05
mm increments.
e. Locate the rounded-off value and
the measured valve clearance in
the chart "PAD SELECTION TA-
BLE". The field where these two
coordinates intersect shows the
new pad number to use.
Use the new pad number only as a
guide when verifying the valve clear-
ance adjustment.
f. Install the new pads "3" and the
valve lifters "4".
• Apply the engine oil on the valve lift-
ers.
• 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.
3-17
g. Install the camshafts (exhaust
and intake).
Refer to "CAMSHAFTS" section
in the CHAPTER 5.
Bolt (camshaft cap):
h. Install the timing chain tensioner.
Refer to "CAMSHAFTS" section
in the CHAPTER 5.
Turn the crankshaft counterclockwise
several turns so that the installed
parts settle into the right position.
i.
Recheck the valve clearance.
j.
If the clearance is still incorrect,
repeat all the clearance adjust-
0
ment steps until the specified
clearance is obtained.
5
10
6. Install:
• All removed parts
Install all removed parts in reversed
order of their removal.
ENGINE
10 Nm (1.0 m•kg, 7.2
ft•lb)

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