Yamaha YZFR1Y(C) 2009 Service Manual page 121

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a. Remove the valve lifter "1" and the valve
pad "2" with a valve lapper "3".
Valve lapper
90890-04101
Valve lapping tool
YM-A8998
TIP
• Cover the timing chain opening with a rag to
prevent the valve pad from falling into the
crankcase.
• Make a note of the position of each valve
lifter "1" and valve pad "2" so that they can be
installed in the correct place.
b. Select the proper valve pad from the follow-
ing table.
Valve pad range
Valve pad thickness
Available valve pads
TIP
• The thickness "a" of each valve pad is
marked in hundredths of millimeters on the
side that touches the valve lifter.
Nos. 120–240
1.20–2.40 mm
(0.0472–0.0945 in)
38 thicknesses in
0.05 mm (0.002 in)
increments
PERIODIC MAINTENANCE
• Since valve pads of various sizes are origi-
nally installed, the valve pad number must be
rounded in order to reach the closest equiva-
lent to the original.
c. Round off the original valve pad number
according to the following table.
Last digit
0 or 2
5
8
EXAMPLE:
Original valve pad number = 148 (thickness
= 1.48 mm (0.058 in))
Rounded value = 150
d. Locate the rounded number of the original
valve pad and the measured valve clear-
ance in the valve pad selection table. The
point where the column and row intersect is
the new valve pad number.
TIP
The new valve pad number is only an approxi-
mation. The valve clearance must be mea-
sured again and the above steps should be
repeated if the measurement is still incorrect.
e. Install the new valve pad "1" and the valve
lifter "2".
3-8
Rounded value
0
5
10