Yamaha YZ450FA 2011, Owner'S Service Manual

Page: 88 / 318

3-17
ENGINE
c. Measure the valve clearance "e" using a
feeler gauge "1".
Record the measured reading if the clearance
is incorrect.
5. Adjust:
• Valve clearance
Adjustment steps:
a. Remove the camshaft (intake and exhaust).
Refer to "CAMSHAFTS" section in the
CHAPTER 4.
b. Remove the valve lifter "1" and the valve pad
"2" with a valve lapper "3".
• Place a rag in the timing chain space to pre-
vent 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 select-
ing table.
The thickness "a" of each pad is indicated in
hundredths of millimeters on the pad upper sur-
face.
d. Round off the last digit of the installed pad
number to the nearest increment.
EXAMPLE:
Installed pad number = 148
Rounded off value = 150
Pads can only be selected in 0.05 mm incre-
ments.
e. Locate the rounded-off value and the mea-
sured valve clearance in the chart "PAD SE-
LECTION TABLE". The field where these
two coordinates intersect shows the new
pad number to use.
Pad range
Pad Availability: 25
increments
No.
120–No.
240
1.20
mm–2.40
mm
Pads are available in
0.05 mm increments
Last digit of pad
number
Rounded valve
0, 1 or 2 0
4, 5 or 6 5
8 or 9 10