Yamaha YZ 2019 Series, Owner'S Service Manual

Page: 105 / 398

ENGINE
3-17
b. Align the top dead center (TDC) mark “a” on
the rotor with the alignment mark “b” on the
crankcase cover.
TIP
Check that the alignment mark “c” on the cam-
shaft sprocket and the alignment mark “d” on the
intake camshaft sprocket are aligned with the
edge of the cylinder head.
c. Measure the valve clearance “e” using a
thickness gauge “1”.
TIP
Record the measured reading if the clearance is
incorrect.
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5. Adjust:
• Valve clearance
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a. Remove the camshaft (intake and exhaust).
Refer to “CAMSHAFT” on page 5-11.
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.
Thickness gauge
90890-03268
Feeler gauge set
YU-26900-9
a
b
d
c
e
e
Valve lapper (ø14)
90890-04101
Valve lapping tool (14mm)
YM-A8998
1
1
3
2
2
3