Yamaha 2004 YP400, Service Manual, Page: 90 / 417

3 - 11
CHK
ADJ
ADJUSTING THE VALVE CLEARANCE
NOTE:
_
• TDC on the compression stroke can be
found when the camshaft lobes are turned
away from each other.
• In order to be sure that the piston is at TDC,
the punch marks
c
on the intake camshaft
sprocket and the punch mark
d
on the
exhaust camshaft sprocket must align with
the cylinder head mating surface as shown in
the illustration.
c. Measure the valve clearance with a thick-
ness gauge
1
.
NOTE:
_
If the valve clearance is incorrect, record the
measured reading.
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5. Remove:
• intake camshaft
• exhaust camshaft
NOTE:
_
• Refer to “CAMSHAFTS” in chapter 5.
• When removing the timing chain and cam-
shafts, fasten a wire to the timing chain to
retrieve it if it falls into the crankcase.
c
d
1
6. Adjust:
• valve clearance
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a. Remove the valve lifter
1
and the valve pad
2
with the valve lapper
3
.
NOTE:
_
• 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.
Valve lapper
90890-04101