Yamaha F80B, Service Manual

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6D93G11
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CAUTION:
Do not get the lapping compound on the
valve stem and valve guide.
10. After every lapping procedure, be sure to
clean off any remaining lapping com-
pound from the cylinder head and the
valve.
11. Check the valve seat contact area of the
valve again.
Checking the camshafts
1. Measure the cam lobe. Replace if out of
specification.
2. Measure the camshaft runout. Replace if
above specification.
3. Measure the camshaft journal diameter
c
and cylinder head journal inside diam-
eter
d
. Replace the camshaft and cylin-
der head if out of specification.
Checking the cylinder head
1. Eliminate carbon deposits from the com-
bustion chambers and check for deterio-
ration.
Cam lobe
a
:
Intake:
36.48–36.58 mm
(1.4362–1.4402 in)
Exhaust:
36.90–37.06 mm
(1.4528–1.4591 in)
Cam lobe
b
:
Intake:
29.95–30.05 mm
(1.1791–1.1831 in)
Exhaust:
29.92–30.08 mm
(1.1780–1.1842 in)
Camshaft runout limit:
0.03 mm (0.0012 in)
Camshaft journal diameter
c
:
24.960–24.980 mm
(0.9827–0.9835 in)
Camshaft cap inside diameter
d
:
25.000–25.021 mm
(0.9843–0.9851 in)
S6D85450
S69J5970
d
c
Cylinder head