Checking The Cylinder Head - Yamaha F90D Service Manual

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)
2. Measure the camshaft runout. Replace if
above specification.
Camshaft runout limit:
0.03 mm (0.0012 in)
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.
6D81G11

Checking the cylinder head

1. Eliminate carbon deposits from the com-
bustion chambers and check for deterio-
ration.
2. Check the cylinder head warpage using a
straightedge 1 and thickness gauge 2
in the directions shown. Replace if above
specification.
S6D85450
d
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)
2
Cylinder head warpage limit:
0.1 mm (0.0039 in)
Cylinder head
1
c
2
S69J5970
3
4
5
6
7
1
S6D85470
8
9
S6D85460
5-32