Yamaha F225F, Service Manual

Page: 339 / 576

7-56
Cylinder head
0
1
2
3
4
5
6
7
8
9
10
A
Checking the cylinder head bolt
1. Measure the diameters
a
and
b
of the
cylinder head bolt at the specified mea-
suring points
c
and
d
. Replace the cyl-
inder head bolt if the difference between
the diameters is above specification.
Checking the valve spring
1. Measure the valve spring free length
a
.
2. Measure the valve spring tilt
b
. Replace
if above specification.
Checking the valve
1. Check the valve face. Replace if pitted or
worn.
2. Measure the valve margin thickness
a
.
Replace if out of specification.
Cylinder head warpage limit:
0.10 mm (0.0039 in)
Cylinder head bolt diameter difference
limit:
a
–
b
= Less than 0.20 mm (0.0079 in)
Measuring point
c
: 10.0 mm (0.39 in)
Measuring point
d
: 85.0 mm (3.35 in)
b a
c d
Valve spring free length
a
:
48.1 mm (1.89 in)
Valve spring tilt limit
b
: 1.7 mm (0.07 in)
Valve margin thickness
a
:
Intake:
0.750–1.150 mm (0.0295–0.0453 in)
Exhaust:
0.900–1.300 mm (0.0354–0.0512 in)
a
b
a