Checking The Cylinder Head Bolt; Checking The Valve Spring; Checking The Valve - Yamaha F225F Service Manual

Cylinder head warpage limit:
0.10 mm (0.0039 in)

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.
d
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)

Checking the valve spring

1. Measure the valve spring free length a.
b a
c
Valve spring free length a:
48.1 mm (1.89 in)
2. Measure the valve spring tilt b. Replace
if above specification.
Valve spring tilt limit b: 1.7 mm (0.07 in)

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.
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)
Cylinder head
a
b
a
7-56
0
1
2
3
4
5
6
7
8
9
10
A