Assembling The Cylinder Head - Yamaha F4B Service Manual

3. Measure the thermostat valve opening a
at the specified water temperatures.
Replace if out of specification.
a
Water
Valve opening a
temperature
58–62 °C
(136–144 °F)
above 70 °C
3.0 mm (0.12 in) or above
(158 °F)

Assembling the cylinder head

Do not reuse a gasket or oil seal, always
replace it with a new one.
1. Install a new valve seal a.
a
Starts opening
2. Install the valve b, spring seat c, valve
spring d, and valve spring retainer e in
this order, and then install the special
service tools f and g.
e
d
c
b
Valve spring compressor f:
90890-04019
Valve spring compressor attachment g:
90890-06320
3. Compress the valve spring, and then
install the valve cotter h.
h
h
Cylinder head
f
g
10
7-36
0
1
2
3
4
5
6
7
8
9
A