Checking The Valves And Valve Guides - Yamaha XF50W Service Manual

VALVES AND VALVE SPRINGS
EAS00239
CHECKING THE VALVES AND VALVE
GUIDES
The following procedure applies to all of the
valves and valve guides.
1 . Measure:
8valve-stem-to-valve-guide clearance
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter a -
Valve stem diameter b
Out of specification
guide.
2. Replace:
8valve guide
NOTE:
To ease valve guide removal and installation,
and to maintain the correct fit, heat the cylinder
head to 100°C (212°F) in an oven.
• • • • • • • • • • • • • • • • • • • • • • •
a. Remove the valve guide with the valve
guide remover 1 .
b. Install the new valve guide with the valve
guide installer 2 and valve guide remover
1 .
c. After installing the valve guide, bore the
valve guide with the valve guide reamer 3
to obtain the proper valve-stem-to-valve-
guide clearance.
NOTE:
After replacing the valve guide, reface the valve
seat.
• • • • • • • • • • • • • • • • • • • • • • •
5-24
ENG
-* Replace the valve
Valve-stem-to-valve-guide clearance
Intake
0.010 ~ 0.037 mm(0.0004~0.0015 in)
<Limit>: 0.08 mm(0.0031 in)
Exhaust
0.025 ~ 0.052 mm(0.001~0.002 in)
<Limit>: 0.10 mm(0.0039 in)
Valve guide remover (4.0 mm)
90890-04111(YM-04111)
Valve guide installer (4.0 mm)
90890-04112(YM-04112)
Valve guide reamer (4.0 mm)
90890-04113(YM-04113)