Checking The Valves And Valve Guides - Yamaha TW125 1999 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:
2. Replace:
NOTE:
To ease valve guide removal and installation,
and to maintain the correct fit, heat the cylinder
head to 100_C in an oven.
a. Remove the valve guide with a valve guide
b. Install the new valve guide with a valve guide
c. After installing the valve guide, bore the
NOTE:
After replacing the valve guide, reface the valve
seat.
4-19
S valve-stem-to-valve-guide clearance
Valve-stem-to-valve-guide clearance =
Valve guide inside diameter a –
Valve stem diameter b
Out of specification ! Replace the valve
guide.
Valve-stem-to-valve-guide clear-
ance
Intake
0.010 X 0.037 mm
Limit: 0.08 mm
Exhaust
0.025 X 0.052 mm
Limit: 0.10 mm
S valve guide
remover 1 .
installer 2 and valve guide remover 1 .
valve guide with a valve guide reamer 3 to
obtain the proper valve-stem-to-valve-guide
clearance.
Valve guide remover (6 mm)
90890-04064
Valve guide installer (6 mm)
90890-04065
Valve guide reamer (6 mm)
90890-04066
ENG