Yamaha RS90GTZ Service Manual page 260

VALVES AND VALVE SPRINGS
2. Replace:
• Valve guide
TIP
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.
Replacement steps:
• Remove the valve guide with the valve guide
remover
• Install the new valve guide with the valve
guide installer
.
• After installing the valve guide, bore the valve
guide with the valve guide reamer
obtain the proper valve-stem-to-valve-guide
clearance.
TIP
After replacing the valve guide, reface the
valve seat.
3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
5-35
ENG
.
and valve guide remover
Valve guide position
14.8 ~ 15.2 mm (0.583 ~ 0.598 in)
Valve guide remover (4.5 mm):
YM-04116
Valve guide remover (ø4.5):
90890-04116
Valve guide installer (4.5 mm):
YM-04117
Valve guide installer (ø4.5):
90890-04117
Valve guide reamer (4.5 mm):
YM-04118
Valve guide reamer (ø4.5):
90890-04118
:
to