Yamaha FX Nytro 2008 Manuel D'atelier page 448

VALVES AND VALVE SPRINGS
• 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.
3. Eliminate:
• Carbon deposits
(from the valve face and valve seat)
4. Inspect:
• Valve face
Pitting/wear → Grind the valve face.
• Valve stem end
Mushroom shape or diameter larger than the
body of the valve stem → Replace the valve.
5. Measure:
• Valve margin thickness a
Out of specification → Replace the valve.
5-33
ENG
Valve guide remover (ø4.5):
90890-04116
Valve guide remover (4.5 mm):
YM-04116
Valve guide installer (ø4.5):
90890-04117
Valve guide installer (4.5 mm):
YM-04117
Valve guide reamer (ø4.5):
90890-04118
Valve guide reamer (4.5 mm):
YM-04118
Valve margin thickness:
Intake:
0.80 ~ 1.20 mm
(0.0315 ~ 0.0472 in)
Exhaust:
0.50 ~ 0.90 mm
(0.0197 ~ 0.0354 in)