Valve Guide Remover; Intake 4.5 Mm (0.18 In) Exhaust 5.0 Mm (0.20 In); Ym-4117/90890-04117; Ym-4098/90890-04098 - Yamaha YZ450F Manuel D'atelier Du Proprietaire

VALVES AND VALVE SPRINGS
NOTE:
After replacing the valve guide reface the
valve seat.
3. Inspect:
4. Measure:
4 - 36

Valve guide remover:

Intake: 4.5 mm (0.18 in)
YM-4116/90890-04116
Exhaust: 5.0 mm (0.20 in)
YM-4097/90890-04097

Valve guide installer:

Intake:

YM-4117/90890-04117

Exhaust:

YM-4098/90890-04098

Valve guide reamer:

Intake: 4.5 mm (0.18 in)

YM-4118/90890-04118

Exhaust: 5.0 mm (0.20 in)

YM-4099/90890-04099

• Valve face
Pitting/wear → Grind the face.
• Valve stem end
Mushroom shape or diameter larger than
the body of the stem → Replace.
• Margin thickness a
Out of specification → Replace.
Margin thickness:
Intake:
1.0 mm (0.039 in)
<Limit>: 0.85 mm (0.033 in)
Exhaust:
1.0 mm (0.039 in)
<Limit>: 0.85 mm (0.033 in)
ENG