Yamaha WR250FM service manual Margin thickness Intake Mm 0.0315 in Exhaust Mm 0.0276

VALVES AND VALVE SPRINGS

ENG

Valve guide remover:

Intake: 4.0 mm (0.16 in)

YM-4111/90890-04111

Exhaust: 4.5 mm (0.18 in)

YM-4116/90890-04116

Valve guide installer:

Intake: 4.0 mm (0.16 in)

YM-4112/90890-04112

Exhaust: 4.5 mm (0.18 in)

YM-4117/90890-04117

Valve guide reamer:

Intake: 4.0 mm (0.16 in)

YM-4113/90890-04113

Exhaust: 4.5 mm (0.18 in)

YM-4118/90890-04118

NOTE:

After replacing the valve guide reface the valve seat.

3.Inspect:

•Valve face

Pitting/wear → Grind the face.

•Valve stem end

Mushroom shape or diameter larger than the body of the stem → Replace.

4.Measure:

•Margin thickness a

Out of specification → Replace.

Margin thickness:

Intake:

0.8mm (0.0315 in) Exhaust:

0.7mm (0.0276 in)

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