Yamaha WR45OFR service manual Inspection, Valve

VALVES AND VALVE SPRINGS

ENG

INSPECTION

Valve

1.Measure:

● Stem-to-guide clearance

Stem-to-guide clearance = valve guide inside diameter a – valve stem diameter b

Out of specification → Replace the valve guide.

Clearance (stem to guide): Intake:

0.010 ~ 0.037 mm

(0.0004 ~ 0.0015 in) <Limit>: 0.08 mm (0.003 in)

Exhaust:

0.020 ~ 0.047 mm

(0.0008 ~ 0.0019 in) <Limit>: 0.10 mm (0.004 in)

2.Replace:

● Valve guide

Replacement steps:

NOTE:

To ease guide removal, installation and to maintain correct fit heat the cylinder head in an over to 100 ˚C (212 ˚F).

●Remove the valve guide using a valve guide remover 1.

●Install the new valve guide using a valve guide remover 1 and valve guide installer

2.

●After installing the valve guide, bore the valve guide using a valve guide reamer 3 to obtain proper stem-to-guide clearance.

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