Yamaha YFM50S Service Manual page 135

STARTER CLUTCH AND OIL PUMP
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3. Measure:
• inner-rotor-to-outer-rotor-tip clearance a
• outer-rotor-to-oil-pump-housing
b
• oil-pump-housing-to-inner-rotor-and-outer-
rotor clearance c
Out of specification → Replace the oil
pump.
1 Inner rotor
2 Outer rotor
3 Oil pump housing
Inner-rotor-to-outer-rotor-tip
clearance
0.05 ~ 0.07 mm
(0.002 ~ 0.003 in)
<Limit>: 0.15 mm (0.006 in)
Outer-rotor-to-oil-pump-housing
clearance
0.013 ~ 0.036 mm
(0.0005 ~ 0.0014 in)
<Limit>: 0.106 mm (0.0042 in)
Oil-pump-housing-to-inner-rotor-
and-outer-rotor clearance
0.06 ~ 0.10 mm
(0.0024 ~ 0.0039 in)
<Limit>: 0.17 mm (0.0067 in)
4. Check:
• oil pump operation
Rough movement → Repeat steps #1 and
#3 or replace the defective parts.
ENG
clearance