Yamaha WR250FM service manual Inspection, Oil pump

OIL PUMP

ENG

1 2

3

4

INSPECTION

Oil pump

1.Inspect:

•Oil pump drive gear 1

•Oil pump drive shaft 2

•Rotor housing 3

•Oil pump cover 4 Cracks/wear/damage → Replace.

2.Measure:

•Tip clearance a

(between the inner rotor 1 and outer rotor 2)

•Side clearance b

(between the outer rotor 2 and rotor housing 3)

•Housing and rotor clearance c (between the rotor housing 3 and rotors

1 2)

Out of specification → Replace the oil pump assembly.

Tip clearance a:

0.12mm or less (0.0047 in or less)

<Limit>: 0.20 mm (0.008 in)

Side clearance b:

0.09~ 0.17 mm (0.0035 ~ 0.0067 in) <Limit>: 0.24 mm (0.009 in)

Housing and rotor clearance c:

0.03~ 0.10 mm (0.0012 ~ 0.0039 in) <Limit>: 0.17 mm (0.0067 in)

3.Check:

•Unsmooth → Repeat steps #1 and #2 or replace the defective parts.

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