Removing The Oil Pump; Checking The Oil Pump; Assembling The Oil Pump - Yamaha WR250R Service Manual

EAS24940

REMOVING THE OIL PUMP

1. Drain:
Engine oil
G
(completely from the crankcase)
Refer to "CHANGING THE ENGINE OIL" on
page 3-11.
2. Remove:
Idle gear "1"
G
Oil pump assembly"2"
G
1
3. Remove:
Balancer weight gear "1"
G
Balancer drive gear assembly "2"
G
1
EAS24960

CHECKING THE OIL PUMP

1. Check:
Oil pump drive gear
G
Oil pump driven gear
G
Oil pump housing
G
Oil pump housing cover
G
Cracks/damage/wear → Replace the defec-
tive part (s).
2. Measure:
Inner-rotor-to-outer-rotor-tip clearance "a"
G
Outer-rotor-to-oil-pump-housing
G
"b"
Oil-pump-housing-to-inner-rotor-and-out-
G
er-rotor clearance "c"
Out of specification → Replace the oil pump.
OIL PUMP AND BALANCER GEAR
2
2
1. Inner rotor
2. Outer rotor
3. Oil pump housing
3. Check:
Oil pump operation
G
Rough movement → Repeat steps (1) and
(2) or replace the defective part (s).
clearance
EAS25000

ASSEMBLING THE OIL PUMP

1. Lubricate:
Inner rotor
G
Outer rotor
G
Oil pump shaft
G
(with the recommended lubricant)
5-47
Inner-rotor-to-outer-rotor-tip
clearance
Less than
0.120 mm (0.0047 in)
Outer-rotor-to-oil-pump-housing
clearance
0.090–0.160 mm (0.0004–0.0013
in)
Limit
0.230 mm (0.0091 in)
Oil-pump-housing-to-inner-ro-
tor-and-outer-rotor clearance
0.030–0.100 mm (0.0012–0.0039
in)
Limit
0.170 mm (0.0067 in)