Polaris 2012 Sportsman Forest 500 International, Service Manual

Page: 93 / 432

3.38
ENGINE
9923412 - 2012 Sportsman 400/500 and EFI Tractor Service Manual
© Copyright 2011 Polaris Sales Inc.
One Way Valve
The one way valve prevents oil from draining out of the oil
tank and into the crankcase when the engine is off. It must
be clean and have adequate spring pressure in order to
seal properly.
1. Remove cap bolt (A), sealing washer (B), spring (C),
and one way valve (D) from PTO side crankcase.
2. Inspect free length of spring and check coils for
distortion.
3. Inspect valve for wear.
4. Check seat area for nicks or foreign material that may
prevent proper sealing of valve.
Crankcase Separation
1. Remove flange bolts (10) from magneto side
crankcase evenly in a criss-cross pattern.
2. Separate crankcase by tapping with a soft faced
hammer in reinforced areas.
3. Tap lightly on balancer gear with a brass drift through
the hole in the crankcase if necessary, to ensure the
balancer shaft stays in the PTO side crankcase.
Watch the gap along the crankcase mating surface
and separate the crankcase evenly. It may also be
necessary to tap the oil pump shaft lightly to separate
the crankcase.
4. Remove the Mag (RH) crankcase from the PTO case.
Oil Pump Removal / Inspection
1. Remove pump shaft bearing (A) and thrust washer
(B) from pump shaft.
2. Remove (2) bolts holding pump drive gear (C).
3. Inspect drive gear teeth for cracks, damage or
excessive wear.
4. Remove three oil pump retaining bolts and pump.
One Way Valve Spring Free Length:
Std: 1.450” (3.68 cm)
D
C
B
A
CAUTION
Do not strike the oil pump shaft at an angle or the
shaft may bend, causing irreparable damage.
Tap only lightly on the pump shaft if necessary.
C
B
A