Crankcase Separation; One Way Valve - Polaris SPORTSMAN 400 2003 Service Manual

2. Remove blade and inspect for cracks, wear, or
damage.
B
3. Remove cam chain (B). Inspect chain for worn or
missing rollers or damage. Stretch chain tight on
a flat surface and apply a 10 lb. (4.53 kg) load.
Measure length of a 20 pitch section of chain.
Replace if worn past service limit.
Chain Service Limit:
5.407² (13.7 cm)
4. Using the special socket, remove the crankshaft
slotted nut (A). NOTE: The slotted nut is a left
hand thread.
5. Remove cam chain drive sprocket (B) and
Woodruff key from crankshaft.
6. Inspect sprocket teeth for wear or damage.
7. Inspect Woodruff key for wear.
8. Replace any worn or damaged parts.

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.
D C
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.
One Way Valve Spring Free Length:
Std: 1.450² (3.68 cm)
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.
ENGINE
A
B
3.33