2001 Polaris Sportsman 400-500 DUSE and H.O. Service Manual, Page 52Get this manual
MAINTENANCE
AIR BOX SEDIMENT TUBE
Periodically check the air box drain tube located toward the rear of the machineDrain whenever deposits are visible in the clear tubeNOTE: The sediment tube will require more frequent service if the vehicle is operated in wet conditions or at high throttle openings for extended periods1Remove drain plug from end of sediment tube2Drain tube3Reinstall drain plug
Sediment Tube
BREATHER FILTER INSPECTION
Four cycle ATV engines are equipped with breather filterThe in-line filter is similar in appearance to fuel filter, and is visible on the left side (Location A)1In-line breather filters should be installed with the arrow pointing toward the engine (away from the air box)NOTE: In-line breather filter service life is extended when the foam air box pre-filter is in place and maintained properlyNever operate the engine without the pre-filter