1985-1995 Polaris ATV and Light Utility Hauler Service Manual, Page 302Get this manual
ENGINES Magnum Engine DisassemblyInspection 7Remove valve and check where the Prussian BlueTM indicates seat contact on the valve faceThe valve seat should contact the middle of the valve face and must be the proper width If the indicated seat contact is too high on the valve face, use the 30 or 31 cutter to lower the valve seat If too low use the 60 or 75 cutter to raise the seatWhen contact area is centered on the valve face, measure seat width If the seat is too wide or uneven, use both top and bottom cutters to narrow the seat If the seat is too narrow, widen using the 460 cutter and re-check contact point on the valve face and seat width after each cut8Clean all filings from the area with hot soapy water, rinse, and dry with compressed air9Lubricate the valve guides with clean engine oil, and apply oil or water based lapping compound to the face of the valve