2007 Polaris Sportsman 700/800/800 X2 EFI Service Manual, Page 82Get this manual
ENGINE Combustion Chamber
1Clean all accumulated carbon deposits from combustion chamber and valve seat area with carbon cleaner and soft plastic scraperIMPORTANT: Do not use wire brush, metal scraper, or abrasive cleaners to clean the bottom of the cylinder headExtensive damage to the cylinder head may resultWear safety glasses during cleaningNOTE: Valve seat width and point of contact on the valve face is very important for proper sealingThe valve must contact the valve seat over the entire circumference of the seat, and the seat must be the proper width all the way aroundIf the seat is uneven, compression leakage will resultIf the seat is too wide, seat pressure is reduced, causing carbon accumulation and possible compression lossIf the seat is too narrow, heat transfer from valve to seat is reducedThe valve may overheat and warp, resulting in burnt valves
Combustion Area
Valve Seat Reconditioning