2010 Polaris Sportsman 850 Service Manual, Page 127Get this manual
ENGINE Cylinder Head Warp Inspection
1Lay straight edge (A) across surface of cylinder head at several different points and measure warp by inserting feeler gauge between the straight edge and the cylinder head surfaceIf warp exceeds the service limit, replace the cylinder head
Cylinder Head Disassembly WARNING
Wear eye protection when removing and installing valve springsNOTE: Keep mated parts together for assemblyIt is important to put cylinder head parts back in the same locationMark parts or place them in rack as you remove themValve Spring Compressor: PV-1253 (or PV-4019 with adapter PV-43513-A) 123Compress valve spring and remove split keepers (B)Remove compressor, then remove top retainer, spring, and seal (C)Discard sealsRepeat for all remaining valvesClean combustion chamber and head gasket surface