2007 Polaris Sportsman 700/800/800 X2 EFI Service Manual, Page 84Get this manual
ENGINE 9Lubricate the valve guides with clean engine oil, and apply oil or water based lapping compound to the face of the valveNOTE: Lapping is not required with an interference angle valve job10Insert the valve into its respective guide and lap using lapping tool or section of fuel line connected to the valve stem4Valve seals should be installed after the valves are in the head to avoid valve seal damageInstall new valve seals on valve guides
11Rotate the valve rapidly back and forth until the cut sounds smoothLift the valve slightly off of the seat, rotate 14 turn, and repeat the lapping processDo this four to five times until the valve is fully seated, and repeat process for the other valve(s)12Thoroughly clean cylinder head and valves