1997-2001 Honda TRX250 Fourtrax Recon Service Manual, Page 112Get this manual
CYLINDER HEADCYLINDERPISTON VALVE SEAT INSPECTIONREFACING Clean the intake and ex haust valves horo ughly to remove carbon deposi tsApply light coating of Prussian Blue to the valve seat sLap the valves and seats using rubbe hose or other hand-lapping too lHAND-LA PPIN G
Remove and inspect the va lvesCAUTION :
The valves cannot be groundIf valve face ;s burned or badly worn or if it contacts the seat unevenly, replace the valve
Inspect th width of eac valve seatSTANDARD: 1.2 mm (0.05 in) SERVICE LIMIT: 1.5 mm (0.06 in) If the seat is too ide, too narrow or has low spots, th seat must be ground
VALVE SEAT REFACING