1998-2004 Honda Foreman 450 factory service manual, Page 144Get this manual
CYLINDER HEADCYLINDERPISTON VALVE SEAT INSPECTIONREFACING Clean the intake and exhaust valves thoroughly to remove carbon depositsApply light coating of Prussian Blue to the va lve seatsTap the valves and seats using rubber hose other hand-lapping tool
Remove and nspect the valvesCAUTION:
The valves cannot be groundIf valve face ;s burned or badly worn or if it contacts the seat unevenly, replace the valveInspect the width of each valve seatSTANDARD: 1.2 mm (0.05 in) SERVICE LIMIT: 1.5 mm (0.06 in) If the seat is too wide, too narrow or has low spots, the seat must be ground
VALVE SEAT REFACING
Follow the refacer man ufactu re's operating instruction Reface the valve seat whenever the valve guide has been replaced Be carefu not to grind the seat more than necessaryTOOLS: Valve seat Valve seat Valve seat Valve seat Valve seat