2006-2014 Honda FourTrax ATV TRX250 EX TRX250X Service Manual, Page 133Get this manual
CYLINDER HEADVALVECAMSHAFT After cutting the seat, apply lapping compound to the valve face, and lap the valve using light pressureNOTE:
Excessive lapping pressure may deform or damage th seat Change the angle of the lapping tool frequently Ii' to prevent uneven seat wear Do not allow lapping compound to enter the guidesAfter lapping, wash any residual compound off the cylinder head and valve and recheck the seat contact