2000-2003 Honda TRX350 Rancher factory service manual, Page 115Get this manual
CYLINDER HEADVALVE Using 45 seat cutter, cut the seat to the proper widthVALVE SEAT WIDTH: 1.2 mm (0.05 in) SEAT WIDTH
Make sure that all pitting and irregularities are removed
Excessive lapping pressure may def orm or damage the seatDo not allow lapping compound to enter the guides
After cutting the seat, apply lapping compound to the valve face, and lap the valve using light pressureChange the angle of lapping tool frequently to prevent uneven seat wearAfter lapping, wash any residual compound off the cylinder head and valve and recheck the seat contact