1988-1994 Honda TRX300 Fourtrax, 1988, 1990-1994 TRX300FW Fourtrax Service Manual, Page 86Get this manual
CYLINDER HEADIVALVES Install 45 degrees finish cutter and cut the seat to the the proper widthMake sure that all pitting and irregularities are removedRefinish if necessary
Apply thin coating of Prussian Blue to the valve seatPress the valve through the valve guide and onto the seat to make clear patternNOTE The location of the valve seat in relation to the valve face is very important for good sealing
(1CONTACT TOO HIGH
(2) OLD SEAT WIDTH
If the contact area is too high on the valve, the seat must be lowered using 32 degrees flat cutter