2007-2009 Honda TRX300EX TRX300X service manual, Page 129Get this manual
CYLINDER HEADVALVE Using 60 interior cutter, remove 14 of the existi ng valve seat materialTOOLS: Interior cutter, 30 mm (60 INEX) 07780-0014500 Cutter holder, 5.5 mm 07781-0010101 or equivalent commercially available in U.S.A
Using 45 seat cutter, cut the seat to the proper width VALVE SEAT WIDTH: 1.2 mm (0.05 in) Make sure that all pitting and irregularities are removed
After cutting the seat, apply lapping compound to the valve face, and lap the valve using light pressu reNOTE: