2006-2014 Honda FourTrax ATV TRX250 EX TRX250X Service Manual, Page 131Get this manual
CYLINDER HEADVALVECAMSHAFT Inspect the valve seat face for: Damaged face- Replace the valve and reface the valve seat Uneven seat width:Replace the valve and reface the valve seat
DAMAGED FACE Contact area (too high or too low)Reface the valve seat
UNEVEN SEAT WIDTH
TOO HIGH
REFACING
Follow the refacing manufacturer'S operating instructions