2004-2009 Honda TRX450R/TRX450ER Service Manual, Page 216Get this manual
CYLINDER HEADVALVE REFACING NOTE: Follow the refacer manufacturer's operating instructions Be careful not to grind the seat more than necessay
If the contact area is too high on the valve, the seat must be lowered using 32 flat cutterIf the contact area is too low on the valve, the seat must be raised using 60 interior cutter
CONTACT TOO HIGH
OLDSEAT WIDTH
CONTACT TOO LOW
OLDSEAT WIDTH