2008 Yamaha Rhino YXR70FX Factory Service Manual, Page 181Get this manual
VALVES AND VALVE SPRINGS
eIf the valve seat is too wide, too narrow, or the seat is not centered, the valve seat must be refacedLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLLL
9Lap: valve face valve seat TIP: After refacing the valve seat or replacing the valve and valve guide, the valve seat and valve face should be lappedMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM