2004-2005 660 Yamaha Rhino Factory Service Manual, Page 155Get this manual
VALVES AND VALVE SPRINGS
REMOVING THE VALVES AND VALVE SPRINGS 1Check: valve sealing Leakage at the valve seat Check the valve face, valve seat and valve seat widthRefer to "CHECKING THE VALVES AND VALVE SPRINGS"MMMMMMMMMMMMMMMMMMMMMMMMMMMMMMMM