2006 Honda TRX680 Rincon Factory Service Manual, Page 211Get this manual
CYLINDER HEADVALVECAMSHAFT Measure each follower bore I.DSERVICE LIMIT: 22.54 mm (0.887 in) Subtract each follower O.Dfrom the corresponding bore I.Dto obtain the follower-to-bore clearanceSERVICE LIMIT: 0.07 mm (0.003 in)
CYLINDER HEAD REMOVAL
Remove the following: thermostat (page 7-8) throttle body (page 6-43) exhaust pipe (page 3-19) cylinder head cover (page 9-6)