2007-2009 Honda TRX300EX TRX300X service manual, Page 135Get this manual
CYLINDER HEADVALVE Install new O-rings into the groove of the rocker arm shaftsI nstall the rocker arms and shafts aligning the cutout in the shafts with the cylinder head cover bolt holes
Align the dowel pin holes in the cylinder head cover and rocker arm shaft using flat head screwdriver, and install new dowel pins
CYLINDER HEAD COVER INSTALLATION
Rotate the crankshaft counterclockwise and align the "T" mark on the flywheel with the index notch in the crankcase cover so the camshaft cam lobes face down