2006-2009 Honda TRX250EX/TRX250X Service Manual, Page 128Get this manual
CYLINDER HEADIVALVECAMSHAFT Remove the liming hole cap from the left side of the rear crankcase cover
Turn the crankshaft counterclockwise and align the mark on the flywheel with the index mark on the crankcase cover
Make sure the piston is at TOC (Top Dead Center) on the compression strokeThis position can be confirmed by checking for slack in the rocker armsIf there is no slack, it is because the piston is moving through the exhaust stroke to TOCRotate the crankshaft one full turn and match up the mark 8gain