1999-2004 Honda TRX400EX FourTrax Service Manual, Page 104Get this manual
CYLINDER HEADNALVE Install the cam sprocket onto the cam chain so that the index lines on the sprocket with the upper surface of the cylinder headI
Install the camshaft onto the cylinder head through cam sprocketInstall the cam sprocket onto the camshaft flange securelyMake sure that the index lines on the cam sprocket with the upper surface of the cylinder head when the "T" mark on the flywheel is aligned with the index notch in the left crankcase cover
Apply locking agent to the cam sprocket bolt threadsA the holes the cam sprocket and camshaft flange and install the cam sprocket boltThe crankshaft should be turned only counterclockwiseThis must be done to prevent the oneway decompressor system functioning