2008 Arctic Cat 400/500/650/700 ATV Service Manual, Page 175Get this manual
BCamshaft lobes directed down (toward the piston)CCamshaft alignment marks parallel to the valve cover mating surfaceDRecessed side of the sprocket directed toward the cam lobesECamshaft alignment pin and sprocket alignment hole (smallest) are aligned ! CAUTION
14With the cam lobes directed down (toward the piston), maneuver the camshaftsprocket assembly through the chain and towards its seating position; then loop the chain over the sprocketNOTE: Note the position of the alignment marks on the end of the camshaftThey must be parallel with the valve cover mating surfaceIf rotating the camshaft is necessary for alignment, do not allow the chain and sprocket to rotate and be sure the cam lobes end up in the down position
If any of the above factors are not as stated, go back to step 11 and carefully proceed
16Place the tab-washer onto the sprocket making sure it covers the pin in the alignment hole