2008 Arctic Cat 400/500/650/700 ATV Service Manual, Page 63Get this manual
12With the alignment pin installed in the camshaft and the cam lobes directed down (toward the piston), place the camshaft in position and verify that the timing mark on the magneto is visible through the inspection plug and that the timing marks on the camshaft sprocket are parallel with the valve cover mating surfaceNOTE: When the camshaft assembly is seated, make sure the alignment pin in the camshaft aligns with the smallest hole in the sprocket MD1270
8Install the two lower nuts securing the cylinder head to the cylinder, one in front and one in rearTighten only until snug
13Loosely place the cam sprocket (with the recessed side facing the camshaft lobes) onto the camshaft and place it into position with the cam chain over the sprocket
732-307B MD1192