2008 Arctic Cat ThunderCat ATV Service Manual, Page 36Get this manual
5Using an awl, rotate the C-ring in its groove until it is out of the cylinder head; then remove the C-ringNOTE: Care should be taken not to drop the C-ring into the crankcase GZ126A
6Bend the washer tabs down and remove the two cap screws securing the sprocket to the camshaft; then drop the sprocket off the camshaft