2006 Arctic Cat ATVs 400/400TBX/400TRV/500/500TBX/500TRV/650H1/650 V-Twin Service Manual, Page 228Get this manual
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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