Use the Comet LA 350 series centrifugal clutches for 4 cycle engines to 6 hp, and 2 cycle engines up to 9 hp. “Variable cam” rotor action adjustable for gradual or abrupt engagement. Excellent for industrial and utility applications plus go-karts, mini snowmobiles, etc. Ease of installation and maintenance with fewer parts to be concerned about. 3/4″ bore for #40, #41, or #420 chain. Stock this clutch engages at 1800/2000 rpms. Other springs available to change the engagement rpm from 1100/1300 to 3100/3300 rpms.