Arctic Cat 650 V-Twin Stock & oversized tires 27-28 inches. 472-DKA6570MT: This kit combines our popular plain/purple secondary clutch spring with the blue primary. This cost-effective combination has proven most effective for the 650 V-twin. Stock flyweights are best for most applications on this model and we prefer not to sell you more than what you need. The engagement speed of this kit is only very slightly more than stock, so it maintains excellent characteristics for slow speed maneuvering.