This is the Carburetor for the O.S. 21TM-R Engine, OSMG2082. FEATURES: Slide valve design insures greater response at the beginning and end of the power band for on-road racing Three needle set-up, needle valve, mixture control screw, and throttle stop screw Cast aluminum body with steel adjustment screws INCLUDES: One Carburetor for the O.S. 21TM-R One Rubber Gasket REQUIRES: Installing on engine SPECS: Throat Diameter: 0.35" (9mm) Air Cleaner Opening Diameter: 0.47" (12mm) cnh 5/1/09 ir/jxs