Includes: 1 14 Tooth clutch and 1 size #420 120 link chain (60 inner pins, 60 outer pins). Works with many 13HP go karts. Clutch bore size is 1 inch. 14T clutch also works with size #40 and #41 chains (not included). Includes: 1 14 Tooth clutch and 1 size #420 120 link chain (60 inner pins, 60 outer pins). Works with many 13HP go karts. Clutch bore size is 1 inch. 14T clutch also works with size #40 and #41 chains (not included). Please check that your old clutch you are replacing is also a 14 tooth with a 1″ bore/shaft.