Wider than stock, thus stronger starter clutch gear for Evolution Big Twin 1991-1999 and Twin Cam 1999-2006, except 2006 Dyna. Fits OEM as well as many 1.2 and 1.4 kW aftermarket starter motors. Replaces starter clutch gear in OEM 31663-90 & 31516-94 starter clutches and takes stock bearings and output shaft. Features Limited Lifetime Warranty.