Abstract: A crankshaft assembly for a motorcycle includes a first flywheel half with a polygonal-shaped aperture therein and a second flywheel half with a polygonal-shaped aperture therein. The first and second flywheel halves are interconnected by press-fitting opposing first and second polygonal shaped end portions of a crank pin into respective polygonal-shaped apertures of the first and second flywheel half. A bearing is positioned at least partially on a surface of a cylindrical central portion of the crank pin and a connecting rod has an aperture at least partially receiving the bearing.