Casting mold for a hollow member

Abstract

A casting mold is provided for a body frame for a motorcycle including a head pipe for supporting a rotary shaft for a handle, a pair of left and right main body frame elements, connected to the head pipe and extending rearwardly of a car body, a pair of left and right engine supporting members, connected to and extending downwardly from the main body frame elements adjacent to said head pipe, and a horizontally extending frame element connecting said left and right main body frame elements to each other at intermediate portions in the longitudinal direction. The engine is supported at least at a lower end portion of the left and right engine supporting members and intermediate portions in the longitudinal direction of the left and right main body frame elements and an upper end portion of a shock absorber is connected to the horizontally extending frame elements. A cast body frame is constructed of a light alloy and assembled by joining a leftward and a rightward divided block formed in shapes being vertically divided at the head pipe portion to each other. The main body frame elements are formed from a tubular member having a rectangular cross section wherein the widths of the opposite side walls are larger relative to the widths of upper and lower walls, and the widths of the side walls gradually vary from a front end portion connected to the head pipe to a rear end portion for forming at least a smaller area between the front end portion to the rear end portion.