Body Frame of Motorcycle, Assembling Method of Mounting Engine on Body Frame, and Motorcycle Having Body Frame

摘要

A body frame of a motorcycle in which strength and rigidity against external forces are secured while increased cost is suppressed. A mainframe has an upper bearing and a pipe main body of a head pipe and is extended rearward. A down tube includes a first tube having a lower bearing of the head pipe and extended rearward and second tubes joining the first tube and bosses of the mainframe. The first tube is joined to the mainframe by welding, and the second tubes are detachably joined to the first tube.