INTERNAL COMBUSTION ENGINE

摘要

An internal combustion engine includes a crank shaft having a crank web, a crank pin on one end of the crank web, and a weight on an opposite end of the crank web, a crank case supporting the crank shaft therein, a cylinder, a piston reciprocally fitted in the cylinder, a rod coupled to the piston by a piston pin and connecting the piston to the crank pin for reciprocally moving the piston in the cylinder, the crank case having an opening and extending obliquely to axes of the crank shaft and the cylinder. The cylinder has an end corresponding to a bottom dead center of the piston and having a first recess opening toward the opening, the first recess being of a size allowing the piston pin to pass therethrough when the piston is in the bottom dead center. The weight on the crank web has on one side a second recess of a shape defining with the end of the cylinder a space allowing the piston as disconnected from the rod to pass therethrough.