Patent ID: 7165597

Claim:
A combination for an internal combustion engine, comprising: a cylinder comprising: a cylindrical body having a slightly smaller outer diameter than the diameter of bore of the cylinder to be obtained; a scavenging port-forming portion projecting radially outward from the cylindrical body and having substantially the same cross-sectional configuration as that of the scavenging port; a suction port-forming portion projecting radially outward from the cylindrical body and having substantially the same cross-sectional configuration as that of at least the cylinder bore-side end portion of an suction port; an exhaust port-forming portion projecting radially outward from the cylindrical body and having substantially the same cross-sectional configuration as that of at least the cylinder bore-side end portion of an exhaust port; and an insert core capable of cooperating with the cylinder comprising: chamfered portion-forming portions for forming a chamfered portion at each of the rim portions on the cylinder bore side of said scavenging port, said suction port, and said exhaust port.