Patent ID: 7225769

Claim:
A two-stroke cycle engine, comprising: a cylinder having a scavenging port and a scavenging passage communicating with the scavenging port; a crankcase including front and rear portions that are separated by a plane, which is at a right angle to a crankshaft and contains an axis of the cylinder, wherein the front and rear portions are attached to each other by fasteners, wherein a crankcase scavenging passage is formed inside a wall in each of the front and rear crankcase portions symmetrically with respect to said crankcase separating plane, wherein a crankshaft bearing part in each front and rear portion is formed within a diameter of the cylinder such that said front and rear portion scavenging passages are formed above the crankshaft bearing part and offset laterally from an extension line of the diameter of the bearing part, wherein the scavenging passage has a top opening above a cylinder mounting surface and an outlet at the side of the crankcase at a right angle to the crankshaft with a microscopic gap between the opening and the end surface of the crank webs, wherein the scavenging passages of each of the front and rear portions are arranged to provide fluid communication between the scavenging passage of the cylinder and a crank chamber of the crankcase so as to allow a fuel-air mixture to flow from the crank chamber to the scavenging port, and wherein the cylinder is attached by fasteners to a mounting surface on the crankcase, and an air supply chamber which is provided above the crankcase separating plane, intersects the plane and supplies air from an air cleaner to the scavenging passage of the cylinder.