STRATIFIED SCAVENGING TWO-STROKE CYCLE ENGINE

The engine can improve a leading air suction efficiency, has a simple structure and a low cost. Accordingly, in a stratified scavenging two-stroke cycle engine provided with an exhaust port (22) and a scavenging port (21) which are connected to a cylinder chamber (10), a leading air suction port (24) not connected to the cylinder chamber and a crank chamber (11), an air-fuel mixture suction port (23) connected to the crank chamber, a scavenging flow passage (20) connecting between the scavenging port and the crank chamber, and a piston groove (25) connecting between the leading air suction port and the scavenging port and not connecting between the air-fuel mixture suction port and the scavenging port at a time of a suction stroke, and disposed in an outer peripheral portion of the piston (4), the leading air suction port is positioned at an opposite side to the air-fuel mixture suction port with respect to an axis of the cylinder (3).