LEAD AIR CONTROL DEVICE OF STRATIFIED SCAVENGING TWO-CYCLE ENGINE

In an insulator (21) inserted between a carburetor (30) and a cylinder (3) for a purpose of insulating heat, there are formed an intake passage (22) connected to the carburetor (30), and a pair of first air passages (23) connected to respective air flow paths (14) communicated with a pair of scavenging ports (10) formed in the cylinder (3). Air control valves (25) are respectively provided within a pair of first protruding portions (33) communicating with an air cleaner (32), and are connected to the pair of first air passages (23) via a pair of connection members (35). Portions from the air passages within the pair of first protruding portions (33) to the pair of first air passages (23) are respectively formed as smooth air passages in which a change of an inner diameter cross sectional area in a connection portion is small.