Abstract: An improved two cycle internal combustion engine, preferably of a stepped piston type, having a unique arcuately shaped transfer deflector valve, which varies by its controlled sliding movement within an inlet passage, the size of exposed opening of an elongated inlet port in the cylinder. The inlet port extends circumferentially part way around the cylinder. The leading end of the valve is preferably angled, in cooperation with the preferably almost tangent orientation of the inlet passage, to induce arcuate movement into each fresh full charge entering the combustion chamber for enhanced fuel charge mixing. In the preferred embodiment, two such valves are symmetrically positioned around the cylinder and arcuately move in unison between closed and open positions over corresponding opposing inlet ports.