Modification to the current two-stroke cycle internal combustion engine, using reduced height piston constructed solidly with piston rods and having rotary valves installed in the transfer and exhaust ports. The piston pre-compresses the fuel-air mix in its lower part without allowing it to enter the crankcase, using auxiliary one-way flow valves operated directly by pressure differentials and transfer parts for the fuel air-mix from the lower part of the piston to the upper part, and a receiving chamber interposed to maintain the pre-compresed fuel-air mixture temporarily.