Abstract: A two stroke engine having a variable compression ratio combustion chamber wherein the size of the combustion chamber is changed by threading a closure into or out of the combustion chamber. The combustion chamber is defined by the inside surface of a sleeve, the top surface of a piston, and the bottom surface of the closure. The piston and the sleeve reciprocate within the engine block in a not quite opposite manner. Inlet ports and outlet ports in the sleeve and engine block regulate the flow of gas into and out of the combustion chamber. The engine is equipped with a turbocharger system to provide air to the engine, and the engine is fuel injected.