Toyan FS-S100GA 4 Stroke RC Engine Gasoline Engine Model Kit for RC Car Boat PartsAbout Four stroke engine Four Stroke Cycle Engines. A four stroke cycle engine is an internal combustion engine that utilizes four distinct piston strokes (intake, compression, power, and exhaust) to complete one operating cycle. The piston make two complete passes in the cylinder to complete one operating cycle. Intake stroke: The piston moves downward to the bottom, this increases the volume to allow a fuel air mixture to enter the chamber.