This model shows the internal structure and operating principles of a water cooled four-stroke engine. The valves are clearly evident, cams being driven by a gear train from the rear of the main crank. A cross section of the carburettor is shown. Hand powered motion supplied through a crank demonstrates the moving parts of the engine. Crank shaft, piston, valves and cams cycle through all stages of the four-stroke process as the hand crank is rotated. Ignition light can be simulated by using a 2 AA Batteries (not included). All  construction are of  aluminum and plastic, mounted on metal  base with a placard on the base labels all key components.