The engine casing is the outer shell of the engine and serves as a structural frame that holds the various internal components of the engine together. It is usually made of a sturdy metal, such as aluminium or steel, and protects the engine from external influences and damage.
The complete engine of a motorbike includes all the essential components responsible for converting fuel into mechanical energy. This includes cylinders, pistons, crankshaft, camshaft, valves, ignition system, fuel system and other attachments. A complete engine is a complex unit that works together precisely to produce the desired power.