An I-head arrangement where the valves are located over the piston in the cylinder head.

Over Head Valves where the inlet and outlet valves are in the cylinder head (in contrast to side-valves). Valves are operated by push-rods from a cam-shaft at the side of the engine.

Describes an engine, which has its valves in the cylinder head, but with the valve gear, operated by pushrods from a camshaft situated lower in the engine.

ORV Acronyms for ff- ighway ehicle and ff- oad ehicle. These have motors and are not bicycles.

Off Highway Vehicle