Air Cooling

An air-cooled engine gets rid of heat directly into the air flowing past it. The cylinder and cylinder head carry cooling fins that increase the surface area. Some engines also use engine oil to carry away extra heat, which is called oil/air cooling.

Air cooling is simple, light and cheap, with no radiator, pump or coolant to leak. The downside is less precise temperature control, so engines are usually built with looser tolerances and produce less power per litre than liquid-cooled ones.

Keep the fins clean, avoid long idling in traffic or slow off-road sections in hot weather, and use the oil grade the manufacturer specifies. Rising oil consumption or pinking under load can be signs of overheating.