Lubrication System

The lubrication system delivers oil to the moving parts of an engine, such as the crankshaft bearings, pistons, camshafts and, in most motorcycles, the gearbox and clutch. Oil reduces friction and wear, carries heat away and holds dirt in suspension until it is caught by the filter.

Most four-stroke motorcycles use a wet sump, where oil is stored in the bottom of the crankcase and pumped around the engine. A dry sump keeps the oil in a separate tank, common on some off-road and sports bikes. Two-strokes burn their lubricating oil: it is either premixed with the fuel or injected by an oil pump.

Use oil of the specified grade and a motorcycle (JASO MA) specification for wet clutches, and check the level regularly.