Oilhead

The newest line of BMW motorcycle, nicknamed thus because they are oil-cooled, in contrast to the venerable air-cooled "R" series ("Airheads").

Airheads are fuel-injected, oil-cooled, have a horizontally-opposed twin-cylinder motor with four overhead valves per cylinder, unique Telelever front and Paralever rear suspension, and shaft drive.

The first oilhead, the R1100RS, was introduced in 1993, after which time BMW AG gradually phased out the airheads. Oilhead models include:

• R850R, R1100R and R1150R, so-called "roadster" or basic models;
• R1100S, a sport model;
• R1100RS, a sport-oriented sport-touring model;
• R1100RT and R1150RT, a more comfort-oriented sport-touring model;
• R1100GS and R1150GS, positioned as a dual-sport (on- and off-road) bike but a bit heavy for real dirt riding;