The BMW F800S is a sport bike introduced by BMW Motorrad in 2006 as the successor to the F650CS. Along with the F800S, other bikes in the F-bike range are the dual-sport F800GS, the sport touring F800ST, and the naked F800R.
BMW developed with Rotax a 798 cc parallel-twin engine with a 360 degree firing order. This produces an exhaust note reminiscent of BMW's signature air-cooled Boxer Twins. However, this firing order requires both pistons to move up and down at the same time. To counter the significant inertia produced by the pistons reciprocating, BMW devised a third vestigial conrod connected to a balance mechanism. The result is a parallel twin with significantly reduced vibration compared with other parallel twin engine designs. The engine is oiled by a dry-sump system, and a soft ignition-cut rev limiter engages at 9,000 rpm. The engine is notable for early and powerful onset of torque. Chris Pfeiffer used a modified F800S before moving to his signature F800R, utilizing the low-end power of the engine for stunting. BMW has also tuned the F800 series engine to run lean, typically with air-fuel ratios in the range of 15:1 to 16:1.
The F800S and ST both use maintenance-free belt drives and single sided swingarms. Bikes equipped with ABS also include a rear-wheel lift detection system.
In some markets, notably the United States, the F800S was discontinued after the 2007 model year. A distinguishing cosmetic difference for 2009 is the black painted engine; earlier models are painted silver.