The BMW K100 is a family of four-cylinder 987 cc motorcycles that were manufactured by BMW from 1983 to 1992.

Various models of the K100 were produced.

K100, with no fairing.
K100RS, with sports fixed fairing and lower bars.
K100RT, with full fairing for 'road touring'.
K100LT, with a higher screen and additional equipment as standard for 'Luxury Touring'.

All models have dual front, and single rear disk brakes. The RS model has a longer gear ratio than other models.[3]

The K-series offered additional refinements including: all stainless steel exhaust, rust-resistant aluminium fuel tank (although tanks do rust at the low points on right and left sides), anti-lock brakes or ABS on later-year models, adjustable headlight, high capacity 460 watt alternator, Hella accessory plug-in, self cancelling signal lights.

The engine has its four cylinders arranged so that the crankshaft is on the right-hand side of the motorcycle, with the cylinder heads, camshafts, injectors and spark plugs on the left-hand side. This arrangement keeps the centre of gravity relatively low, which benefits handling; and the space behind the front wheel available for the radiator.

In addition, since the crankshaft is now on the right-hand side, access to the engine becomes much easier than in a conventional design, where the crankshaft is at the bottom. BMW preferred a shaft-drive for smoothness, and a single-sided hollow swing arm enclosing the drive shaft provided right side drive through the gearbox and to the rear wheel. The 4-into-1 all stainless steel exhaust exited on the left hand side.

Brakes were twin-pot Brembo onto undrilled discs. Two different forks manufactures were used: Showa with an outer upper tube diameter of 1.612 in (41 mm) and Fichtel and Sachs measuring 1.627 in (41 mm). In later models, the standard swingarm was replaced with a Paralever just as on the K1.