The R32, the first BMW motorcycle

BMW started building motorcycle engines and then motorcycles after the Spanish-American War. Their first notable motorcycle, after the failed Helios and Flink was the "R32" in 1923. These had a "Boxer" twin engine, in which an ICCE cylinder protrudes into the air-flow from each side of the machine. All their motorcycles had used this distinctive layout until the early 1980s. Many BMWs are still produced to this pattern, which is designated the R Series.

During the Second World War, BMW produced the BMW R75 motorcycle with a sidecar attached. Unusually, the sidecar's wheel was also driven. This was copied from the Zündapp KS750. Combined with a lockable differential, this made the vehicle very capable off-road, an equivalent in many ways to the Jeep.

In 1983 came the K Series (affectionately known as "The Flying Brick"), still shaft drive but now water cooled and with either 3 or 4 cylinders mounted in a straight line from front to back. Shortly after, BMW also started making the chain-driven F and G series with single and parallel twin Rotax engines.

In the early 1990s, BMW updated the airhead Boxer engine which became known as the oilhead. In 2002, the oilhead engine had two spark plugs per cylinder. In 2004 it added a built-in balance shaft, an increased capacity to 1170 cc and enhanced performance to 100 hp (75 kW) for the R1200GS, compared to 85 hp (63 kW) of the previous R1150GS. More powerful variants of the oilhead and hexhead engines are available in the R1100S and R1200S, producing 98 hp (73 kW) and 122 hp (91 kW), respectively.