Low, aerodynamic, and relatively long, the R18 Roctane borrows a handful of styling cues from some of the most emblematic models in BMW’s past, including the R 5 released in 1936.

German motorcycle builder Dirk Oehlerking has turned the BMW R18 into a stunning one-off called The Crown to celebrate the firm’s 100th birthday. While this isn’t his first R18-based build ...

The R18's headline feature is its massive 1.8-liter horizontally opposed twin-cylinder engine. This is the biggest boxer that BMW has ever offered -- by over half a liter -- and it's still air-cooled.