BMW introduced an inline six-cylinder café racer concept at the 2009 EICMA show in Milan, Italy.
Inline-six engines have a staple in BMW’s automobiles for decades and the German manufacturer’s motorcycle division took on the challenge of adapting the straight-six to a bike without making it too long or too wide. The result is the BMW Motorrad Concept 6, and an evolution BMW says “will further expand the K-Series in the foreseeable future”.
The Concept 6’s engine is about four inches slimmer than BMW’s production inline-six engines, making it just a bit wider than a large-capacity four. To keep the width down, the engine has a relatively long stroke with very small gaps between cylinders. Electrical ancillaries and their drive components are positioned behind the crankshaft and above the transmission to further minimize engine width.
