BMW took the boxer engine style, traditionally used by the likes of Porsche and Subaru, and took it one step farther putting a two cylinder boxer engine in one of their motorcycles. Check out the animated cutaway of this bike to see how it works. The benefits of this boxer configuration is that fact that it lowers the center of gravity of the bike and they can rev the engine higher than normal as well.
Crazy!! Be sure to check the out next video below.