BMW got serious about making motorcycle engines in 1923, when aircraft engine designer Max Friz delivered the first flat-twin to BMW. More than 100 years later, the Boxer engine remains the soul of BMW despite the company's success with many other engine layouts including the inline fours and sixes, plus singles and parallel twins. Technical Editor Kevin Cameron and Editor-in-Chief Mark Hoyer discuss the evolution from that first flat twin to the remarkable R 1300 that powers the new R 1300 GS, R 1300 RT, and more.