BMW Boxer Twin Engine Family

BMW has used a horizontally-opposed twin-cylinder (boxer) engine since the R32 of 1923 — over a century of continuous development in the same configuration. The modern ShiftCam 1,254cc unit in the R1250GS Adventure produces 136 hp with infinitely variable valve timing; the "Big Boxer" 1,802cc in the R18 cruiser evokes pre-war nostalgia. All BMW boxers share the fundamental design principle: air-cooled (or oil-air-cooled) cylinders protruding horizontally for natural airflow and a low centre of gravity.