BMW R100GS

BMW’s GS series, including the BMW R100GS, created the adventure/touring sportbike

All GSs used BMW's two-valve airhead opposed twin, the last in a long line of two-valve, air-cooled BMW engines
All GSs used BMW’s two-valve “airhead” opposed twin, the last in a long line of two-valve, air-cooled BMW engines.
Photo by Robert Smith