BMW’s trademark Boxer engine is more than iconic. Introduced as an industrial engine in 1921 and first fitted in a motorcycle two years later, those jutting, horizontally opposed cylinder heads have been a signature of BMW motorcycles for nearly 90 years. And no bike has been more closely associated with the Boxer engine in recent years than the equally iconic R1200GS, which invented modern adventure touring when it was released as the R80G/S in 1980. The giant GS has since become BMW Motorrad’s best-selling model. More than 30,000 examples are sold worldwide each year, accounting for one-third of total BMW motorcycle sales. Why on earth, then, would the Munich-based manufacturer risk massive customer loyalty and consumer acceptance by making a major change like adding water-cooling to this flagship model?