The
R32 became the foundation for all future boxer powered
BMW motorcycles. BMW oriented the boxer engine with the
cylinder heads sticking out on each side for cooling as
per the earlier British ABC. Other motorcycle manufacturers
aligned the cylinders with the frame, one cylinder facing
towards the front wheel and the other towards the back
wheel. For example, Harley Davidson introduced the model
W, a flat twin oriented fore and aft design, in 1919 and
built them through 1923. |