Harley-Davidson models. In the late summer of 1929, Harley-Davidson introduced its 45 cubic inches (737 cm³) flathead V-Twin to compete with the Indian 101 Scout and the Excelsior Super X. This was the "D" model, produced from 1929 to 1931. Riders of Indian motorcycles derisively referred to this model as the "three cylinder Harley" because the generator was upright and parallel to the front cylinder. The Great Depression began a few months after the introduction of their 45 cubic inch (737 cm³) model. Harley-Davidson's sales fell from 21,000 in 1929 to 3,703 in 1933. Despite this, Harley-Davidson unveiled a new lineup
Harley-Davidson XA Harley-Davidson XA The Harley-Davidson XA (Experimental Army) was a flat-twin, shaft drive motorcycle made by Harley-Davidson for the US Army during World War II. During WWII, the U.S. Army asked Harley-Davidson to design a specification of a motorcycle much like the BMWs used by German forces, with shaft drive, a boxer engine, and several other features that made the BMWs exceptionally reliable and low-maintenance machines. Harley was already producing the WLA, based on its traditional 45-degree V-twin but the army specifically wanted the one feature that the WLA didn’t have: shaft drive. So the company produced the XA, whose engine