In 1906, Harley and the Davidson brothers built their first factory on Juneau Avenue in Milwaukee, at the current location of Harley-Davidson's corporate headquarters and produced about 50 motorcycles.
In 1907, William S. Harley graduated from the University of Wisconsin–Madison with a degree in mechanical engineering, Harley-Davidson expanded the factory increasing production to 150 motorcycles and the company was officially incorporated. In 1911, the company introduced an improved V-Twin model engine that gave their motorcycles better performance. Around 1913, experimentation and innovation were driven by the popular new sport of motorcycle racing, with its powerful incentive to produce tough, fast, reliable machines. Despite the competition from the Indian Motocycle Manufacturing Company, Harley-Davidson was already pulling ahead and dominated motorcycle racing after 1914. In 1917, the United States entered World War I and the military demanded motorcycles for the war effort and purchased over 20,000 motorcycles from Harley-Davidson. Indian motorcycles were purchased as well. By 1920, Harley-Davidson was the largest motorcycle manufacturer in the world producing over 28,000 machines with dealers in 67 countries, and an Italian immigrant named Ernesto Cerini took notice as one of those dealerships would emerge in Donora…