Harley and the Davidson brothers tested the power-cycle of their first motor-bicycle and they used it as a valuable learning experiment. The boys immediately began on a new and improved second-generation machine and the first “real” Harley-Davidson motorcycle was born. The bigger engine and loop-design took the motorcycle out of the motorized bicycle category and marked the path to future motorcycle designs. Outboard motor pioneer Ole Evinrude also gave the boys a helping hand.
By September 8, 1904, a Harley-Davidson prototype competed in a Milwaukee motorcycle race held at State Fair Park. It was ridden by Edwin Hildebrand and it placed fourth. This is the first documented appearance of a Harley-Davidson motorcycle in historical record.
In January 1905, small advertisements were placed in the Automobile and Cycle Trade Journal offering bare Harley-Davidson engines to the do-it-yourself trade. By April, complete motorcycles were in production on a very limited basis. That year, the first Harley-Davidson dealer, Carl H. Lang of Chicago, sold three bikes from the five built in the Davidson backyard shed. Years later the original shed was taken to the Juneau Avenue factory where it would stand for many decades as a tribute to the Motor Company's humble origins until it was accidentally destroyed by contractors cleaning the factory yard in the early 1970s.
In 1906, Harley and the Davidson brothers built their first factory on Juneau Avenue, at the current location of Harley-Davidson's corporate headquarters. The first Juneau Avenue plant was a 40 ft × 60 ft