What year was the first Harley Davidson built?

In 1903, the first Harley-Davidson was built based off the blueprints drawn in 1901 of a engine designed to fit a bicycle by William Harley. The first Harley-Davidson was a racing bike with 3-1/8-inch bore and 3-1/2-inch stroke engine.

In 1903, the Harley-Davidson workshop that completed the first motorcycle was a simple shed where someone scribbled the words "Harley-Davidson Motor Company" on the door. A school friend of William Harley and Arthur Davidson, Henry Meyer bought one of the first Harley-Davidson that first year. A year later, C.H. Lang of Chicago, Illinois, became the first dealer to offer Harley-Davidson bikes.