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 Topper Harley-Davidson Topper The Harley-Davidson Topper was the only motor scooter that the Harley-Davidson Motor Company ever produced. The Topper had a single-cylinder two-stroke engine mounted horizontally between the floorboards. The engine required a premixed gasoline/oil mixture. The starter was of the rope-recoil type similar to lawn mowers or the Lambretta E model. Unlike most scooters with enclosed engines, the Topper's engine did not have a cooling fan. It was expected that the low, horizontally mounted engine would be cooled by air passing under the scooter, but some Toppers developed overheating problems. The engine used a reed valve in its induction