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 Milwaukee-Eight engine Harley-Davidson Milwaukee-Eight engine The Harley-Davidson Milwaukee-Eight engine is the ninth generation of "big twin" engines developed by the company, but only Harley's third all-new Big Twin in 80 years, first introduced in 2017. These engines differ from the traditional Harley Big Twin engines in that there are four valves per cylinder, totaling eight valves, hence the name. It also marked a return to the single-camshaft configuration as used on previous Harley Big Twin Engines from 1936 to 1999. In addition, the engines all have internal counterbalancers, whereas Twin Cams were counterbalanced only on Softail models, where the engine was rigidly