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 FL Harley-Davidson FL The Harley-Davidson FL is a model designation used on Harley-Davidson motorcycles since 1941. The FL prefix is mostly applied to Harley-Davidson's large-framed bikes, including the current Touring series, and also the Softail series, especially those with traditional styling, 16-inch front wheels, and either Springer forks or large-diameter telescopic front forks. The FL was introduced to the Harley-Davidson model line in 1941. It used a version of the "Knucklehead" OHV engine that powered the EL in form. The FL shared its frame with the EL and with the U and UL, which used a 74 cubic inch flathead engine.