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 formed a club for owners of its product taking advantage of the long-standing nickname by turning "hog" into the acronym HOG., for Harley Owners Group. Harley-Davidson attempted to trademark "hog", but lost a case against an independent Harley-Davidson specialist, The Hog Farm of West Seneca, New York, in 1999 when the appellate panel ruled that "hog" had become a generic term for large motorcycles and was therefore unprotectable as a trademark. On August 15, 2006, Harley-Davidson Inc. had its NYSE ticker symbol changed from HDI to HOG. Harley-Davidson FL "big twins" normally had heavy steel fenders, chrome trim, and other