a famous and expensive US motorcycle. Harley-Davidsons are long and heavy, with powerful engines that make a loud sound. William Harley and Arthur Davidson built the first three in 1903 in Milwaukee, where the company's main office has always been. Popular models have included the 1936 Knucklehead, the 1957 Sportster 'super bike' and the 1990 Fat Boy. Riding a Harley-Davidson on the open road is part of the American dream for many people If you're overweight and middle-aged, riding a Harley-Davidson won't change anything.