Harley's iconic V-twin

Anno 1903: "Serial Number One", the first model from Harley-Davidson

The first motorcycle from Harley-Davidson "Serial Number One" which came in 1903 had a small 1-cylinder engine of 405 cc, with an output of about 3 hp. In 1907 the first prototype of the V-twin was ready. It was 880 cc, and was the basis for the first V-twin for production, the Model 5-D of 811 cc which was ready in 1909. Things did not really pick up speed until 1911.

By 1911, Harley-Davidson had solved the problems with the V-engine that had arrived in 1909.

The new V-twin, model 5-D, however, proved to be unreliable. It was therefore taken out of production to undergo technical improvements. It took a couple of years before it met its goals, and in 1911 it was put into full production. Since then it has been further developed a number of times, and has become the very symbol of HD; The Big Twin.

Big Twin................

The development of the V-twin has been steady in Milwaukee, and the term Big-Twin has become almost synonymous with Harley-Davidson despite the fact that they were far from the only American motorcycle manufacturer to use this engine type. Here are some of the most important V-twin engines from Harley-Davidson .