Something to share with Kama, which tickles the hell out of me. From the Wikipedia entry on "Motorcycle history".
However, if one counts two wheels with steam propulsion as being a motorcycle, then the first one may have been American. One such machine was demonstrated at fairs and circuses in the eastern United States in 1867, built by Sylvester Howard Roper of Roxbury, Massachusetts. There exists an example of a Roper machine dating from 1869, but there is no patent existing and nothing proves it was a working model. It was powered by a charcoal-fired two-cylinder engine, whose connecting rods directly drive a crank on the rear wheel. The Roper machine pre-dates the invention of the safety bicycle by many years, so its chassis is based on the
"boneshaker" bike.