The Harley-Davidson XA was a flat-twin shaft drive motorcycle made by Harley-Davidson for the US Army during World War II. During WWII, the US Army asked Harley-Davidson to design a specification of a motorcycle much like the BMWs used by German forces, with shaft drive, a boxer engine, and several other features that made the BMWs exceptionally reliable and low-maintenance machines. When production had began, the Jeep had become the Army's general purpose vehicle of choice, ending production after only 1000 XAs were produced.