Harley-Davidson XA
Encyclopedia
Harley-Davidson
Harley-Davidson , often abbreviated H-D or Harley, is an American motorcycle manufacturer. Founded in Milwaukee, Wisconsin, during the first decade of the 20th century, it was one of two major American motorcycle manufacturers to survive the Great Depression...
for the US Army during World War II
World War II
World War II, or the Second World War , was a global conflict lasting from 1939 to 1945, involving most of the world's nations—including all of the great powers—eventually forming two opposing military alliances: the Allies and the Axis...
.
During WWII, the Army produced a specification for a motorcycle much like the BMW
BMW
Bayerische Motoren Werke AG is a German automobile, motorcycle and engine manufacturing company founded in 1916. It also owns and produces the Mini marque, and is the parent company of Rolls-Royce Motor Cars. BMW produces motorcycles under BMW Motorrad and Husqvarna brands...
s used by German forces, with shaft drive
Driveshaft
A drive shaft, driveshaft, driving shaft, propeller shaft, or Cardan shaft is a mechanical component for transmitting torque and rotation, usually used to connect other components of a drive train that cannot be connected directly because of distance or the need to allow for relative movement...
, a boxer engine, and several other features that made the BMWs exceptionally reliable and low-maintenance machines. Harley-Davidson produced the XA, which was based closely on the BMW. Though an excellent machine, only about 1000 were produced. The XA was expensive and, by the time production had begun, it was clear that the Jeep was the Army's general purpose vehicle of choice. The less advanced but cheaper WLA was considered sufficient for its limited roles.
According to the American Motorcyclist Association's Motorcycle Hall of Fame Museum, regarding the World-War-II-vintage Harley-Davidson XA, which has an opposed twin engine — "Mechanically, the large cooling fins stuck straight out in the breeze, reportedly keeping the XA’s oil temperature 100 °F (56 °C) cooler than a standard Harley 45." The latter was a transversely mounted V-twin, in which the air stream cannot reach the cylinders, especially the rear cylinder, as efficiently as on longitudinally mounted flat twin.