Harley-Davidson XA engine sound

During WWII, the U.S. 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. Harley was already producing the WLA, based on its traditional 45-degree V-twin but the army specifically wanted the one feature that the WLA didn’t have: shaft drive. So the company produced the XA, whose engine and drivetrain were based on the flathead BMW R71 (1938-1941) versus the overhead valve (OHV) BMW R75 (1941-1946). 1000 XAs were produced for evaluation. By the time production had begun, it was clear that the Jeep was the Army&general purpose vehicle of choice. No more XAs were ordered after the initial order of 1000. The less advanced but cheaper WLA was considered sufficient for its limited roles. In 1943, the XA&leading link fork was replaced with Harley-Davidson&first telescopic fork.