- Engine: 45 cu in (740 cc) SV flat-twin
- Bore / stroke: 3.063 in × 3.063 in
- Compression ratio: 5.7:1
- Horsepower: 23 hp @ 4,600 rpm
- Top speed: 65 mph
- Ignition: 6-volt battery and coil; no distributor
- Transmission: 4-speed foot shift
- Wheelbase: 57.5 in
During WWII, Harley-Davidson was already producing the WLA based on its traditional 45-degree V-twin, when the Army indicated one feature the WLA didn’t have: shaft drive. The U.S. Army asked Harley-Davidson to design a motorcycle based on the BMWs used by German forces that would incorporate shaft drive and a boxer engine. The result was the XA. Harley based the engine and drivetrain on the German’s flathead BMW R71 rather than the overhead valve (OHV) BMW R75.
Harley-Davidson produced 1000 XAs for evaluation. Soon after production had begun, it was clear to the Army that the Jeep would fill the majority of its general purpose vehicle needs. The Army did not order any more XAs, opting instead for the less-advanced—but cheaper—motorcycle, the WLA.