Military Vehicle Spotlight: 1942 Harley-Davidson XA

1942 Harley-Davidson XA owned by Kersting’s Motorcycle Center and Museum Photograph by Doug Mitchell

Harley-Davidson XA

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

Displacing 45 cubic inches and sending the 23 horsepower through a four-speed gearbox before reaching the shaft drive made the XA a durable and reliable motorcycle. Doug Mitchell

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.

Lt. John E. Harley, director of motorcycle training at Fort Knox in 1942, astride a Harley XA. The horizontally opposed engine is visible just forward of his leg. Patton Museum

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.

Steering and suspension on the XA was delegated to the leading link fork design combined with a pair of stout shock absorbers. The solid steel wheels kept debris from getting caught in what would usually be a set of spoked wheels. Doug Mitchell