Radical Bike

The WLA is very similar to civilian models, specifically the WLD. Among the changes making it a military model:

• paint and other finishes: painted surfaces were generally painted olive drab or black and chrome- or nickel-plated parts were generally blued or Parkerized or painted white. Some parts were left as unfinished aluminum. However, Harley Davidson was apparently very practical in its use of existing parts and processes, and many finishes remained in their bright civilian versions for a time, and, in some cases, for the whole production run.
  
• style="font-family:arial;">blackout lights: in order to reduce nighttime visibility, WLAs were fitted with a second set of blackout head and tail lights.
• fenders: to reduce mud clogging, the sides of the standard fenders were removed.
• accessories: a heavy-duty luggage rack (for radios), ammo box, leather Thompson submachine gun scabbard, skid plate, leg protectors, and windshield could be fitted. Most came with at least these accessories less the windshield or leg protectors.
• air cleaner: an oil bath air cleaner, originally used for tractors and other vehicles in dusty environments, was fitted to handle the dust of off-road use and to allow easier field maintenance. Oil bath cleaners require only the addition of standard motor oil rather than replaceable filters.
• fording: changes to the crankcase breather reduced the possibility of water intake into the crankcase.
  
  

The US Army would use motorcycles for police and escort work, courier duties, and some scouting, as well as limited use to transport radio and radio suppresion equipment. Allied motorcycles were almost never used as combat vehicles or for troop mobility, and so were rarely equipped with sidecars as was common on the German side. Nevertheless, the WLA acquired the nickname "Liberator", since it was seen ridden by soldiers liberating occupied Europe. To this day Belgium is a major center of WLA enthusiasm.

Technology

The engine of the WLA is a side-valve design, which is reliable though not particularly efficient in comparison to overhead-valve designs. Harley Davidson already had overhead valve engines in production for its Big Twin lines, but the "small twin" flathead design was popular in applications needing reliability more than power. This engine remained in production from 1937 to 1973 in the Servi-Car, although it was superseded in two-wheeled motorcycles by the more advanced flathead engine used in the Model K in 1952.

Though the model designation suggested high compression, the motor was available in several compression ratio ratings. For reliability, the Army version actually used a medium-compression version. In modern terms, the WLA's compression ratio of 5:1 is very low. Due to this low compression, a WLA will run on 74 octane gasoline, necessary due to the poor quality of refining at the time, although fuel technology would improve rapidly during the war.

The WLA also features springer front suspension. Harley-Davidson would not adopt telescopic front forks until after the war. The rear wheel had no suspension, giving this type of motorcycle the nickname "hard tail".

With American involvement in World War II on the horizon in the late 1930s, the U.S. War Department knew exactly what it wanted in a military motorcycle.

And this Harley-Davidson WLA wasn’t it. It was, however, one of the reliable, workhorse machines officials finally decided on as the two-wheeled Jeep of the U.S. Army. And for that, you can thank William Harley, and his insistence that the WLA would be perfect for military duty. The machine’s story actually started in 1938, when War Department officials asked American motorcycle manufacturers to design a 500cc motorcycle that could ford streams, not overheat at idle or during slow running, and sustain 65 mph. Times were tough, and both Harley-Davidson and Indian designed machines in hopes of securing the military contract. Indian followed the military specs perfectly, producing the 500cc Model 741 that was based on its civilian Junior Scout. William Harley at the Motor Company, however, balked at producing a 500cc machine, to the point of confrontation. He was adamant that the military needed a 750cc (45 cubic inch) motorcycle for war, and he based his design on the W-series side-valve motor. The WLA featured alloy cylinder heads for better cooling, more ground clearance, a cargo rack and saddlebags. Simplicity and reliability were key, so compression was lowered (hence the “L” in the name) and an oil-bath air filter was added. In the end, with war imminent, the Army approved purchase orders for both the Harley and the Indian. In practice, though, the Harley was the preferred machine, and more than 90,000 were produced before war’s end. Though eventually overshadowed by the multi-use Jeep, military motorcycles found a niche in reconnaissance, traffic control and dispatch duties throughout WWII. And they endured well enough that, after the war, many Americans picked up surplus models, like this 1943 example, now owned by retired U.S. Army Brigadier Gen. George Ogden Jr.