1938 Harley-Davidson W Motorcycle with Sidecar

Harley-Davidson’s 45-inch twins date back to October 1927, when the new side-valve ‘Flathead’ motor was first unveiled to the public, before going on sale the following year.  The Model D’s new engine was essentially two 21-cid singles sharing a common bottom end, using a three-speed transmission and a frame similar to the one lungers of the day.  In response to lacklustre sales, Harley-Davidson redesigned the frame and made other improvements to lure buyers, the heavily revised Model R boasting new crankcases with better lubrication and alloy pistons.  Faced with the challenge from Indian’s Sport Scout, the 45-inch baby ‘Flathead’ underwent further changes in 1937, adopting the styling and many of the mechanical features already seen on the new Knucklehead.  Designated the W in Harley parlance, the new model also came with roller bearings in the bottom end, one-piece cam gears, stronger transmission gears and a new shift mechanism.  Particular attention was paid to the lubrication system, with an upgraded oil pump adopted, along with cooling fins on the timing case cover and left-hand side of the crankcase.  In addition to the standard W, the model range consisted of the WS (sidecar), high compression WL Sport and WLD Special Sport versions.  Harley-Davidson also offered a production racer, the WLDR, for Class C category events for amateur riders using bikes delivered with full road equipment, featuring raised compression and larger valves.  The V-twin was adopted by the United States military for service when that country entered the war in December 1941, the WLA (with 'A' standing for Army) proving a natural choice thanks to the rugged build quality and exceptional reliability.  With higher compression and dry sump lubrication compared with the civilian W-series, the WLA were most often finished in drab olive.  Thousands of WLAs were sold as military surplus in the immediate post-war period before civilian production resumed, with few changes made (1948 models received a new speedo), but by 1952 demand had all but dried up and the model was discontinued, although the Flathead motor lived on.  Popular with Harley-Davidson collectors, the W-series motorcycle was the workhorse of its day and is now an ideal choice for weekend runs and club events.