Historical and technical profiles written by Harley-Davidson expert Dain Gingerelli and masterful motorcycle photography by David Blattel come together in Art of the Harley-Davidson Motorcycle (Motorbooks, 2011). The result is a breathtaking review of over 100 stunning Harley-Davidson greatest hits from the early 1900s to today. The following excerpt is taken from Chapter 1, “Finding Form: The Early Harley Motorcycles.”
1940 Model UL
By 1940 the venerable flathead Big Twin engine had been thoroughly sorted out by Harley-Davidson engineers, making it one of the most reliable models of its time. But taking leads from the new overhead valve Model E and EL, the engineers adapted a dry sump lubrication system and four-speed transmission to the flathead model, refining it even more in the process. There was more to come: for 1940, the larger UH engine was given forged aluminum cylinder heads that had deeper fins for improved heat dissipation. The heads were lighter in weight as well, and brass sparkplug inserts were cast in to help prevent stripped threads during plug changes. UL customers could also order the silicon aluminum heads as options, making them choice items for collectors today. While the flathead Big Twins remained popular into the 1940s, production ceased on virtually all civilian models when war broke out so that Harley-Davidson could focus its production on the smaller 45-cubic-inch WLA used by the U.S. armed forces throughout World War II. A limited number of UL models were produced during that time for specific civilian and military use, but for the most part the WLA constituted the bikes that Harley-Davidson built until the war ended in September 1945.
Engine Displacement: 74 cubic inches
• Semicircular floorboards were equipped on Harley models starting in 1940.
• 3,893 ELs were built in 1940, compared to 822 ULs.
More examples of Harley-Davidson innovation from Art of the Harley-Davidson Motorcycle:
Main Article: Finding Form: Early Harley-Davidson Innovation
This excerpt has been reprinted with permission from Art of the Harley-Davidson Motorcycle, published by Motorbooks, 2011.