The 1931 Harley-Davidson Model D switched from F-head to flathead (side valve) V-twins. First was a new 45ci model to compete with the Indian Scout. The next year the 61ci and 74ci Big Twins were changed to a flathead design. Read about the Model D.
The 1934 Harley-Davidson VLD motorcycle helped Harley survive the Great Depression. The Great Depression killed off all the major U.S. motorcycle manufacturers except for Harley-Davidson and Indian. Learn about the classic 1934 Harley-Davidson VLD.
The 1936 Harley-Davidson EL motorcycle introduced the famous Knucklehead engine to the Harley line. It became one of the most popular Harley-Davidson models of all time. See pictures and learn more about the Harley EL.
The 1938 Harley-Davidson UL motorcycle featured a Flathead V-twin instead of the newer Knucklehead. It was a Sport Solo model with new colors and striping available. See pictures and learn about the Harley UL.