Dale's Wheels Through Time - The '36 Knucklehead - The 1936 Harley-Davidson Knucklehead is considered to be the grandfather of the modern motorcycle. Harley-Davidsons new OHV 61c.i. engine and dry-sump circulation oil
Harley-Davidson Knucklehead V-Twin Motorcycles, HISTORY OF THE BIG TWIN | Cycle World