Harley-Davidson 61 OHV "Knucklehead"

Harley-Davidson started a revolution in 1936 with the OHV Knucklehead that is still going strong today. This Over Head Valve V twin had a displacement of 61 cubic inches/1000cc. In 1941 Harley added the FL model bike featuring a 74 cubic inch/1200cc knuckle head engine.