The first Harley Davidson motorcycle to feature a clutch and gear shifter on the left side of the bike was the Harley Davidson Model J. Introduced in 1915, the Model J was a significant milestone for Harley Davidson as it marked the transition from the company's earlier F-head models to the more advanced side-valve engines.
The Model J featured a left-hand mounted clutch lever and a foot-operated gear shifter on the left side of the motorcycle. This setup allowed riders to engage the clutch with their left hand and shift gears with their left foot, which became the standard configuration for Harley Davidson motorcycles and many other motorcycles produced thereafter.
The introduction of the Model J and its left-side clutch and gear shifter arrangement brought greater convenience and ease of use for riders, contributing to the evolution of Harley Davidson motorcycles and their continued popularity.