Harley-Davidson
Realistic Tattoo The knucklehead is a retronym used by enthusiasts to refer to a Harley-Davidson motorcycle engine, so named because of the distinctive shape of the rocker cases.[1] The engine is a two-cylinder, 45-degree, overhead-valve, pushrod-driven V-twin with two valves per cylinder. It was the third basic type of V-twin engine used by Harley-Davidson, replacing […]
