XL Sportster

1957 Harley-Davidson XL Sportster Technical Analysis & Specification Breakdown

Built around Harley-Davidson's sport motorcycle platform, the 1957 Harley-Davidson XL Sportster pairs a 883 cc (53.9 cu in) v2, four-stroke architecture with road-focused gearing. In factory specification, peak output is rated at 42 HP (30.7 kW) at 5,500 rpm, transferring power to the rear wheel through a 4-speed gearbox and chain final drive. With a specific output of 47.6 HP per liter, the engine character is prioritizing low-RPM tractability, mechanical longevity and relaxed throttle response over peak redline numbers.

Within MotoLibrary's Harley-Davidson archive, this model family spans 3 indexed model years from 1957 to 1959, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.