XS 650

1981 Yamaha XS 650 Technical Analysis & Specification Breakdown

At the heart of the 1981 Yamaha XS 650 sport touring motorcycle, Yamaha relies on a 654 cc (39.9 cu in) air-cooled twin, four-stroke powerplant. In factory specification, peak output is rated at 50 HP (36.5 kW) at 6,800 rpm while maximum torque reaches 54 Nm (39.8 lb-ft), transferring power to the rear wheel through a 5-speed gearbox and chain final drive. With a specific output of 76.5 HP per liter, the engine character is indicating a tractable, stress-free state of tune focused on everyday usability and broad torque delivery.

On the scales, the XS 650 measures 225 kg (496 lbs) wet (curb), translating to a power-to-weight ratio of 0.22 HP/kg (4.5 kg per horsepower). Rider ergonomics and chassis geometry center around a 785 mm (30.9 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,435 mm (56.5 in) wheelbase engineered for balanced agility and highway composure. The 15-liter (4 US gal) fuel tank paired with a rated consumption of 5 L/100 km provides an estimated theoretical range of roughly 300 km (186 miles) between fill-ups, while factory top speed is listed at 171 km/h (106 mph).

Within MotoLibrary's Yamaha archive, this model family spans 9 indexed model years from 1975 to 1984, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.