XJ 650

1981 Yamaha XJ 650 Technical Analysis & Specification Breakdown

Built around Yamaha's classic motorcycle platform, the 1981 Yamaha XJ 650 utilizes a 653 cc (39.9 cu in) air-cooled in-line four, four-stroke layout. In factory specification, peak output is rated at 71 HP (51.8 kW) at 9,400 rpm, transferring power to the rear wheel through a 5-speed gearbox and shaft drive (cardan) final drive. With a specific output of 108.7 HP per liter, the engine character is reflecting a performance-oriented street tune that balances strong mid-range pull with an energetic top-end rush.

On the scales, the XJ 650 measures 231 kg (509 lbs) wet (curb), translating to a power-to-weight ratio of 0.31 HP/kg (3.25 kg per horsepower). The 20.5-liter (5.4 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 197 km/h (122 mph).

Within MotoLibrary's Yamaha archive, this model family spans 5 indexed model years from 1980 to 1984, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.