Byson FI

2021 Yamaha Byson FI Technical Analysis & Specification Breakdown

Built around Yamaha's naked motorcycle platform, the 2021 Yamaha Byson FI relies on a 150 cc (9.2 cu in) air-cooled single cylinder, four-stroke powerplant. In factory specification, peak output is rated at 12.9 HP (9.4 kW) at 8,000 rpm while maximum torque reaches 13 Nm (9.6 lb-ft) at 6,000 rpm. With a specific output of 86 HP per liter and a 2,000 rpm working window between peak torque (6,000 rpm) and peak power (8,000 rpm), the engine character is indicating a tractable, stress-free state of tune focused on everyday usability and broad torque delivery.

On the scales, the Byson FI measures 133 kg (293 lbs) wet (curb), translating to a power-to-weight ratio of 0.1 HP/kg (10.31 kg per horsepower). Rider ergonomics and chassis geometry center around a 790 mm (31.1 in) seat height — offering a neutral standover height that accommodates most average-inseam riders without sacrificing cornering clearance, combined with a 1,340 mm (52.8 in) wheelbase engineered for quick, flickable steering geometry. The 12-liter (3.2 US gal) fuel tank supports practical everyday commuting and weekend road stints.

Within MotoLibrary's Yamaha archive, this model family spans 2 indexed model years from 2017 to 2021, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.