125 S

1978 MV Agusta 125 S Technical Analysis & Specification Breakdown

Positioned in MV Agusta's classic motorcycle lineup, the 1978 MV Agusta 125 S pairs a 123 cc (7.5 cu in) air-cooled single cylinder, four-stroke architecture with road-focused gearing. In factory specification, peak output is rated at 9 HP (6.6 kW) at 8,200 rpm, transferring power to the rear wheel through a 5-speed gearbox and chain final drive. With a specific output of 73.2 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 125 S measures 108 kg (238 lbs) wet (curb), translating to a power-to-weight ratio of 0.08 HP/kg (12 kg per horsepower). The 14-liter (3.7 US gal) fuel tank supports practical everyday commuting and weekend road stints, while factory top speed is listed at 111 km/h (69 mph).

Within MotoLibrary's MV Agusta archive, this model family spans 4 indexed model years from 1975 to 1978, allowing buyers to track year-over-year changes in emissions tuning, weight and equipment.