| MODEL | MV AGUSTA 861 S MAGNI 1979 |
| Year | 1979 |
| Engine Type | Four stroke, transverse four cylinders, DOHC, 2 valves per cylinder |
| Displacement / Capacity | 861 cc / 52.2 cu in |
| Bore X Stroke | — |
| Compression Ratio | 10.3:1 |
| Cooling System | Air cooled |
| Max Power | 71 kW / 92.5 hp @ 10000 rpm |
| Max Torque | — |
| Ignition | — |
| Induction | 4x 27 mm Dell'Orto carburettors |
| Start System | Electric |
| TRANSMISSION SPECS | |
| Lubrication | — |
| Gear Box | 5 speed |
| Clutch | Multiple disc in oil bath |
| Final Drive | Chain |
| CHASSIS SPECS | |
| Frame | Tubular steel, welded, double cradle |
| Front Suspension | 38 mm Forcelle Italia telescopic forks, preload and rebound damping adjustable |
| Rear Suspension | Dual Koni shocks, preload adjustable |
| Front Brakes | 2x 280 mm discs |
| Rear Brakes | Single 280 mm disc |
| DIMENSION SPECS | |
| Overall Length | — |
| Overall Width | — |
| Overall Height | — |
| Seat Height | — |
| Wheelbase | — |
| Ground Clearance | — |
| Dry Weight | 200 kg / 440 lbs |
| Wet Weight | — |
| WHEEL SPECS | |
| Front Tyre | 110/80-18 |
| Rear Tyre | 150/70-18 |
| FUEL SYSTEM | |
| Fuel Capacity | 19 Litres / 5.0 US gal |
| Fuel Consumption | — |
| Top Speed | — |
The 861S was built by Arturo Magni and sons on a stock 750S base, with a new Magni frame, enlarged 861 cc engine with high-compression pistons and street cams, chain drive and Conti exhausts. Bodywork, tank and seat were also new. Output rose to about 92 hp.
