The Ducati '85 Sport' was developed by engineer Renzo Neri at Ducati Meccanica. It was one of a series of Ducati entry-level models in the late 1950s. The production of the Ducati '85 Sport' lasted only three years, from 1958 to 1960 and was not hugely popular with its target audience, most likely due to the relatively low power developed by the four-stroke engine..
Neri joined Ducati in 1943, which at that time mainly produced for the arms industry. After 1945, Neri was principally involved in the development of the Cucciolo 48cc 'clip-on' engine and its successors, the Ducati Cucciolo 55, 60 and 65cc. However the first half of the 50s were the glory days of the Cucciolo after which its days were numbered as the autocycle became less fashionable.
Ducati began developing new lightweight engines early on, to hold its own in an ever-expanding competitive market of lightweight motorcycles.
Ducati Meccanica was one of many Italian companies that did well in the 1950s with the production of sporty lightweight motorcycles, such as the Ducati 98, 98N, 98T, 98TL, 98 Sport (98S) and 98 Super Sport (98SS). These were single-cylinder OHV engines with pressed steel 'open cradle' frames, which were produced between 1952 to 1958. The '98 Sport' was sold in London in 1956 for £178.10.
During the same period, other engine manufacturers began to move into this market of lightweight motorcycles and gradually the Italian streets were flooded with light two- and four-stroke machines.
Engine: Single cylinder four-stroke OHV
Bore & stroke: 45.5 x 52 mm
Compression ratio: 7.5:1
Engine Capacity: 84.55cc
Maximum power: 5.5 h.p. (4.1 kW) @ 7,200 rpm
Valve train: Overhead valves arranged in "V" form
Carburettor: Dell'Orto ME 15BS
Cooling system: Air cooled
Ignition: 6V, 28 W generator (type: Marelli CW 250 N)
Lubrication: Wet sump forced circulation with mechanical gear pump
Transmission: Gear primary, chain final (3/16" x 8.5mm Regina chain)
Clutch: Cable operated, wet clutch with multiple discs in oil bath
Gearbox: 4-speed foot-change
Throttle: Cable operated
Frame type: Double cradle tubular and pressed steel
Front Suspension: Telescopic fork
Rear Suspension: Swinging fork and semi-hydraulic dual shocks
Front Brake: Drum
Rear Brake: Drum Ø 116mm x 25mm
Front Tyre: 2.50 x 19 inches
Rear Tyre: 2.50 x 19 inches
Seat: Dual seat
Fuel tank capacity: 12.78 litres
Fuel consumption: 2.1 litre per 100 kilometer
Top speed: 76 km/h
Weight: 80 kg
List price in 1959: 141.000 Lira
Source: Hessink's NL