The Ducati 851 became the first Ducati production motorcycle to combine desmodromic valve control with a liquid-cooled four-valve-per-cylinder V-twin engine.
Ducati introduced the 851 in 1987 as a major technical break from its earlier air-cooled two-valve models. Its 851 cc engine used four valves per cylinder, liquid cooling, electronic fuel injection, and Ducati’s desmodromic system, which mechanically closes the valves rather than relying only on springs.
The model was developed with World Superbike competition in mind and helped establish Ducati’s modern superbike formula. Its racing success and technical layout led to the closely related 888, followed later by the 916 family.
The 851 is sometimes confused with the Ducati 888 because the two motorcycles share much of their architecture. The 851, however, was the earlier production model and the key starting point for Ducati’s liquid-cooled four-valve superbike line.