The original Ducati Desmoquattro engine used four valves per cylinder.
Ducati’s Desmoquattro was a liquid-cooled, 90-degree V-twin engine with four valves for each cylinder. The name combines “desmodromic,” referring to mechanically controlled opening and closing of the valves, with “quattro,” the Italian word for four.
The design was developed for Ducati’s high-performance motorcycles and became closely associated with the 851 and its successors. Four valves per cylinder allowed the engine to move more air at high engine speeds than a conventional two-valve arrangement, supporting the company’s racing and superbike ambitions.
Desmodromic operation is often misunderstood as meaning four valves total. It does not: “quattro” identifies the number of valves per cylinder, while desmodromic describes how the valve train controls them. Ducati’s later engines used several related configurations, so the answer applies specifically to the original Desmoquattro architecture.