GIF: Motorcyclist Magazine on YouTube
There was once a time when Desmodromic valve technology was cutting edge and a necessary competitive advantage for Ducati in racing. The Desmo head doesn't use a valve spring to return the valve to the closed position, instead relying on a second valve rocker and a second lobe on the camshaft to pull the valve closed. In the early days of motorcycle racing, the metallurgy simply wasn't available to build the strong valve springs necessary to avoid valve float at the engine speeds Ducati wanted to build.
The technology was initially invented in 1896, and was employed by some mid-1950s Mercedes Grand Prix racers. Even the famed 1955 Mercedes 300SL race car used Desmo technology. As mentioned in the video, the technology even saw use in other motorcycles before Ducati started using it in 1956, but only Ducati has continued developing the system through to today.
While the tech was initially finicky and required an expensive service at shortened intervals, Ducati has apparently finally figured out how to make Desmo valves work as reliably and on a comparable maintenance schedule to sprung valves. Now going as much as 28,968km between valve adjustment services, current liquid-cooled Ducatis still use the 1950s valve tech. Have the Italian bike makers stuck with a dated technology for too long, or has it just taken 50 years for it to be perfected?