Desmodromic, combining “desmos” and “dromos” from Greek etymology, to coin a valve system that undoubtedly was the most iconic breakthrough in motorcycling history in the 20th century. It’s a system that sets Ducati apart from virtually every other brand at the time, and perhaps still to this day. Desmo holds the distinction of being the trademark of the Borgo Panigale brand.
The technology that Ducati has employed since 1956 eliminates traditional valve springs by employing a mechanical system that controls both the opening and closing of engine valves. For over half a decade, the system did its job to the tee. Provide superior valve control at high RPMs and prevent valve float.
In conventional four-stroke engines, valves are opened by a camshaft but rely on spring pressure for closing. This works well for most use cases but limitations rear its head once the engine gets pushed harder and harder.
Instead of using valve springs to close the valves, the desmo system employs a second set of rocker arms and cam lobes that directly pull the valves closed. This creates a positive mechanical control over valve movement in both directions – opening and closing, eliminating any dependency on spring tension for the critical valve closing phase.
The mechanical operation is relatively straightforward in principle: one cam lobe and rocker push the valve open, while a complementary cam lobe and forked rocker arm pull it closed. This paired action creates a controlled pathway for valve movement that eliminates the possibility of valve float regardless of how high the engine revs.
A brief history
The system actually first gained prominence in the 1950s when Mercedes-Benz incorporated desmodromic valves in their racing engines, most notably in the 300SLR racing cars and W196 used in the early days of Formula 1.
Ducati’s history with desmodromic valves began in 1956 when the company, under the guidance of chief engineer Fabio Taglioni, developed a 125cc single-cylinder racing engine featuring the technology. The system was adopted primarily to address a significant problem of that era: the metallurgical limitations of valve springs.
For Ducati, the desmodromic valve system provided a competitive advantage in racing by allowing its engines to reach higher RPMs than its competitors, without blowing up.
What began as a solution to a material limitation evolved into a defining characteristic of the red bikes. While other manufacturers abandoned desmodromic valves as valve spring technology improved, Ducati stuck to their guns, incorporating it across their model range and making it part of their brand identity.
Trademark service costs
However, it’s not all rose-tinted glasses, the desmodromic system comes with significant drawbacks. The most notable is its complexity. From a manufacturing and ownership standpoint, this only leads to higher costs and challenging maintenance.
The system requires more components, more precise machining, and more complex adjustment procedures, which also require specialised tools and knowledge. Such a system also has more points for wear and failure, which outlined two additional characteristics of Ducati: costly and frequent services.
From a functional perspective, modern technology has all but eliminated the valve spring issues of yesteryear. The additional weight and complexity of the desmodromic system do little to justify its usage today other than its heritage.
Perhaps that’s why Ducati has taken a slight step away from their bread and butter in recent years. Take the Multistrada for example, which has springer valves instead of the Desmo systems. For many riders, this makes complete sense as there is no need for racing technology on longer-distance road bikes. The costs and headaches that come with maintaining the system are simply not worth it.
But even given this, it is unlikely that Ducati will ever drop the system altogether. Desmo makes up a significant part of the brand’s DNA and we’ll never see them separated.
