Keith, Desmodromic valvetrains were developed back in the the early part of last century. Ducati didn't use the principle till 1956 (taglioni 125cc ducati grand prix bike). In context - back in the pre 40's days, springs weren't too clever and so to ensure reliability the desmodromic valvetrain was a better option because of all the things listed above, but also because it took a known weak point of failure out of the equation. Spring failure through metal fatigue there's no theoretical advantage to Desmo valves, those advantages are actual fact. However, with advances in technology the advantage has reduced. Disadvantages are that the conventional valve train is lighter and cheaper than a desmo setup, and with progressively would valve springs the main point of fatigue was also reduced enormously. Valve float was analyzed and found to be caused largely by resonance in valve springs that generated compression waves among the coil in the same way a slinky does. High speed photography showed that at specific resonant speeds, valve springs were no longer making contact at one or both ends, leaving the valve floating before crashing into the cam on closure. Pneumatic valves are a whole different ball park, and outside of race engines doesn't (yet) have the longevity or durability to be implemented on road vehicles. This is where I'm about to get a shoeing, but... Ducati are in a bit of a Dilemma really you see, Desmo is as much about Ducati as is the Twin engine - its a brand identity now, and as has been pointed out they have over half a century or development of the system. Short of weight and durability (near eliminated with dlc coated critical areas) the system is pretty much a known quantity and bulletproof, and you can ensure accuracy whereas even today with conventional valve trains you're relying on a spring to do its work properly. Why fix what isn't broken and all that. For what you're revving out to its not worth losing sleep over. its not like the R6 with its 16K redline is it, and ducati play the CC game rather than the RPM game - which they clearly can't match unless they dump twins and start running sedici's. Can I can see them dumping Desmo valves in the same way as they finally conceded and dumped dry clutches?, probably but that probably won't be anytime soon (maybe a decade or two). Its such a strong engineering identity that I think Ducati would rather give you a fully titanium V4 engine before conceding that the Desmo is done. If anthing will kill desmo it'll be the left liberal noise police, but then engine cases and bodywork just gets more padding to dampen the sound. On a road bike, and with real world riding talent... don't lose sleep over it, just enjoy, its a Ducati
Wow thanks for that, I knew about Bristol & Fedden's products, the RR Crecy and of course "The One Ton Monster" that was the Napier Sabre, need to pour over that article you linked too Many Thanks Crecy Anybody
