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Posted by Mark N on March 13, 2007, 11:01 am
Julian Bond wrote:
> "robotiser@googlemail.com"
>> Are there any known reasons why the Ducati engine is so good? The BBC
>> commentators mentioned the Desmo valve system several times. But if it
>> was just the Desmo system itself, the patent on that must be long gone
>> and the other teams could just duplicate it. Unless the real benefits
>> of the desmo valve system are dependent on more recent refinements,
>> which are still secret.
>>
>> Or is it that the Ducati engine is just a good design and well refined
>> all round?
> Just look at the top end. We've got Yamaha and Honda using valve
> springs. Kawasaki, Suzuki and Illmor using Pneumatic valves. Ducati
> using Desmo. Everybody using 4 valves per cylinder. You would expect the
> non valve spring people to be able to get higher revs. But that takes
> short stroke as well or the crank/rods become the limiting factor. Now
> look at Ducati's heritage of very over-square large bore V-Twins. You
> have to think that they have learnt something about making highly
> over-square engines with high compression work.
>
> The theory about Desmo is that it not only allows you to use big valves
> and high revs but also to use very aggressive opening and closing ramps
> on the cams. More so than even pneumatic valves.
>
> Then there's the screamer 360 degree V-4 they're using this year. The
> paired cylinders firing 360 deg apart allow them to run a better tuned
> exhaust than the straight 4s although they share this with the other V-4s.
>
> Whatever it is, Ducati are now right out on the bleeding edge of 4
> stroke engine design.
For a racing application, perhaps. But you have to factor in that part
of the reason Honda and Yamaha do what they do re valve actuation is
what they think makes sense on the street, and part of what they are
doing in MotoGP is done as an R&D exercise. That may not win them as
many races, but it may make a lot of sense in terms of the results for
us street riders. Desmo has always been a mixed blessing at best for the
bike owner.
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