OHV vs OHC: Which is better?

PGkelly · 03-12-2001, 07:45 PM

yes, it is Ducati. their desmodromic valvetrain uses a regular cam to tilt a rocker arm that raises the valve, then is has a second cam, tilting a second rocker arm to close the valve a hold it closed. it uses springs but only to close the last 0.005". both cams are on the same shaft. Mercedes-Benz pioneered this system in the forties, when engine speeds in racing were getting too high for the spring material. Desmedromic timing effectively solved the problem, but the Mercedes system was very cumbersome. and it was made useless when the japanese discovered stiffer spring material. But Ducati chose to use the desmo system anyways, using the theory that it would eliminate valve float and give a higher rev ceiling. the current ducati redlines at 11,000 something, while most japanese bikes redline at 13,000 plus. but the Duc has much more torque at a much lower rpm, and it handles a lot better.

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If it ain't broke, make it go faster

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03-12-2001, 07:45 PM	#1
PGkelly Registered Member Join Date: Feb 2001 Posts: 274	yes, it is Ducati. their desmodromic valvetrain uses a regular cam to tilt a rocker arm that raises the valve, then is has a second cam, tilting a second rocker arm to close the valve a hold it closed. it uses springs but only to close the last 0.005". both cams are on the same shaft. Mercedes-Benz pioneered this system in the forties, when engine speeds in racing were getting too high for the spring material. Desmedromic timing effectively solved the problem, but the Mercedes system was very cumbersome. and it was made useless when the japanese discovered stiffer spring material. But Ducati chose to use the desmo system anyways, using the theory that it would eliminate valve float and give a higher rev ceiling. the current ducati redlines at 11,000 something, while most japanese bikes redline at 13,000 plus. but the Duc has much more torque at a much lower rpm, and it handles a lot better. ------------------ If it ain't broke, make it go faster