Desmodromic valve system

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  1. AndyW

    AndyW Member

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    The Ducati Desmodromic Valve System

    Ducati motorcycle engines employ the Desmodromic (Desmo) Valve System


    The Desmodromic valve control system is totally unique to Ducati engines. Throughout the evolution of petroleum powered engines many have tried to utilize the Desmodromic valve system but only one company has succeeded, Ducati. Thanks to Fabio Taglioni, the original creator and genius behind the Desmo valve system, Ducati is now a name known all around the world for the unbeatable performance of their motorcycles. Read more on Fabio Taglioni here or explore the full history of Ducati here, on the official Ducati website.

    Ducati Desmo Valve System animated model / operation of valve system animation
    The Ducati Desmo Valve System animation below was modeled by Bluming Inc. in 2003 and animated in order to show the motions of the Desmo valves.
    Many thanks to Miroslav Mitrović (mdesignconsulting.com / bluming.com / ducatidesmo.com) for kind permission to use the following animation and images later in this article.

    http://www.ducatiforum.co.uk/newsite/ducati_desmo_valves.swf

    [flash=360,300]http://www.ducatiforum.co.uk/newsite/ducati_desmo_valves.swf [/flash]

    picture1.JPG
    Ducati Desmodromic Valve System explained the HowMotorcyclesWork.com way
    By kind permission of Cody Christian of www.HowMotorcyclesWork.com

    Click images for larger versions;-)

    Ducati_Desmodromic_Valve_System_001.jpg
    Ducati_Desmodromic_Valve_System_002.jpg
    Ducati_Desmodromic_Valve_System_003.jpg

    www.HowMotorcyclesWork.com....recommended viewing! :D

    Ducati_Desmodromic_Valve_parts.jpg
    multistrada_1200_desmo_valves.jpg

    Additional info on Desmo Valves here on Wikipedia

    Why do Ducati motorcycle engines use the Desmodromic valve system?

    Ducati engines are short stroke high revving engines (as far as twins go that is). The more conventional valve control systems used in Japanese motorcycles use a valve spring to return the valve to its closed position when the lobe on the camshaft releases its downward force. The problem with this system can be that as engine revs build up, a spring can suffer lag which in turn means that the valve may still be slightly open when the piston reaches top dead centre. If you are lucky, this will give loss of compression, for those less fortunate it can cause total destruction........expensive!

    The Desmo system uses a second rocker arm to positively lift the valve back to its closed position ensuring that there is always piston to valve clearance.

    Ducati-Multistrada-1200/Multistrada-MTS1200-diagrams

    ducati_desmodromic_desmo_valve_gear.jpg
    ducati_desmodromic_desmo_valve_gear2.jpg
    ducati_desmodromic_desmo_valve_gear3.jpg
     
    #1 AndyW, Mar 10, 2015
    Last edited by a moderator: Apr 4, 2015

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