These are pictures of Jan Muller’s unique and curious (“semi-desmodromic”) Delayed Tension Valve System (D.T.V.). The valve angle is very outdated and so is the form of the in- and outlet ports. The complexity is at least as high as of desmodromic gear. Jan couldn’t confront and answer the basic question why to choose for D.T.V. and not for a completely desmodromic system. As so often the industry showed no interest at all. He tragically died soon after he had applied for a patent and had visited me leaving a 125 cc Jonghi head and valves and the encouragement to make a DTV-system for the collection.
Source pictures: Private collection H. cloosterman. See also: Patented Systems
Article (in Dutch) about Jan Muller’s patented Delayed Tension Valve system and the model I made. This article was published in Strada, the magazine of the Dutch Ducati Club.