The Desmo Story

WORDS: Alan Cathcart
PHOTOS: Kel Edge

Though motorcyclists typically associate desmodromics with Italian Ducatis, the term doesn't have Latin roots. It's actually derived from two Greek words: desmos, meaning controlled, and dromos, for the run, or track, an object follows. In engineering terms, it refers to a valvetrain that opens and closes its valves positively, using a solid lever mechanism instead of a spring. British engineer F. H. Arnott obtained the frst patents for a desmodromic valve system in 1910, and the frst practical application of the technology appeared in the Peugeot L76 racer that won the 1913 Indianapolis 500. But Ducati remains the only frm on two wheels or four to have successfully applied desmodromics to mass production.

It therefore makes sense that "Desmo Story," a year-long exhibit chronicling the history of desmodromic valve actuation, is hosted by the Museo Prunaro in Budrio, 15 miles east of Ducati's factory in Bologna. "Bologna was the Città Desmodromica in the 1950s, when no fewer than six different car and bike manufacturers in this area were working on desmo engine designs," says Ducati's Technical Director Gianluigi Mengoli, organizer of this exhibit. "I regarded it as a duty as well as a pleasure to help Ducati enthusiasts understand the history and development of the desmo concept."

This exhibit wouldn’t have been possible without the[ assistance of Dutch engineer Henk Cloosterman, who has assembled details of 877 separate patents granted around the world for positive valve operation. Nicknamed “Dr. Desmo” by the organizing team, Cloosterman has constructed more than 60 full-scale models demonstrating the function and layout of the key desmo designs. Many of these models are on display in Budrio, often alongside the engine containing that very technology.

Ducati is well represented, of course. Famed engineer Fabio Taglioni frst brought desmodromic technology to the bike-builder when he joined the company in '55, and it's been decades since any motorcycle has left
the Borgo Panigale assembly line without such valve gear. Highlights from Ducati's history run the gamut from its frst desmo-equipped bike, the triple-cam 125cc GP racer from '56, to Casey Stoner's World Championship-winning 800cc MotoGP racer from '07. Desmo motorcycles from Mondial, MV Agusta, BMW and Honda are displayed as well.

[Other examples of desmo technology are wide-ranging, especially on the automotive side, and Desmo Story also features designs from Mercedes Benz, Ferrari, Peugeot, Audi, Toyota, Honda and more. Juan Manuel Fangio won the Formula 1 World Championship in ’54 and ’55 for Mercedes, and an example of the German car-maker’s desmo-equipped W196 straight-eight is displayed here, alongside modern F1 prototypes including Ferrari’s ’91 V-12 and an ’03 design by Toyota.

These are just a few highlights from a fascinating and comprehensive exhibition tracing the evolution of this unique engineering system that has won so many races and championships over the last century of competition. If you fnd yourself in the Bologna area during the next year, a stop in Budrio is mandatory!