Desmosedici!

DESMOSEDICI!

While Ducati's 190-horsepower V-Twin Superbikes can lap some circuits as quickly as 500cc Grand Prix two-strokes, the new 990cc four-stroke MotoGP bikes are expected to be much faster. Ducati's solution? A V-Four that behaves like a Twin!

S WE SPECULATED LAST month, Ducati's new "SuperTwin" four-stroke Grand Prix engine isn’t a Twin at all! It’s a 989cc V-Four with 16 desmodromic valves, which gives it its tongue-twisting name, Desmosedici.

According to Ducati Corse Technical Director Filippo Preziosi, the new MotoGP rules don’t give twin-cylinder machines enough of a weight advantage (just 22 pounds) to be competitive with the forthcoming fourand five-cylinder prototypes, so he went looking for alternatives. At first, an oval-piston V-Twin was contemplated, along the lines of Honda’s V-Four NR500 GP bike of 1979-82, but that was discarded in favor of a V-Four with each of the two cylinder banks firing in unison. Dubbed “Twin-pulse,” this configuration gives the engine the characteristics— and, perhaps equally important, the sound-of a V-Twin.

Gimmick? Not according to Preziosi, who claims using four cylinders let him reduce stroke without having to increase bore to the point that combustion would be problematic. Moreover, the designer stresses that those features of existing Ducati V-Twins that were carried over

to the V-Four have major advantages. Not only does the 90-degree Vee-angle give perfect primary balance “fundamental in an engine that must arrive at 18,000 rpm,” the designer says-desmodromic valve actuation was found to result in reduced power loss, cost and reliability problems compared to other systems, in particular the Formula One-standard pneumatic valves.

No fewer than 16 employees are currently working on the project, w'ith assistance from Weber-Marelli and High Performance Engineering, the engine design and consultancy firm headed by Piero Ferrari. Track testing is expected to

commence in July in preparation for a two-rider assault on the 2003 MotoGP World Championship.

Buona fortuna!

Brian Catterson