Ducati Desmosedici 990

Ducati abandoned the Grand Prix racing scene at the start of the 1970s. For many years the 500 class was essentially a class for two-stroke motorcycles, an engineering technology that was far removed from the four-stroke road-going machines sold by Ducati. Technical rules changed in 2002, giving priority to four-stroke machinery and turning the 500 class of World Road Racing into the MotoGP Championship. This convinced Ducati to make a much-awaited return to the track in the new MotoGP class.
Desmosedici chronology at the Ducati Museum

Ducati history is classically based on L-twin engines, using desmodromic valve technology. Initially, Ducati considered the possibility of creating a MotoGP ‘super-twin’, taking advantage of the MotoGP regulations that give twin-cylinder machines a considerable weight reduction over four, five or six-cylinder bikes. However, analysis indicated that a twin-cylinder engine would not have been able to produce the required amount of power, more than 230 hp (170 kW), without excessively increasing the number of revs. A twin would have had to rev at over 17000 rpm, but this would require a very short stroke and a very large bore, as a result producing possible combustion problems.

The basis of the design of the Desmosedici engine therefore is two classical Ducati L-Twins next to each other, making a Double L Twin with two-cylinder Stroking at the same time (also called Twin Pulse). With four valves per cylinder, the total number of valves is sixteen - Desmosedici means desmodromic distribution with sixteen valves shortened in Italian

Design had started in 2001, the bike was unveiled at the 2002 Italian GP at Mugello, for use in the following seasons MotoGP World Championship. Vittoriano Guareschi, the Ducati Corse test-rider, followed every phase of the Desmosedici’s development process from early testing to track debut and the project’s evolution. In 2007, Ducati's pilot Casey Stoner, riding a Desmosedici, obtained Ducati's first MotoGP World Championship Title.
[edit] GP3

While still fully committed to Superbike racing, the Ducati Marlboro Team of Loris Capirossi and Troy Bayliss would compete in all rounds of the 2003 MotoGP championship. The Desmosedici GP3 quickly scored a series of results with Loris Capirossi, who stepped onto the podium in the opening round of the championship in Japan and won the GP Catalunya in Barcelona. Riders Capirossi finished fourth in the final championship standings and Bayliss sixth; while Ducati finished second overall in the Manufacturers’ standings
[edit] GP4

In 2004 the Desmosedici GP4, again in the hands of Capirossi and Bayliss, underwent a series of major modifications. A large part of the season went by before the bike became competitive, but the season concluded with both riders on the podium.

At 989 cc, the GP4's top speed record of 347.4 km/h (215.9 mph) was set by Loris Capirossi at IRTA Tests in Catalunya, Spain.
[edit] GP5
Loris Capirossi riding the GP5
...and GP6.

The GP5 version lined up for Ducati’s third season in MotoGP, with Bayliss replaced by the Spanish rider Carlos Checa. Thanks to a collaboration agreement with Bridgestone, Ducati could finally contribute to the development of new tyres and by the end of the season the Desmosedici became a competitive machine. Bridgestone found that hard tyres suited the bike more than softer tyres to create grip - simply put, allowing it to spin the rear wheel gave better control. Capirossi took two wins in the Grand Prix of Japan at Motegi and in the Malaysian GP at Sepang, while Checa scored a brace of podium finishes
[edit] GP6

Launched at the Italian skiing resort of Madonna di Campiglio, the GP6 is a lighter and more powerful version of the GP5. Involving better aerodynamics and a better fuel tank position, most importantly, although more powerful, the engine delivery was smoothed to make the bike more ridable. This made the bike slower on top speed, but quicker into, around and out of corners.[1]

The new rider with Capirossi was Spanish rider Sete Gibernau. After encouraging winter tests, the Desmosedici GP6 took its first win of 2006 in the opening GP at Jerez de la Frontera, Spain, followed by a podium in Qatar. Capirossi led the championship for a short while, but at the start of the Grand prix de Catalunya at Barcelona, Gibernau's bike collided with Capirossi's after Gibernau braked too late and compressed his brake lever further after impacting it on the back of Capirossi's bike. Both riders ended up injured and in the hospital, with Gibernau sustaining a broken collar bone, and both missed the Dutch Grand Prix at Assen. Capirossi returned at the British Grand Prix, while Gibernau was replaced by German Alex Hofmann for the Dutch Grand Prix, the British Grand Prix, and also the Czech Grand Prix after undergoing additional surgery. With Gibernau sidelined for the final round of the season at Valencia following a collision with Casey Stoner, Ducati recalled Bayliss, who was recently crowned World Superbike champion. The race was won by Bayliss, his first MotoGP victory, with Capirossi taking second place for the first Ducati 1-2 finish.

2004 GP4

2005 GP5

2006 GP6