The Yamaha YZR-M1 was developed in 2001 by Yamaha Motor Company Ltd.
In 2001, regulations for the new MotoGP World Championship motorcycle road racing 500 cc class were changed drastically for the 2002 season. 2-stroke engines were as previously limited to 500 cc and 4 cylinders, but 4 stroke engines were allowed to up to 990 cc and an unlimited number of cylinders
Seasons 2002 and 2003
Yamaha's YZR-M1 came to the track in 2002, with Max Biaggi who had arrived from Honda onboard. The YZR-M1 was thought to be the complete package, and able to take Yamaha back to winning races.
However, it was found to have a combination of problems which made it very difficult to ride. Firstly the chasis was described by Biaggi as "evil" that chattered often, and a harsh 2stroke like power delivery. In two seasons it achieved 2wins - ironically, both in the wet where it was said to be even more diabolical. In the 2003 season Biaggi became almost nonchalant and open rather than discrete on his comments of how bad and useless the bike was, and if only he could be on a Honda, how everything could be OK
There was much speculation during the second half of the 2003 season about World Champion Valentino Rossi's plans for the future. Most suspected that he would succeed in his bid to claim a third consecutive title and wondered where the amazingly talented Italian would go in the future.
His contract with Honda was up at the end of the year and there were rumors that Rossi had become somewhat disillusioned with his ride at Honda. His tenure at Honda had effectively run its course; he had provided Honda with a 500cc World Championship as well as consecutive MotoGP World Championships, he had helped perfect the Honda RC211V into a formidable, almost unstoppable racing machine. Rossi complained about Honda's reluctance to pay to secure his services in 2004, seemed to have overstayed his welcome. To Honda's credit, they offered Rossi a significant and lucrative contract but ultimately it wasn't enough to keep Rossi where he felt he no longer belonged. Partnered with increased skepticism that the reason for his success was the dominance of the RC211V rather than Rossi's talent, it was inevitable that Honda and Rossi would part.
Mid-season rumors pointed towards a possible move to Ducati, which sent the Italian press into a frenzy; the concept of the great Italian on the great Italian bike seemed too good to be true. Ducati did indeed try to seduce Rossi into riding their MotoGP bike, the Desmosedici, but for numerous reasons Rossi passed the offer up. Critics say that compared to the other manufacturers, Ducati had a significant way to go before being competitive even with Rossi at the helm. This proved to be the truth with Ducati's lacklustre performance in the 2004 season, which had actually been worse than their inaugural year in MotoGP in 2003.
Season 2004 and 2005
Rossi signed a two-year contract with Yamaha, reportedly worth in excess of USD$12 million; a price no other manufacturer, even Honda, was willing to pay.
Rossi's move to Yamaha was written of as "baptism of fire" in the press. His fiercest critics claimed that on an inferior machine like the YZR-M1, Rossi would not be able to recreate his World Championship wins of the previous years, especially with increased development of the RC211V and the likes of Max Biaggi and Sete Gibernau on Hondas. The RC211V was a superior machine in almost every aspect although it was guaranteed that the gap would shrink with the defection of Rossi and Jeremy Burgess (chief mechanic for Rossi at Honda, whom Rossi had also convinced to join).
However, the 2004 season gave Rossi the opportunity to prove that it was his talent rather than his bike that won him his championships.
With the traditional first race of the season at Suzuka off the list due to safety considerations, the 2004 season started at Welkom in South Africa. Rossi shone through to claim first, and silenced his critics who thought the Yamaha would still play second fiddle to the Honda. Rossi would go on to claim 8 more GP wins and the Championship, and ended up with 304 points to Sete Gibernau's 257, with Max Biaggi on a Honda 3rd with 217 points.