1999

Max Biaggi and Carlos Checa competed this season from the Marlboro Yamaha Racing Team, while Simon Crafar and Regis Laconi competed from Red Bull Yamaha WCM and Norifumi Abe from Antena 3 Yamaha D'Antin team, all on the YZR500. Biaggi, who joined Yamaha from this season, finished it ranked 4th on solid results including a win in South Africa. This season Yamaha achieved three wins, with one each by Biaggi, Abe and Laconi.

Biaggi raced in front from the opening race in Malaysia, but retired midway through the race due to machine trouble. Problems getting the setup right in the following Japanese GP caused him to finish 9th. However, he showed his true potential in the third round in Spain. He fought for the lead with Alex Criville (Honda), and although he was beaten out at the finish by a margin of only 0.15 seconds, he took his first podium finish under the Yamaha banner. Just as he was getting into stride, however, he took a fall in the following round in France, dislocating a finger, and damaging some of the ligaments. From here, he fought the pain in the following round in Italy, his home race, to take his second podium finish of the season. However, the effects of the injury started to take its toll on him during mid-season, resulting in a series of inconsistent performances. The championship outlook became grim, however, after he was forced to retire in rounds six and nine.

There was a one-month break, however, before the next round in the Czech Republic, where he finished 4th. Then he took his first win of the season in South Africa in round 14, which brought him up to 4th in the ranking. Biaggi's teammate, Checa, finished 2nd in the first race in Malaysia and went on to finish the season ranked 7th, with four 4th-place finishes and two 5th-place finishes.

Abe began his fifth season in the series with a no-pointer by getting caught up in another machine's fall in the opening race. In Motegi, he finished 3rd by holding off Criville (Honda) and Sete Gibernau (Honda). In the subsequent races in Spain and France, he finished 5th and 6th respectively. There were a few no-pointers for Abe mid-season, but in Germany he finished 3rd for the second time this season. Then in round 15 in Rio de Janeiro, he took his first win of the season. This was his second career victory in the class, and another Yamaha rider, Biaggi, took 2nd place in this race. Abe finished 3rd in the final round in Argentina to sew up 6th place in the season ranking.

Laconi was battling most of the early part of the season in the second group, with his best result a 7th in the Spanish GP. However, after taking 5th in Imola in round 11, he got his first GP500 win in the following race in Valencia. He also took 3rd in the 13th round in Australia.

From the seventh round in the Netherlands, Garry McCoy replaced Crafar, who dropped out during the season. The initial goal for McCoy was only to finish the races, but he quickly adjusted to the machine and began improving his race positions rapidly. He took third in the following round in Valencia, and shared the podium with Laconi.

The Yamaha factory team returned to the 250cc class for the first time in three years. Shinya Nakano and Olivier Jacque from the Chesterfield-Yamaha Tech 3 team raced this year on the YZR250 and finished 4th and 7th in the championship ranking respectively.

Nakano led at the start in the opening race in Malaysia. It looked as though he would lead to the finish, but he was passed by Loris Capirossi (Honda) and Tomohisa Yukawa (Honda) in the final lap to finish close behind them in third. In the following race in Japan, he established a five-second margin over the rest of the pack by mid-race and kept that lead all the way to the end to take the win. He was foced to drop out of the race in round three due to machine trouble, but then came back to claim a spot on the podium after the finishing 2nd in the next race. In the middle of the season, Nakano was unable to finish near the top due to a string of unfortunate accidents, but he kept adding to his points tally with solid performances including a 3rd in the eighth round in Britain. He finished 4th in round 13 in Australia, and a 2nd in the next race brought him up to 3rd in the ranking. He took a fall during the next race in Rio de Janeiro but was able to restart the race and managed to get a single point by finishing 15th. This unfortunately dropped his ranking to 4th. He managed a 5th in the final round, but this was not good enough to raise his ranking position.