1998

Norifumi Abe and Jean-Michel Bayle from Yamaha Team Rainey, and Simon Crafar and Regis Laconi from Red Bull Yamaha WCM all competed this season on the YZR500. While the Honda team took the majority of the wins, Yamaha riders Abe, Crafar and Laconi finished the season ranked 6th, 7th and 10th respectively, with Yamaha's the only win coming from Crafar.

Bayle, injured in pre-season testing, sat out the first half of the season. Substituting for Bayle, was Yamaha's development rider Kyoji Nanba, who raced in the opening round in Japan. Noriyuki Haga also raced as a wildcard. These three Japanese riders, including Abe, raced on their home ground on the YZR500. Abe made contact with another rider and finished 14th, but Haga finished 3rd and Nanba also put on a good show to finish 5th. In the sixth round in Madrid, Abe finished 2nd, just two tenths of a second behind Carlos Checa (Honda). He also took 3rd-place finishes in round eight in Britain and round 12 in Catalunya. Abe rode well as the ace of the Yamaha factory team with consistent results all season. One of the highlights was a 4th-place finish in the final round after starting from 17th position on the grid.

Crafar took some time to adjust from Superbike in the early stages, but he finished 3rd in the seventh round in the Netherlands, and followed that with a pole position in the next GP in Britain. He fought equally with Abe and Mick Doohan (Honda) in this round, recording the fastest lap of the race to take the lead and grab his first-ever GP win. This was the first win for Yamaha in 22 races, since the final round of the 1996 season. Crafar also finished 2nd in the 13th round in Australia.

After racing in the Japanese GP, Namba competed in rounds two to four, and in round nine. Despite eventually having to drop out of the race, he led in the early stages of the race in round two in Malaysia. In this race, Norihiko Fujiwara entered the race from the BP Yamaha Racing team and finished 7th. Luca Cadalora substituted for the injured Bayle in rounds five and six in France and Madrid, and he also managed to finish 6th in France. Bayle returned to racing from round 10 in the Czech Republic. He went on to take the pole position and a 5th-place finish in round 11 in Imola, but his long absence meant that he was only able to finish the season ranked 16th. Laconi injured himself in the free practice run of the Japanese GP and missed the first few races. He returned in the third round in Spain, where he finished 5th, and from there he finished inside the points in all races.

Yamaha factory teams did not participate this season, but the YZR250 was brought in for the opening round in Japan and in the 13th round in Australia. In the Japanese GP, Shinya Nakano from the BP Yamaha Racing team, and Naoki Matsudo from the YESS Racing team competed as wild cards. There was a three-way battle for the lead between the two Yamaha riders and Daijiro Kato (Honda). Kato ended up winning the race with Nakano in 2nd in the first GP start of his career, and Matsudo 3rd. After clinching the Japanese 250cc championship, Nakano raced in the Australian GP held in October. He took 3rd in qualifying, and finished 4th in the race. Takeshi Tsujimura, who entered the series on the production racer TZ250, scored series points in all races to finish the season ranked 8th. This made him the top-ranked Yamaha rider of the season. The champion this year was Luis Capirossi (Aprilia), followed by Valentino Rossi (Aprilia).