In 1994 and 1998 he was in the 125 cc class of the Motorcycle World Championship World Champion Aprilia.
Kazuto Sakata began his career in the Japanese 125 cc Championship, which he won in 1990. In the motorcycle world championship he made his debut only in the relatively high age of 25, in 1991 ³ on a Honda in the class at the Grand Prix of Japan to 125 cm. The first time attention to himself he made then at the last race of the season, the Malaysian Grand Prix when he imports the pole position, and later was second in the race behind world champion Loris Capirossi. In the overall classification, he finished with 55 points to 13th place.
The following season it ran for Sakata less promising, despite three pole positions he could not retract the podium and finished with 42 points 14th place overall. Therefore, he thought at the end of the season in mind to withdraw from the World Cup again.
For the 1993 season Sakata went but at the start, turn on Honda, and yet he did not live to world champion, was the most successful season of his career. After three second-place finishes for the season opener him his first win was the fourth race of the season, the Grand Prix of Spain, just before the German Ralf Waldmann, ever. At the race in Brno later, even his second. The Japanese came this year in all 14 races to the finish, went 13 times to the podium and 14 points behind his teammate Dirk Raudies Vice World Champion.
Despite the very successful season on Honda to Sakata decided to go to the 1994 season to Aprilia. Already in his first year for the Italian manufacturer, he was able to win the world title. With three victories, eight podiums and seven pole positions, he won superior with 30 points ahead of his compatriot Noboru Ueda.
In the following season, it was enough for Kazuto Sakata with two wins, but 74 points behind World Champion Haruchika Aoki yet for the World Championship. In the 1996 season he scored just two third places and he took knocked off the eighth place overall. In 1997, it went for Sakata then ascend again, he could go on the podium seven times and made the fourth world rank.
In the 1998 season, Sakata was then able to win his second world title on Aprilia team UGT 3000. After the World Cup last year, Valentino Rossi, was changed in the 250 cc class, he started immediately with a victory at his home Grand Prix in the season. In the first part of the season he won a total of four races, second in his performance to be a little to and its closest competitor, compatriot Tomomi Manako came to him in the overall standings still dangerously close. Ultimately Sakata managed to save a lead of twelve points for his second 125cc title to the finish.
For the 1999 season, Kazuto Sakata then switched back to Honda and started for the MTP team of Paolo Pileri, the 125cc world champion in 1975. He did not make it this year, but only once to the podium, his best result was a seventh place in the Grand Prix of Catalonia. Sakata finally finished with only 56 points a disappointing 14th place in the standings and finished his career then.
Overall, Kazuto Sakata played in his career, 107 125 cc Grand Prix, which he won eleven. He ran 41 times onto the podium, won 29 pole positions and 29 fastest laps.