1987

From this season, the race start procedure was changed from push-starting to a green light signal start with the riders line up on the grid with their engines running. This was also the first season with Japanese round for the GP500cc series. In the 15-round series, Randy Mamola of Team Lucky Strike Roberts finished 2nd and Eddie Lawson of the Yamaha Marlboro Team finished 3rd in the season ranking. With these results, Yamaha won its second consecutive manufacturer's title.

In the season opener at Suzuka in Japan, Mamola showcased his skills as the wet-condition specialist won the race. In the 13th round in San Marino he won the race in completely opposite conditions under a scorching sun. Mamola was well positioned in the title race towards the end of the season thanks to his consistent riding regardless of track conditions. He scored points in all but one race. By contrast, the defending champion Lawson slid his bike wide and off the track in the opening round to end up with a no-pointer. Despite getting back into the championship hunt by finishing 2nd in the following Spanish GP and winning the third round in West Germany, he was unable to win a second straight championship title, as he missed out on valuable points in Austria and France. Tadahiko Taira, who for the first time entered the full season in the 500cc class from the Yamaha Marlboro Team, held off Lawson and maintained 2nd place until lap 11 of the race at Brno. He dropped to 3rd towards the end of the race, but held off his rivals and mounted the winner's podium for the first time in the 500cc class.

In the 250cc class, Yamaha, Honda, and Aprilia were in the mix for the championship fight. Yamaha's YZR250 was ridden by Carlos Lavado (Venezuela) from the Venemotos Team, Martin Wimmer (West Germany) and Luca Cadalora (Italy) from the Yamaha Marlboro Team, Juan Garriga (Spain) from the SESMA Team and Patrick Igoa from the Sonauto Team.
In the second round in Spain, Yamaha riders Wimmer, Cadalora and Garriga swept the podium and another Yamaha rider, Igoa, finished 5th to prove the potential of the Yamaha machine. However, poor results followed due to bad luck, despite gaining pole position in some races. Lavado, who returned to racing from the sixth round in Yugoslavia after his injury in the opening round, took his first win of the season there. He would have to sit out races again, however, after breaking his collarbone towards the end of the season, which he finished 10th in the ranking. Honda dominated the top of the championship ranking and the highest ranked Yamaha rider was Cadalora in 7th place.