Shinya Nakano
In 2003, the engine went from carburetion to fuel injection, and the engine brake control system was replaced with an Idle Control System that automatically adjusted the throttle valve opening on two of the four cylinders to improve stability and handling during deceleration. M1 riders were Checa, Alex Barros, Olivier Jacque, Marco Melandri, Shinya Nakano and Norifumi Abe, and there were no wins and Yamaha came in third in the manufacturers' championship.