Round 4 of the 1990 500 World Road Racing Championship at Misano. Wayne Gardner (Honda) was handicapped by two cracked ribs, Wayne Rainey (Yamaha) made a rocket start from pole position but didn't like the rain and Kevin Schwantz (Suzuki) seemed happier at taking the odd risk than the championship leader. Mick Doohan (Honda) gave a sparkling performance as did Phillipe Ruggia. Gutsy Brit Niall Mackenzie rode strongly while Randy Mamola won admiration too despite a still healing wrist. The 250 class event saw John Kocinski take the lead from pole with rivals Luca Cadalora, Jochen Schmid and Helmut Bradl in hot pursuit in what proved to be an action-packed event.