1981 Grand Prix motorcycle racing season developed in the 1950s, to aluminium frames featuring large, twin beams as first pioneered by Spanish constructor, Antonio Cobas. The following Grands Prix were scheduled to take place in 1981: Points are awarded to the top ten finishers. A rider has to finish the race to earn points. 1981 Grand Prix motorcycle racing season The 1981 Grand Prix motorcycle racing season was the 33rd F.I.M. Road Racing World Championship season. Suzuki riders Marco Lucchinelli and Randy Mamola battled it out to the final race of the season with the Italian rider claiming the crown and Mamola finishing runner-up for the
2013 Grand Prix motorcycle racing season at Estoril since 2000. The United States hosted three races, the other two being the United States Grand Prix at Mazda Raceway Laguna Seca and the Indianapolis Grand Prix at the Indianapolis Motor Speedway. Points are awarded to the top fifteen finishers. A rider has to finish the race to earn points. Points are awarded to the top fifteen finishers. A rider has to finish the race to earn points. Points are awarded to the top fifteen finishers. A rider has to finish the race to earn points. Points are awarded to the top fifteen finishers. A rider has to