Grand Prix motorcycle racing refers to the premier category of motorcycle road racing. It is divided into three distinct classes: 125 cc, 250 cc and 800 cc MotoGP. Grand prix motorcycles are prototype machines not based on any production motorcycle. Dorna Sports, MotoGP’s parent company, has announced that the 250 cc class will be replaced with a 600 cc class as early as 2009.MotoGP, the premier class of GP motorcycle racing, has changed dramatically in recent years. From the mid-1970s until 2002 the top class of GP racing allowed 500cc with a maximum of 4 cylinders, regardless of whether the engine was a two-stroke or four-stroke. A Road Racing World Championship Grand Prix was first organized by the Fédération Internationale de Motocyclisme (FIM) in 1949. The commercial rights are owned by Dorna Sports. Teams are represented by the International Road Racing Teams Association (IRTA) and manufacturers by the Motorcycle Sport Manufacturers Association (MSMA).Superbike racing is a category of motorcycle road racing that employs modified production motorcycles. Superbike racing motorcycles must have four stroke engines of between 800 cc and 1200 cc for twins, and between 750 cc and 1000 cc for four cylinder machines. The motorcycles must maintain the same profile as their roadgoing counterparts. The overall appearance, seen from the front, rear and sides, must correspond to that of the bike homologated for use on public roads. By the 1970s, two-strokes completely eclipsed the four-strokes in all classes. In 1979, Honda made an attempt to return the four-stroke to the top class with the NR500, but this project failed, and in 1983, even Honda was winning with a two-stroke 500. The 50cc class was replaced by an 80cc class, then the class was dropped entirely in the 1990s, after being dominated primarily by Spanish and Italian makes.