From Yamaha press release
Yamaha Motor Europe's officially-supported Yamaha Motor Italia squad will switch from the Supersport World Championship and enter a two-rider team in the 2005 Superbike World Championship.
Yamaha's Italian distributor has been one of the most active teams in the history of the Superbike World Championship. Between the inauguration of the series in 1988 and 1994, Yamaha Motor Italia, under its former name of Belgarda, financed and managed its own superbike programme - taking several race wins and regularly finishing in the top five in the series championship. In 1995, when Yamaha decided to make an official entry into the championship it was only natural that the factory team was based at the Yamaha Motor Italia workshops.
Yamaha withdrew from the series at the end of the 2000 season, after Noriyuki Haga finished second in the championship, to concentrate on development for the YZR-M1 MotoGP project and exploring new four-stroke technologies also for the benefit of future production models. Between 2001 and 2004 Yamaha Motor Europe focused its attention to supporting the YZF-R6 entry in the Supersport World Championship.
Yamaha will confirm the rider line-up for its 2005 world superbike campaign at a later date.
Laurens Klein Koerkamp (Yamaha Motor Racing - European Racing Operations manager): "Yamaha Motor Europe felt the time was right to return to world superbike. Our MotoGP programme is now firmly on track and since we last competed the regulations have been changed to allow four-cylinder 1000cc sportsbikes to enter the championship. The R1 is Europe's best selling supersport bike and has already proven its competitiveness in 2004, winning the Endurance World Championship and claiming the top four positions in the European Superstock Championship. We are sure that our return to world superbikes will further reinforce the R1's sporting image."