You are missundertoding the terms. The F1 and GP are completely different. One thing is the F1 (U.S. Natonional Championship??) and other thing is the World Road Racing Championship, called this season MotoGP, (two years before was known as GP500), in the MotoGP Championship there wasn't be any F1 class, and never had 750cc bikes, in the history of this Championship the only classes were 50cc, 80cc, 125cc, 250cc, 350cc, and 500cc.
MotoGP is the most prestigious Motorcycle Championship in the World.
MotoGP has no relations with FIA/Bernie Ecclestone show, the MotoGP Championship is promoted by DORNA Promociones del Deporte, a Spanish company. FIA and FIM are two different international federations, with no relations between they.
If you want to know about the MotoGP Regulations, and about the participation onit of the four stroke bikes (maximun of 990cc, not 1000cc) visit
http://www.500motogp.com/ENG and click the following links:
2000 MotoGP Rules
2002 4 stroke rules 2002