This might sound crazy as hell but I have a good friend that races 600 and 750 for team Suzuki. And while everything that he has told me so far have been correct I must admit that I am very apprehensive about trying this on my bike (maybe one of his seven practice bikes but not by busa!)
Basically he says (not sure of the technique but will ask him this weekend) that you can be in a sweeper and apply enough rear brake to cause the back wheel to slide allowing you do to do tighter turns at high speeds.
He also says that you must get on the gas after the slide to counter the slide and force the bike forward as its inertia is pulling differently than the direction of the bike.
(Sort of how dirt track racers turn except on asphalt and doing 100+ mph)
I dont recommend trying this unless you have a disposable bike, full leathers and hotnuts of steel!