Never had that on my 6r but my 954 gets like that and also R1's and r6's are like that. I think it has something to do with suspension setups.
2002 954RR
2001 ZX6R (stunt bike)
http://home.sc.rr.com/minytrker/bike.htm
2002 954RR
2001 ZX6R (stunt bike)

http://home.sc.rr.com/minytrker/bike.htm