4500rpm vibration

the bike has developed a noisey vibration at 4500rpm , you can play at tune with the sound it makes by riding at 4500rpm , sounds like it coming from the front but i've removed the nose cone and all the plastics and checked for something loose but nothing obvious found. At first i thought it might be the radiator cover making the sound but i removed it and still makes the sound. Anyone had a similar prob with there 08-10 zx10 , ive spent 3 nights on it trying to find it with no luck , any ideas?