There have been a lot of questions about tires "Humming" on the Busa's front over the years. I have heard it on mine, off and on, with the stock tires, Michelin Pilot Road when they first came out and the M1's which I have used about three sets of. I have the new M3's on it now and no hum. I think it is a characteristic of the bike to have the tire humm under certain conditions, since it does not do it on all bikes, and off and on with others like mine. I have cut off the motor and coasted in neutral down hills, turning the wheel, using the brake and varying the speed and when it is in the humm mode it does it under all conditions, more when the wheel is turned. For my bike, I think it is the wear pattern of lack of same that influences it. I've checked the bearings, fork tension on the legs being equal, alignment and all that I could think of and nothing makes any difference. No humm on the m3's yet, got 1000 on them now.