[Odrapnew]

I have a 00 CBR F4 with about 9k miles on it and there is a humming noise coming from the front brakes when I'm going about 20-30mph and apply the brakes. The hotter it is outside, the more it does it. It's not a squeal, like a car, but a deeper pitched hum.

Does anyone know what this is? It's getting annoying and I want it fixed.

Nick

 

[RayOSV]

Sounds like the pads may be vibrating. Check to see if they are seated right (remove and replace them). Also make sure that the pistons move freely. If not that, I think there is some goop that you can (carefullY) put on the backing to help eliminate the vibration.

 

[ca249]

Odrapnew, are you new to sportbikes, or is this particular bike new to you? If the answer to either is yes, then this may be the nature of the beast.

When the brakes are applied heat is generated in the rotors. The holes in the rotors trap air that is heated when the hole pass under/through the pads. When this heated air is released on the other side of the caliper, the expanding air "hisses".

You hear it at about 20-30 mph as you described under heavy braking. Any slower and not enough heat is generated, any faster and the hiss is drowned out by road/wind noise.

 

[Odrapnew]

ca249-Its only going from 20-30 down to zero under light loads; under heavy braking it doesnt do it at all. When the weather is warmer, it does it more often. Its not like in my car when I brake hard, then the brakes squeek for a little while till they cool down.

I bought the bike new in 00, but it started doing this at about 8K miles. I dont know a whole lot about bikes, I'm more of a car guy, but I consider myself knowledgable in the motorvehicle area.
Thanks for the input.
Any other ideas are appreciated

Nick

 

[ca249]

Nick, sorry, from the initial description it sounded like rotor hiss to me. When you do figure it out come back here and let us know what it was. I take an interest in fix-it type problems and attempt to learn from other's experiences. Good luck.

Ray