When I get on the brakes I hear a buzzing sound that sounds like its coming from the l turn signals.. I've tired to hold it down and find out where its coming from but can't seem to isolate it. My nightster didnt do this, but the fat bob that I test rode did.

 

Might be that BEE buzzing around in your helmut. Just kidding, couldnt resist. Noises and leaks can cause one a great deal of grief in trying to isolate them. Be patient , eventually you will succeed in finding this problem. Personally , i cant here anything when im riding. My bike is so loud.

 

front or rear brakes? i had the buzz from a loose license plate clamp.

 

I hear that too sometimes. I think it is the front brake. Doesnt really bother me though.
MikeM

 

I've had several bikes do this. It is coming from the master cylinder. Not sure what causes the sound. I'm guessing its the fluid surging back to the cylinder?

 

Really? I thought maybe it was because of the drilled rotors..... Just a guess though...

 

Normally it's the sound of the pads make from the none solid rotor. With the air space, it's creates a form of high speed farting
Ron

 

That's what I attribute the noise I hear from my Rocker when I apply the front brake.