Since it is a "used motor" that you got your hands on, has anyone suggested to change the bearings? If it's not timimg, or the esc, or rotor, or shimming..nothing else touches anything else to make a noise. I too have been experimenting with everything from timimg to rotors to make this thing faster and nothing has made a noise. Worst case was when I used the green rotor and gave it lots of end bell timing. It cogged and stuttered a bit in the corners but no clicking noise.