My riding pal has a kona kikapu with hayes 9s 180mm fitted.The rear brakes click continually!!! He has checked the rotor for straightness and allignment, centred the pads and de-glazed them, alligned the caliper and made sure the retaining clips are working and clear of the rotor. It dont do it when on the stand or upside down.It only does it when there`s weight on it! any ideas would be more than welcome…….

Loose hub cones, or worn rear suspension pivots are both likely culprits.