I have a Aprilia Mille SP, the rear brake frequently grinds to a halt with the piston locking up, espicially when its a hot day? I have tried running the master cyclinder half full down to nearly empty, but this has not cured it. It will only be a matter of time before it locks up instantly to throw me down the road. Please help!!!!!!!!!!!!!!!!!!!!!!!!!

Motorcycles - Aprilia - RSV Mille SP - 2000 Aprilia RSV Mille SP