We need to get Deejay on the case. My concern is that your thrust bearing (a ball race inside the clutch) may have failed, which could be the source of the heat which has melted the plastic thrust pad. However the whole clutch needs to be assembled and adjusted strictly in accordance with the SB instructions, or expensive damage may occur (SB parts are not all that cheap). Because you have had a problem with it, I think the clutch will need to be disassembled, inspected, and set up correctly. Deejay has experience with that, including rebuilding his own clutch in detail just a few weeks ago.
