During a race a couple of weeks I was a bit overenthusiastic with the clutch and it started to slip. I stripped it down and all seemed to be OK so I put it back together, with an oil and filter change to be on the safe side. Tested it and again it was fine - no problems. However, racing this weekend, a couple of hours in to the event the clutch started to rattle when engaging. It was OK when fully engaged and OK when fully disengaged, but when feeding it/slipping it, it would rattle. Considering it just started happening (ie not there one minute, then it was - I don't think it's just wear and tear). I'm going to strip it down tonight to have a look, but has anyone got any pointers as to what the problem might be?