I would suggest checking the plates and the fiber discs. You said they are good. But did you use a micrometer and compare them to spec in your manual? Every time I burned up a clutch in my CR125, is was always because I had word the plates and discs. Replaced them and it was good to go again. Also, make sure you don't have any plates or discs out of order. There should be a fiber disc on the inner most and outer most parts of the hub. And make sure you have you clutch cable tension set right. Should be a couple millimeters of free play at the clutch lever. A good rule of thumb, is you should be able to fit a nickle in between the lever and clutch perch before it actually pulls on the cable. Good luck!