| Another possible slant on the problem. I fitted a slipper for a customer last year that he'd bought off E-Bay.
It was a lot worse than the problems you're having in that it repeatedly lost drive. Pick up was terrible and it took a few hours to suss out.
What was happening was the tangs on the friction plates, at the outer most side of the pack, were catching on the spring steel ring that goes around the circumference of the basket.
When cold, the fit was "snug" but they cleared it and the clutch worked. Once the smallest amount of heat was in the clutch, the plates started rubbing. The other symptom was the clutch lever went all spongy, through there be reduce spring presure from the clutch.
The pack thickness is important, as Shaazam suggests, but if the friction plates are rubbing just a little bit, but the spring pressure is still strong enough to engage the clutch, you won't really notice anything worse than the grinding you're experiencing.
Worth a close check of the basket and outer edges of the tangs for scuffing marks or even light polishing.
A new Surflex clutch pack solved the problem in this case but if your plates are in good condition, maybe a light dressing of the tang edges could solve it.  |