Anyone know much about lock-up clutches?

[T0MMY]

Asked this on locost builders but thought I'd check here too as it's quite specific knowledge.

I have a barnett lock up clutch in my Vortx's R1 engine and I'm just trying to get to the bottom of why the clutch is nearly unusable!

Basically you can pull away VERY slowly at idle but if you give it almost any revs it seems to lock up violently and stall, unless you give it so many revs it wheelspins off the line.

I guess the problem could be wear on the clutch basket so the plates get caught as they slide on the arms but I'm also wondering if there's something wrong with the lock up mechanism. At what sort of revs should it start increasing the clamping force significantly? I was thinking if it's over-weighted could it be clamping the clutch too tightly at low revs (like 3000 or so as you might use for gently pulling away)?

Anyone else using these clutches without an issue? From a thread from the previous owner it seems it may have especially strong springs in it too but as the pedal action is light enough to modulate easily I don't see that being the issue.