Scooterotica

Having problems with my Cosa clutch, as far as I know its the original that was fitted on my p2,its a 2001 lump. The guy I got it off fitted new plates and corks and had only done about 300 miles when I got it and I found it had clutch drag. I fitted new Newfren plates, corks and springs and it seemed ok but only had clutch bite quite far out. It had seemed ok on short runs but the other day 2 up after about a 10 mile run it had the same problem and would not disengage properly but worked fine on return run. I have measured the basket and it seems to be about 20 m.m. deep, no burrs or damage am I right in thinking after market kits are thicker and it will need taking out to around 21 m.m. Thanks in advance.