By chance, did you make sure to replace those stock, aluminum, top and bottom gasket seals with re-usable copper replacement gaskets when re-assembling the cylinder/head unit???
That could explain a lot if its unable to hold compression...DAMIEN
Also...Why was it necessary to disassemble and reassemble the cylinder, I dont believe this was mentioned by you in this posting as possibly relating to your problem/question about clutch and clutch pads and reasons for riding the clutch, and might have a very real bearing on what your actual problems truly are.