So with the clutch lever all the way out, you can go down to the clutch arm on the engine and wiggle the exposed cable and feel the slack? I have always used stock clutch disks. I have a stack of friction disk from various parts bikes. I also seem to be pulling my clutch apart regularly for what ever reason. I visually examine them and replace the ones that are worn. Always seems that there is one disk that is worn and the others are not. THe worn one will have the little friction squares worn down. Replace that one, and have never had clutch slip.