Originally Posted by dunlop0_1
The hydraulic movement of the push-rod/cylinder should not alter as it is fixed. If anything wear or air in the system would create less movement. Sounds more like the stack is incorrect/rusty/dirty or has too many plates. Possible drum issue so It really needs a complete strip down.
Stack height is correct as spec 38mm (Haynes) and its quite new. The issue only came about when I fitted a lever with a greater span adjustment and could pull it back to the bar further. This translated into more clutch movement and off popped the plate. I have an Oberon slave fitted so maybe this allows more piston movement and hence more rod movement..