When you put the helix on the clutch you have to "clock" or pre wind the spring and by this I mean you set the spring in the holes you want,you said 3 and 3,so once that's done you twist the helix clockwise until the 3 bolts in the secondary sheave line up with the holes in the helix.This gives the spring a pre tension and this might be what your lacking if it's opening up but not closing itself back up.Other than that check the bushings,there's one in the helix and one in secondary sheave.These are steel bushings with a teflon (I think ) coating on them and if the coating is wore off they will stick open because you will have steel on steel,not good.I have a helix bushing do this once,the clutch would up shift but when I slowed down it wouldn't backshift.I had to lift the hood and hit the clutch to get it to close back up.