Moped Army

I just read something about this in another thread but I want to avoid jacking it. I have done e50 clutch mods a handful of times without incident, but I cannot get this one to engage. It's a cheapo 3-shoe, lightened to 63 grams per shoe, and with paz springs. I have tried it tightened in many positions and I am pretty good at using feel to know when it will engage (I can't even get this one to engage at all with the screws backed out all the way to flush with the edge of the plate).

Anyway, it doesn't have a wood ruff key slot. Is it possible that the clutch is slipping on the crank?