Re: loose clutch = useless bike
I had this same problem with my bike. I traced it to the small pin, in your first pic. The small ball bearing that this pin engages was wearing a divot into the end of that pin. Every time I would replace that pin the clutch would work like a champ and the bike ran great. After a few miles it would start to do the same thing again.
I bet you're having the same problems I had. I tried everything I know. I hope you find a fix and if you do please post it here.
"I would rather be exposed to the inconveniences attending too much liberty than to those attending too small a degree of it." - Thomas Jefferson