My experience thus far;
1. Carb jet fell into reservoir bowl, bike wouldn't run without choke. Open that, tighten it down
2. Pinion gear (small gear next to big gear) flat head bolt came loose and chewed up woodruff key, installed a crush washer and used impact drill to mount it
3. Throttle got stuck wide open because bracket to intake was too tight, loosened that and all is well
4. Bolts on the head, one was missing a washer so added that and tightened back down
That's all so far, it's always something, I'm sure I'll be posting again soon.
Shout out to all the people on here, I really appreciate all your help