All you do is change the stator, pick up, coil, cdi, and regulator, wiring may need to be spliced or use the wiring harness from the donor bike.
Its actually really easy. Youll find that the plugs are not the same but the wiring is all there and you just have to splice them.
When changing from the 50cc 1e40qmb to the 90cc 1e50qmf I got to have fun with dc to ac conversion. I could have just changed out stator to the ac bike but screw that its ore fun dc! actually I dont notice a difference ha.