Hi, I'm thinking of doing the same. I have a skipper engine also i want to fit with 172. I think i know how to mount it but i want to ask if you have any other advice. I know to swap wire loom etc. Any help or advice would be good to know. I also know to extend the rear shock.
Use a piaggio zip 4 stroke 50cc wiring loom use a 2 stroke subframe turn it around grind the sides a little bit and it should work if you need more help i can link you a video