"The Riding Dead"

[Roughhouse/buddy]

I'm new on MB, so I'd like to intro myself with a current situation. I'm in the grtr Boston area & just before we got buried under all this snow, I found what I believed to be a pretty sweet deal on a 2012 RH 50: the entire bike is in killer condition aside from high miles (about 10k)&the fact that despite starting right up effortlessly... There's no compression. Won't go much over 10-15mph & it takes about 1/4 mile to get there.
I've got a 12' Buddy 50 as well & it's unstoppable.
I'm guessing it's probably time for a top end replacement.... Any opinionz/advice despite the limited info? It's time to dig them out & I'm dying to reanimate the new toy. I bought a Prima exhaust & (deal was too good to pass up) & would prefer putting it on the RH. I found a new stock 50cc top end for $50(havnt bought it yet.... Pending some feedback hopefully). Cash is tight .... can the Prima work w/out a bbk? Am I possibly correct in the piston/cylinder diagnosis? Any info is great any fellow Bostonians w/hands-on experience are welcome to reach out.
Btw, I paid $100 for the RH..... Really. So i think it's well worth ressurecting. If a recording of the bike starting, running etc. is helpful... I can make one as soon as i dig out. Thanks, J.