I used to own a Polini racing pocket bike which i bought at an auction. Polini is the real stuff not the chinese stuff and man, this thing FLEW.
Rolling from 10km(id wheelie off the line/single gear), i would beat my mates 97 laser to 60km/h (topped out) by 2 lengths...haha...thats pretty fast for a little bike ey?
The reason a turbo kit wont work is because you need EFI, otherwise it just leans out like a bitch. UNLESS, you do what the guys on the nitro car scene do and use the boost pressure to increase fuel pressure, infact, that could actually work. Run a +ve pressure line from the turbo out to the fuel tank to increase the fuel pressure...hmmmm....!! Regardless you would need one SMALL SMALL assed turbo for a 50cc engine. Even a turbo off one of those 600cc cars would be too big. If you had the tools, manufacturing would be the way...
Nos will work no problems, but you will need to tune the thing into mega rich. This wont help the idle out but at least when you hit that button the a/f ratios will remain good...
The best idea would be
-Nos, used to spool the turbo
-Turbo increasing FP
-tuned rich to compensate for turbo and nos
Now that, i could see working.
Sounds like a fun little project really, but quite a lot of fabrication. Custom exhaust manifold, intake, carbby, etc.
BTW, the guy in sydney, i think they installed EFI.