I promised to report from the Swedish forum about the big bore kits in some other thread.
Apparently people that has changed to 80cc from 50cc have figured out that the original carb is not optimal.
After changing to a Dellorto 17,5 mm the result is supposed to be amazing. After "Cali" changed his carb he wrote: "I created a monster!". He has not tested it properly due to the bad weather over here (-20 C and snow...).
The new carb is a Dellorto 17,5 mm PHVA. PHBN is supposed to fit even better. It cost 551 SKr (40 GBP).
The bigger the carb, the more air and fuel you get into the engine. This is supposed to make a big difference according to the few people that have done it. Those people that have done it so far on the swedish forum has a big bore kit. No one has done it yet with the normal 50 cc engine.
I have not done it. I am just reporting from over here as I promised ;-)
I reckon it would probably be ok, about 10 or more years ago I put the twin webber carb and k+n filter from a 3.0 capri onto my 2.0......seemed like a few more horses under the bonnet, induction noise was great. theoretically your looking at similar................