19 or 26mm carb?

That 19mm carb should be big enough for a 50cc, my 110cc came w/ the 19mm I put a 26 Mikuni, way to big. Try rejeting the main jet one size bigger. These have a pilot jet next to the main that comes out, its long, and clogs real easy, bike won't run right if its clogged.

i like to keep the carb close to the intake valve size, that motor is 23mm i think, so a 22mm carb is the biggest id put there
agree on the 19mm for you

Thanks. I thought the 26 might be a little too much, and that thought has been confirmed. Are their any good and cheap power mods to do to this engine? I don't want to spend a ton, because I think I'm just going to restore this thing to better than new condition, and then try and find a good used 110cc super pocket bike. This 50cc one is going to be a great trainer for riding and working on, but I plan on relegating it to a "for my friends to ride" bike.

you could get this 88cc kit
http://tboltusa.com/store/tb-88cc-big-bore-kit-br-fits-honda-crf70-engines-p-32.html

Blitz, nice kit, the best part is the alum cyld and high compression piston. That would make a big difference, might want to think about a high lift-duration cam also.

33 more cc and high comp should be close to double hp

Thanks for the tips guys. That engine mod looks sweet. With that and a cam, maybe a couple of other little things, maybe I'll get it to go fast enough that I don't need to buy a 110cc bike.

that 88 will burn that 110 up
i saw a very expensive 88 with a very good rider make people look like amatures at vir

Good to know. Sounds like I'm going to love it! Now, to get cash around, and the time to do everything...