atc70 with 125cc swap

[sstark82]

Ok guys heres the issue....I bought at 79 atc70 a couple weeks back. I dont know the manufacturer but its a pretty strong motor. Anyway, it has a Mikuni 22mm on it. When i got it, she had set up a while but i cleaned the fuel system, carb, lines, etc. When i would go through the gears it would spit and sputter like no fuel was getting to it. I adjustrd the needle valve to go richer and adjusted the fuel mixture a little richer but it was still sputtering at high rpms. I could get to about 3/4 throttle and no more. Today, i went to the local bike shop and bought a 105 main jet, the one it came with was a 100. I installed it, and yes she opens up very well through the gears but when i try to go wide open in 4th gear.....she bogs down again. Initially when i put the new jet in, i put the needle valve back in its original position and it ran terrible. When i put it back on the lowest (richest)setting it ran better. Should i just go to adjusting the air/fuel mixture again? Or buy another larger main jet?

[sstark82]

Here is the motor. Any ideas on who made it?