I have a Moki 120 that I have been trying to get to run properly.
It starts and idles good runs at full throttle OK but it sputters or cuts in the midrange transistion.
I have replaced the 0 rings in the carb and have played with the low end adjustment it seems to run better at a one point. It will transition if you don't let it idle for more than a few seconds.
I have the needle set at two turns out. I did notice the front bearing has a little play. I am wondring if it may be drawing air through the front and leaning the mixture.