Anyone tried one of the Nibbi carbs ? Hoping it will be an improvement on the old Mikuni  

In my experience dont buy the chinese carburetors. They may "fit" but they are so far out of adjustment that you need to replace all the jets and even the slide needle. The problem is the thread pitch for the jets (in my experience) are a different pitch than the Mikunis. All i have is Mikuni carbs and jets so it would have been a guessing game trying other carburetor brands to figure out which ones would screw in. All the kits i looked at never said what the thread pitch was only the sizing. I tried it once and i said never again, waste of time and money.

Appologies 'Enduro Nut' i know i shouldn't stir the pot but just my personal experience so don't follow my advice unless you don't mind problems.
i've had no problems with 3 or so carbs for various bikes but 'yes' had to adapt a mikuni jet in one.
AT1/with 175 Reed topend. I'll see if i can find a short video. Not a NIbbi Carb & they look better than what i bought.
photos.app.goo.gl/RLph91m1bdsyhZxU6

Don't be afraid by looking at all the jets on the floor haha.
Only needed a smaller main than what it came with.
Mind you pilot jet is probably a different story but mine was ok as is for pilot & needle.
Just my experience. Used one on a kids 4 wheeler 50 twostroke & on a honda XL185 4 stroke with no jetting required.
I've seen more expensive but still cheapy carbs up there on Aliexpress with a range of pilot & main jets supplied.
Personaly for the price i coulddn't stop myself.

Had it not been for the different thread pitches I'm confident I could have gotten mine to work. Mine was for a 73 CT175. Well I shouldn't say it didn't work because it did but talk about flooding to death and that was without the air filter on. There wasn't much I could do unless i wanted to start buying random jets which i could have easily spent more on the jets then what i did for the carb. I prefer to dig in the bins at the swap meets for an original. You can buy them in pretty good shape for under $20. I ended up bringing 2 home from mid Ohio for that bike.
I just haven't had good experiences overall dealing with stuff from china. Im at the point now where i would rather spend a few extra dollars to get what i know will work vs taking a gamble on having to mess with it for several more days because what i bought isnt working. But thats just me and my experience.

 I ended up bringing 2 home from mid Ohio for that bike
So you're the reason I couldn't find a carb for my CT2 up there! LOL D