Thanks for the reply. It just has to be for a 15mm carb opening correct?

I have look at my X12 after the sunday race.....high end needle is 5 turns out from closing, and low end needle is 3.5 turns from closing.

Temp was 200 after 5 minutes of running............still, the engine sounds TOO COLD for me, but the speed is right there, may be I can lean the top end 1/2 turn in or so....

Correct.....usually, look for something like 1/8th 3.5 engine use filter cause X12 carb intake neck is the same as the 1/8th engine (I think that is correct, right...?)

There are only 2 types that I am know of...the OS small type and the Nova Rossi type.