I've searched for help on this but haven't found anything yet.

My 12A with 45 DCOE has a problem that makes it really annoying to drive on the street. It is fine under acceleration but under light throttle (like trying to maintain a constant speed) it kind of hesitates and lurches a little bit.

Would this be a problem with my idle circuit? Too rich or too lean? Or is my timing off or something? I really don't know. I read the idle jets are in control 80% of the time, and the progression circuit utilizes the idle jets.

Any thoughts?

 

Start with smaller idle jet.

 

Here's my current jetting:
Idle Jets: 65f8
Main Jets: 180
Air Correction Jets: 170 (from previous posts, this seems way off)
Emulsion Tube: F7 (also incorrect?)
Needle and seat: 300
pump jet: 45
chokes: 38

So, when you say smaller idle jet, would that be like a 60 f9 or what would you suggest? I wanna order some jets pretty soon to start trying to dial this slug in.

Thanks for the help.

 

I have a Mikuni 44 carb that has been jetted too large for my application and I have the same problem. Might try smaller jets like previously said. Sometimes it cant be helped with a larger carb, if you do fix the low rpm hesitation you will more than likely cause problems or power loss elsewhere. Mine jetted the way it is, is made for best mid to top endp ower, so I live with the low end studders for now