I recently had an issue with the bike started misfiring at 4000 rpm stumble and no power.....Thought it was a Ignition module issue at the time... I went out one day and went full throttle it started missing again then cleaned out and went to redline.... So I decided it was a carb issue. So I rebuilt the carb its not my first one so I know my way around S&S carbs ... However now I get a pop/backfire between 1,2,3 shift very mild but annoying had a couple sneezing threw the carb too very very rarely. Now I set the mixture screw with tuning tach so I know it theoretically correct..... the float level is correct too any thoughts 97 FLHR ,,, Screaming Eagle heads ,EV27 cam, S&S Super E, Thunder Header pipe

 

What jets are installed?

 

well I'm not sure there I had a Harley shop convert my bike from Fuel injection to carb years ago around 20 years it ran perfect then so I wasn't concerned about messing with the jets nothing else been changed.... The bike runs even better than before, now just that annoying pop... BTW it pops when I let off of the throttle to shift not under load

 

What's the idle mixture screw at? It's nothing to take the bowl down and record what jets are in it... It's pretty essential for us to know what you have in it if we're to help you..

 

So gentleman, let me chime in a little information. so lets think of the carburetor as a unit to hold and disburse fuel and air mixture into the engine via the venture area, thru using different delivery circuits,
- you have your idle circuit,
-you have your low speed circuit
-you have the half throttle circuits
-you have wide open throttle
-you have enrichment circuit
-you have accelerator pump circuit in 5 circuit types of carburetors basic theory
.... So there are different types of carburetors 5 circuit and 7 circuit and there are other configurations. but for conversation sake lets keep it simple. flat slide uses 7-8 circuits and s&S use 5 circuit

now that we have some under standing when the circuit is operational at certain throttle opening we can now determine the circuit that is the cause of the failure in the area which the failure occurs.
-- I hope that the information is enough to have an idea what is happening at your concern speed.