This is what I came up with:
Installed 2 into 1 exhaust.
Installed large volume intake
Installed dynatec 2000i
Installed ev23 andrews cam
Installed quickee pushrods
installed S&S lifters

Went by all the paperwork as far as recomendations as far as boosting the cv. Dont do it.

Pulled the cv and tore it down.
sonic cleaned the carb.
Replaced all diaphragm's and gaskets. Here is where I went wrong.
Replaced needle with the upgraded needle and added 1 washer.
replaced jets from a 190 main to 185 main
replaced slow jet from a 42 to first a 45 then a 48.
Put carb back together. Sneezing and exhaust back fire on decel.
Pulled carb again trying different jets to no cure.
Final install.
put the original needle in without the washer.
185 main, 48 slow jet.
Before installing the carb I replaced all intake gaskets.
installed the carb I made sure that it was fully pushed into the intake.
Then while installing the intake filter I bolted the plate into the cv bolt holes and torqed it in. This is where it got interesting. The plate was 1/4 inch awy from the carb. When you bolted up the intake filter to the carb it was pulling the carb out from the intake. Hence the sneezing out the carb. Fabricated a spacer for the plate to carb and bolted it all up.
I must have pulled that carb 20 times changing jets and needle to tune this sucker.
Final:
Original spring and needle.
jets from 190 to 185, 42 to 48.
Made sure the timing was right on.
Idle set at 800 rpm.
Air fuel mixture set at 1.5 turns. Now to do the plug read next. I was told a 48 is to big to go to a 46. I have to agree because of how low the air mixer srew is in.
Bike doesn't sneeze anymore. No more backfiring. Bike runs great.
I guess when you do a stage 2 make it simple. Dont believe everything you read. The andrews sight said to go to 190, 48 but I tried to “super tune” the carb, nope dont do it. Keep it simple stupid.

Hope this helps.

first time fatboy owner, never even seen a cv carb till now

 

I know exactly what you went through. Been there and done that. Glad it's all worked out and thanks for the update.

 

What year was it again? 800 rpm's is a bit low unless you have a shovel or pan and older.

 

1995 Fatboy. The cam I put in was a ev27 not 23. The air intake was a Roland Sands turbo air intake. I just brought the rpm up to 850. The book says 900 to 1050 Idle but the lower rpm sounds better. The one thing that I still want to check is bringing it up to spec on rpm. I understand that that allows more fuel in on the low circuit so we will see, maybe better throttle response? Main issue with lower rpm was oil pressure. My buddy has the same motor on his classic 93 and the place he takes it to set them up at 600 rpm to get the P A T A T O out the exhaust. Oil pressure on his was good but he has things done to his that we aren't fully aware of maybe a high volume pump he doesn't know. Going to put a gauge on her to see what I have for pressure. Thanks to all.