Seca 650 Defective Carbs?

I'm having tremendous difficulty figuring out why my Seca 650 is running rich. Here's the story:

About a year ago I purchased a Seca 650 with about 10k miles. I already owned another Seca 650 for about 5 years and when I saw another one for sale I bought it because it looked newer and better, ect. I will call my previous Seca 650 Seca "A" and the newer one Seca "B".
While working on the carbs I noticed that the Seca B did not have the original emulsion tubes, jets, slide needles, ect. So I took all the "guts" out of the carbs from Seca A which had all the correct components and transferred them to the new Seca B carbs. I transferred everything by the way. Jets, emulsion tubes, diaphragms, slide needles, floats, everything!
Unfortunately, the Seca B started running extremely rich averaging about 30 mpg. It also boggs down when I crack open the throttle and the rpm's would dip down temporarily when I make a quick stop. So, I took the carbs from the Seca A, transferred the jets and emulsion tubes back from B to A and put the Seca A carbs onto the Seca B. Problem solved and the Seca B runs great.

As an experiment I recently did all the above again and put the Seca B carbs with the Seca A components (original jets, tubes, ect) back on and all the same issues came back. Does anyone have the slightest idea why the Seca B carburetors are giving me all these issues?

 

Including the air jets that are sometimes stubborn to get out, and the two back near the intake boots - I am not sure if those will come out. Anything left in there I would try to measure the size, particularly since you said the carbs had been "tuned" by someone previously.

Maybe another thought is the bowls on Seca B and the enrichment jets. I am not sure what happens if those are enlarged by someone thinking they are cleaning them. The choke lever should shut off fuel flow, but perhaps the seats are not sealing well so closed is not closed.

Did you actually do a colortune when swapping jets, or just set the idle enrichment circuit to the standard 2.5 turns out?

 

I definitely transfered all the air jets. They were no problem getting them out. I transferred the enrichment jets as well. I also made sure the choke plungers are closing properly so no problem there. I have to admit I did not do a colortune. Is it possible that I'm losing that much gas through the idle enrichment circuit. Would that explain the bogging when I crack the throttle open?

 

It is POSSIBLE that they are running way rich….

I wouldn’t be too concerned with the air compensator jets at the intake: it’s 36 for all of those.

But questions:
1. What slide needles are in the carbs?
2. I don’t see anything about checking/adjusting shim clearances?

 

So did you set them to 2.5 turns out from the soft seat? Maybe try them at 1.5 turns and see if bogging improves, or it the idle starts to hang. And if you can or have the opportunity setting the initial turns off the bike make sure the tip extends all the way down into the carb body with the soft seat and that you aren't getting a false bottom.

I am not sure about the first part, but bogging is a symptom of being rich. In your last thread the pictures of the plugs you posted certainly looked rich, but that may have been before you discovered all the non stock parts.

https://www.xjbikes.com/forums/threads/running-rich-not-sure-why.133037/#post-689504

I suppose fuel level comes into play too, even though you are swapping the floats and needles you would need to do a wet check just to be sure you are running the same levels

But are the seats corroded and not sealing?