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More stuff. Can't magnify the completed bike picture but do You have 17mm bowl nuts that expose the main jets? Choke lever was different on the 72-73 also. Should look like the red painted one in picture. Also what's Your intent with this? I have a Friend that lives in Asheville that i do his engine rebuilds/carbs/ replating, etc. That's why i had brought it up initially.

More photo stuff, didn't want to load too many pics initially

If this 73 is for sale please give me call. 219-669-5557 cheers

Thanks. What is the purpose of the modification? It looks interesting
My bike is stock apart from the Kerker exhaust. I would probably want to fix whatever is wrong before adding another variable.

No modifications, just pics of things to check. That one carb with the red marker stripe is the path of your air correction passageway to the main jet holder hole. These carbs have a 1mm or #61 twist bit equivalent, brass air correction jet pressed in the casting. Not sure what You are cleaning when you said you've had them off multiple times? But make sure that correction jet and passage is completely clear! A plugged correction jet will make it run rich and erratic. And, like Mikaw suggested, record the Main and Pilot jet sizes and brand type. These carbs, if true 72-73's used a unique taller #20 pilot and 112.5 Main jet originally. Couldn't count how many times i've ran across persons installing some main jets like 135-155 in them. Total misconception of thought, I got me a header, gotta be high performance, so i'll jam the biggest friggin jet i can find in there.   

Thanks all for your help. I finally resolved the issue and it was not carb related. It turns out that I had not properly eliminated the ignition system. I completely replaced the points plate (including points and condensers with a new set that I held as a "spare". Condensers were bad and giving me a weak spark. Of course during the diagnostic process I had induced other unrelated problems and started chasing my tail with those issues too.
All in all quite an embarrassment and another lesson learned the hard way!
On another note..... does anyone have a 78 - 80 clutch release (13231-020) for sale at a reasonable price. The clutch is getting a little heavy for my 70 yo hands.

Just here to help if i can! Check Your posting of heavy handed clutch pull you'd broached later from this original on a different thread topic. Might be informative or insightful.