Not sure what fixed it, ...Feels like ... I added 50 more Horsepower or something.
Its all all of the above, and you did a lot of other good things before, while trying to debug the problem, which helped more once you got the fuel/air mixture right.
Had to laugh about adding 50HP, its a 40HP engine so that is about right, before it was sucking all the energy out of you
now its giving it back
I use to fly R/C gas airplanes. The engine had a screw main jet that you cranked out half a turn to get it rich to start, then with the prop spinning (engine loaded) you slowly turned that screw in, and when you hit the correct fuel/air ratio that little 1/4 HP engine wound up like a giant angry bee.
An engine will start and run with the fuel/air mixture way off... barely... but when you get it right then you got some power.
Dont know if I mentioned before, the peak HP curve on a 650 maxes at 55 in 4th gear, and 75 in 5th gear. Most people think these engines should sound like a HD, and tend to shift too soon. Try it on your next ride on the open road - WFO at 55mph in 4th gear the air intake box growls with glee, then again at 75 mph in 5th. The engine has a rev limiter, so as long as you dont down shift too soon and let the clutch out you will not red line the bike.
Those hose clamps in the air box to the top of the carbs are a PITA. Spent half an hour on mine once getting it to stay seated, almost like the top of the carbs are tapered, and when you tighten the clamp its like squeezing a bar of soap. Maybe wiping the top of the carbs, and the inside lip of the air box with 90% Isopropal alcohol might clean all the oil off so they will get a good grip on each other.