Very close, but still doesnt seem right

I just finished a engine rebuild on 77 kz650. Cleaned the carbs, put larger jets for 4-1 pipe, and k&n filter. I also did the bench sync.
The bike starts up fine, warms up with the choke, just like it should. Then, once it is warm enough to idle smoothly with no choke, Im ready to take off. But when I engage the clutch it will just bog down and die unless I rev it way up.
But here's the thing. If I rev it enough to get it moving, It will get going. Then take it around the neighborhood. Go through the gears, maybe ride it around a mile or two, It will settle back down to nice idle, and pull away just fine.

Is it just now warm enough??
It doesnt seem likely since it idles fine w/ no choke.

Maybe jets are too big? I went up two sizes on the mains. I think that I left the pilots stock.
Maybe need to go up on the pilots?
Is this a symptom of too rich, or too lean.

Plugs look black and dry.

thanks in advance for any ideas.

Doing the engine rebuild did you check compression? Valve clearances? How about verifying the timing is correct (with a timing light)? These three things need to be done (in that order) before trying to get carbs dialed in or you'll likely beat yourself silly trying to get the carbs right when the carbs aren't really the issue.

Sorry for skipping some details. Compression is good in all four. It should be with new pistons, rings, and a bore job. Valve clearance is good. Timing has also been adjusted.
These items seem true also because once I ride it around a bit (and my guess is completely warm) It runs quite well. Accelleration is good, no backfires or popping. Seems to run real sweet.
Just when it first starts up. But warm enough enough to idle nicely w/o choke.

Really just wondering if this is obvious symptom of the jetting changes or pilot settings?