Runaway idle but sooty plugs???!

Got a color tune kit. Now it'll be easy right?

Not really. Get it so the color just gets right, too much it will be too lean and won't run for SHT. Takes a little trial and error.
Steve

Got the colortune and have played a bit but doesn't make sense. The idle is lumpy and erratic. Colortune shows orange/rich when choke is on but then when choke is turned off the idle slows, flame turns mostly blue with the occasional yellow flicker but then the bike dies. Put in the tiniest pilot jet I had, a #15, still going off the assumption I'm running too rich. Didn't seem to change a darn thing. color tune still giving me the blue at idle, but once I blip the throttle that idle drops and bike chokes out. Often when it dies I get a big gassy pop back through the carb.
Been on a few mile ride with the thing and it's great when its got some throttle behind it, but when I head down a hill and am engine braking, I can feel the surging and irregularity of the engine and once I pull up to the stop it will eventually choke and die at idle.
I finally got a timing light and confirmed yes indeed the timing is good!

Help!

Could be too lean or valve adjustment or both.
Steve

Hey guys I'm back. I know jetting is a long tedious process but I can't even get the thing to Idle!!!

Been trying a lot of things and while its better, it's still mystifying me!
Fixed the runaway idle (was a sticky throttle cable like you guys guessed!)

I checked the valves again and they are quiet at .15mm on intake .20mm on exhaust. Was down to a 12.5 pilot jet and still smelled rich, smokey exhaust. So dropped to the smallest jet available a #10!!! Seemed to help! less gas smell and seemed to hold idle better. I had to screw the mixture screw in all the way to make it run best (color tune agreed).

But STILL extremely lumpy idle and if I slowly open the throttle it struggles for a second until rpms come up, sometimes even pops back through the carb and/or will die. Running with choke seems to help starting but run rough if left on. Just doing short rides and every time plugs come bag sooty.

Needle clip still in the middle, tried raising and lowering one notch and it ran worse.
Quadruple checked for vacuum leaks. None.
Checked timing with a timing light. Dead on.

Could I have a damaged intake valve??? Everything points to lean or timing off (I am running a #10 jet!!!) But if I go any richer it won't run for crap. Float level has been checked over and over but is it possible too high and other jets are interfering?
Weak coil??
Pod filter just not possible? I've followed so many builds with kz400s using pods successfully tho

Thanks for any ideas

I tune carbs top down, so main jet selection on WOT first, then needle. You are getting good top end power and decent plug readings here? I wouldn't go any further until this bit is right.

Could the float height need changing -from the standard setting for this custom application? maybe turn off fuel and see if the idle cleans up as the float bowls empty? if so maybe go down a couple of mm on float height?

Is the carb correctly sized? go to big and it loses all bottom end. Slide carbs flow much more air then the same sized CV. Could there be something wrong about the 2-1 manifold design?

New carb? NOS? (new old stock) or cheapo Chinese unbranded? either way I would check it over carefully and assume nothing.

Check and reset the points for dwell angle rather than gap, also try altering your plug gap? this can also be a symptom of bad ignition, The mechanical advance/retard mechanism can get sticky as mentioned earlier.

Major breakthrough!!!! Thank you Tyrell!

I torched both plugs to remove fouling, reinstalled, and lowered float height 2mm past mukini specs. Immediately thought I felt it running better, but drove it around and pulled plugs and for the first time ever they're not sooty! Don't smell like gas! Three short drives around neighborhood and plugs look like this: (even one short drive before would make it comepltely black
Float height!!! Good lord.

I guess now I'll start jetting all over again since now my plugs don't foul. Still have a power lag right when taking off from stop sign (will even choke out if cold) so from what I understand that's needle clip...
Thank you so much for giving me hope!