Carbon build up?

Working on fine tuning my carbs and I’m getting close to being done, but I do have a slight hesitation at times at about 4500 RPMS. It’s odd because it’s not constant, but more sporadic. My idle also sits about right, but does seem to want to idle down and die if it sits too long.

I’ve been checking my plugs after riding, and noticed my 1 and 4 plugs seem light grey/whitish while the top of the pistons have no carbon build up and are just slightly brown; they look borderline wet. The 2 and 4 plugs look just right, a light to medium brown and the piston tops have burnt carbon build up on top. Bike has about 350 miles since my rebuild and the carbs are spotless in and out. Just resynced the carbs via the vacuum gauge and they’re spot on, with the valves all in check. Very light popping on decel.

Wondering what the carbon build up is telling me. Does the carbon on 2 and 4 show too much fuel in 350 miles? Does the lack of carbon and plug condition on 1 and 4 seem proper or too lean?

 

Carbon is normal to see on the piston crown.
1 and 4 are lean, which is confirmed by the popping on deceleration.

 

That’s what I was thinking, but wanted a second opinion. Has to either be a mixture setting or possibly my floats are a touch too low.

 

Bump the idle mixture up about the width of a dime. Ride and listen for the deceleration-pop. Repeat until it's gone.

 

Been continuously richening the mixtures on my 1 and 4 cylinders and feel i'm to the point where they're getting too rich, yet my plug electrodes look lean. The base of the plugs are starting to get a bit sooty and black, while the ceramic and electrode look light grey/whitish. Not sure how well the pictures come across.

I've checked repeatedly for air leaks and can find nothing, and i've done several carb syncs and they're all synced well. Valves have been checked and rechecked and are all within spec, and plugs 2 and 3 look just fine - light brown. The bike seems to run well once warmed, with a very faint fuel smell at stop lights. The oil doesn't appear to have a fuel smell, and the thing doesn't appear to use excess amounts of fuel. It's got 460 miles on it since the rebuild - new pistons, rings and a .5mm overbore. My 1 and 4 plug wires with the dyna coils check at 23.5 ohms of resistance and my timing is all lined up. Perhaps i'm looking at issues that aren't there, but the plugs definitely seem a bit lean to me while also showing signs of too much fuel. When I remove the 1 and 4 plugs I do get a ring of fluid remaining where the plug seal sat against the head, with the cylinders appearing a bit wet compared to 2 and 3. The centers of the piston heads have slight carbon build up in a perfect round shape about the outer inch or so are still showing metal with a brown hue. Decel popping is there slightly at times, but pretty minimal compared to what it was. Any idea what these issues sound like?

FYI - Two bikes and three different colortunes and i've never had success with a colortune. Bike just misses and dies as the colortune arcs and it's impossible to property tune. Tried more insulation and taping the connection but it has no effect.