Topic: 73 CB750K Plug Fouling 1&4

[mrmach5]

I'm battling some carbon plug fouling on #1 and 4 . 2 and 3 look great.
Good compression , valves adjusted, stock air box, electronic ignition, timing spot on, 105 main jets, 35 pilots, needle in the 3rd slot , floats set to spec clear tube method. Bike runs nice and idles good but after a short test drive I can tell those two plugs are fouling and will only get worse. Seems like its right around 2200 rpm where there is the slightest hic-up.
I've replaced the coil, firing 1 & 4 , new wires and plug caps as well. ND X22ES-U plugs. All four carb idle mixture screws are at 1 turn out.
Nothing I seem to try seems to have any effect. The exhaust is a brand new Italian made HM300 reproduction 4 into 4  set.
I'm about out of ideas.
Thanks in advance for any wisdom.

[M 750K6]

Maybe swap condensers and see if the problem moves?

[mrmach5]

No condensers, electronic ignition.
thanks though

[newday777]

Do you have Hondaman's 750 book? He goes into this on cleaning the carb internal ports that get clogged with old powdered MTBE gas additives (thanks to epa mandates of the late 70s to mid 2000-2015), that messes with the air injection into the fuel mixture to properly atomize the mixture.