Carb settings cb400f with 4-2 exhaust

[ka-ja]

Don't forget that fuel level alteration also effect the mix over the whole range, dropping the fuel level could result in too lean a mix when on larger throttle openings, needless to say very damaging to the top end. As already suggested, it may be more prudent to experiment with smaller pilot jets

[Lynx]

If it's just rich at idle all you have to do is open the idle air screws 1/4 turn.

[Erwin83]

Changed the float level to 24mm now..... And we've got reliable idle!
Also a nice coffee brown color on the plug.

Still with a hot engine (seriously hot), it drowns on pick up from idle to any throttle.
Will look into the air screws a bit see what that does.

Out playing with a bigger sister today:

[Clem2112]

On the float bowl seal issue.
The ones I have used also swell up and grow 5mm in length but have not degraded visibly.
A few hours to dry out and they shrink and fit the groove again.
I must have fitted the same set many times and they have never leaked.

The fuel level (21 mm float height) is supposed to be a few mm below the joint face but the petrol will still wet the seal in normal use, banking over, accelleration or just through evaporation etc.