Z1100ST 2nd cylinder loosing spark

 HI
Here is the situation:
- first of all I did wrong fuel level and previously measured 18,6 mm from the gasket not from the lip, but that is done now
- all carbs adjusted aand cleaned.
- spark plugs are iridium (got it as a legacy from previus owner)
Now the problem:
- when cold 2nd cylinder woks randomly even idling like loosing spark
- when gets warm it is better but up to 2500rpm (ca) it is still disconnecting one cylinder and because is hot can not say which one but would guess 2nd.
- from 3000rpm goes allmost smoothly, but each gear change drops rpm and again loosing ignition.

The question s where to looking for the isse? Maybe there is some common issue in this mode I do not know abou?
In my opinion must be somthing with ignition coil but can be anything!!!!

Piotr

Unless it's a dodgy/fouled spark plug or lead ( it won't be the coils as you would loose both 2 and 3 as these are paired ) it's most likely to be a blocked or partialy blocked pilot jet on number 2 carburettor.
After around 2500 you are off the pilot jet and fuelled mainly on the needle and mains.
I'd check the plug first , Just try swapping plugs and see if the problem follows the plug.

 

I clean up carbs very well, each pilot screw and pilot jet. All is very clean and no sign of residues. Must be something else and I do not know what that could  be! Will swap plugs tomorrow but all of them looks like a new.