Z1OwnersClub GB

KZ1000 1978, i have now got 1,2+4 of the plugs running with the correct burn colour, but number 3 plug still will not adjust from running rich. i have sonic cleaned all the carbs, twice on no.3. still the same, did a compression check, hot engine, all 150psi. Swapped no3 carb for no1 as they are the same hand, still no3 running rich!!!!! at least i know it`s not the carb.
Just found the article on here about possibly a lack of full voltage to the coils,(never would have thought of that) will try that next.
But if anyone has any other ideas please get in touch.
Thanks for reading my moaning.
martin

Low coil voltage would affect both number 2 and 3 cylinders so it's unlikely to be that.
And with you ruling out the carb it's probably oil fouling from a faulty stem seal or similar. .

If the coil is just a bit "under-par" it may have enough punch to fire just one plug properly - the one with least resistance.

Have you checked & swapped plugs yet.