Idle on 3 cyls

Hi guys.

My 79 kz650sr idles on 3 cyls. No 2 exhaust stays cold but if i pull the ht lead off it does make a slight difference to engine note. Revs drop a bit.

Does this sound like a float set too low?

Thought id ask before i pull them apart.

Thanks guys.

Pulling the lead on 2 will affect the spark on 3 that's why the revs drop.
If it's only running on 3 cyls at idle and on all 4 over that then unless it's a faulty plug it's most likely a blocked or partially blocked pilot circuit or pilot jet.
If your carbs are the pilot fuel screw type then the needle tip of the adjustment screw could also have broken off and be blocking the fuel orifice in the base of the venturi.

Not saying this is your issue, but I have read about issues with a vacuum petcock allowing way too much fuel to enter #2 via the vacuum take off on that carb (torn diaphram) causing #2 to be flooded and not running.

Cheers for that. I'll have a nose at that.

Thanks