Wet spark plug, firing issues (Z1000ST)

Hi,
I'm not sure whether this problem belongs here on in the carburetor section, also english is not my native language so I may use the wrong technical terms but I'll try to be as precise as possible.

So, when I got my bike in august it was seating for years without running. Since the beginning I have recurring issues with cylinders 1 and 4, their spark plugs get fouled very often and/or the cylinder is simply not firing and the spark plug is wet with fuel, even if it's clean (i.e not sooted).

Here is what I did:

• check compressions : almost the same on cylinders 1, 2 and 4, a bit higher on 3. I can't remember exactly but everything was within the specs range.
• changed plugs: tried with NGK then with a bit hotter Bosch plugs, as I drive mainly in the city center I thought this might help but with no luck.
• carbs cleaning and synchronizing => HUGE improvement after that but still not perfect, I checked the fuel level while I was working on the carbs and it was OK.
• brand new Dynatek coils instead of the original ones => once again a big improvement when the motor is cold but the bike is still not reliable.
• new made in japan high quality petcock, I'm a 100% sure this one is leak free and reliable.

Edit: valves have been adjusted too.

Before doing all that starting the bike was a nightmare and it was almost not rideable.After that the motor runs well, even when cold, and the cylinder 4 seems to be OK. However I still have issues with the cylinder 1 and I don't know what to do. Yesterday it was once again not firing at idle, I tried to ride for a few minutes and went back home, its exhaust pipe was barely warm and the spark plug was full of unburned fuel but not sooted. The problem does not come from ignition, I got enough electric shocks yesterday to know it was working, moreover cylinder 4 runned fine. The only unusual thing was that the bike was sitting on its side stand whereas I usually put it on the central stand when I'm home, however as I said above the petcock is not leaking.

I would be very grateful if you have any idea because I really don't know what to look at.

Thanks !

Have you adjusted the valves?
Steve

Yes I did that too, I forgot to say it.

Do you think that an excessive leaning angle on the side stand could cause the leftmost carb to leak into the cylinder and drown it ?
I noticed today that my side stand has a huge fitting clearance, see below:




Depending on the stand position I measured a leaning angle from 13° up to 20°, I checked on another more modern bike and found 15°.

Why would you let the bike run while sitting on its side stand? I have not done that with my KZ650 and I've owned if for a bit over 40 years. Instead of guessing about the side stand simply put your bike on the center stand and see if the problem persists. Ed

It was not running on its side stand, it was sitting on it for a dozen of hours and the problem occured after I started it again.I was then seated on the bike and it was horizontal.

I'd only like to know if an excessive leaning angle when the bike is parked is a realistic explanation for what happened and then what's the correct leaning angle when the bike is sitting on its side stand.

Well, it was nothing more than yet another broken spark plug...