ZL600 #1 plug fouling

I replaced spark plugs yesterday, prepping the bike for a trip to Gettysburg bike week. During a 3 mile test ride, the bike idled poorly and stalled out twice. I checked the plugs, and #1 was black. I decided to put the old plugs back in, went for a short test ride and once again, poor idle and  #1 plug is carbon fouled black. Resistances through plug caps, wires, and coil is good. #1 plug is giving a crisp blue spark.

 

Well it doesnt seem like ignition is a likely issue. Im assuming you sorted through the carbs and whatnot. Did you check compression, valve clearances, or look for evidence of burning oil? The fact that plug 2 also is a little dark leads me to believe that it could still be a carb issue.

Seems like Zed1015 always states, a defunct choke plunger issue. This is always true. Check for complete closure of #1 plunger, it's hidden behind carb castings and holder. If that's not the case then check for source of Petcock vacuum, is it sourced from the #1? If that's the case then the petcock membrane for vacuum is distraught and pulling fuel in petrol. Easy fix..  

This problem was discovered just 2 days prior to riding the bike on my trip to Gettysburg. I didn't have time to pull and properly fix ihe carbs, so I had to take the backup bike. (360 miles on my KZ305).
Today, I tested the vacuum petcock on the ZL600 by pulling vacunm with a syringe. After holding vacunm for a few seconds. fuel started flowing into the air box. Looks like carb rack will have to be pulled and sorted out on the work bench.

That'll do it. You can probably assume that one or two of the float valves arent sealing for one reason or another.

This may be something screwed up in translation, but the Kawasaki service manual is calling what I think is an air box, a surge tank. The plastic box to the rear of the carburetors, connect to through rubber connectors.There is no way this is a surge tank, correct?

Probably something got lost in translation as the "air-box" does provide an element of baffelling to aid smooth running and reduce noise

This sounds silly, and it might not even be your issue, but I noticed that the jets if you don’t tighten them enough, rattle out and create massively rich environments for just one cylinder.

my ZN700 did that shortly after I put it together. Imagine my surprise to find jets laying in the bowl of #1. 

Here's what I found in the float valve of #1 carburetor. It is soft and semi-transparent, probably a bit of silicone sealant. I think I'll be adding an inllne fuel filter.