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ok, back again Dr G ....so, I have replaced the needles and the o-rings that you rec'd ......off on long ride this afternoon with 2 buddies, bike has been starting, idling, running well since the carb maintenance, but now after first 30 min into this long ride, doing the leak thing at #2 (from front brake lever side going in) carb again...not pissing out of the 2 upper holes, the bowl fills, and then the lower air cleaner fills then it runs out from the bottom of air cleaner & carb  .....had to leave my buddies and head home, but once I got home, no leak, bike idling, revving great ???? took off on ride close to home, ran excellent and no leak from that #2 carb ....????? .....so this problem does it, then does not do it, then does it, then does not do it .....highly frustrating .....do the air-fuel screws affect this ?? does a hotter or colder plug affect this ?? .....really want to get this rack of carbs to stop behaving like this, can I package up and send the whole rack to someone / a carb shop you may know to go thru them fully ?? .....getting tired of taking them on & off my 650 .....thanks for the assist  TO NOTE: see plugs, the #2 carb that's doing the leak / then no leak / then leak / then no leak thing is running rich, or richer than the other three

How many times have the carbs pissed gas? Only that one time?  If it was only that one time I got a feeling something got caught between the needle and the seat. Gas tank COMPLETELY CLEAN?? No scale, or any type or rust?? Petcock filter is perfect shape, no tears or holes?? I have NEVER used any type of inline fuel filters in my life on any bike I ever owned. If the petcock screen is in perfect shape nothing should get by it. I would check both to make sure both are in great shape. The pilot air screw has nothing to due with fuel level. Number one plug is the first one on the left side sitting on bike. Its left to right. I always check check the fuel in bowl for rust or trash by draining the bowl into a clear cup. Let it sit for a while then tilt it to one side and look to see if there is any trash in the fuel. Your two plugs on the right show signs of being richer than the other two. The carbon build up on the outer rings shows rich to me compared to the other two. My CR's sat for 30 odd years. When I got the bike back together I had one cylinder that did not respond to jet changes. What it turned out to be was the rubber piece on the end of the choke plunger was hard as a rock and it never completely sealed off when it was in the close position. Kz650 I believe they run a NGK B7ES plug. Are your fancy plugs the same heat range as the B7ES?? 

I will reply & at length tomorrow Dr G, thanks for the great info ....more to come ....

ok, I'll try to stay on point for to your reply & questions....so, there are 2 types of piss gas from CRs I've experienced: 1) when the float completely sticks and gas pisses out of the 2 teeny upper vent holes on the back of the carb, literally shooting out almost to swingarm and 2) the carb fills with gas and gas pisses out of the bottom of the carb & air cleaner ......since I have removed & replaced the o-rings & needles, two times I have experienced the 2) type gas piss, and both times it was #3 carb (3rd carb in from left side, the one running richest) ......this is only happening at idle after I come back down from high Rs riding, and it stops as soon as I take off fast down the road ........gas tank, petcock filter, etc spotless, ultra clean .....I will be draining the bowls as you suggest, capturing the fuel and seeing if anything in fuel in bowls .....I'm also going to drop all 4 bowls and look across / measure float drops with bike level on center stand to see if they are all the same  ......when I had the rack off for the o-ring & needle replace, interior of carbs were ultra clean.....yes, B7ES standard / factory rec plug, but I have had major top end work (2nd over pistons & rings, A P E valve guides & springs, GPZ 750 cams, etc) so I run colder plug, the iridium BR8EIX ......questions:
can the pilot air screws be adjusted complete in / down / closed ? what do they do ? what air do they control ?
all of my rubber pieces on all 4 choke plungers are hard as rocks, guessing I should replace all 4 ? 
what jet having a speck of something in it would cause this at idle but then stop it once bike was flying down the road at high Rs ? 
can the teeny vent holes on the carbs and their venting chambers be clogged ? (I plan to blast carb cleaner into & down them and then blow them out with compressed air) 
lastly, I think I may send them off for this service: