new to me 1978 KZ 1000

Hey Guys
The pic of the carb is the same as I saw yesterday. # 3 has the vacuum port for the Vacuum petcock, so I left it capped.
When I got the bike they were already capped. So I never thought twice about them.
The new carb mounts came with caps. But they seemed sloppy and I had a hanging idle. So I replaced them, thinking I had a bad air leak.
I tried the carb cleaner trick down the carb throat, it didn't fire. I had the laser thermometer on the pipe while I did it.
After I uncapped the carb vents, the spark looked wet and smelled like gas. I checked it again for spark, and it was good.
Can I swap #2 and #4 carbs? Just to eliminate carb vs engine/cylinder. 
Thanks

If it's "wetting" the plug it may be a bad choke plunger ?

Re: the carb vents...carbs work by drawing fuel up the jets and into the airstream.  This occurs because the air pressure in the throat is lower than the pressure in the bowl, which remains at atmospheric pressure due to the vent.  Therefore it is essential for the air vents to remain open.  From memory, the vent on #2 also serves #1 and the vent on #4 also serves for #3.  The one normally used on the petcock can be capped.

It looks like you have more than one problem.  If your carbs are like the one in the photo with vent instructions you won't be able to swap 2 with 4 because of the fuel connections.  The good news is you are getting fuel and spark.  Do you still have 100 lbs of compression?  To measure it you need to pull all the plugs, install your gauge and crank the engine with the throttle wide open.

I’ll grab a different compression tester. Just to be sure.
looking at the carb pics again. I have the double inlet like pic #2.
so swapping may work!?
So that cylinder may be over fueling/flooding!
if the choke plunger is bad, how can I check?
If I close the pilot screw to a 1/2 a turn or less. Might that close off enough fuel to get it to fire?
Thanks again!

If one cyl not firing from to much or to little/no fuel  you can try to start the engine and then use a little screwbit  to turn on the mixturescrew .First turn it all in until it stops, but be careful use  light force!!. then you turn the screw out until you can hear the cylinder fires. it can somtimes be difficult to hear that when idling so blip throttle a little and you will hear if it runs on all 4. You dont want to overheat engine so work fast and on a cool windy day or use fans infront of engine.

I would use a tight fit rubber fuel line to adjust the fuel screws.
You can also make a DIY socket like melting a plastic stick/tube and molding it by imprinting on the screw head.
It´s easier to handling this tricky task.

If you have a single fuel supply from the tank I don't think you can swap 2 and 4.  2 has a fuel inlet on one side and an outlet to 1 on the other side.  4 only has a fuel outlet on one side so it cannot replace 2.  But you might be able to swap 2 and 3 if they both have fuel inlets and outlets.

If you have a double fuel supply you will not be able to swap any carbs.

There are several overlooked places that people often forget to clean when they clean the passages in their carbs.  You will notice a hole in your carb bowl near one of the corners, located on the rim.  There is a small connection at the bottom of the hole that runs into the bowl to allow fuel to transfer from the bowl to the hole.  This must not be blocked.

The second place is the brass rod that fits into the hole when the bowl is attached to the carb.  It has a tiny hole that runs into the carb body that supplies fuel to the choke circuit.  It must also be clear and unobsrtucted to allow the carb circuit to function correctly.

Thanks for all the come back guys!
Well I'm pretty much at wits end. 
I totally dismantled carb # 2. I had carb cleaner coming out of every possible passage and orifice there was. The one in the bowl and the tube going into the starter plugger as well.
The starter plugger/ choke looks perfect fine. I can't see anything wrong with it.
I adjusted the pilot/ fuel screw, all the way from 0 to 1/4 turn, 1/2 turn, 2 turns and all the way out to 4 full turns. not firing.
I'm getting fuel in the cylinder, as the carb holder on #2 is wet like all the other cylinders when I pulled the carbs. And also the sparkplug was wet.
I have good spark and also swapped  #2 and #3 wires and sparkplugs.
I haven't gotten a different compression tester yet. But it should fire with 100 Lbs if it was accurate.
If I can't swap carb positions. Should I swap all the guts from one of the running carbs/cylinders?
This makes no sense! 
 

It is strange !! ultimately you need four things for it to fire

• Fuel (three working cylinders would suggest fuel quality isn't an issue)
• Air
• Spark "at the right time" (timing can't effect 1 cylinder)
• Compression (yes even with 100 psi it should fire)

Without reading back through, have you checked the valve clearances ?

Wookie58 wrote:

It is strange !! ultimately you need four things for it to fire

• Fuel (three working cylinders would suggest fuel quality isn't an issue)
• Air
• Spark "at the right time" (timing can't effect 1 cylinder)
• Compression (yes even with 100 psi it should fire)

Without reading back through, have you checked the valve clearances ?

Yes I did check the valve clearances, when I first got the motor unstuck/ unseized. They were within specs. 
It's probably something very simple and stupid on my part. But it's just waiting to slap me in the face!
 

The mystery deepens.  I wonder if the valve is opening and closing correctly...as already mentioned...how is the clearance? 

If you have another carb or a rack of carbs you could try them to see if that helps.