No vacuum on cylinder 4 after carb rebuild

[SinNombre]

So, I rebuilt my carbs for my 81 gs550L. Went through with the colortune and got em firing Bunsen burner blue, well blue at any rate. Hooked up the carbtune and can't get any vacuum reading on cylinder 1 (leftmost cylinder). I swapped hoses on the carbtune to confirm that it wasn't the tool that was the issue.
I will assume I have a vacuum leak somewhere. I will mess with them again tomorrow but am hoping for any feedback from someone else who might have encountered a similar situation. If anyone has an idea as to the culprit let me know, thanks. I know the title for the thread says cylinder 4.... but its cylinder 1.

[hampshirehog]

Did you bench synch first? The bad carb might be so far out that it won't give you a reading.

[AJ]

That would have to be one heck of a leak. Did you pull off the carb boots on the cylinder head when you had the carbs off the engine? If not, and your boots aren't cracked, then that wouldn't be where the leak is. But just to check it, spray some water around the boot with a squirt bottle while you're cranking. I'm only suggesting water so you don't mess up your carbtune with other chemicals like someone else on this forum had happen to him.

It might be possible that your slide is hanging up, not that I think that's likely. Still, you can easily pull the carb top off that outside carb to check it without pulling the whole set of carbs off the bike.

[SinNombre]

Follow UP:
I just removed the carbs from the bike altogether, opened up carb one and cleaned a bit. The first carb was indeed way off from the others which I don't understand since I did bench sync them the first time. Did another bench sync and put them back on the bike. Made sure I tightened the set screws and nuts this time before I wrestled them into their location. Probably took all of 40 minutes. Fired it up and all cylinders show vacuum, so yay for me. Hampshirehog hit the nail on the head with his prognosis.

[Suzuki_Don]

Well done Wally. On the money agin.