1977 kz1000 number 4 carb very dirty

Hello
      I have a set of stock kz900 carbs that I ran on my bike for about four hundred miles.
Today I removed the bowls and all of them were clean except number four. there was a very heavy coating of gummy dried gas inside the bottom bowl and all stuck to the sides of the float. The main jet was all coated too. I wonder if the man who did the carb overhaul forgot to clean the carb body or maybe something clogged the jets or it was only barely functioning .

Has anyone ever seen this before?
Thank You

Due to the ever-increasing proportion of bioethanol in the gasoline produced today, it unfortunately often happens that components of the rubber/plastic gasoline lines dissolve in the gasoline, or the "plasticizers" in the lines dissolve,... and then find themselves as sediment in the float chambers....and the side effect is than, that all the jets, needle valves and calibrated channels been full stucked with that shit...

Perfect example of why you should work on your own bike, or only use people you know to be trustworthy.

And clean your gas tank, if it's dirty, and use Staybil in the gasoline if your bike sits much.

gsarchive.bwringer.com/bikecliff/images/vm_carb_rebuild.pdf

 

Recently I took my Z1B out of sleep mode.  When I put it to bed a couple of years ago I drained the carbs, changed the oil and filter and covered it up.  When I took it out of storage it started up but was running really rough and #3 cylinder wasn't running at all.  So I took the carbs off and checked them.  #1, 2 & 4 were nice and clean inside but #3 was covered with dried green sludge.  Why only one carb?  I really don't know.  It took two cleaning attempts before everything was back to normal, but the next time I put a bike to bed I think I'll pull the carbs off the bike completely.

1) Use Stabil in the fuel
2) Remove the fuel line from the petcock.  Maybe it's dripping
3) Drain the float bowls before storage.