Gas to carbs

I have a 1980 cb900 custom. This is a 4 carb bike. The carbs have just
been rebuilt and the tank was just coated with kreem.

I am getting gas to carb 1 and 2 but not 3 or 4. I know the gas linkage
line are clear, the carbs were cleaned in a carb cleaner and blown out.
I dont believe that there is any kind of blockage.

Has anyone ever experienced this problem??

 

linkage line are clear, the carbs were cleaned in a carb cleaner and
blown out. I dont believe that there is any kind of blockage.
Has anyone ever experienced this problem??

Some carbs have a small fuel filter built into them, right above the
float needle valve seat, so you might want to check into the
possibility that those filters are plugged...

Another possibility is that the float needle valves themselves are
gummed up and are stuck shut...

I would drain the gas out of carb #1 and #2, catching the gasoline in
an old rag. The I would squirt aerosol carburetor like STP or
B-12 down the fuel hose until it is full and then let the stuff sit in
there for an hour to see if more will go in when the needle valves
open...

Then drain the float bowls down and refill the carbs with gasoline...
That would beat having to remove the carbs for cleaning...