Two carbs getting gas, two do not.

No, nothing fits there. They are just from the common mould used for 1&2 and then then one from 3&4..
If you push a probe down you'll find the are blind. 

Those small joining hoses, between 1-2 & 3-4, are to join together for float bowl venting.  So, there are two vents, instead of having to run four.



This particular diagram is for the larger VM26 carbs, so the details about the fuel feed Tee's doesn't match your VM24 carbs.  Disregard that part.

Update:  I have broken down the carbs, soaked the carb bodies, cleaned the passages and cleaned the jets, replaced the O rings (Thanks Nessism), reassembled the carbs, set the float heights, checked for floats hanging up, watched YouTube videos for additional ideas, consulted with a neighbor AND the number two carb is still getting no fuel and number three is getting minimal fuel.  The floats appear to have free movement/not hanging up.  This is the original problem with the carbs.    The bike is a 79 KZ 650 with air screw Mikuni carbs.  (VM24?)

What else should I check?   I would be pulling my hair out, but I'm already bald.  

Thanks in advance for any suggestions.  

 

Sorry but I am sure I have read all of this topic/post but have not gone back and re-read it.  So take this with that info, but since they are from a 79 model year stock it would of had a vacuum petcock running from a port on #2 carb.  If the diaphram in the petcock has a tear in it, it can pull fuel up the vacuum hose from number 2 and flood the carb/cylinder with fuel.and change the ratio of fuel to air in number 2 and not run correctly.  If this is true it may also add fuel to the crankcase.

Since number 1 carb appears to be working fuel is passing from the fuel inlet between 2 and 3 and passing on to number 1. Is there fuel in the bowl on number 2?

There should be a joiner between 1 and 2, and 3 and 4.  Therefore no need for a joiner between 2 and 3.  If your carbs are mounted correctly on the rack you may find that the outlet in the photo was never drilled out.

There is no fuel in the number 2 carb bowl.  Dry.

gd4now wrote:

Sorry but I am sure I have read all of this topic/post but have not gone back and re-read it.  So take this with that info, but since they are from a 79 model year stock it would of had a vacuum petcock running from a port on #2 carb.  If the diaphram in the petcock has a tear in it, it can pull fuel up the vacuum hose from number 2 and flood the carb/cylinder with fuel.and change the ratio of fuel to air in number 2 and not run correctly.  If this is true it may also add fuel to the crankcase.

Since number 1 carb appears to be working fuel is passing from the fuel inlet between 2 and 3 and passing on to number 1. Is there fuel in the bowl on number 2?

There is no fuel in the number 2 bowl.  Dry.  
 

What happens if you squirt carb cleaner up the float vavle seat on #2? Where does it come out.?
It can only be a fuel feed blockage or a air vent blockage. But if it was an air vent blockage the bowl wouldn't be bone dry. 
 

Warren3200gt wrote:

What happens if you squirt carb cleaner up the float vavle seat on #2? Where does it come out.?
It can only be a fuel feed blockage or a air vent blockage. But if it was an air vent blockage the bowl wouldn't be bone dry. 

The carb cleaner mostly comes out the fuel inlet T.  Some blows back but I guess that's to be expected.  

 

Are you sure you have each carb in its correct position on the rack?  1 and 4 should only allow fuel through the inside of the fuel insert.  The outsides should be blanked off.  On 2 and 3 you should be able to see daylight if you look through the fuel insert.  Both sides should allow fuel into the carbs.  2 is the one with the pump.  

You should have two nipples on #2 carb.  One is near the downstream side and is used to provide vacum for the petcock.  If you're using a gravity only petcock this nipple must be blocked off.  I normally use one of the rubbers that go on the intake manifolds.

hardrockminer wrote:

Are you sure you have each carb in its correct position on the rack?  1 and 4 should only allow fuel through the inside of the fuel insert.  The outsides should be blanked off.  On 2 and 3 you should be able to see daylight if you look through the fuel insert.  Both sides should allow fuel into the carbs.  2 is the one with the pump.  

You should have two nipples on #2 carb.  One is near the downstream side and is used to provide vacum for the petcock.  If you're using a gravity only petcock this nipple must be blocked off.  I normally use one of the rubbers that go on the intake manifolds.

Yes.  All of what you describe sounds exactly the way mine are arranged.  I've had the bike running, with fuel getting to all the carbs except for number 2.   I'm thinking that there is a problem with the float or the float or the float needle valve on number two.  Unfortunately, nothing obvious.  

Have you tried removing the float and needle assembly, put the bowl back on and turn on the fuel - does the bowl now flood?
Yes: fault relates to the float or needle
No: fault is a blockage in the carb body