Could a vital part be missing from my 83 carb?

[GlennInLouisville]

After taking the airbox off the top of the carbs and looking at the carbs from the top, I noticed that one carb is missing what looks like a small brass ball from a tube chamber in the top of the carburetor body.  I've got a schematic for an '82 carb and am not sure what I'm looking at with the '83, but I'm thinking the piece I'm seeing in the other carb is a tiny brass weight.  In the carb that is missing this piece, there are is a air passage with a tiny passage in it's side below where the brass piece would have been.  
It looks like I'm missing a vital piece to my carb?  Am I right?  The carb that is missing the piece, feeds the back cylinder and actually is the only cylinder that fires (all it really can do is idle while on full choke).

Thanks,  Glenn

[jason morris]

both carbs are not the same. Remember the front controls the flapper door.

[Lucky]

that is an air bleed for the main jet. the front one is blocked off because it gets it's air bleed from the round plastic filter attached to the right side of the ft carb.
--Lucky