Struggling to get this going guys I think it's a carb issue. More info below.

I have this 1980 kz250 LTD hasn't run Ina long time and I'm not to this stuff but so far seems to be going really good can't figure out these damn carburetors they perplex me.

I think this is a issue with the carb I replaced it as the old one was.missing a ton of parts but still can't figure it out I feel it's not getting enough gas but a second opinion would be greatly appreciated IL attach a video below. Ask questions as Im not sure what info is needed!

youtube.com/shorts/5Qw3Az_9aQc?feature=share
 

You need/check the right air/fuel mixture (jetting), ignition/cam timing (spark and valve lash), and compression (min.120 psi) to start or run an engine. Your new carb could have the wrong jetting (lean mixture), so try to spray some break cleaner into the air box or carb inlet to richen up the air/fuel mixture.

Is the carb getting any fuel?
Was the carb properly set up before installation?
Did you insure that every tiny passageway inside the carb is clear of debris?
Is it the correct carb?

Also what Scirocco said.

Here is how a constant velocity carburetor works.