81 XJ-550 Wont run

Hey everyone, I just got given a 81 XJ-550, over-all good shape but not running, fixed all electrical issues, took rack off and cleaned and rebuilt carb's, reinstalled rack, battery is new and have a battery tender on it.
Now the issue i am having is, when i try to start it, it want's to start but wont stay running, if i throttle up it will run, but at 4000 RPM.
I am lost as to what to do, any help would be grateful.
Thanks

 

Welcome! A lot of us have started with a non-running or barely running bike. I'd direct you to this, since not everybody has the same idea when it comes to rebuilding carbs. https://xjbikes.com/forums/threads/the-secret-life-of-carburetors.14751/

I had mine done by @hogfiddles and they've been fantastic (as the bike has been). I'm tearing down another set of carbs for my other Yamaha right now because I didn't go far enough the 1st time.

Another thing to check (and you should) is valve clearances. They can have a big effect on how the bike runs, esp if they're well past their check-by mileage. https://xjbikes.com/forums/threads/airhead-valve-adjustment-with-pics.14827/

 

Agreed to check valve clearances before anything else. From what I understand, it is the starting point for just about every other "tuning" issue.