Rebuilt carbs and synched... still sputters

[bigs_gs]

So I bought a 1980 gs850L and it was stored with the fuel petcock left in prime position. I had all kinds of gas in my oil.So I changed my oil and I bought 4 carb kits and rebuilt the carbs. And now I have the same problem. The engine won't rev like it supposed too but rather pops and sputters when it reaches around 3k rpms. Anyone got any ideas what else might cause this problem?

[chiphead]

It's not leaking fuel anywhere, right?
Perhaps an electrical issue. Fresh plugs after the carb rebuild? Battery fully charged? Stock air filter and air box?

[bigs_gs]

New plugs. Carb 3 was dripping a little but got it fixed but airbox wasn't on. Would that not being make that much of a difference where it barely runs.

[nabrams]

Zero chance of bike running properly without airbox - Been discussed a million times here.
Also check for air leaks, exhaust leaks, compression, blah, blah, blah...

[bigs_gs]

Ok will try