Stalling XJ 900s Diversion

So, I cleaned the carbs, checked and adjusted the valves (and changed oils front & back, changed the air filter also).
I followed the instructions stated at the "in-the-church-of-the-clean" post's, and everything went surprisingly well. I bench synced the carbs, and did a real sync using the synchronisation tool. All the parts were in good condition, and I replaced what needed to be replaced (float needles, o-rings etc.). Double checked everything, put it back together.
And then, it starts good, idle is at 1100 and it runs smoothly. But when I give it throttle, it revs up to 2500-3000, then just stalls. If I keep the throttle engaged, it shuts down, if I let it go, the bike will go down to 1000rpm but stays on. Rarely I can get it to 5000-6000rpm, but no more. The fuel intake system is good, I checked the whole line all the way to the carbs.
Anyone else had this kinda problem? I'm pretty lost here, I'm wondering if I should take the carbs out again, but I do not want to do that if it aint necessary.
Any help I can get is welcome! Thanks in advance.
The bike is XJ 900s Diversion, -95 with Mikuni carbs.

The picture is from the day I took the carbs out the first time.

 

Just a thought, make sure the vacuum line between the petcock and carbs is good.

 

You try running with the fuel tank cap open? Could be a plugged up vent.

 

Thank you both, I will try these today!

 

Well, neither of those werent the problem.. I checked every hose and disassembled the carbs again, but everything was the way it should. So Im back to square one..

 

Does it shut off immediately like you hit the kill switch or more of a sputtering mess?

 

So, what about with no fuel, but you spray some carb cleaner into the carbs. Does it rev well for a few seconds that way? It sounds like it's not getting fuel from the needle jets. Are the slides moving smoothly and clunking? Not sure if there's a vent line for these carbs, but, if there is, is it connected (or disconnected) as it should be? My daughter's Ninja 250 was acting kind of like this, and it was because I had thought the vent line was a fuel vapor EGR line, and I had connected it to a port on the fuel tank that was actually blocked off.

 

make sure all hoses are not pinched or folded when the tank goes on.
Set it on the centre stand and run it from an auxiliary tank and see if it still does this.
It sure sounds like a fuel issue.
How much fuel is in the tank?

 

Jay: it kind of like slowly fades, like running out of fuel (and it may very well be the case ). But if I let go of the throttle, it rises back to 1K.
SQL: I need to try the carb cleaner tomorrow. Slides are moving good, and there is vacuum. I dont remember it having a vent line, but I may be wrong. There is two open little holes on the top of the carb, where it seems like it should have some kind of hoses, but it never has had those, even when it ran good. You can see them in the photo I attached.
Simmy: I did, I was super careful with all the hoses. I checked the tank today, it has zero problems and has about ten litres of fresh, good fuel in it. I checked the petcock, and it is working great. I also checked the fuel filter.

I does seems like it is not getting enough fuel. Can this be a problem maybe caused by a fuel pump going bad? I did not have enough time today to go fully on the carbs, will do that in the weekend. Is there something specifically I should check in the carbs? I cleaned all the jets today, but did not mess with the floats. Is there some tips on how to adjust the float needles? Thanks guys for helping me out, Im still relatively new when it comes to this whole motorcycle mechanics thing, altough I've been riding them for a while now.

 

Definitely sounds like fuel issue. Float heigh(or fuel level) is really important. Will run lean and if too low can starve at higher rpm’s.

Does that bike have a pump? Could be the cause also, you should be able to find the PSI rating and/or GPH rating to test it.

 

Yes, it does have a pump, will check it after I try setting the floats. Thanks!

 

This one.