82 GPZ750 carb problem

Bike starts & idles fine but when you go to rev it up it dies after reving to about 3000. I checked fuel flow thru petcock, took carbs off checked diaphragms by holding finger over hole & slides dont drop, took carbs apart, checked float levels & cleaned carbs, put them back on & bike does the same thing,checked for vacuum leaks & there are none, manifolds are good. Ive built a bunch of these carbs & cant find a problem, Any help would be appreciated. These are 34mm Mikuni Cv carbs. Bike ran fine last time I rode it. Im stumped !

advancer on ignition working properly?bj

Its not the advancer It was working but I lubed it up & it still does the same thing. Starting to think I have a diaphragm problem. Ill pull the carbs again & check it out. God,I love these factory air boxes !

I just pulled and re cleaned 2 of the things today, those airbox connectors really suck, but the airbox gives the needed signal so the CV slides work right.
Now when checking this out have you made sure that its not losing spark? With a inductive light hooked up? Maybe you have a low voltage causing missfire/ weak spark?
If you have been through the carbs and know how then unless you have missed some thing, I would check the electrical. Maybe you still have a fuel supply issue, have you tried to see the fuel running out of the bowl drains with petcock on "Prime"?

For consideration, new soft pliable airbox hoses from Z1E.

Click > Airbox Hoses

Good Fortune!

Air box boots are fairly new & soft. I checked fuel flow on prime and its good. I even tried it with my portable snow blower tank that I use to sync the carbs with. It feels exactly like the slides arent lifting. When you rev it up it stutters amd dies. The battery is a year old but starts it fine. I lifted the slides and covered the hole in the front of the carbs with my finger & they didnt drop. Im taking the damn things off again, something is wrong some where. Thanks for the help guys, keep it coming. Ill try anything at this point. The thing starts & idles fine

Took carbs off again and went completely thru them cleaning & checking everything. Put it back together & it runs perfect except I have no clue what I did to fix it. I can live with that though.

Well as ole Grandpappa Johnston said:"even a blind hog finds an acorn now and then." Lol. I think we have ALL been there.bj

I got a Buddy with a GS850, he had someone working on it and spent $800. Would not run above Idle, took me a couple of tries to straight it out. Found out on these Suzi BS carbs, there is a spring that goes in before the needle goes in the slides, these guys had it holding the needle down. It was Super Lean, wouldn't go 10mph. Needless to say thanks for the internet parts diagrams as one look and the "LIGHT" turned on.
He was told he needed a new motor, he's the 1st owner and 18,000mi. They had charged him for carb rebuild, Mix screws were seized in place, floats all out, and no new parts. Broken intake manifolds, wasted air box boots, etc.
Runs great now.