jetting stumble

I have a kz-650 with pods--kz-1000 26 mm carbs--120 main--needles all the way up--clip on lowest position--4into 1--set valve lash--carb sink--points set and timed.
Had a bad stumble about 5000 rpm--steady crusing..raised the needles all the way up and she ran much better. but if i swing my legs out and pods get some fresh air at 70 mph she drops the #1 and #4 cylinder--or just starts to miss--as soon as i pull my legs back in the cylinders pick up.
I'm thinking of putting a shim under the needle to raise it even more.
plugs have no significant color--just not white.
The bad thing is I'm gonna be at mid-ohio racing and you crawl all over the bike when cornering and
I can't have the cylinders dropping--mid corner.
I tried cutting up an air box and blocking off some of the air that is rushing by at 70 to 80
and had a slight improvement but its amazing how hot that air passing over the engine to the carbs is
at 70 to 80 mph--the other thing is I have zx 6 front end on it and the front fender may be creating some turbulance--the stronger the head wind the more the stumble--any thoughts--hows your crystall ball working

By what you have written I would say your running rich. I would put your needles in the middle slot. Lean mixture symptoms at neutral throttle is surging not a stumble. Also 120 mains are way to big for a stock 650

I should have said surging.

I tried needles in middle position--ran poorly--so i raised needles and it improved but didn't get rid of surging--so I raised needles all the way up and surging went away unless I hang my leg out
to drag a knee--then it drops a cylinder.

also tried 115 mains--then 117.5--then 120--runs best wide open with 120's

Something is not right, your settings are way out of wack. Check for any vaccum leaks around the manifolds and head. Make sure all the vaccum nipple covers are in place and sealing. Have you done a complete tune-up. I run a highly modded 650 with VM26 carbs and my settings were
mains- 112
pilot jet 17.5
needle in the middle slot.
Ran fantastic unitl the crash.

Go up on the needle jet.
Pilot jet is idle.
The needle jet is just off idle to about
1/2 throttle then the needle add's fuel
till about 3/4 and the main's take over.

If your needing to pull the needle up that far
the needle jet's to small.

I replaced the intake manifolds to fit the kz-1000 carbs.
Bike runs good as long as I keep my legs in.

I didnt run 120s in my 1105 motor when it had the stock 26s on it. It ran best with 115s even with a street ported head, 10.25-1 pistons and bolt in 395 260/260 cams. Do the manifolds fit the head properly ? Could the legs out be leaning the outside carbs out ? Still seems too rich or theres a leak some where. Good luck with it.

just got back from mid ohio
ran good until 5000 rpm
stumbles from 5000 to 6000
but screams if i just hold it wide open--
its just that mid corner holding the throttle in a steady position stumble.
on the next to last lap i started to run out of gas and it sounded exactly like the stumble and wouldn't pull until i put it on reserve unfortunately i lost a position on that lap.
I'm gonna look and see if there's a needle chart on kzr.
I only got 105 miles on that full tank--- racing this weekend.

You were right I checked the needle jets and they were 0.5--stock on a kz 1000 carbs.
I pulled the needles and needle jets from the stock kz 650 and they were 0.8s.
installed the 0.8 and no mid corner stumble.
clean pull threw the power band and when i hang off in corners no stumble.
you would think that the 1000 would have fatter needle jets than the stock 650 carbs.
Cant wait to get to Road America and Mid-Ohio next year.
I'd be at Daytona on the Oct 19-20-21 but I'm gonna miss it.
Thanks for everyones input !!!!!!!