Kz750 Keihin carbs

Hello, My rebuilt engine is now running.. I put 2  needle shims in my 4 Keihin Cv34. The problem is that the needle cannot have his own « play » like stock .before putting the shims I saw that the needles has a play even if the bolt is tight!! But no play when I put shims and tight the bolt!! So I let the bolt just loose a bit ?! Run very well .. but the bolt is loose!!!???

I've never shimmed the needles on CV34's, but if the needle holddown screw is loose, I'd add a couple of drops of medium strength loctite.

As far as i know, i never hear something about "needle play" if you shiming. Shiming needles (1 - 2 mm) is only lifting up the A/F ratio to the minor fat side. So no need to adjust any play at all!!! The needles are centric located to the carb slider/needle jet/main jet bleeder tube. Not tighting the bolts of the diaphragm top end cap causes an air leak to the lean side A/F ratio and malfunction!

Thank you guys, If I torque the hold down needle nut, the diaphragm doesn’t come back all the way like with no shims.. no shim let the needle loose a bit yes.. play to left and right, not fix at all.  Ive shimmed them because of the Pods, milled head and porting. I need more fuel at medium throttle. And main jet function is to 3/4 to WOT. So If I remove the 1mm shims, I will be lean a bit at 1/2 throttle?! 
thank you  

So to put down the diaphragm  all the way, I need to push a bit on it by the top.. and it goes all way down.. No shims with the torqued nut, it goes all the way down. With a loose on the nut with shims, all the way down!!! Very confusing 

Dynojet sells a jet kit for the CV34 carbs.  Those may be a good option for a bike with pods and/or hot rod parts.

Yes I already contact them.. and the guy doesn’t make me confidant about his stuff.. he say that for 150$ he will ship me 3 kind of jets and try them!!! So I prefer to play with Keihin Jet for 4$ each one!!