request help aftermarket carburetors for kz400b 75

Hello everyone. As already written in the introductions, my name is Danilo, I am Italian and a few years ago I invested a few hours/days/months/years of my life to rebuild from scratch and transform an old kz400 now reduced to a pile of rust. The result is visible in the introductions. In any case, I am writing here on the forum because one of the problems that I continue to have on the z is the poor performance of the original carburetors that continue to offer different performance depending on how it goes. Since you can find Chinese copies of the Mikuni VMs, I thought I would do some tests to see if with that cheap junk, the little one would have done better, and so I bought a pair of VM30s. Too bad only one arrived... the seller then apologized and sent me another... and a vm34 arrived... and then he apologized again and sent me another... and a VM32 arrived. At this point, aside from the irony of the story, I ask you: Which road do you think is more viable with these similar mikuni? I will definitely have to buy another one, but at this point what do I take? vm30, 32 or 34? The engine has undergone some small adjustments to the ducts, but nothing exceptional (as I said elsewhere, I have 4 other bikes with much higher power and consequently the z is mostly a nice piece of heart to keep), and in addition to the cone filters, I also have a homemade exhaust with a crossover expansion tank, but practically free exhaust. With this configuration, is it better to insist on the Vm30, or maybe switch to the vm32? What I am looking for is not performance, but linearity of operation without too much hassle or suffering..

Thanks in advance for any advice.

 

Lots of options to play with. Might i say smaller venturi will technically give better starting and tractability within the "tooling around" you seek. Of course sooo many other variables, slide CA, needle jet/jet needle, air correction jets, etc. Have no clue what those Chinese came with, play-on!!   

Dual Chinese copy VM30's on this KZ400 project :

kzrider.com/forum/11-projects/611489-dueling-kz400s?start=24

The thread explains some of the key jetting differences and issues to get that combination tuned properly.

Buongiorno!

The VM30s are good for the KZ400. Two VM32s would be too much and two VM34s would be far too much.

I have seen single carburetor conversions for the KZ400 and KZ440 from a company called 11th Hour Industries. They use a single VM34, so if you can find the correct intake manifold for the 400, you might be able to use one of your spare carburetors. (I have one of the manifolds + a VM34 but have not installed it yet.)

You could also use the VM32 the same way, but I have no information about how well it would work. Even with the VM34, it appears the single carburetor will make slightly less power than the two originals but may be easier to manage (than two carbs).