Banshee Carbs on a 76 KZ400?

Hello guys,
This is my first post on the forum, but I have been reading A LOT of awesome information here and figured this is probably one of the best places to ask my question. I teach Metals, Welding and Fabrication and to show students how they can apply the skills from my courses I am currently working on a '76 KZ400 rigid bobber project. I have been exploring carburetor options and came across a local guy that "Should have" a set of Yamaha Banshee carburetors available. First I am not sure if they are the Keihin, or Mikuni or what year quad they are off of, since I don't have them in-hand yet... My question is whether or not these would be a viable option on my bike. If so, what would I need to do to them to operate correctly on a four-stroke engine. I will do the TORS delete, if it has not been done. And I am planning on having to clean/rebuild the carbs as necessary.

My original idea was to run a single VM34. I built a 2-1 Intake from 1.5" 14ga tube; however I am concerned that the runner diameter might be too big.

Regardless of the carb set-up I choose, I will run Pod filters and open exhaust unless you guys recommend otherwise.
Any advice will be greatly appreciated.

Hello andmoland and welcome to the KZR forum.

First at all you need a 2 in 1 throttle cable mechanism to get a synced movement for the Yamaha Banshee carburetor sliders

Don´t mount the carbs upside down.:lol: :lol: :lol:



Running Pod filters and an open exhaust is not the best idea for a smooth running engine and is very difficult to tune up and took a lot of time for the right jetting and adjustment.
I would prefer a rebuild of the stock carbs with stock air box.

Michael

:laugh: :laugh: :sick: Not to pass the buck, but one of my student stuck those back on the boots “for the picture”. I didn’t even notice (oops). I currently have a 2-1 intake fabbed up And on the bike now. I did double check to make sure the flanges are correct.
I am struggling to find rebuild kits for the stock carbs. Initially I thought if I’m going to buy new carburetors, I would simply the shenanigans and go with a single. Then I found out this fella has these banshee units sitting on a shelf. And I am looking for some expertise on the subject.

What size are the Banshee carbs?
VM26s will work the best and 28s would be the biggest I would go on a stock 400.
As for filters don't use the filters that have a smaller cross section than the clamping area.
They will mess up your jetting.
If you are looking to get some more power out the 400 give me a call I know a few tricks , I'm in Lincoln.


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Hi Andmoland
i purchased some vm30s from speedmotoco a while back , my z400 bobber runs quite well on them , the supplier jets the carbs for your build spec , straight through exhausts etc if you have them.
Regards

I called them too and they said they could do a pair of VM30’s or a single VM34 tuned for the application. They are great people out there!

Here is a little information to show why anything bigger than 28mm carbs
do not offer a gain in top end performance and probably a loss on the low end.
The port is just to small for anything bigger. It is 30mm at the opening, but
that is with the factory cut that makes it that big. As cast it is 29mm x 28mm
at the opening. Now this is for the early 400 head. The late 400/440 head has
bigger ports and valves. The width is fairly constant to the valve bowl at 29mm.
The height starts at 28mm and necks down to 23mm at the start of the short side radius.


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Seems like I read somewhere that the stock Banshee carbs are 24mm. If so, the would be workable, but may give up a tiny bit on the top end.
I think what is more important are the actual flow numbers
At any rate, Nebr_Rex is right about having carbs that are too big.