KZ440 Single Carb Conversion

Bringing old thread back to life to add to it. Huge thanks to the dudes who've posted on here. I just did a VM34 carb swap on my 79 kz400 using info strictly from this thread. Welded up a cheap 2-1 intake out of some 1 1/2 inch exhaust pipe. Grabbed the GY6 throttle cable suggested earlier (definitely long but bolts up fine). Put everything together and it started immediately. Idles way smoother than it ever did, got a little tuning to do still (hesistates if you open the throttle up too fast) but once it starts to pick up RPM it pulls pretty hard.

Will post pics shortly.

Hey guys, I sold my KZ440 (still a little bummed about it) and am selling a VM34 Roundslide Carb and an 11th hour industry 2 to 1 manifold for the KZ440. Both are brand new, Carb-$75 Shipped and Manifold $85 shipped. If anyone wants em, feel free to hit me up!

bringin old thread AGAIN back to life

anyone having warm start issues with the 11th hour manifold?

vm34 30 pilot top clip 150 main uni filter exhaust cut after mounting bolts

zayleos
still have your carb and manifold for the kz440?

beretto, I'm building a '78 kz400 using a lot of your info on this forum. Would you mind giving me a brief description of what you did for electric/wiring cleanup on that 440 you built? Did you replace the stock wiring system with a newer, slimmer system or just tidy up the old one? Was that 440 electric start or kick only?

harmsworthj wrote: beretto, I'm building a '78 kz400 using a lot of your info on this forum. Would you mind giving me a brief description of what you did for electric/wiring cleanup on that 440 you built? Did you replace the stock wiring system with a newer, slimmer system or just tidy up the old one? Was that 440 electric start or kick only?

Wow. Three years later and I still get notifications from this thread.

The wiring harness was left mostly stock. I think i moved a few things around and welded a few strips across the underside of the seat frame to re-locate the rectifier/regulator. I re-wired the tail light and signals and ran the wires along the seat frame.

This 440 was electric start only because it had the 6-speed gear box. That's how I got the bike originally- the owner blew up the starter motor trying to jump start it and since it was electric start only, he never bothered to change the starter and it sat in his garage for 20 years. It took an ebay starter motor and a new battery to get it running.

CptHaddock wrote: Bringing old thread back to life to add to it. Huge thanks to the dudes who've posted on here. I just did a VM34 carb swap on my 79 kz400 using info strictly from this thread. Welded up a cheap 2-1 intake out of some 1 1/2 inch exhaust pipe. Grabbed the GY6 throttle cable suggested earlier (definitely long but bolts up fine). Put everything together and it started immediately. Idles way smoother than it ever did, got a little tuning to do still (hesistates if you open the throttle up too fast) but once it starts to pick up RPM it pulls pretty hard.

Will post pics shortly.

I recently bought myself a 78 kz 440 with the mikuni vm34 carb conversion already on it. I myself am also experiencing the same issue when you open the throttle up too fast. Did you end of resolving this issue??

Manual slide carbs (with one single bore) normally have the problem of stumbling if you open them too fast. In the old days you needed good throttle control to get the most acceleration. CV carbs let you whack it open as fast as you want. Under load, you can't really do that with slide carbs. (Unless the carb is really small, or has a secondary bore, like on a car.)

So it is really a matter of how bad the problem is... as in how fast are you opening it. Sometimes it means you just have a carb that is too big for the engine. When I open the throttle too fast on the manual-slide 550, the mixture gets too rich. So leaning it out will sometimes mask the problem. This results in a bike that seems to run great as long as you are riding like a bat out of hell and whacking the throttle every time. But casual riding will be very lean and problematic. This results in an overall lean mixture and is not good.

If you can lean the intermediate part of the throttle, but make sure the full-throttle jetting is not lean, it might help things. To do that you would lower the needle, and increase the main jet. But it may require using the choke longer, and will be rougher on cold days.

The intake length may have a part in the throttle response. You could try a torque wing.

Correct jetting will help...the VM34 has a really large needle jet. Dropping that down to a Q-O fixed all my throttle woes.

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Trying to figure out what you folks used to mount the vm34 to the 11th hour intake. I've been trying to find a reducer with no luck. Any help would be great. Thanks.

Loved this. Such an informative thread.

I got a 79 KZ400 with stock carbs, doing okay but now leaking fuel. Been thinking about doing a 2-1 conversion, similar to my xv. but equal length like one here.

I wonder why no one used a more modern flat-slide carb that they say would give 30% more power?