KZ440 Single Carb Conversion

awesome thanks

Nice Bike!! Did you mod the original frame? or is that from another bike. KZ 400 maybe??

This was a 1980 KZ440B so I think it had the same frame as the 400. It's definitely different than the 440LTD.

barreto, I followed your write up as a tutorial for my LTD 440, like you mentioned the frame is different, i had to cut away some to get it to find but it does, i have to ask what with the vm 34, it has 2 pink hoses, do those hook up to anything or re they just over flow? i had gas just in the carb alone and it ran father long with no tank, also idk if the kz 440 has a 2nd smaller hose coming off but i am just curious and cant seem to find much info

The pink hose on the bottom is for draining the bowl and I think the top pink hose is for an overflow, I can't remember exactly. Mine did have a small second hose off the petcock which I think was for vacuum to help flow but someone else might know more about that. The VM didn't have a place for that hose so I capped it off. It didn't seem to hinder fuel flow.

I wish I could be more helpful but I don't have that bike anymore so I can't verify the details very well.

Those pink hoses are vents on that dirt bike carb.


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:woohoo: Man I have been struggling with this damn stock carb on this 440 for months. Thank you so much for putting this post up!

Hey there, Sorry to bring up this old thread, but I've been scouring the web for information on this carb conversion and it seems like you have to closest thing to a "perfect" setup and I really have nowhere else to turn at this point. I have a Mikuni VM34 attached to an 11th Hour Industries manifold on my '80 440 LTD. I've used the same main and pilot jets that you talked about at the beginning of this thread. After ordering a custom throttle cable from Motion Pro, everything is hooked up but I cant get the damn thing to idle. No adjustment of either of the screws seems to make a difference other than about 30 seconds of sputtering and chugging at about 4000 RPM. The only thing I did differently was adding a small, clear fuel filter to monitor the flow of fuel. It almost seems like without the help of that upper vacuum line (to increase the fuel flow) coming off of the fuel outlet that maybe it isnt getting fuel quickly enough? Any tips you may be able to pass along regarding tuning this carb would be GREATLY appreciated, because the manuals are absolutely no help. Thanks!!

Have you tried running it with the petcock on prime? By the way nice choice on the bike. I have the exact same year and model.

This may sound stupid, but it's a problem I've run into several times with mis-matched carbs, cables and throttle grips- make sure the slide is sitting at the bottom of it's seat. I've had several carbs be slightly raised due to cables being a bit too short or an aftermarket twist grip taking up too much cable. I've had to shorten cables housings and/or drilling out the cable adjustment to make sure the slide sits correctly for idle.

Awesome, I'll check it out. As a matter of fact, I DO remember it being a pretty tight fit with that adjustment cap on top. Maybe it's just lifting it up enough to mess with it. Thanks for the quick reply! Yeah I've tried running it on prime, but I just thought that it was strange that no matter how long it sat there, the float bowl never overflowed. I hope the cable isn't too short because I had to send in the grip, grip housing, old cable, and the carb to Motion Pro in California and they made the custom one from their documentation on those parts. Custom cables are kind of their thing, so I would sure HOPE that they didn't make the cable incorrectly. It would be a shame if that cable was useless for me. Did you have any problems with adjusting the air adjustment or any other adjusters when you fired it up for the first time?

The carb should never overflow. If it does, then the needle valve is no longer working or is badly mis-adjusted.

If the bike has a vacuum petcock that does not have a vacuum line hooked up to it, then the only way to get fuel from the tank to the carb is to turn the lever to PRI. If there is no vacuum and fuel flows, even a little, when the lever is on RUN or RES, then the petcock likely needs rebuilding.