TOPIC:

Hello, 
I am working on a 1980 KZ440A, with stock CV carbs. The one has a small puncture in the diaphragm. I’ve tried cleaning jets, cleaned passages, replaced jets, new float needle etc and it still leaks from the bowl and will not start. At this point, I have struggled significantly with the carbs and airbox, and am sick of both. I would like to replace them with 1 or 2 mikuni VM carbs. What are your thoughts on running dual carbs or a 2 into 1 conversion?

For dual carbs, it would be an easier installation, but I would need a split throttle cable, and would require more effort to jet or tune if needed. Or I could make a mechanism to lift both carbs with a single cable

For 2 into 1, I could use a regular cable, andI hear I will have to cut part of the frame for the carb to fit. It would also be easier to jet and tune. Also I would like to fabricate my own manifold if possible (I’m aware of the 11th hr industries), but I do not have a welder

Let me know what you all think!

Thanks

Since you asked...what I think is that you should rebuild your existing carbs properly, without shortcuts, and reinstall them with the stock airbox.  You only have two carbs there, it's NOT difficult work.  JBM sells diaphragms that are simple to install.  I do a lot of carb rebuilds, and while the 440 Keihin's are a little more difficult to rebuild than a mechanical slide carb, in the end, rebuilding them is a simple one-day job, even if doing the job fully and properly.  

NO SHORTCUTS.  You must ungang the carbs, remove all the soft parts, take apart the carbs fully, soak the bodies and jets in carb dip, and clean, clean, clean.  Also, make sure the float bowl vent tubes, if your carbs have them, are not cracked.  It's not rocket science.  It just takes WORK.  But that work will be much less than trying to reinvent the wheel with some aftermarket carb setup.

Edit: you are going to need to buy an O-ring kit for those carbs, or order the O-rings from Kawasaki part by part.  I have a kit that will save you time and money compared to ordering from Kawasaki.  Aftermarket carb kits do NOT have these o-rings.  You need to get them separate.

Just my opinion but I think fabricating a 2-1 conversion and getting it to run right is significantly more work and expense than persevering with what you have

FreshMark wrote:

Also I would like to fabricate my own manifold if possible (I’m aware of the 11th hr industries), but I do not have a welder 

 

Do you have any tools that would be suitable for shaping/cutting metal tubes? If you do make the parts, including the flanges, how do you propose to hold them together? I suppose there could be a JB Weld variant that would do the job, but this seems like a lot of work to do (and will probably decrease performance) instead of fixing the stock carbs. My $.02.

EDIT: which is what Wookie just said. NM.

 

I'll disagree with our experts some. If you like fiddling with things, trying to make them better, out thinking the factory engineers, go for it.
I'm that kind of guy. Most things I own have been modified to improve their function. I can't recall any successes yet, but I'll keep trying. And someday......
In the words of Doc Brown "I finally invented something that works."
 

ckahleer wrote:

I'll disagree with our experts some. If you like fiddling with things, trying to make them better, out thinking the factory engineers, go for it.
I'm that kind of guy. Most things I own have been modified to improve their function. I can't recall any successes yet, but I'll keep trying. And someday......
In the words of Doc Brown "I finally invented something that works."

 

I am one of the last people to talk about "keeping it stock" as my preferred option but it really depends on what your "driver" is. Don't forget that manufacturers spend six figures and more on R&D to ensure (in the main) that what goes into production "works". It would be economically unsound to produce something that doesn't work and results in endless warranty claims from dealers to try and resolve.
In my opinion there is a significant difference between sitting looking at your bike and thinking one of the below

1. "I want to experiment and try something different just to see what happens, maybe I can make it work" (there is lot's of this on the forum)
2. "I am frustrated because I can't get it to work properly so, without an R&D budget, the required fabrication equipment or a sound knowledge of induction design principles I am going to try and make my own in the hope that "it works better than stock"

If you want to "innovate" I salute you, if you want to "fix a problem" stick to OEM