kz400 intake boots/carbs

cyglide

Active Member
I just picked up new intake boots for my KZ400. The old ones were rotted and the PO had tapped them up as a bandaid but I like things done right. After finally getting the old ones off (the right side screws were stripped out), it looks like there was maybe a dab of silicon or copper gasket put on them.

When I install the new ones, is there a gasket that goes between the head and the boots? Should I use some light RTV on it? I would suspect since the boots are rubber that should mate up tight enough but I guess I'm unsure.

I'm also having an issue with fuel leaking out of the left side carb. I can't pin point where it's coming from, but I pulled the carbs (since I was doing the intake boots anyways), and will check float level and that the float isn't stuck. Is there anything else I should check here?
 
If your boots are new and soft you shouldnt need Rtv. Check the float needles like you said, if they are the rubber tipped ones I would replace regardless of condition.
 
Alright, got the carbs off and cleaned up. Float needle moved freely and was pretty well clear of debris. Turns out the clamp I used on the fuel line cut into the line and that's where the fuel was coming from. I figured as long as I had the carbs out I would clean them both up. The left carb has a little retainer that sits over the main jet which I believe is stock and how its supposed to be. The right carb had a spring pushed over the main jet which pushed against the bowl to keep the jet in. I'm assuming this was the previous owners half ass job. I'll post pictures tonight. Photobucket doesn't work well on my phone.

Anyone know where I can find one of these? It doesn't look like they come in the carb rebuild kits or anything.

Second, I'm looking for air box to carb boots. Can't seem to find any on EBay or anything. Anyone know where to find these? I think I have a line on a set, but the guy is waiting to see if he needs them for his build before selling them to me.
 
Are you talking about the plastic plug? Some people say you don't need them but I ran them in my carbs. As far as I'm know there are no replacements for the airbox boots. I have used radiator hose on other bikes with good success.
 
Here's the pic of the "jet keeper". The left one is the stock keeper, and the right one is the one with the spring. The little plugs are in there, however the one on the right side is a little chewed up.







 
Also notice, the little silver clips for the float needle to float tang are missing. Some of the diagrams I've seen have them on there, some don't. Were they not used from the factory on these carbs?

I will say, the bike is running pretty good as is, even with that filter stuff clamped to the inlet side of the carbs (another previous owner hack job). After putting the new intake boots on the bike idles smooth, doesn't hunt as much, and returns back to idle better after reving or pulling in the clutch. Before it took several seconds for the idle to slow after reving.
 
So I found the intake boots for a 78 and 79 kz400. Anyone know what the difference in boots is for my 76 to the 78/79?
 
There is a difference in the offset so they are not an exact fit.

Something I found on kzrider.com:
The answer is the 78 & up ones can easily be made to work, and are half the price to boot.

The only issue is that the '78 ones have the mounting holes on the centerline and the earlier ones are offset by 1/8". Drill the hole bigger and it fits fine. Actually, it will bolt up without modification, but the intake on the head will be mismatched with the holder.

Some more info with measurements: http://www.kzrider.com/forum/3-carburetor/489795-kz400-carb-holder-options

When I replaced mine on my 76 KZ400 I used manifolds from a KZ1000 - they have the same issue as the later KZ400 ones, the offset is not the same. I just had to drill out the bolt holes a little to get them to line up properly. Sorry, I do not remember the part number. Sadly, a lot of this information used to be on the KZ400 forum that disappeared a year or so back.

I found this from a previous post:
1. The carb holders from some KZ1000s will work if you use a rat tail file to open up the mounting holes just a hair.
2. There is a Mikuni set of holders that matches up perfectly and is easily available anywhere including Amazon.
The drawback to both of those holders are that they are about 1/2" - 3/4" shorter than the stock holders so there may be some fitment issue if you are using the stock carb boots and air box. But since you are using pods then you should be in good shape.

If you get the 78/79 holders let me know what kind of modifications it needs.
 
Thanks for the info! I think we are talking about 2 different parts maybe. I'm trying to find the airbox to carb boots, I have a set of carb to head boots that I found on eBay. The airbox boots are super hard to find I'm finding out.

I wish that the KZ 400 forum was still going, sounds like there was a ton of good info on there.
 
Ah, sorry for my confusion. I'm not sure of the measurements of either. I have read of people using sections of silicone or radiator hoses for the carb to airbox boots or rancho shock boots or cv joint boots. I think a shock boot being flexible would be a great option though I don't know how long it would last based on shock boots on my forks drying out and cracking in a year or two. The radiator hose would be a good option if you can find something that fits the measurements of the carb mouth and the airbox inlet and has the right bends to it.
 
There's a gent on eBay from across the pond that makes new kz400 intake carb holders since Kawi doesn't have any. They are well made, Oem quality for sure. Just search on eBay and you'll find them. I haven't seen any carb to air box boots available, but you can easily make them as others said. I'll give you mine if you want them they're nice. Message me. Kawasaki said in a service bulletin to use a gasket on the carb holder to prevent air leaks due some screw ups in the design of the carb holders. If yours are in good shape you should be fine, but the gaskets are available on eBay. Check out kz400.com to read up on the history


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