Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?

Hi everyone,
a few days ago I managed to pick up a Z1A or Z1B VM28 carburetor setup at a pretty good price.
I’ve always wanted to run these old 28mm carbs on my Z1000A2 (a combination I’ve never actually tried in all these years,I`ve just used to run carburetors like that on the Z1000 using only open velocity stacks—or just the airbox's internal screens—without the large airbox housing itself.)
Now I’m facing a problem: The "old" 28mm carbs are about 10–12 mm shorter than the later VM26s (from the Z1000) and VM28s (from the Z1R, MK2, and ST). Consequently, the intake rubbers between the airbox and the carburetors might be—logically—too short.
Has anyone here ever run or installed these "early" Z1- carbs with the Z1000 airbox on a Z1000 ? Are there perhaps "longer" intake rubbers available for the airbox connection?






 

Could you run a Z1 airbox?  It wouldn’t be “stock” appearing for the year but neither are the carbs.  Frames are basically the same, just might need to bottom airbox support to keep the box from sagging.

Later, Doug 

Hi Doug,
No, I had considered that too, but the Z1000 side covers really don't go well visually with the Z1 airbox... I had thought also about running the Z1 airbox *and* the Z1 side covers, but I don't want to grind off or modify the original mounting tabs on my Z1000 frame...Theyre postions ar a bit too far from the Z1 frame, to fit Z1-sidecovers on an z1000 frame... ... sure, I could make and use adapter plates and cut out the bottom of the right-hand Z1 cover to make room for the master cylinder... but, to be frank: I don't have a Z1 airbox or Z1 side covers, either.

I’d already weighed up all those options and was sort of hoping someone here might say, for instance: "Hey, it's easy—just use the intake rubbers from the Z?????..." -

I suppose I could potentially shift my Z1000 airbox those missing 10mm further forward—I’ll have to take a close look at that—but first, I’m going to test these carburetors on my buddy’s engine dyno this Thursday to see how they run. I’ve already set the float levels, installed new jets, stripped the original clear coat off the top covers, and—of course—machined the stainless screws down to the correct diameter. , see my other thread here..haha!




((If I can't find a technical and aesthetic solution that works for me, I'll try swapping these carburetors—which are still in pretty good shape—for a VM28 from a Z1R, MK2, or ST... then everything would fit just fine... but I just really love the "old" Z1, Z1A, and Z1B carburetors....
 

I have a Z1 airbox and VM26 (1976 version) carbs on my 1980 KZ1000 LTD.  I have a spare set of VM28's but have never tried them on the KZ1000.  I prefer the 26's to the 28's.  Easier to synch.

Could you mill some spacers to fit between the head and intake rubbers (as a bonus a longer intake should boost low end torque)

Hi Hardrockminer,That is certainly the experience I—and many others—have had: the later carburetors are a) easier to synchronize, and b) the synchronization holds for longer.
I remember all too well how, with the early 28mm carburetors, after successfully synchronizing them, the synchronization gauges would show completely erratic and disordered readings again after just three or four sharp twists of the throttle. But i still love them, beginning on their response by quick open the full throttle, to the early design, and of course on the very early `72-`73 models, the central drain plug, that allows a quick-change of main jet on the highway ...

Hi Wookie, unfortunately, that’s no longer an option for me; as part of closing down my workshop here, my milling machine hasn't been operational for about two weeks—so I have NO way to do any milling anymore (sigh)... ((I’m still hoping someone buys the machine; otherwise, I’ll unfortunately have to dismantle and scrap it...))—One other possibility would be to turn some "extensions" on the lathe to fit *behind* the carburetors; we'll see how things pan out... I'm still a bit undecided!


That—sketched out simply—would be one option: if I were to machine four such adapter spacers on the lathe, I could make up the missing 10–12 mm without having to cram the airbox forward... Let's see how the carburetors run the day after tomorrow, and then I'll take action accordingly.
 

Golly Joe! Looks like you won't be needing my offering now ha.  

Well, Clay, you haven't let me hear anything further about that offer of yours... ha!

You have to excess my delay, we cut a lot of sod/grass. That's the prosperity function, motorbikes have to take a side regard. To of shipped crap to You my Friend, I would of have to go to town and assessed shipping fees and Customs doctrinarian. I'm not soo sure these days since our retard president keeps shapeshifting every other day based on his cold oatmeal, or too hot breakfast? Still.Love You my Friend. My German relation from afar.   

Yikes!

t’s all good, Clay—as I’ve mentioned a few times: please don’t feel pressured or put yourself out on my account; everything is fine just the way it is! Best regards, my distant relative.
 

I visited my longtime Kawasaki-loving buddy again today;
he happened to have a 900cc engine set up on his makeshift test stand.
We hooked up my 28mm carburetors (I had already performed a basic static synchronization and set the float levels, with the idle mixture screws backed out two turns).

And—lo and behold—the engine fired up immediately on the second turn of the starter. After a very brief warm-up, it ran smoothly and beautifully with these carbs, both at idle and when the throttle was snapped open. A surprising and fantastic result. (There was a tiny bit of fuel seeping from the left T-connector, but it isn't loose; I think it will seal itself up again through contact with the fuel... otherwise, I'll replace it! The choke plungers also appear to be sealing well.)

Indeed, a NiZe-surpriZe !...I was absolutely delighted!


Now I can get to work cleaning up the exteriors of the carburetors a bit more and fabricating the adapters for the airbox... my plan is to have them installed and ready to ride by the start of the next biking season in March '27.


((On Sunday, we’re planning another nice 350 km ride to visit his brother; the weather is supposed to be dry, and I’ll be riding my black A2... it’ll probably be the last long ride of over 100 km for me this season.))