Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
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Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
31 Aug 2026 09:38
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?
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?
Z1000 A1 1976
Z1000 A2 1977
Greetings, Joe
Z1000 A2 1977
Greetings, Joe
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- StreetfighterKz
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
31 Aug 2026 09:46
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
Later, Doug
1978 z1000 Streetfighter
1976 z900 ‘Stripfighter
1978 z1000 w/RC Turbo
1979 z650 Resto-Mod
1983 Gpz750 Resto-Mod
2018 Z900RS
1976 z900 ‘Stripfighter
1978 z1000 w/RC Turbo
1979 z650 Resto-Mod
1983 Gpz750 Resto-Mod
2018 Z900RS
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
31 Aug 2026 10:22 - 31 Aug 2026 10:37
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....
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....
Z1000 A1 1976
Z1000 A2 1977
Greetings, Joe
Z1000 A2 1977
Greetings, Joe
Last edit: 31 Aug 2026 10:37 by MFP-Joe.
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- hardrockminer
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
Yesterday 04:51 - Yesterday 04:51
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.
I have several restored bikes along with a 2006 Goldwing with a sidecar.
Last edit: Yesterday 04:51 by hardrockminer.
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
Yesterday 05:18
Could you mill some spacers to fit between the head and intake rubbers (as a bonus a longer intake should boost low end torque)
1982 KZ1000 Ltd
www.kzrider.com/forum/11-projects/617631...-82-begins?start=192
kzrider.com/forum/faq-wiki/616810-electr...-fault-finding-guide
www.kzrider.com/forum/11-projects/617631...-82-begins?start=192
kzrider.com/forum/faq-wiki/616810-electr...-fault-finding-guide
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
Yesterday 06:15 - Yesterday 07:29
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.
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.
Z1000 A1 1976
Z1000 A2 1977
Greetings, Joe
Z1000 A2 1977
Greetings, Joe
Last edit: Yesterday 07:29 by MFP-Joe.
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
Today 03:27
Golly Joe! Looks like you won't be needing my offering now ha.
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Re: Z1A / Z1B-VM28 carburetors on a Z1000 with original airbox?
Today 06:32
Z1000 A1 1976
Z1000 A2 1977
Greetings, Joe
Z1000 A2 1977
Greetings, Joe
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