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Modern carb suggestion? 31 Oct 2017 15:38 #774059

  • loudhvx
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Wow, the permutations are mind boggling!
So it looks like all the carbs in question use a 92 spacing between 2 and 3, which is the 2-to-3 port spacing on Kz/Zx 550 motors (and maybe Zr550 and Zx600?). So the inner two carb holders wouldn't need to be offset on the 550's correct? But then the outer two would need to be offset.

Corey, who raced Zx550's, said Zx600 carbs fit on the Zx550, but he didn't mention the offset rubbers.

Did the port spacing on the Kz750 motors retain the same spacing as on the 650's such that you could presumably use 650 carbs on a 750 with centered (non-offset) rubbers?

I wonder why they moved the outer two carbs inward on the Zx600 from the original Kz550 spacing. Were the ZX600 cylinders closer together due to water cooling? Strange because the headers supposedly interchange with the Kz/Zx 550 headers.

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Modern carb suggestion? 31 Oct 2017 17:03 #774064

  • Daftrusty
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Wow, the permutations are mind boggling!
So it looks like all the carbs in question use a 92 spacing between 2 and 3, which is the 2-to-3 port spacing on Kz/Zx 550 motors (and maybe Zr550 and Zx600?). So the inner two carb holders wouldn't need to be offset on the 550's correct? But then the outer two would need to be offset.

Corey, who raced Zx550's, said Zx600 carbs fit on the Zx550, but he didn't mention the offset rubbers.

Did the port spacing on the Kz750 motors retain the same spacing as on the 650's such that you could presumably use 650 carbs on a 750 with centered (non-offset) rubbers?

I wonder why they moved the outer two carbs inward on the Zx600 from the original Kz550 spacing. Were the ZX600 cylinders closer together due to water cooling? Strange because the headers supposedly interchange with the Kz/Zx 550 headers.


The zr550 inner carb boots are a straight shot while the outer boots angle in. Same with the zr750's. The boots also differ from kz/gpz550 boots in that the cvk carb inlet boots have a larger inner diameter than the stock carb inlets to accommodate the larger carb throats. So zr550 carb boots are needed to fit cvk carbs to the gpz's. I'm 90% sure that is what Corey is using. I believe he originally started with cvk30's from a zr550 and then went to larger cvk32's. Once again, the 30 and 32's are identical excepts for the inner diameter of the carb throats.

zr550 intake boots


Zephyr 750 and zr-7 boots on kz750


The kz750 and kz650 port spacing is identical. So carbs can be switched around as long as the specific inlet rubbers are used as some of the carb throats are different sizes.

Kawasaki made all the cvk carbs with standard spacing for their entire range. It was apparently easier/cheaper to manufacturer specific inlet boots for each model rather than have different throttle assemblies and carb racks for all the different spacings.
The zx600's exhaust spacing is also identical to the kz/gpz/zr550's so it is strange that the intake spacing is different. They use straight inlet boots, so the spacing must be different because of the water jacket or because of the larger dual intake valves.
I have never seen a zx600 head up close so I am at a loss to explain it.
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Modern carb suggestion? 31 Oct 2017 18:28 #774066

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Thanks!

I guess if you're going to re-design ports for 4 valves, it's just as easy to move them over a bit to fit the carbs.

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Modern carb suggestion? 01 Nov 2017 03:24 #774080

  • Ojisan rider
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Thanks Daftrusty! My budget for under $200 applies to getting the carb. Price of rebuilt is not included in that. I know most of the carb, new or old, will need some kind of attention, so I don't include rebuild cost in that. However, knowing that it needs rebuild, and I have RS carb somewhere in my house, is one of the reason whyI want to stay under $200 for the carb.

Anyway, I want to thank everyone for all the great info. Now I know what I need to look for.

BTW, how is modern 32 compare to old 34's? I have brand new 34 rubber boots for all four cylinder. Will that work on 32? If not, I want to stay around 34 as soon as I find the RS, I'm gonna put that on (I'm pretty sure that was 34.).
82' KZ750-R1 cafe racer style. Clip-on, Rear set, Fork-Brace, Mikuni Flat-slide (forgot the size), Kerker.
84' GPz750 (basket case). everything are in pieces.
89' ZX750-H1 (ZX-7 Ninja). Resurrection project are on going with my KZ750. Everything is stock.

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Modern carb suggestion? 01 Nov 2017 06:43 #774082

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You would have to use 2001-2005 zr-7 intake boots to fit cvk32's to your bike. RS34 or stock kz boots are not the proper size or offset.
CV carbs and flatside carbs can't be compared by intake sizes. 750 motors can use vm28's, smoothbore 29's, cr29's, cvk32's, bs34's, fcr31's, rs34's.....etc
Because there are at least three different kinds types of carbs (flatsides, cv and roundslides) they all react and fuel differently when attached to the same motor. A rs34 provides way more fuel and in a very different way than a stock cv34 or bs34. So you can't determine the proper carb size by what it had stock, but by the style of carb and your particular engine.
The rs34 is best for a bored out, big valve, ported, hot cam 750 motor. A near stock engine dosen't have a strong enough vacuum signal to properly draw/meter fuel from a carb that big. It will bog all over the power band.

IF you decide on the cvk32 route, here are some helpful links to the cheapest quality rebuild kits I have used:

Yes... The kits are for a zg1000 Concours, but they use cvk32's also. ( for more torque )
www.murphskits.com/product_info.php?cPath=1_94&products_id=130

www.murphskits.com/product_info.php?cPath=1_94&products_id=414

And if you want a jet kit that is designed specifically for use with (the kz/gpz/zr750 engine) an airbox and 4-1 or pod filters and 4-1 exhaust and dosen't require drilling the slides (like dynojet) Factory Pro has the best one. They aren't cheap, but they are worth it.

www.factorypro.com/Prod_Pages/prodk75.html
(starcycle.com will special order any Factory Pro jet kit for way less $$ than Factory Pro sells it. Just call them and order it by phone, as they no longer list the zr750 kits on their website.)
Just food for thought

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Modern carb suggestion? 16 Apr 2019 13:04 #802240

  • krstich
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I have '92 Zephyr 750 and I'm in need of new set of carbs.
1. I should look for carbs from zr-7 or zx600a/b/c but which years?
2. which intake boots will i have to get?
3. will my air box still work with these carbs?
4. Will i have to use same size jets that i have in mine now?

Thanks
Sasha

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Modern carb suggestion? 20 Apr 2019 05:44 #802454

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I have '92 Zephyr 750 and I'm in need of new set of carbs.
1. I should look for carbs from zr-7 or zx600a/b/c but which years?
2. which intake boots will i have to get?
3. will my air box still work with these carbs?
4. Will i have to use same size jets that i have in mine now?

Thanks
Sasha


1: 1999-2003 zr-7 or zx600a/b/c models were made from 1985 to 1997. (At least here in the US)
2: Your Zephyr already has the correct intake boots. They use the exact same ones the zr-7 uses.
3: Yes! Zr-7 and zx600 cvk32 carbs are identical in dimensions to the cvk32 your Zephyr currently uses. They will connect to your air box using your Zephyr boots.
4: Yes!! You will need to move all the needles and jets from your old carbs to your “new” carbs. If you get zr-7 carbs, you will need to also swap out the emulsion tubes as well as needles and jets.

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Modern carb suggestion? 16 May 2022 01:02 #867146

  • Jenno
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Morning Fellas.....I know this is an old thread but thought I'd dive in and take a chance anyway..
An incredible amount of information but I still managed to get lost....so here's my issue. 
Kawasaki zephyr 550 1992 with carbs that despite the best efforts of Harry Potter still stuck in air..
Told its probably the Throttle Shaft Seals and best to get a replacement set of carbs...
As I'm sure you're aware....Zephyr 550 CVK30 carbs are as rare as a virgin in a maternity ward..
So the question is....what carbs are my options 
                                ....WillI need to change the boots
                                .....Should I bite the bullet and replace the Throttle Shaft Seals
if you can help fellas that would be amazing and I would be eternally grateful 
    Thanks everyone in advance......Jenno...

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Modern carb suggestion? 16 May 2022 10:18 #867158

  • Stereordinary
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I would say if replacing the throttle shaft seals fixes the problem, just do that. But I also have no idea how difficult that would be. 
A breeze from the west.
‘90 ZR550 Zephyr aka Zephanie
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Modern carb suggestion? 16 May 2022 10:57 #867159

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I have found a Web site that not only sells an upgraded seal kit but also has step by step 
instructions.....it does involve splitting the carbs...removing the butterflies, which have inherently 
troublesome screws , removing the shaft...removing said seals and replacing......then reverse the 
procedure.......no small job and it does say to practice on an old set to gain confidence......
Do I then purchase a replacement set of carbs...strip and replace all the seals and hopefully 
end up with a all bar new set of carbs......

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Modern carb suggestion? 16 May 2022 20:55 #867187

  • Zaddict
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Just a reminder that there are many used parts still available from Japan. I use jauce.com a lot (much more than ebay these days).  It can get pricey with shipping but there are loads of carbs and carb rebuild kits for the zr400 (which will fit a 550, and from what I learned on this thread also a 750) -

www.jauce.com/search/Zephyr+400+carburet...elect=02&n=100&link=
 
1990 Zephyr zr550 B1
Factory Pro Stage 1 jet kit
zx550 cams
SPII ignition system
Kerker stainless steel race exhaust with 1.5" competition baffle
K&N Air Filter...
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Modern carb suggestion? 17 May 2022 01:28 #867196

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Thank you my friend.....what an incredible discovery.....this is my new go-to website 
one brief look and I'm like a kid in a sweet shop....thanks again.....Jenno..

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