Topic: Question for KZ750/900/1000 Experts?

[BenelliSEI]

I’m working a set of Mikuni carbs that came on my CB750 Chopper Project. I thought they were from a KZ1000, but am probably wrong. They’re fitted to the CB750 with a set of SUDCO adapter manifolds. Mains:110 and Idle: 17.5

I can’t seem to attach pictures right now, but if you visit “Project Shop” and look at the last page of my “1975 Chopper” posting, there are two good photos. I need to order 4 X new float bowl gaskets. Any idea what year/model these came on originally?? Thanks for your input.

[Medyo Bastos]

Prolly vm26


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[StockRider]

Are they marked?

On the flange of Mikuni mechanical slide VM series carburetors there is an ID mark which identifies them... Look under the choke lever on the flange where the carb flange meets the bracket that holds all four carbs. The ID mark will be either four or five numbers or numbers and letters. If it has four numbers, there will be three numbers on the top and one on the bottom generally. An example:

147
  3

If there are five numbers/letters, there will be three on top and two on the bottom:

105
 5A

[BenelliSEI]

Will check today. Thanks!

[BenelliSEI]

Are they marked?

On the flange of Mikuni mechanical slide VM series carburetors there is an ID mark which identifies them... Look under the choke lever on the flange where the carb flange meets the bracket that holds all four carbs. The ID mark will be either four or five numbers or numbers and letters. If it has four numbers, there will be three numbers on the top and one on the bottom generally. An example:

147


If there are five numbers/letters, there will be three on top and two on the bottom:

105
 5A

Checked very carefully for numbers and there are none. Measured the throat diameter at the end closest to the intake manifolds, 27 mm.

[BenelliSEI]

After much searching. SUZUKI part number 13251-43010 looks identical. Ordered.

Any more input appreciated,

[StockRider]

WARNING: I have experience with only one vintage Mikuni rack and I never figured out what bike they belonged to....  But, some internet search results make me wonder if the gaskets in your other thread match the carbs...



Notice how there is an imprint on your gasket in the area near float mounting posts? But, then, do the bowls belong? I was told by a KZ fan that there were often bowl swaps and gasket mismatches between the pumpers and non-pumpers (accelerator pump).

If I only had your carb bodies as a reference I would think that they use the gasket in image #1 below which supposedly goes with these:
VM24 - VM26 - GS750 GS1000 - KZ650 KZ900 KZ1000
https://www.z1enterprises.com/gaskets-float-bowl-vm24-vm26-gs-kz-200-3037.html

However, your gasket image looks like image #2 which supposedly goes with these:
1977-79 Kawasaki KZ650 KZ650C KZ650D KZ650B
https://daminedingmoto.com/4-x-77-80-kawasaki-kz650-kz650c-kz650d-kz650b-carburetor-carb-repair-rebuild-kit/

A bit of info specific to KZ1000s:
"OEM MANUAL THROTTLE SLIDE CARBURETORS [VM Mikuni]
The original Z1 900’s came with VM28 Manual Throttle Slide Mikunis. Some people really like those carburetors. Personally, I think they’re inferior to the late model VM28’s with accelerator pumps. The early 28’s had a horrible linkage setup and could be a chore to synchronize accurately. 30 plus years of wear hasn’t helped them any. Still, all things considered, not a bad set of carburetors but not the best that ever came down the assembly line. Years do tend to bring improvements and carburetors are no exception.

In 77 Kawasaki downsized the carburetors to 26mm with completely revised throttle linkage. They performed adequately and were a lot nicer to synchronize. However, the 2mm decrease in throat size makes them less than the ultimate OEM carburetor for all out performance. Don't misread that statement though. Those carburetors work just fine on a stock motor.

The 79 MKII saw the return of the 28mm carburetor with the superior throttle linkage [like the 26’s] and accelerator pumps to boot. Those, IMO, are the best carburetors fitted to a KZ 1000 from the factory. LEAVE THE FUEL PUMP ADJUSTMENT ALONE. The 1980 LTD also had the late model 28’s with accelerator pump."
https://www.kz-1000.net/

There was also a page at Z1 Enterprises website for many years which was removed in a website "upgrade". It is still available via Internet Archives: https://web.archive.org/web/20120204062747/www.z1enterprises.com/reference/z1-carb-guide.aspx

[BenelliSEI]

Stockrider..... thanks for all this, i’m Reading and looking through all of it. I think you are correct and the float bowls I have are not original to my barbs. The carb body has the circular hole in it (matching the gaskets I ordered) but the float bowls do not. My old gaskets are imprinted with the body outline. I suspect the gaskets I ordered will work fine. The bike ran really well, but the floatbowls were stained and nasty. Hopefully I’m not just creating problems for myself!

[Stev-o]

There was also a page at Z1 Enterprises website for many years which was removed in a website "upgrade". It is still available via Internet Archives: https://web.archive.org/web/20120204062747/www.z1enterprises.com/reference/z1-carb-guide.aspx

Thanks for posting this, I have looked for this page a couple times and could never find it.

I have posted this info on a new thread in the "Other Bikes" sections and have asked the mods to make it a stickie.