My VM24 carbs should be pumpers?

This thread (KZ650 CSR Accelerator Pump Clip Question) got me thinking about the VM24 carbs that came with my '81 650 CSR. This is the third thread on the carburetor mysteries surrounding my bike so I won't rehash it all here. The bottom line is that my carbs are NOT pumpers. Should I care?

Thanks,

Barry

Does the bike run okay?If so,dont worry about it.From what I've read on this forum,its no big deal.The pump just gives a small squirt of gas as you rev from idle.

stokes wrote: Does the bike run okay?If so,dont worry about it.From what I've read on this forum,its no big deal.The pump just gives a small squirt of gas as you rev from idle.

Well, it doesn't run at all right now except on starter fluid so that's why i'm rebuilding the carbs. I just bought it and the carburetor situation was a bit vague at the time of purchase. See here for details.

I'm thinking along the same lines as you, though. I'm not too concerned about it but if there's a reason why I should be, the guys around here would surely know.

Barry

The main purpose of the pumper carbs was to prevent stumbling under sudden throttle opening on U. S. spec bikes that were jetted very lean to satisfy the gubmint. If you jet them for a more reasonable mixture, you won't need the pumps.

TexasKZ wrote: The main purpose of the pumper carbs was to prevent stumbling under sudden throttle opening on U. S. spec bikes that were jetted very lean to satisfy the gubmint. If you jet them for a more reasonable mixture, you won't need the pumps.

Oh, perfect. We already established that my slides match the non-US specs for my year, so that's adding up now. It looks like the pump version carbs were US spec for a few years, hence the more anemic jetting for US models in the manual. That's all I needed to know. I'll be using the non-US jet specs to match the slides ( as you suggested ) so I should be good.

Thanks so much,

Barry

I would try to figure out for certain if you have the stock carburetors or earlier carbs.
It could be that someone disabled the pump or the carbs were replaced altogether.

Kawasaki service manual pdf. jarlef z650 . the 1981 KZ650 pdf is in the Files section.

Carb spec table from the pdf.


1979 KZ650 VM24 carburetors w accelerator pump. just for comparison. the 81 650-CSR carbs are similar (USA).
i.imgur.com/0SmxFe2.jpg ... i.imgur.com/OuQ8Kj7.jpg .... i.imgur.com/b52Epan.jpg ... i.imgur.com/XW3LdlG.jpg

martin_csr wrote: I would try to figure out for certain if you have the stock carburetors or earlier carbs.

Hi Martin,

Yeah, that's what I've been trying to do and I think I've come up with the answer. I wasn't really planning to pull the slide assemblies apart but I just did in order to identify all of the components. Here's what we now know about my carbs:

• They're VM24SS non-pumpers
• Slide cutaways are 1.5
• Needles are 5DL31-4
• Main jets are 102.5
• Pilot jets are 15

These numbers all line up with the specs for some of the late 70's KZ650's - but they're also not far off from the specs for a non-US '81 CSR (needle is different). I'm thinking the best thing to do at this point is to forge ahead with everything as-is and see how it goes. The setup should be good enough to get anything in the 650 family running, right?

Barry

I didn't think the 1981 KZ650-H1 came with pumper carbs. Take a look at the links below. I looked but didn't see accelerator pumps - maybe I missed something? In any case your bike should run fine without pump carbs. I have never had any problems with my 1977 KZ650-C1 carbs in nearly 40 years, and they are not the pumper type. Ed

www.powersportswarehouse.com/p/Kawasaki#...50-H1-1981/070087C-9

www.powersportswarehouse.com/p/Kawasaki#...50-H1-1981/070087C-7

650ed, the accelerator pump is in a separate diagram, the 1st one in the list of diagrams, just ahead of the airbox.

stratman: are you in Canada or near there? I'm assuming you're in the USA.

650ed wrote: In any case your bike should run fine without pump carbs. I have never had any problems with my 1977 KZ650-C1 carbs in nearly 40 years, and they are not the pumper type. Ed

Great. Thanks again, Ed.

Barry

martin_csr wrote: stratman: are you in Canada or near there? I'm assuming you're in the USA.

I'm in Massachusetts.

Barry

martin_csr wrote: 650ed, the accelerator pump is in a separate diagram, the 1st one in the list of diagrams, just ahead of the airbox. .......

Thanks! Here's a link to it. Ed

www.powersportswarehouse.com/p/Kawasaki#...50-H1-1981/070087D-4