Which carbs do I have?

Hi all,

Due to some engine troubles I am going to clean my carbs. Because I will be boiling them in a lemon juice/water mixture, I will need new gaskets. Trouble is, I am not sure which carbs I have. The bike is a 1977 Z650B1, which should have either Mikuni VM22SS (Kawasaki manual) or VM24SS (Haynes manual).
Measuring the inner diameter of the carbs exits, I get about 26mm (25.8-something). Doesn't that mean I have VM26's?
If so, how should these be jetted? I use the standard airbox/filter and a Marshall 4-1 that (according to the factory) does not need rejetting.


Thanks!

Zthou1977 wrote:

Hi all,

Due to some engine troubles I am going to clean my carbs. Because I will be boiling them in a lemon juice/water mixture, I will need new gaskets. Trouble is, I am not sure which carbs I have. The bike is a 1977 Z650B1, which should have either Mikuni VM22SS (Kawasaki manual) or VM24SS (Haynes manual).
Measuring the inner diameter of the carbs exits, I get about 26mm (25.8-something). Doesn't that mean I have VM26's?
If so, how should these be jetted? I use the standard airbox/filter and a Marshall 4-1 that (according to the factory) does not need rejetting.


Thanks!

did you measure the inside diameter on the cylinder head side?

Nebr_Rex wrote:

did you measure the inside diameter on the cylinder head side?

Yes, it is about 26 mm (25.8 or so). Strange thing is, I have a later set of Mikuni carbs (with a different kind (stump instead of sharp) and position (diagonal on the side instead of at the bottom) of the pilots). This later set also measures about 26mm on the inside diameter on the cylinder head side. These were sold to me as a set of late-model Z650 carbs.

I have a set of verified VM26SS from one of my KZ1000A1's off my bike as I type. They measure 26.6mm...

Take the measurement inside the carb bore near the throttle slide.

The VM24 carbs measure ~26mm at the engine side opening, but 24mm near the slides on either side.

I could be wrong (and most likely am! :woohoo: ) but heard that the 24's had the three ribs on the body and the 22's did not?

@ JMKZHI:
I just tried to measure the inside diameter at the slide. But because I only have a slide caliper that cannot quite reach there, I had to align it by eye. Best guesstimate is that the diameter at the slide is 22mm. It is also the most likely, as the Kawa manual says so. I cannot measure the newer set, as I put these on the bike yesterday.
All of this started because it would only run on three cylinders. With the newer carbs (which are spotless inside, and with the vacuum line capped) the bike wouldn't even run.
Guess I'll have to order 4 carb kits and wait. Not a problem right now, as I can only work on the bike between the downpours. Ghastly weather here.

@ Bleumeanie:
The carbs have three ribs, like yours.

Thanks for the replies everyone!

@ Z1... Carb Identifications for KZ models...

www.z1enterprises.com/reference/z1-carb-guide.aspx

Carb Theory and tuning manuals...

kzrider.com/index.php?option=com_docman&...d&gid=461&Itemid=108

OMR

OEM seems to be VM24's...

jarlef.no/Kawasaki/Series/Z/650/z650b.htm

Try fitting a socket from your socket set into the engine side of the carb bore.
Find the largest one that matches the fit up to the slide, then measure the outside diameter of the socket.

Both VM22SS & VM24SS carbs have the 3 ribs IIRC.

I've tried measuring carbs and they never measure the mm you expect. Yes the 22 and 24s have the ribs, the 26 and 28 are larger at both inlet and outlet so if you have the stock airbox these are not what you have. All 22-28mm carbs from Mikuni use the same gasket, some aftermarket are trash and don't have the hole cut for the acc pump on the pump carbs used in 79-80, but all factory Kawasaki gaskets were the same.

Zthou1977 wrote:

@ JMKZHI:
I just tried to measure the inside diameter at the slide. But because I only have a slide caliper that cannot quite reach there, I had to align it by eye....

I simply cut a piece of stiff cardboard to 24mm then use that as a measuring device.