VM 28mm

I guess so cause it don’t wanna go in. I used my digital dial and check the new vs old and there was a very slight difference so slight that I didn’t think my cheap gage was being accurate ,it’s one form harbor freight

I also am using the 28mm pumpers. I used KY-5439N kits. I didnt need the needle jets as my original were good. I just measured the ones in the kit and the OD where the fit into the carb body is 5.21 mm

I just measured mine again re-zeroing my dial a couple times and the old ones are 5.16 the new are 5.20. That’s the part that goes threw the body of the carb.

Some photos of the carbs would be useful to identify them. Kawasaki used different internals in different years.

I had re assembled them last nite , till I figure this out. Stamped on the flange by the choke lever is 120
5.

Not well versed on later years than Z1's, but the top caps look like VM26's.

What is the ID of the intake-side throats?


Good Ridin'
slmjim & Z1BEBE

When I first got them I measured just a little shy of 28mm.

Took them off real quick wanted to make sure on the measurements.

I'm not certain, but I believe only the VM28 had the idle adjuster screw on the bottom side. The VM26 generally had it on the top.

I am certain that the '78 Z1R came with VM28 carbs, and that the '78 VM28 idle screw is on the bottom. But you have accelerator pump carbs, so yours would be from a '79 or '80.

Ok, would the needle jet on those year carbs be the same or are they different for each model bike for those two years?

Or what’s the chance that the carb body is deformed a little at that spot making the new jets not fit because there round.(new)?

From the photos it appears that your carbs have fuel/air screws and don't have the pilot adjusters. They also have a pump on the bottom of #2 carb. I think you said your old needle jet was an O4? That would make the carbs either a '79 or '80 KZ1000 for the US market. (Canada was a bit different.) The needle used in '79 was a 5CN17 adjustable with 5 slots. In 1980 they used a 5CN29 needle with no adjusting slots. What needle is in your bike?

Edited to add that the '79 LTD used the same carbs but a larger needle jet....O6.

Edited again to add that sometimes the nets are a loose fit but sometimes they are like an interference fit. What I've done in the past for tight ones is to use a piece of wood dowel (and a small hammer) in the main jet tube to tap the needle jet into place.