TOPIC:

I recently acquired a 1980 KZ750-E1. It hadn't been operated for over 10 years, so I was pretty sure there would be carb issues. I've reviewed information that I could find online and in manuals and have since taken the carbs apart. As I dig deeper into this project, I have realized all of the information related to KZ750's from this era seem to be fore Keihin cv34 carbs, not the Mikuni's that are on my specimen.
Can anyone tell me if I've got an odd ball that may have been modified along the way? It's pretty much stock and in-tact overall with less and 8,000 miles. The only real modification is a Kerker 4-1 exhaust.
I have to replace at least one jet, and I also will need the associated rebuild kits overall for these Mikuni's. Additionally, one of the diaphragms at the top of Carb 2 has some perforations in it, so I need to at least replace it.
Any advice or direction is appreciated. Even if you can recommend an economical carb upgrade, I may consider that.

Your bike came with Keihin's so obviously someone changed them to Mikuni's.

I would NOT replace the jets in the carbs now, clean them and reuse. Get all NEW O-rings, and float bowl gaskets if yours are in poor shape.

This carb rebuild tutorial may help. Follow all steps, including unganging the carbs. Short cuts are long cuts when it comes to carbs. If you follow this tutorial you will KNOW they are properly clean.
zeus.mtsac.edu/~cliff/storage/gs/Mikuni_...Rebuild_Tutorial.pdf

Thank you Nessism! I'll take your advice and proceed as the instructions say.
Just curious, are the Mikuni any better/preferable to the Keihin? I know the guy I got the bike from is a GS fanatic, so it's not surprising that the instructions you linked to have a GS on the cover.
It's a work-in-progress, but I'll get it there...

can you post some photos of the carbs you have? they will help with identification

Given my druthers I'd take the Mikuni's. I like the choke system better among other things. That said, the driveability of my KZ750 is pretty much flawless so there is nothing wrong with the Keihin's, although they are more difficult to maintain.

As requested by DoctoRot, here are some pictures. First is of them still on the bike. The next one has it cleaned up a bit. Third pic shows it on the bench. Last pic has the bowls off and some of the internals removed.
Pilot jet is a 42.5, main jet is a 125.
I unfortunately striped one of the pilot jet's, so I'm wrestling with it and how to extract it (it's way down in). Any suggestions are welcomed. I'm at the point of planning to buy an easy-out and mildly heat the aluminum body to try and get it out. It's been soaking in penetrating oil for days now.
Since the bike has the Kerker 4-into-1 pipe and the post-stock Mikuni carbs, are there any suggestions on what the jet sizes should be? Do these look workable?

Not to steal the thread here, but the tutorial Ed posted on rebuilding these carbs is really helpful. Is there something similar for the VM26's on a '77 KZ-1000?
Thanks....Sorry for the interruption.
Rick H.

Rick H. wrote: Not to steal the thread here, but the tutorial Ed posted on rebuilding these carbs is really helpful. Is there something similar for the VM26's on a '77 KZ-1000?
Thanks....Sorry for the interruption.
Rick H.

It's not as detailed Rick but this may help...members.dslextreme.com/users/bikecliff/i.../vm_carb_rebuild.pdf