Kz750 carb issues + balancing

So my balancer works well, but I'm having an issue with the carb that has the choke on it. The vacuum is tremendous on it. I cannot get it to calm down. The other three balance well, but that one fills the jar with fluid quickly. I've turned the adjustments on all every way i can. What could be causing it to do that?

Hello One1

This remembers me on my last carb sync issues on a Honda RC08.
PO or someone else try to rebuild the carbs and reassemble one the sync mechanism screws wrong.





here a little video i have done



maybe it solves your sync issue

Michael

Before i can get back to balancing i HAVE to figure out something with these air screws. They are so far off the bike won't even rev past 4k. I set them all at 2.5 turns, thought that was stock settings for these? They were 3-1/4 out on a few of them before i rebuilt the carbs and that wasn't right either. After the engine got warm it would idle very high, still did after the rebuild...... but when i set the pilot screws at 2.5 it all went to hell now its not kicking the right side carbs on until at least 3k when it burbs into life and its bogged down and stalls off throttle. Uhg..... any advice for setting those screws back close to where i can begin tweaking them? I'm decent with a single carb bike, but it's intimidating me doing these carbs. The bike hasnt needed major carb service in the year plus i have owned it until now. I'm usually on my Vulcan 750, which i find tuning easy on the v-carbs.

2.5 turns open is fine. The bike should run very similar from between 2-3 turns. Doesn't matter much other than maybe steadiness of the idle.

Hello One1
Before you go deeper to tune your turns of the pilot screws, check that all parts
under the pilot screws are in place and in the right order and nothing is missing.
Check all pilot screws needle tips are in good shape and not bend or one broken of.




Michael

Thank you! I've been smoking it over and i think the plug has fallen out of that pilot in the float bowl. I remember one being looser than the rest and I've got a suspicion its not in place anymore. I'll find out tonight.

Below are the results of my float test. No issues.

Current symptoms: bog, high idle rpm that hangs.
Boots on both sides are clean and secure on every carb.

I've checked everything suggested in the thread any other ideas to the update just before this one

It's really hard to say what could be wrong. I've advised you to take the carbs fully apart and soak everything in carb dip but pretty sure you didn't. Maybe some small passages are plugged?

Your photos show use of a hose clamp on one of the airbox boots so that's not right and it's likely you have some air leaks in the system somewhere.

In order for the carbs to run properly they need to be surgically clean and everything fully sealed air tight. All vacuum plugs need to be in place and the carbs vacuum synced properly too. Your sync tool looks a little sketchy but I'm not sure about that either.

I just bought a set of those carbs off ebay. I'm going to go through them and make a rebuild tutorial to help you guys out. There are two of you guys right now here struggling with your 750 carbs.

I know that pics can be misleading, but in the first three clear tube pics, the fuel level look pretty low.

Nessism wrote: It's really hard to say what could be wrong. I've advised you to take the carbs fully apart and soak everything in carb dip but pretty sure you didn't. Maybe some small passages are plugged?

Condenseding help isn't help, and unwanted. Just because what you suggested hasn't worked to fix it doesnt negate it's issue nor my effort.

Carb rebuild guide