I have a '80 KZ1000 that sat for a long time with gas in it (10 years). I have cleaned everything out and it has been running/driving.

I couldn't get the stock VM28SS carbs on it to run right. It was always popping out the carbs and when reving the engine, it would not come down in RPMs very well...

So I got a set of VM26's off my brother in law and I had those tuned as well as I could so that the bike would run. While I had them a little rich, they were still working pretty good. I needed to tune them and move the clip on the slide needle. So I took them apart and cleaned them again when moving the clip. The problem with this set is the pilot air screws seems hard to get in and out. Now I have one stuck. I think the threads are dirty. If anyone knows the tap and die I would need to clean the threads, let me know...

So tonight I put the 28's back together to try to get them to work. The 26's were kind of doggy anyway. I have them in and the bike runs, but I think I have a vacuum leak. It's popping out the carbs, alot when cold, a little when warm. If I twist the throttle, it will rev up to 4000 rpms and not come back down for 5 to 10 seconds. It will stay there for a very long time. If I open the choke up, the RPMs will increase slightly then come down very very little. Then if I close the choke, it will come back down to idle. I know the carb boots are ok and not leaking. I also know the petcock is not the problem since both of these things were fine with the 26s. I've sprayed some starting fluid around the carb bodies and the throttle doesn't seem to change at all.

Any ideas? I'm out of them.

 

When you rebuilt the 28's did you clean all the passages out with compressed air? Also, did you check the slide needles to make sure they operate freely? Maybe the idle air screws are set too lean.

 

Yes I did... Compressed air, carb cleaner, I've even given them a couple baths in Chem dip (after removing all rubber stuff). The needles seem to move very well.

I'm going to try a few things tonight. I'm going to wrap my air box up in some shop towels to see if restricting the air flow a little makes it run any better. If it does, then I will know it's just getting way to much air. That air box is an aftermarket chrome one that has some light screen material in it. I also need to check to see if the pumper is working now that I have rebuild it. It didn't seem like there was a whole lot of travel to the arm... However, if it is working, maybe I have too big of pilot jets in it and it's getting too much gas causing it to stay high on the rpms.

 

Well, it sounds as if you're doing everything properly.

There are some knowledgeable carb guys on KZrider.com. If you can't figure it out, try asking over there too.

 

I am being lazy, what are the [quote][I couldn't get the stock VM28SS carbs on it to run right./quote]

They a cv? just asking

 

No, they are the VM series, all mechanical slides.

I did some more stuff to it last night and I am completely stumped. I wrapped some heavy duty paper towels around the air filter and it didn't run any better, but when I shut it off, I noticed a bunch of gas on the towels on the bottom side of the air filter. Took the air filter off and ran it for a while without and no gas coming out of the air box side of the carbs. The pumper is not working either, and I just rebuilt it.

I'm so tired of messing with these things I took them off and I am getting a different set. I'm going to pick up some BS34s.