TOPIC:

Almost guaranteed you have blocked idle circuits in the carbs. If you can't get the bike below 2000 rpm it's an idle circuit problem. BUT before anything, the first item on the list to check is the float level. If the float is off and out of range EVERY circuit in the carb will be compromised. Once you've insured the float is correct you can start with diagnoses. The idle circuit usually goes up to around 2000 rpm then there's a blending of the idle and the main circuit till about 3500-4000 rpm then the main circuit takes on the full time job of supply above 4000 rpm.

And agreed your bores are not oval. Whoever told you that, you need to stay away from. He has no idea of what he's talking about. Are you the guy in London Ontario looking for someone to borrow a set of decent carbs from? (Saw an ad on Kijiji)

One tool I like to use for checking for vacuum leaks is a propane cylinder with a burner nozzle Like you use for soldering plumbing. Take the burner nozzle off of the neck and put a piece of tygon tubing (about a 3-4 ft. length) over the end of the neck. Make sure the orifice is still in the end of the neck . Then crack the propane valve until you can just smell the propane coming out of the end of the hose. Now you can direct the end of the hose around all the fittings on the intake while the bike's running. if you have a leak, the revs will come up. The best part is it's not messy.

I just had a look at your previous post 3 months ago about the idle choke issue and I can see your frustration brewing. I'm sorry to hear that. If it's any compromise, I've been sitting on a KZ1300 basket case for 18 years and never rode it. Now I have the time to get in to it.
Back to your issue. If you get it running at the present idle you suggested was 2000 rpm, and grab a flashlight and look down the throat of the carbs, I'm sure you'll see gas burbling up and around the main needle jet, then the idle circuit is not being fed fuel. That confirms to me that you've got the main circuit actually running the bike at the lowest possible rpm and any lower and it cuts out. For sure if that's what you see then the idle circuit is not getting any fuel. You'll have to pull the carbs again, pop off the carb bowls, take out the main jets, and remove the emulsion tubes under the main jets and get a syringe and flush out the fed tube from the emulsion tube tower through to the idle jets.
Take a really good look at Scotch's write up on this in the Blog section. I know you've been there because you commented on his article.
I also have an ultrasonic cleaner at home and after using it when I was working at the nuclear plant I know that they do an incredible job cleaning surfaces because the ultrasonic waves through the cleaning solution cause microscopic explosions on the surfaces exposed but doesn't do anything beyond the surfaces. That being said, there's no ultrasonic activity inside of the passages within the carb. I always flush out the passages or confirm them clear with compressed air.

I have a '79, make sure the idle jet screws are at least 3 1/2 to 4 full turns out on all carbies, check the float levels and make sure they are at the correct height, make sure the slides work easily, and check your timing, set it to the mark for idle and see if it advances when reved, you said you had the carbs cleaned so i'd say it's either lean idle mixture, or your not supplying enough gas to the carbies, make sure the fuel line is clear, and flowing freely enough, also check the needle valves in the carby bowls, sometimes they don't open full and the bowls run dry or low, Pete.

Oh if she does run after that, invest in a colortune plug and a good set of gauges to balance the carbs

sixpipes,

I have a little experience with these carbs.

Don't do anything or have anything done to the carbs !!!!

Get them back, (unmolested) and when you do, P.M. me.

I'll ask you for some specific pictures and details,
then we'll plan the attack !

One thing for certain: It won't involve "Teflon" or "springs" !

scotch

Hi
I had the same issues as you with my 79, wouldn't idle and had to keep the revs up to keep it going. I put mine in an ultrasonic cleaner, twice but still the same and I fitted new carb kits. Eventually found out that the pilot jet air ways were gummed up as they pick fuel up from the main jet on idle. I ended up suspending them one at a time in a pot of water and boiling them each for about 1/2 hour and them blowing them out with compressed air while they were still hot. This worked for me as now it idles and runs great.
Hope this is of some help