Is my KZ1000 running lean, or something else?

I bought my 79 KZ1000B last summer after it had been sitting for a few years. It has the stock airbox and filter, and a 4 into header (unsure of the brand) with no baffles. I also replaced the stock B8ES plugs with some B7ES NGK's. I went through the carbs numerous times getting them clean, until the bike ran on all four cylinders. During the winter I ordered a stock rejet kit four all the carbs, and was sure to synch the the floats the "wet" way, with a clear hose on each bowl to check the level. I also left the needle in the stock position.

After rebuilding my carbs, I would ride the bike if the weather was nice. I doubt I rode in anything less than 50 degree weather, but the bike would need choked in order to ride it. If I didn't use the choke, the bike would run, and the exhaust would make an almost pulsating sound- it is very hard to describe. The bike wouldn't have much power until I pulled the choke on. Anytime I would pull up to a stop sign, the bike would be idling way too high due to the choke being on. I have also noticed the bike doing this after a cold start on a warm day as well, but it goes away once the bike is warmed up, or if I pull up the choke. Is this a common sign that the bike is running lean?

After doing some searches, it seems like any time you change the air filter style or modify the exhaust, you need to rejet richer. This model of carbs has an enrichment screw on the bottom of each carb bowl, which I'm sure I could adjust some, but I don't know if it would be enough to make the bike run without the choke. I'm also thinking about running an open header, which I'm sure will make things a little worse. If anyone could give me some insight on this, I'd appreciate it. Thanks!

Yes, you too have embarked on a lifelong journey of trying to figure these damn carbs out.:laugh:

Do you know which carbs you have?
I have been messing around with the Mikunis for my tenure.

I think you non-accelerator pump type KZ1000 VM26 carbs on your bike based on the pilot fuel mixture screw under the bowl. Adjusting the mixture screw won't help much other than affect idle and the off idle transition. The bike should run fine with stock jetting given you have the stock airbox/filter... perhaps a tad lean at the very top of the rpm range depending on which type VM26 you have. Ok... having said all that, you don't have a jetting issue, you really need to clean those carburetors. If the bike won't run on main jet without the choke on, either somebody has installed a VERY VERY small main jet or there is some obstruction or you have a fuel delivery problem... in other words, clogged fuel filter, vacuum issue (as in the gas cap), clogged fuel rails... something is keeping gas from flowing as it should.

My carbs do have an accelerator pump, but I forget their model number. I know they are Mikunis for sure though. As I mentioned, I did install a new main jet which was the stock size. The old main jet was made of plastic, which kind of threw me off. I guess if I ever get brave enough, I will rip the carbs apart once again. Thanks for the info!