Next carb adjustments?

Hello all!

Ive got a 1982 KZ750 LTD-4 that was given to me approximately 2 years ago. It was in rough running shape and slowly but surely I've gotten it going decently. Id been riding it all last year and the glaring issues it seemed to consistently have was it would idle high and not want to come back down, especially after warming up, and it was hard starting. I'd figured that was some sort of vacuum leak. So this year I replaced the carb boots and also did a fresh valve adjustment. The valve adjustment seems to have solved the hard starting issue as it pops right to life now. And with the new carb boots, the idle is better, but still after about a half hour of riding (nice and hot engine) the idle still doesnt want to come down readily and I have to wheel brake it in gear to below 3k rpm, to get the rpms to settle at 11-1200. I'm thinking there are still some carb adjustments to be made and was wondering where you guys would start? For the record it does have a kerker 4-1 megaphone exhaust without the baffle (the baffle had rotted out so I removed it completely as it was just rusty chunks rattling in the muffler can), but is otherwise stock. Thank you for your time!

First off, get a baffle. Not only will your bike run better but the general populous that suffers the unholy noise will thank you too.

You mention the carb boots but what about the airbox boots? It's critical that the carbs are sealed at the back and that the airbox is intact along with a proper filter or the bike will run drastically lean.

Have you ever cleaned the carbs properly, including removing the pilot screws, pilot jets, fuel pipes, etc and made sure everything is free and clear? If not, I'd do so. When setting the pilot screws make sure to open them to about 3 turns from lightly seated. The pipe will lean the mixture but that typically doesn't have drastic effect at idle but you never know.

First, thank you for the response. Ive been looking for baffles for it, but havent found one that will fit and may either end up getting a new muffler or some such. We'll see. But yes, I agree, I would like to get a baffle. Carb boots are new, and airbox boots feel fine, plenty flexible and no cracks or tears at all. Air filter is new last year, and the year I got it (2 years ago) I cleaned the carbs real good like, and replaced o-rings/gaskets. Took them apart, soaked them in an ultrasonic bath of carb cleaner. Seem to be pretty clean, but I can yank them apart and check again. I have the screws set to 2 turns out now, I'll back them out one more turn and see what happens. Thanks again!

Have you vacuum sync your carbs after the rebuild???

Hello! Yes I should have mentioned, I did synchronize them per the manual to the best of my abilities, and let me tell you, the bike runs very well and has plenty of power and throttle response is good apart from this idle-down issue. Thank you!

Have you carefully inspected and lubricated the throttle cables?
How about the ignition advancer?

The 750 might use the same baffle as the 1000. If so, new ones are available. You might contact Supertrapp/Kerker, or one of its big dealers to find out.

Hello! Yes throttle cables move freely and have been lubricated. I have a tool that I bought for my last bike for that very purpose. The ignition advancer was one of its original problems when I first got it. It was frozen and the bike wouldn't go above 4k rpm. Took it off and cleaned it real good and lubricated it and it seems to have worked well since then. I'll look into a baffle for a 1000 though I just found a baffle on ebay that seems to have the same dimensions as the one that rotted away and my go with that option. Thank you for the reply!