Frustrated, Carb Problems! 1981 KZ750 LTD

I have been trying to tune this bike for a few months, and still have not got it right. It will start good, but even when warmed up, it has a dead spot at about 4K RPM. Above that, it runs good. It still has some hiccups below 4K too. I have cleaned the carbs numerous times, paying close attention to the pilot circuit, even installed new pilot jets. Lately when I start the bike when cold, I spray water mist on the exhaust, and cylinder #1 exhaust stays cool until I take it off choke. Not sure what is going on. It seems that cylinder is not getting enough fuel at lower rpm? The bike is stock except for a Kerker 4 into 1. I have heard they are harder to tune with this pipe? Any ideas would be helpful. This bike has the Keihin CV34 carburetors. Thanks.

Wow... it is sometimes hard to say this, but your cleaning efforts were inadequate. There is no enrichener so the bike relies on the choke and pilot circuit. As far as the dead spot, might be related to the pilot circuit issue but since you didn't mention jetting or your airbox/pipe combo, I won't even hazard a guess.

It still has the stock jetting. I don't have all the jet numbers handy but I know the pilot is 35 and primary main is 62. Not sure on the secondary main jet. Stock airbox with paper element filter (not K&N). The pipe is a 4 into 1 Kerker.