KZ750 acts like it's running out of gas
I've been trying to chase down this problem for a little while now, and it's driving me a bit crazy.
It started a little while back, after riding the bike for almost the whole summer and it running great, intermittently it would act like it had no power, felt and sounded like one of the cylinders wasn't firing, basically the same symptoms as when you're running out of gas. It didn't happen very often, and after a few seconds it would go back to normal and things would be fine for a while.
Things escalated a bit, and it happened on my way to the shop. Parked it outside, grabbed a couple things in the shop, came back and one of my carbs was pouring fuel into the parking lot. Got it home, set all the float levels and cleaned the carbs (which I had done recently, mysteriously one was way out already) and figured that my problem was solved, until it happened again a few days later, started pouring fuel out of a different carb this time. Again, took it home, re-checked all the float levels and set them a millimetre lower than spec (spec is 4mm) and crossed my fingers. At this point I also checked my valve clearances, ignition system, and timing. Clearances were good, got fat blue spark from all 4 plugs, no resistance issues in the leads, and timing was good. I also synced the carbs with a homemade manometer, so not a great job, but got them pretty close. Now I'm still having this issue. At pretty much anything other than W.O.T. the bike sometimes decides to act like its fuel starved. It doesn't happen often, but when it does it's hard to keep the bike going. If I have my hand off the throttle at a light or something it will die instantly, but I can always start it right back up again. When the engine is under load it loses almost all power for a bit until it works through whatever is wrong with it and then it's back to normal. Other than this it's running great, if a bit lean, and idling better than it ever has, so I don't know what else to look for here.
Anybody have any thoughts as to what I might be missing here? Ideas on what to check next? It's not dumping fuel anymore, which makes it rideable, but it's not a good problem to have. Seems to happen more at low rpm than high rpm.
It's a 1982 KZ750 with Keihin CV34s and pod filters (I know, I know, but it was running fine for a long time before this stuff started happening) and a 4-into-1 exhaust. It's got Dyna S ignition and coils.
1982 KZ750 LTD