Getting sick of my carb situation KZ750 H3

Not to be too pointed, but if the rebuild was done correctly, you wouldn't have leaks...at least not or a while.. The problem here is likely faulty float needles.  The needles are "rubber" (nitrile) tipped. They wear and harden with age.  Aftermarket carb kit parts are NOT a precise, identical fit.  For example, the jet plug o-rings aren't even close: both ID and OD are wrong, and they don't fit.  Also, the aftermarket float bowl gaskets are fine for a year, but deform and harden if the bike sits and will leak on start up for several minutes until they heat back up and expand. Ditto the drain plug o-rings.  OEM o-rings don't do this.  So, a perfect rebuild should use OEM parts. BUT, it's expensive.  One OEM jet plug o-ring is $19.87, plus tax and shipping. A set of 4 =100!  Craziness...but the OEM parts work!  Problem number 1 is the float bowl needles are probably aged if original or not a perfect fit if aftermarket.  Wait, it gets worse.  If the float bowl needle seats have been worn or deformed from polishing, even OEM needles may no longer work.

That being said, the carbs will be a constant source of trouble...forever.  It's what they do and a big reason fuel injection now rules.

And while we're on KZ carbs, if any of you high mileage KZers and losing top end power and peak out at 85 MPH or so, take a careful look at the vacuum valve slider tubes machined into the carb bodies.  Eventually, they become oblong from wear when viewed from the top.  Air will leak by and the vacuum valves will no longer fully lift preventing the main jet from
being fully opened.  "New" carb bodies are needed in the case, and a rebuild of those...with as many OEM parts as you can find. My '82 KZ750 H3 LTD is still on the road and runs close to perfectly with 94k on the clock, but it's a lot of time and $$ to keep her happy.