Carb rebuild woes...kind of.

Last night I took on my first carburetor rebuild. All in all, I thought it was successful. Everything went back into place the way it should and the reassembly was smooth and effortless. I was quite proud of myself.

Unfortunately, somewhere along the lines I think I messed something up (likely). When I started the bike back up, it was idling very low. I had it on full choke, let it warm up about 5 minutes, and continued to adjust the choke accordingly as I have done every day since before the rebuild. As I closed the choke off more, the idle would suffer, until eventually with the choke closed and a little throttle given the bike would sputter and backfire. I figured this was just the bike getting everything running again after being completely drained of all gasoline. So I took it out for a little spin with the choke open a tad. I opened her up down some side roads and everything SEEMED ok for a bit. I parked in a lot about a mile and a half from my house, and let the bike sit for a minute running. Rode it home, and as I was pulling in my drive and she started to die. White smoke coming from the front I think? Didn't see any spitting out of the pipes. Parked in the garage, went inside and washed my hands. When I came back about a couple minutes later there was a POOL of gasoline on the ground directly underneath my bike. I saw 4 hoses that lead to nowhere off of the carbs that were spitting gas. It looked like just from the right carburetor.

Should I go back and pull them apart again to rebuild and hope I just missed something? Does this sound like I totally messed something up horribly? My local shop that I normally go to is 3 weeks behind on everything and this is my only form of transportation at the moment so I'm hoping this is a fix I can do on my own.

They are Mikuni carbs and they're on a '78 KZ750 Twin B3.

I can provide some photos if necessary of the hoses I'm talking about, but from what I've done trying to research I've found they're overflow hoses. Do those lead someplace or just off into the void to spit gas all over when needed?

Check your fuel levels and oil. I had the same problem the other day. Turns out it was caused by the floats letting too much gas in that it was spilling over into the cylinders and air box. A ton of gas ended up in my crankcase and I had to change the oil and reset the float heights

For whatever reason, it's not uncommon for the float valve in a freshly reassembled carb to leak when gasoline is first introduced, which results in discharge from the overflow circuit.

It may help -- while the engine is idling and gasoline discharging from the overflow tube -- to rap smartly against the side of the float bowl with a plastic hammer or large screwdriver handle, which sometimes stops the overflow discharge.

Good Fortune!

I got the float working correctly. I'm not entirely sure of what was causing the issue, but I pulled the carbs apart again today, test road and everything is fine. Hammer not needed! Just figuring out the float was the issue helped. Thanks!