Rebuilt carburetors still leak out overflow tubes

Good morning all.

I rebuilt a set of carburetors for a 1979 KZ650 SR yesterday with kits. All the gaskets, O-rings, floats, etc. are new. I had the carb bodies cleaned in a service shop parts washer so the bowls, etc. are spotless.

It is the carburetor set with an accelerator pump on the #2 carburetor.

I put everything together per the bike manual, put them on the bike and when i opened the fuel tap they immediately started to leak from the overflow tubes on the carburetor float bowl bottoms. Float height issue? Ideas? The fuel POURS out freely.

the floats push up on the needles. if the needles do not seat tight the fuel will pass by them and continue to flood the bowls.
i would start be checking the needles and seats.

Check if you might have put one of the floats upside down,or didnt tighten the float needle nut,or possibly a pet cock problem,I have experienced all of the above at one time or another.and your right also it can be a float height issue.

I have the exact same issue. Gas spilling out of carb #2 so i rebuilt another set of carbs. Once i put the new carbs in gas continued to spew out of carb 2..

After i let her run a bit the leakage stopped..

weird coincidence or conspiracy? :laugh:

Where clean dry carbs are fitted, a fuel valve sometimes leaks.

With engine idling, try rapping smartly against float bowl with plastic mallet or large screwdriver handle, which often stops the leakage, and restores float valve to proper function.

Good Fortune!