Mikuni VM26 Float Overflow

Update: Took the carbs apart, verified the float needle operation of each carb with the bowl removed. Reassembled the carbs and they started overflowing almost immediately. Out of frustration I whacked them a couple of times with a heavy/soft rubber mallet on the side of the #4 carb and the floats magically started working. Not sure what the deal was but it hasn't overflowed since. I haven't taken it up to highway speed yet but things are looking up. Thanks for the help!

DoubleDub wrote:

Update: Took the carbs apart, verified the float needle operation of each carb with the bowl removed. Reassembled the carbs and they started overflowing almost immediately. Out of frustration I whacked them a couple of times with a heavy/soft rubber mallet on the side of the #4 carb and the floats magically started working. Not sure what the deal was but it hasn't overflowed since. I haven't taken it up to highway speed yet but things are looking up. Thanks for the help!

That's a popular remedy for dislocating crud or grit which might be interferring with the float needle-seat interface.

Small plastic hammer or screwdriver handle also sometimes works pretty well for rapping on the float bowl.

Won't hurt to also drain the float bowls in hopes of flushing such dislocated crud or grit on out of the carbs.

Good Luck!

Not sure crud is being dislocated. When I have seen folks tap a carb and it stopped leaking, many times the float was bent a tad and hanging on the upper part of the carb bowl casting.

That would make more sense to me. Especially since the float operation worked 100% with the bowl removed and I used my hand to operate the float. Not sure how it would've gotten bent - is this something I should worry about coming back? Is it something that warrants new floats?

My floats were sticking and come to find out that when installed, the floats were getting stuck below excess float bowl gasket material keeping the valve from closing thus causing overflow.