vm26 carb overflow

[mvalenti]

It has happened 2x so far in just as many weeks. My bike sits with petcock closed, I open it and after a short time #2 carb starts to overflow. I have removed the bowls, doesnt seem to have sticky floats.. ideas?

BTW I have rebuilt these carbs a couple months ago and hadnt had leaks..

[chuck hahn]

If the floats arent sticking, then it may be the float seat itself or the float valve ( needle) has scoring and not sealing properly. How was the float heights when you rebuilt them. Be sure to note that there are two floats in each carb and you need to check both of them when doing the float hiehgts.

[mvalenti]

thanks for the quick response. I only measured one side, so i will have to remeasure. The valves were new also. but I will check the seats, maybe dibris?

[Steve]

My bike sits with petcock closed, I open it ...

Do you have the stock petcock?

It sounds like you don't, because there is no "opening the petcock" procedure, other than starting the engine.

.

[mvalenti]

correct. it isnt a stock petcock.

[gearheadE30]

That's a pretty sure sign of either a sicking/sunk float or a bad float seal. Usually it's also accompanied by rough running, flooding, and/or running rich.

[mvalenti]

carb overflow update

Well, took some time the other day and pulled the carbs out and apart. I found bits of black rubber in some of the float bowls, and a piece that decided to inhibit the float valve from closing. The rubber is from my fuel line, I noticed some abrasion on the inside where the barb connections were made. I will be switching to tygon clear line.