Carb floats stick when the bike hasn't run for a while

[sayosen]

Here is the situation I am experiences. If I leave my 78 XS400 2E sit for a week or two, the first time I start to it, the carb fills with fuel then over flows through the air filters. If I go a day or two between starts, I don't have this problem. Here is what I have done so far:

I did a proper rebuilt kit on the carb including gaskets and needles.
I have checked the float bowl height.
I did a proper cleaning on the carbs.
I have checked the floats to make sure they do in fact float.

Before I change the floats and needles, is there something else I should try? Has anyone else experienced floats sticking after brief time away?

Thanks in advance if anyone has any ideas.

 

[arfstrom]

I suspect its "Cheap fuel" If you get the fuel that is ethanol free, you will not have this problem. I will get this problem when I get the cheap fuel, with ethanol. I call it corn syrup for that reason.

So if you are using corn syrup gas, then you will need to keep a ready supply of seafoam. 1 tbsp per gallon. that is for the symptom of stuck float.

Okay, this is one theory, The fuel going to the filters, that is is an issue. typically that means fuel is going in to your crankcase.

So what is the next step? My experience showed me that one of my floats had a leak. It would float for my test, then next day, it would be failing the next day. I know you said... but I said that is my experience.

what if you are not using the corn syrup gas? perhaps my last paragraph then.

 

[XS400NJ]

I had similar problem just yesterday, my left carb was leaking. I could not believe it as I just cleaned it recently and have inline filter.

After taking carbs off I did not see any problems - valves were closing nicely. It was after playing for a while I noticed that if I take float all the way back sometimes the float gets stuck. The cure was to adjust(bend) that little stopper on the floats that prevents floats from opening too much. I've never paid much attention to it until yesterday.

Anyway, I adjusted it so that floats go down just enough to open valve and no more. I think it is also good for preventing floats from reaching any water that may collect on the bottom of the carb, keeps them from being corroded.

The way I test floats - I put carbs upside down and blow into gas line. Floats with their own weight completely close valves and I can't blow any air through. While doing that yesterday I was picking floats up to open valve and eventually one did not return back to close valve.

just an idea....

 

[sayosen]

Thanks for the tips guys. I will take them apart , clean and adjust them yet again (insert load groan here). I am using the ethanol free gas. I think I will try the float test again, but will also do the sink test. And I will adjust the tabs and try the blow test.