I'm puzzled.
After starting up my 2007 s40 for the first time in the spring, it starts fine but then leaks gas out the carb. Last year, it flowed, this year it dripped. Last winter the stock petcock was on the bike, this winter I had a Raptor. (And I know that I forgot to turn the petcock off this winter.
)
When this happened last year, I panicked, pulled the carb and opened the bowl expecting to find a stuck float... but the thing was spotless inside and the float looked to be working. This year, I just turned the petcock off and let the bike sit to observe. Hours later, all was dry. I turned the petcock back on, no leak. I idled the bike, no leak. I hopped on and went up and down my street (~200 meters) and let it idle a bit more, no leak. No leak overnight either, and petcock is on Reserve. No leaks at all after the initial leak all last season.
I can't seem to find exactly where the gas is leaving the system; the carb didn't seem wet above the bowl gasket, but I can't be sure. I noticed that the tube from the airbox to the carb intake wasn't seated correctly (last year's carb pull) and as I reseated it I stuck my finger in there and it was a little wet. The air filter didn't really smell of gas, so I don't think the gas got that far.
Any ideas? I'm still blaming the float valve, but I don't know why it self-corrects so easily.
Note that both this winter and last, I didn't end up properly winterizing the bike; it basically sat as I parked it from the last ride all winter, so no gas stabilizer or the like.