[marcust]

Either one of your vents is leaking or the drain is not plugged good enough.

 

[marcust]

I used the end of the screw for the ujoint boot clamp. works good and you can't loose it.

 

[marcust]

Maybe try checking the condition of your hoses make sure none of them are cracked or just replace them because if you can ride that long before you get water in the carb it is a small leak.