I have an otherwise troublefree honda cbr 250 (1989). At the very end of this season I went to ride my bike and I noticed it pee'd itself. I lost a litre over night. I took it out for a ride, and the next day same thing. So after I took it out for another ride I turned the fuel line off, and seemingly nothing since then.
It only leaks when the petcock is "on" or "reserve." I tored the tank off and the airbox to do some digging, and it leaks out of the high low jets through two overflow tubes. I have OEM gaskets which I just fired in last night, and am going to break down each 4 carbs and replace all the O rings aswell. I just wanted to pop the question to you fellows to explore all scenarios. Reed valves look fine, and the carbs were all spotless.
There is no golden answer so something to further look into.