Allow me to boil things down a bit
The oem petcock is cheap and unreliable. While your tank is on the garage floor, chances are you will notice a small puddle of gas on the garage floor under the petcock. I did and I replaced the petcock with a Pingel fuel tap.
The fuel free flows from the tank except for three things:
1. Petcock
2. Fuel line between the petcock and the carbs
3. Float needles.
Leaky petcocks, the ones that do not stop the flow of fuel may allow fuel to be seen on your motor or under your motorsickle in two circumstances, a. bad fuel line/bad fuel line clamps b. float needles that do not seat properly.
What to do?
Remove the petcock side of the fuel line. Dry everything and observe if there is any leakage from the petcock. Holding your finger on the petcock fuel spout will not tell you anything. You need to see if it leaks by observing dribbles or drips. While you are there, take a paper towel and hold it around the petcock/tank mating plate. It could be leaking there. If the petcock dribbles while turned off, that is a problem that manifest itself (gas on the floor/motor) primarily with sticky float needles. Secondarily the fuel line itself may be split/cracked. Highly unlikely but worthy of a closer look.
If the fuel line is good and the fuel line connections are good, then the petcock leakage will not have anywhere to leak out. In essence the fuel flow is stopped. Stopped by the float needles. The needles have a rubber tip that will suffer the effects of alcohol. They may be seated properly but the rubber seat itself is distorted and no longer affords a tight enough seal. The float bowls fill up and the carbs continue to fill up literally until the fuel exits into either the cylinders then into the oil or the fuel simply exits the rear of the carbs (out the air filter side) then you get to see and smell gasoline!
The float needles are controlled by the floats. Floats would be the last thing to check. Check float heights and check for flooded float(s).
help i hope this does.
