Steady leak on rainy days

[MechMessiah]

So two days ago in my area it was a very wet day and I noticed a slow but steady fuel leak coming from the drain tube at the bottom of the front air box that connects to the carbs. But once the weather dried up the leak went away. Has anyone else had this experience or know if this is this a common thing? The bike is an 82 650GL. Thanks in advance.



Also I want to say thanks because I've gotten a lot of useful info from this site over the past few months. Just never had to actually post a question because there's already so much on here.

 

[bwringer]

The fuel leak was due to a stuck float or perhaps a bit of mung in the needle valve.

It probably didn't have much to do with the rain, although I suppose you could postulate some bizarre combination of circumstances where humidity would lead to a fuel leak. Or a not-so-bizarre circumstance where maybe rain got into the tank.

One important question: was this with the bike running or not running, and was the bike out in the rain?

If it was leaking when the bike was not running, you have a petcock problem. The petcock must be able to shut off the fuel flow completely when the bike is off; the floats and needle valves are not designed to hold back a tankful of gas. The best course in this case is to order up a new petcock; the rebuild kits are a low-percentage crapshoot and a petcock every 30 or 40 years ain't too bad as far as these things go.

If it was leaking when the bike was running, but stopped when the engine was off, then you're back to just a sticky float and/or mung in the needle valve. The petcock includes a very efficient screen filter, so this most often happens when there's an olde petcock that hasn't been moved in years. When you do move it, (out of curiosity, ignorance, or the sudden need for reserve) crap from inside the petcock can get into the needle valves and the result is an airbox peeing gas.

If it's not leaking now, then the mung likely worked itself out and is sitting in one or more of your float bowls. Personally, I'd drain each of the float bowls and see if any water or mung comes out -- this stuff will seek the lowest point.

If you get water, then you may need to inspect your gas cap, and consider springing for a new one. The gasket is not available separately.

 

[Brendan W]

The leak could be wicking away more quickly in dry weather and not as noticeable.
Could be the bike is of a nervous dispositon. Back in the day experienced Nurses opened a tap. Running water helps some guys get a sample going

 

[Crank]

Or you are getting water into the airbox.

The drip could just be fuel tainted water.

 

[MechMessiah]

Or you are getting water into the airbox.

The drip could just be fuel tainted water.

Seems like you hit the nail on the head; The puddle that formed was pretty small and had a gas smell but I couldn't tell if it was pure or just tainted water; the bike was under an awning but still getting hit with some side rain; Also if your wondering about the semi colons I just discovered my keyboard has some broken keys and the period is one of them so;