Gas Leaking...Need Help

[Chuckster]

I don't have a manual for my 1981 GS550T that talks about the petcock settings, but one day last week, I turned the petcock from on (down) to facing the back of the bike (looks like it says prime?). The next morning, I had a puddle of gas beneath my bike with it still dripping and my garage full of fumes. Scared the $%^& out of me. I thought I was turning the gas off, but I guess there is really not an "off" position? I then turned it pointing toward the front of the bike which looks like reserve from what I can make out. It finally stopped dripping then. Right now, I have the rear end pulled out putting new front and rear sprockets, tire, etc. on it. It had never leaked before while riding or sitting in my garage. The bike had been sitting for a while as I've been working on it with no leaks at all. I just happened to notice one day that the gas was "on" and thought I would be "safe" and turn it off. I must have usually turned it toward the front of the bike before when I thought I was turning it off. Anybody got any idea what's going on?

[Nessism]

The petcock has three position: On, Reserve, and Prime. Prime allows gas to flow all the time regardless of whether or not the engine is running or not. When in the On and Reserve position, engine vacuum is required to allow gas to flow.

You had the petcock set to Prime thus gas was able to flow even when the engine is off. The reason your carbs overflowed is because the float needles failed to hold back the gas and the float bowls overflowed. First thing to look at is those needles/seats and float height. Next thing, make sure you keep the gas turned to either On or Reserve so you are not relying on the float needles by themselves to keep the gas from overflowing.

As a side note, this bit of information really should be a sticky since so many people have the same problem. How do we go about getting this topic STUCK?

[bradleymaynar]

And to add. You've now probably got gas in your crankcase oil. Change your oil and oil filter before going any further.

Brad bt

[salty_monk]

Good news is prob no lasting damage. Might want to spin the engine over with the plugs out to dry it out a bit although will probably evaporate.

With the petcock working properly you shouldn't have the problem again although the needles should hold the gas back too so you do have an issue there (although it's only an issue if the petcock fails.....)

Dan

[bwringer]

The float needles are not designed or intended to hold back the flow of gas all by themselves.

With the petcock on prime, you will eventually get a crankcase full of gas, a few drops at a time.

So now you know that "on" shuts the gas off, unless the engine is on, then the gas is on, and "pri" is actually on all the time even when it needs to be off. And if it's supposed to be on and the engine is on but it's off, then you might need to put it on "res" because you're almost out of gas.

Welcome to the GS club -- that will start to make sense eventually... :-D

[Chuckster]

Thanks guys for the help. I just changed the dang oil too. If it's (meaning any gas in my crankcase) not showing up in my oil level window and my oil level looks like it did before, am I okay?

[salty_monk]

Up to you.... A gallon of GTX is only 10 bucks though & it takes 10mins.

If it doesn't smell of gas you might be ok, but how can you tell?? Your garage must stink of the stuff....

Dan