fuel leaking from carbs

[Guest]

hey guys, i just finished my engine reseal and put the bike back together. after running it a few times i wanted to change the oil again to get out anything that could have been in the oil. when i drained the oil i noticed it was very thin and instantly smelled gas. i changed the oil and took it for a ride. everything is running perfect and smooth. i left it overnight with the fuel line open. when i came back the next day i could smell the fuel and my first carb (the one on the left side) was dripping fuel. the filter was soaked. so i have reason to believe that it is leaking while sitting. has anyone had this problem? once it runs it isn't a problem at all.

[nejeff]

hey guys, i just finished my engine reseal and put the bike back together. after running it a few times i wanted to change the oil again to get out anything that could have been in the oil. when i drained the oil i noticed it was very thin and instantly smelled gas. i changed the oil and took it for a ride. everything is running perfect and smooth. i left it overnight with the fuel line open. when i came back the next day i could smell the fuel and my first carb (the one on the left side) was dripping fuel. the filter was soaked. so i have reason to believe that it is leaking while sitting. has anyone had this problem? once it runs it isn't a problem at all.

Fuel line open? What do you mean?

[Gs1100e82]

what i mean is leaving the fuel petcock open. and by leaking i mean the carb or carbs seem to be letting gas get into the cylinders while the engine is off. i don't know much about carbs so I'm just hoping someone has had this issue and or knows what it could be

[nejeff]

what i mean is leaving the fuel petcock open. and by leaking i mean the carb or carbs seem to be letting gas get into the cylinders while the engine is off. i don't know much about carbs so I'm just hoping someone has had this issue and or knows what it could be

What is leaving the petcock open?

If the line from your petcock to your carbs is attached then I'd say you have a bad petcock and it's leaking. Possibly back through the vacuum line. If you have not replaced the petcock yet its time anyways, that is where I would start

[GSX1000E]

Yes, by leaving the petcock "open" or in the PRIME position, it will drain/vent fuel into the crankcase. Drain the oil and change it along with the filter. Check that the petcock is still working in the ON position without leaking fuel when the bike is not running (when it not drawing vacuum at the petcock). If worse comes to worse, you might need a new petcock. No big deal. Just remember to not leave it in the PRIME position any more.

[nejeff]

Yes, by leaving the petcock "open" or in the PRIME position, it will drain/vent fuel into the crankcase. Drain the oil and change it along with the filter. Check that the petcock is still working in the ON position without leaking fuel when the bike is not running (when it not drawing vacuum at the petcock). If worse comes to worse, you might need a new petcock. No big deal. Just remember to not leave it in the PRIME position any more.

He left it in the "prime" position What the "h" would he do that for?

[Gs1100e82]

ahhhh that makes sense. would the prime position by any chance be turned left? i can't read anything on the petcock

[tom203]

On mine, lever pointing rear is "PR" . consider this a good time to check petcock for correct operation- stuff often fails at age thirty.

[Gs1100e82]

Yeah i had it facing towards the rear. again by that i mean that the "lever" got twisted counter clockwise.

[nejeff]

Might as well change out the petcock and by the way you need to change that oil again too

[Gs1100e82]

yeah no kidding. it is what it is. thanks for your help guys.

[CivilRock]

Just so you know- since I also have an 82 GS1100E (making an assumption there based on your user name)
forward: reserve
down: On
back: prime

There's (at least) three things that can be the cause of a draining tank:
1. The vacuum activated valve in the petcock is bad.
2. The float valves are bad in the carbs.(or something's stuck in them)
3. the diaphragm in the petcock is bad (letting fuel leak down the vacuum line)

I've also learned recently that the float valves won't hold back a high column of fuel. For example, I put an auxiliary fuel source about 2.5 feet above the carbs and the pressure was too much for the float valves. I thought I had a faulty float valve.

You can rebuild the petcock for slightly less than a new one. But first I'd take it apart and just check for rust particles that got past the petcock screen. And make sure there is a petcock screen. It's the discolored plastic thing that sticks up into the tank.

It's pretty easy to take apart, and interesting to see how it works.

-Kevin

[Handall]

I have a 1980 GS850GL. The Petcock does not have a lever for rotating, it only has a slotted nylon headed screw recessed down in the petcock. I can rotate it continuously with a small screwdriver, but I don't know the correct position; I'd include a picture, but I don't know how. There doesn't seem to really be a reference point so I know where prime is and where the normal run position is. Can anyone help me.

[Handall]

Petcock Position

I have attached a picture of the petcock on my 1980 GS850GL. It does not have a lever or any reference point, so I don't know what is "Prime" and what is "Run". It has the word "Fuel" with an arrow at the top, and the "Pri" at about 11 o'clock; but there is only a slotted nylon screw head down inside the petcock. So there's no reference point on the screw head to know where the petcock is set. Can anyone advise me on this?

[JTGS850GL]

Your petcock is missing a few parts. If it were mine, I'd go ahead and just replace it.