Gas leak coming from overflow line

[BOSEPH]

Hey there fellow GSers!
I've got an issue on my 2009 GS. Upon purchase, the frame petcock leaked. Not too bad, but an annoyance. I manage a bar, and when I parked on the side walk, guests complained of a gas smell, when approaching,  or smoking outside. I began taking the seat and tank off every trip, and shutting off the fuel supply from the tank.
I have since replaced the frame petcock, and have a new problem...
Gas now leaks from an overflow line.
Thoughts?

[rscottlow]

Check your carb floats. They may need adjusted, or the needles may be sticking.

[Bluesmudge]

Which overflow line?
I agree with rscottlow,  probably something related to floats or needles. You will probably have to take the carbs off and investigate. Was the bike been sitting for awhile and running old gas? Are the fuel lines deteriorating? Any rust inside the tank?
Are you leaving the petcock on prime?

[Watcher]

In addition to the float needles if the fuel is overflowing when sitting it also means the petcock isn't shutting off.
Either you left it on prime or your replacement frame petcock is also bad.

[Arpee]

Wondering if the replacement petcock was OEM or perhaps one of the non-vacuum petcocks?
Would explain why it suddenly decides to overflow.  Sometimes the vacuum petcock will mask the high float levels or leaking seats when the petcock is left in the "on" position.

[BOSEPH]

Check your carb floats. They may need adjusted, or the needles may be sticking.

I thought that might be what's going on. I will look on the site for instructions on how  to determine if the float is the issue. Thanks

[BOSEPH]

Wondering if the replacement petcock was OEM or perhaps one of the non-vacuum petcocks?
Would explain why it suddenly decides to overflow.  Sometimes the vacuum petcock will mask the high float levels or leaking seats when the petcock is left in the "on" position.

It is an OEM petcock, from a parted out 04GS. Vacuum line is in tact. Just out of curiosity,  is there a particular setting "on," "pri," or "res," that the petcock should be set on when the bile is parked?
And thanks

[ShowBizWolf]

Hi BOSEPH,

My bike stays set to the 'on' setting all the time except for when I'm riding and I feel it run out of gas... I reach down and switch to reserve and head to the nearest gas station 

I can't think of any time I've ever had to switch to prime... I mean it's there for a reason and I'm sure I've read it on here a dozen times but I've never had to use it.

Good luck with this!! I've been following along but haven't had anything helpful to add 

[BOSEPH]

Which overflow line?
I agree with rscottlow,  probably something related to floats or needles. You will probably have to take the carbs off and investigate. Was the bike been sitting for awhile and running old gas? Are the fuel lines deteriorating? Any rust inside the tank?
Are you leaving the petcock on prime?

The bike had not been down for more than a few weeks. No rust in the tank. All fuel lines are new. I never have had the petcock set on "pri," I couldn't figure out what it's supposed to do.
Thanks

[ShowBizWolf]

Do you have an owners manual? If not, you should totally get one! I bought one and read it... told me lots about my bike. And also if you have the $$, pick up a Haynes or Clymer manual as well. They are awesome help!

[Watcher]

If you see it actively leaking and you tap on the bowls/sides of the carbs with the handle of a screwdriver it should stop if the needle is sticky or has debris on it.
If the floats are out of spec, or the needles/seat are just trashed, it'll keep leaking.


On and Res are vacuum actuated and should NOT flow fuel if the pistons are not moving.
Pri is the Prime position and flows fuel constantly.  Used for filling the carb bowls if they are empty, like if you just had them off the bike for work, or for diagnosing and bypassing petcock vacuum loss.

If you have it set to On and it's actively leaking then for sure the petcock is bad.  I'd contact the seller and see if you can get your money back for it.

A cheap and effective alternative is just a ball valve.  You'll have to shut it off every time you park, but it is FAR less likely to go bad.
I did that to both of my GSs.

[BOSEPH]

Awesome info! Thanks to all. I feel I have a direction to go. I'll report back with an update soon.

[user11235813]

...when I'm riding and I feel it run out of gas... I reach down and switch to reserve and head to the nearest gas station...

FFIW, you should be good for 120Kms/75miles. I did a test recently where I carried a can of petrol waiting for it to run out. I have since determined that the reserve capacity must be a litre more than the specs state, it's supposed to be a 20L tank with a 4.3L reserve but my calculations indicate a 5.3L reserve. That's getting an easy 350K before reserve.

[lefty1615]

If the overflow line your talking about is the one that runs from the airbox, has the little pinch head on the end of it, check that you dont have gas in your crank case. I had a sticking needle valve that got so bad it backwashed gas to the airbox and dumped a bunch into my crankcase. Did a full oil change and got new needle valves and its been rock steady since.