1983 GS1100E Gas in airbox

[Nschultz]

Hey all, as i was doing my nightly checks before bed tonight, I noticed a gas smell coming from my 1100e. Upon inspection I could hear a drip but couldn't nail down where it was coming from. So in a frenzy i took the seat off, turned the petcock to off, and took off the tank, and proceeded to remove the carbs. As I was doing that quite a bit of gas leaked on the floor out of the airbox. I had recently gotten the bike running after replacing float bowl gaskets, and bowl drain orings. Everything else looked good and clean when I had the carbs apart last. So my question here is any idea what could be happening? Should I do a complete rebuild of the carbs? Is it the petcock that is the issue? Should I just be switching the petcock to off when the bike isn't in use? I thought this was a vacuum system on this bike and didnt require the petcock to be in the off position when not running. Thanks in advance for any help, it is much appreciated!

[2BRacing]

Your petcock has an OFF position? OEM petcocks have Res (Reserve); On and Pri (Prime) positions.

And yes, the petcock has a vacuum system that allows fuel to flow when the engine is running and the petcock is in the "On" or "Res" position. When engine is not running, no fuel should flow in "On" and "Res" positions. Fuel will always flow in the "Pri" position (even when engine is not running), so do not confuse that with an imaginary "Off" position.

[TxGSrider]

You will probably need to change your oil before restarting your bike.

[tom203]

Test your petcock while you're doing stuff...

Try this... remove both lines from petcock: get some clear vinyl tubing that fits snugly on petcock vacuum fitting. In "on" and "res" fuel,show flow when you suck on this tubing- otherwise it should not. Any signs of fuel in the tubing means the petcock diaphragm is likely leaking.maybe just when bike is running but maybe at alltimes.

[Redman]

PRIme: lever pointed back, arrow pointed back : is gas on even if no vacuum. Do not leave it in this position for more than a minute.
ON: lever pointed down, arrorw pointed down : is main tank on when is vacuum, otherwize is off.
REServe: lever pointed forward, arrow pointed forward : is reserve tank on when is vacuum, otherwize is off.

If you have left it in the prime position, and if the float valves dont completly seal (which they dont need to), then gas can slowly leak past the float valves, over fill the bowl, run into air box and/or cylcinders. If runs into cylinders then gets into crakcase and you oil is not so much oil any more.

.

[Nschultz]

Your petcock has an OFF position? OEM petcocks have Res (Reserve); On and Pri (Prime) positions.

And yes, the petcock has a vacuum system that allows fuel to flow when the engine is running and the petcock is in the "On" or "Res" position. When engine is not running, no fuel should flow in "On" and "Res" positions. Fuel will always flow in the "Pri" position (even when engine is not running), so do not confuse that with an imaginary "Off" position.

looking closer at some pics, I guess it doesn't. not sure why I thought that the arrow pointing down turned off fuel flow. The pic below shows the position the petcock has been in since I bought the bike. I actually had to get some needle nose pliers on it to move it to the arrow pointing down position.

You will probably need to change your oil before restarting your bike.

Thanks for the tip! she isn't necessarily road worthy just yet. but I will definitely be changing the oil on it before putting it back together and starting it up.

Test your petcock while you're doing stuff...

Try this... remove both lines from petcock: get some clear vinyl tubing that fits snugly on petcock vacuum fitting. In "on" and "res" fuel,show flow when you suck on this tubing- otherwise it should not. Any signs of fuel in the tubing means the petcock diaphragm is likely leaking.maybe just when bike is running but maybe at alltimes.

I only have 1 line coming from the petcock, and 2 electrical wires.

PRIme: lever pointed back, arrow pointed back : is gas on even if no vacuum. Do not leave it in this position for more than a minute.
ON: lever pointed down, arrorw pointed down : is main tank on when is vacuum, otherwize is off.
REServe: lever pointed forward, arrow pointed forward : is reserve tank on when is vacuum, otherwize is off.

If you have left it in the prime position, and if the float valves dont completly seal (which they dont need to), then gas can slowly leak past the float valves, over fill the bowl, run into air box and/or cylcinders. If runs into cylinders then gets into crakcase and you oil is not so much oil any more.

.

Lever/Arrow was pointed back. and has been like that since I bought the bike in May. Im learing at thats what counts.

here is a pic of it that way.

[img]https://photos.app.goo.gl/UNKPFrTzgwQ6CewV2[/img]

[BigD_83]

Yup,

that is in the PRIME position and fuel from the tank will eventually make it's way past all of the seals and into places you don't want it to go. If it was there when you bought it, that probably means the petcock is baffed.

First time ever this week I left mine on PRIME overnight, and was welcomed by the sickening sweet smell of gasoline on the floor of the garage. By oil level through the sightglass it appears not much got into the crankcase, but the nose test tells me some did. The solution is to drain the oil, use a cheap-as diesel oil to flush the engine, then refill with new oil. It's a waste of oil, but better than killing your engine with diluted oil.

[Redman]

yep, PRIme position.

Is there a vacuum line (smaller than the gas line) connected....?

[bonanzadave]

I only have 1 line coming from the petcock, and 2 electrical wires.

??

[Guest]

I only have 1 line coming from the petcock, and 2 electrical wires.

??

I expect the two wires are for the fuel level sending unit.


Mark

[jsandidge]

There should be 2 rubber hoses (lines) attached to your petcock. The larger 1 supplies fuel to your carbs. It should route in between the 2 inner carbs. The smaller 1 is a vacuum line that comes from the front side of the #2 carb. It creates some suction that operates a diaphragm inside your petcock. When the diaphragm opens, it allows fuel to flow through the larger line. When your petcock is switched to on or reserve, fuel should only flow when the engine is running (because engine vacuum is operating the diaphragm in your petcock). When your petcock is switched to prime, there is a metal tang inside the petcock that opens the diaphragm. This causes fuel to flow all the time. There should be no electric wires connected to the petcock, although there may be some passing near it.

[Redman]

If you dont have the vacuum line going to the petcock, that could be why it has been in the PRIme position.
And somewhere there may be the vacuum line open somewhere just sucking air and causing problems with cylinder #2.

Whatever: do not leave the petcock in the PRIme position.
Maybe put it to PRIme if need to for the bike to run, but then turn to other position when bike is parked.

.



.

[Nschultz]

Thanks guys! I'll get a pic of the petcock and bottom of the gas tank today. I'm going to be draining the gas out of the gas tank and draining the oil and putting fresh stuff in it. Maybe I wasn't hooking something up properly.

[Nschultz]

Pic of the carbs. I'm thinking the hose on the left should be the vacuum hose, middle is fuel to carb, and right is just an over flow, correct?


Pic of petcock - fuel is the open connection, and looks like vacuum is capped off?


pic of sending unit? The long hose coming off I'm not sure where that goes, or if it just hangs there. Then you have the sending unit connections there I believe.


thoughts?

thanks for all your help here guys!!

[jsandidge]

The middle hose on your carb rack does go to the petcock. That is your fuel supply for all 4 carbs. Both of the other 2 hoses are air vents. If you look at the other side of the carbs, #2 will have a small brass nipple. There should be a smaller hose that goes from that nipple to the one that is capped off on your petcock.

You are correct about the sending unit. The long hose just routes back along the frame. It is there to keep any leakage from the sending unit away from the hot engine.