Hose question

hamham

Joined
Oct 9, 2024
Messages
6
Age
47
Location
Wisconsin
Bike
1991 st1100
Can someone please tell me what this hooks to? Im assuming it's for the fuel system and would it being disconnected cause it to leak fuel? 1991 st1100. Thanks in advance. 1000000571.jpg
 
No idea, but I did some looking....

Looking at parts fiches, it could be part of the charcoal canister. Or the carburetor assembly. Or the fuel tank. Each of those fiche pages had a rubber hose and a 3-way T. I'd doubt the second, since that would affect being able to start the bike (unless it is some kind of vent hose). I'm sure folks who know, like @Uncle Phil, will chime in soon (well, as soon as he returns safely from his RTE and rests up a bit).
 
It appears to possibly be the fuel cap vent hose. The factory put a “T” fitting along the side of the fuel tank, in case the cap vent hose at the bottom of the bike ever becomes plugged. This way the tank would always be vented.

To check, follow the fuel cap vent hose from the cap, to the “T”, then all the way down to the bottom of the bike. The hose comes out just behind the kickstand next to the float bowl drain hose.
 
It was down by the other three hoses by the kickstand like you said but was not connected to anything. I'm assuming the fuel cap vent hose is the red one? That was my first thought but I don't see how you could hook it up because the diameters of the hose and the t are much different. There are no markings on it. I looked at a few parts fiches and couldn't for sure see exactly what it is. Where is the charcoal cannister? I've never heard of that.
 
Conflicting information... I don't care about the gas leak for now. Leaks can be easily found. Let's try to get this sorted out.
You only have 4 post's on this site. 3 of them are here on this thread. Did you just get this bike and trying to fix it up? What's the history of the bike? Do you have a service manual for the 1991-1994 model years?
If you have 3 hoses down at the kick stand, you have a 49 State standard model bike. Tank vent, float bowl drain and filler neck tray drain hose.
If you only have the 2 hoses down at the kickstand, then you have a "California emissions bike" with the evaporative emission system. The two hoses at the kick stand are the float drain and the tray drain. The charcoal canister is down between the frame rails, just above the center stand. The fuel cap breather will have an orange/red reinforced braided hose that goes from the cap, directly down to the charcoal canister. What do you have?
 
afrymoyer said:
Conflicting information... I don't care about the gas leak for now. Leaks can be easily found. Let's try to get this sorted out.
You only have 4 post's on this site. 3 of them are here on this thread. Did you just get this bike and trying to fix it up? What's the history of the bike? Do you have a service manual for the 1991-1994 model years?
If you have 3 hoses down at the kick stand, you have a 49 State standard model bike. Tank vent, float bowl drain and filler neck tray drain hose.
If you only have the 2 hoses down at the kickstand, then you have a "California emissions bike" with the evaporative emission system. The two hoses at the kick stand are the float drain and the tray drain. The charcoal canister is down between the frame rails, just above the center stand. The fuel cap breather will have an orange/red reinforced braided hose that goes from the cap, directly down to the charcoal canister. What do you have?
Click to expand...
I had a 'plumbing' disaster with our 1991 a short while after we bought it. I replaced several hoses right after getting the bike home and decided to put off hose maintenance 'til later because the remaining ones looked and felt fine. Woke up one morning to the odor of gasoline. There was an enormous puddle of coolant and gasoline on the garage floor. Both the 'L' shaped hoses had split and spilled gasoline onto the top of the engine, causing several water hoses to fail. This was before I realized the tank could remain pressurized. Not intending to be repetitive here, just take it as a warning. I certainly never expected this.
I took photos of the hoses as I disassembled the top side all the way down to the top of the engine. They helped immensely during reassembly. The parts manuals simply show a general location, not the necessary details.
Just a suggestion for first timers.
 
I've had the bike for about 6 years and been on here the same just never posted anything. I think it connects to the bottom of the tank vent hose.
 
Thank you kindly guys and yes everything I've been looking at is coming into question. There's a lot of engineering in there!
 
hamham said:
I forgot to mention that its leaking gas somewhere up by the carburetors.
Click to expand...

@hamham , are you trying to locate from where come the leak, and that is why you are trying to figure out witch hose come from where ?

So, your real problem is the gas leak ? Am I right ?

I ask this, because just a few days ago, I went to get my ST1100 from winter storage.
As soon as I started the engine, my friend came in a hurry, horrified, and was pointing at my boots.
I looked between my foot, under the under the ST, and there was a huge gas leak.
I shut the engine instantly. What was that ? Never had this problem before.
I tried to locate where it came from, looked at those hoses, from the gas filter to the carbs... couldn't see much without removing a few parts...
Curiously, as soon as I shut the engine, the leak stopped.
I started the engine again... and sure enough, the large fuel leak came back.
So I shut the engine again. After a minute of thinking I said I'll be back the next day with my trailer... and try to find out what was going on at home, with the tools and everything.
I was shure a gas line had blown somewhere... Yeah.... Very possible...

It is only on my way home, thinking about it, that I realised it made no sens.
The leak seemed too important to be just one carburator line.
In about 10 seconds, I probably lost half a cup of gas.

First thing I did once I arrived home, is to make a search on this forum : "gas leak".
I found that it had happend to a few guys when they get their bike out of winterisation, just like me. Ah-Ha !
It is normaly just the float on one carb, that stays sticked to the bottom of the bowl, and so the gas entry in that carbs stays wide open, and it soon overflow down from one of those hose.

Me too, the leak was coming near the side stand area, where we have those overflow hoses..

The good news is that there is nothing to do to fix it... I mean, the problem fixes by itself, when you leave the bike alone for a bit.
It is just a question of a few minutes and the float will unstick from the bottom of the bowl.

So the next day I showed up with my trailer to pick my ST1100, but I had to give it a try, first.
I started the engine, waited a bit... Put it in gears, I made a few hundred yards... no more leak.

Of course, it would be a good idea to replace those old gas line.
But it turned out that the problem wasn't the hoses. Not this time.

And since all my friends have fuel injection bikes, no one had a clue.
A carb ? A float ? What are you talking about ?

www.cycleworld.com

It’s a Gas

Engines need fuel, and your motorcycle gets it one of two ways: From a carburetor or from fuel injection. Our tech wizard explores how each works.
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