Gas smell, no leaks

[DLD1]

All,

I have a question for you all. Does your XS smell like gas all the time, even when there are no leaks? My garage always smells like gas when the XS is parked inside, and we do our laundry in the garage (unfortunately). I've checked very carefully, and I have no fuel leaks. The only thing I can figure is that the carburetor bowls are vented, and the fumes get out that way. If anyone has some insight to this issue, I would appreciate it.

DLD1

 

[pamcopete]

dld1,

The aromatics in the carb fuel bowls evaporate through the vents and that is where the smell comes from (aroma). If your pet cocks are shut off, then the evaporated fuel is not replenished and there will be no strong smell, but if your pet cocks are left on or they are leaking into the carbs, then the aromatics are constantly replenished and you will get a strong smell but no evidence of liquid fuel.

Actually, all of the fuel will eventually evaporate, but that takes weeks. It's the lighter aromatics that go first, and they are what makes gasoline, gasoline. When they evaporate, the octane of the fuel drops very low, hence one of the reasons for hard starting.

If your bike has been sitting for a couple of days, open the pet cocks and shake the bike back and forth a few times to replenish the aromatics in the bowl for a faster start.

 

[DLD1]

Thanks, Pete, that's what I had assumed, just wanted to know if there was anything else that I didn't know about. I guess I'll just have to keep parking it outside under a cover. Fortunately I'm in central Ca. and it's not too big of an issue.

DLD1

 

[pamcopete]

DLD1,

Well, as I mentioned above...check your pet cocks for leakage. Not leakage out side of the fuel system, but leakage to the carbs through the gas line.

I have three bikes in my garage, and there is no hint of fuel odor because all of the pet cocks work and do not leak.

 

[uknowme2goog]

I agree... if my garage is closed up for a day or so with the bike inside....as soon as you open the door and walk in you small gas.

Its the gas left in the carbs...make sure ur pet cock is off.

 

[DLD1]

Thanks,

I'll check the petcocks for leakage.

DLD1

 

[sdparis1988]

dld1,

The aromatics in the carb fuel bowls evaporate through the vents and that is where the smell comes from (aroma). If your pet cocks are shut off, then the evaporated fuel is not replenished and there will be no strong smell, but if your pet cocks are left on or they are leaking into the carbs, then the aromatics are constantly replenished and you will get a strong smell but no evidence of liquid fuel.

Actually, all of the fuel will eventually evaporate, but that takes weeks. It's the lighter aromatics that go first, and they are what makes gasoline, gasoline. When they evaporate, the octane of the fuel drops very low, hence one of the reasons for hard starting.

If your bike has been sitting for a couple of days, open the pet cocks and shake the bike back and forth a few times to replenish the aromatics in the bowl for a faster start.

I've got the same smell issue going on in my garage. The bike is new to me and i am new to this forum. In fact this is my first post. My pet cock has no off position but is vaccume operated. I was thinking the smell was coming from the old hard gascap seal. Could this be the case? Help me out! I'm in danger of losing my parking space inside.

 

[pamcopete]

sdparis1988,

Well, I have a vacuum operated petcock on my '81/H and it is one of the bikes in the garage but there is no gasoline odor so perhaps your pet cock is leaking. Again, not leaking to the out side but just leaking into the carbs. Just be sure that the petcock lever is not in the prime position but is pointing down in the on position which becomes the off position when the engine stops and there is no vacuum.

You can test for this condition by pinching your gas line with forceps or vise grips overnight.

The gas tank vent could also be a source of the odor as well. Of course, it could be that you are just more sensitive to the smell of gas because as I mentioned it's not just the aromatics that are evaporating. It's just that the aromatics go first so you could be smelling the rest of the gas that is also evaporating but just more slowly.

 

[sdparis1988]

sdparis1988,

Well, I have a vacuum operated petcock on my '81/H and it is one of the bikes in the garage but there is no gasoline odor so perhaps your pet cock is leaking. Again, not leaking to the out side but just leaking into the carbs. Just be sure that the petcock lever is not in the prime position but is pointing down in the on position which becomes the off position when the engine stops and there is no vacuum.

You can test for this condition by pinching your gas line with forceps or vise grips overnight.

The gas tank vent could also be a source of the odor as well. Of course, it could be that you are just more sensitive to the smell of gas because as I mentioned it's not just the aromatics that are evaporating. It's just that the aromatics go first so you could be smelling the rest of the gas that is also evaporating but just more slowly.

Thanks, I'll check it for leaks tonight when I get home and then clamp it off overnight and see what happens. I've already got the gas cap seal ordered. it needs to be replaced wether its the culprit or not.

My wife is the one with the sensitive nose. She said the garage, laundry room and kitchen smelled like gas this morning. To make it worse, my son parked her car in the garage with the windows down. So now her car smells like gas and I may have to park somewhere else.

By the way, can anyone tell me how to start a new post? Like I said, I am new. i had a few questions I was going to post and introduce myself and my project but have looked all over for a way to start a new post and can't find it. It is probably right in front of me.

 

[Royboy]

At the head of the forum page go to "general discussion" "garage" and look just below XSOTM (top left) and you will find "New Thread". Click on that and you're in.

There are four old but nicely tuned bikes in my shop. Never any gas odor. If there is a gas smell I know something, (petcock, float valve, etc.) is leaking.

roy

 

[sdparis1988]

thanks I found it. I will post tonight after work.

 

[sdparis1988]

sdparis1988,

Well, I have a vacuum operated petcock on my '81/H and it is one of the bikes in the garage but there is no gasoline odor so perhaps your pet cock is leaking. Again, not leaking to the out side but just leaking into the carbs. Just be sure that the petcock lever is not in the prime position but is pointing down in the on position which becomes the off position when the engine stops and there is no vacuum.

You can test for this condition by pinching your gas line with forceps or vise grips overnight.

The gas tank vent could also be a source of the odor as well. Of course, it could be that you are just more sensitive to the smell of gas because as I mentioned it's not just the aromatics that are evaporating. It's just that the aromatics go first so you could be smelling the rest of the gas that is also evaporating but just more slowly.

I clamped down the fuel line with forceps as soon as I parked the bike last night in the garage. Still, within 2 hours the garage smelled like fuel.

At this point I think it has to be the gas cap seal or our noses are far to sensitive. I hope its the seal!

Anywhere else I should look? Could there be something else going on with the carbs?

 

[xjwmx]

The vent hole in the cap, which is also the key hole. Plus the seal of the cap itself. So it's always going to smell like a gas can. Just keep a nose out for unusually strong gas smell...