Strong gas smell on shutdown

[cardinal]

Anybody else get a fairly strong gas odor when they shut down after a ride?
When I pull the bike (1998 SE) into the garage and shut it down, the odor permeates the garage, but there are no puddles on the floor or in the overflow tray under the gas cap.
Is this normal?

[Happytrails]

I get this too. Just the vented gas cap letting us know its still there

[ct1500]

I can guarantee that when new the MC did not spew gas fumes to fill a garage and it needs an inspection to determine the origin.

[cardinal]

I get this too. Just the vented gas cap letting us know its still there

So it's GOOD news. It means the vent is open and working. Even though the less gas I have in the tank, the greater the PUFF when the cap is opened.

[wingdings]

hi - saw your post there !! - does you bike bog down at all if it does - please take a look at this link - viewtopic.php?f=14&t=36257 - it could be your pet **** that would explain the strong smell of petrol when you shut down .

THE SYMPTOMS OF PETCOCK FAILURE

Like any other malfunctioning part, there are a few different symptoms.

One is that the engine will run for a short time and then die. It will not immediately restart but will restart in a minute or two.

Another is the engine bogs down while traveling along in fifth gear and just will not accelerate. But, if you down shift and then crank on the throttle it will pick up and run great at high RPM's but then bog back down again shortly after you up-shift.

Another indication is there will be fuel collecting in the cavity where the fuel cap is but you probably can not see where it is coming from

There are other symptoms but to troubleshoot the petcock, there is a procedure in the service manual to follow. It involves using a small hand held vacuum pump like the Mity Vac. The procedure is in section four of the manual. The petcock is called an Auto Fuel Valve. It is a simple process and should take only a few minutes of your time to test it.

(special thanks here to mike b . for the above paragraph .)

Also take a look at this vid too -

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Hope this helps

[cardinal]

Bike runs fine and steady at all speeds, short and long distances. I noticed that the pressure builds up more in the tank when the fuel level is low. It's always low when I get home, so the pressure is up, so I think maybe the fuel cap is slowly letting the pressure decrease, thus the smell of gas from the fumes.
Whadda ya think?

[bellboy40]

The pressure release when you open the gas cap sounds normal to me. I have had 6 different Goldwings and they all do that. More noticeable when you are low on fuel and stop to fill-up, especially in warm weather. You will get a whoosh of pressure release when opening the gas cap.

[cardinal]

Yup. Same thing happened with my 1995 when would stop for gas.

[Happytrails]

Bike runs fine and steady at all speeds, short and long distances. I noticed that the pressure builds up more in the tank when the fuel level is low. It's always low when I get home, so the pressure is up, so I think maybe the fuel cap is slowly letting the pressure decrease, thus the smell of gas from the fumes.
Whadda ya think?

Mine does the same. Its been doing this pretty much ever since I've had my bike for the last 5yrs now. Bike runs great. I take this as a sign the gas cap is venting and we smell it because the bike is sitting still with vapor built up in the tank. I can't say I've heard any pressure releasing when I stop to fill up but maybe I wasn't listening close enough. I dont take my helmet off when I gas up so I might not hear it.

[Happytrails]

....I have had 6 different Goldwings and they all do that.

do you own 2 1500's now Bellboy? I'm just wondering because I'm looking to buy a newer bike and I've given thoughts to keeping my 1500 for a bunch of different reasons. Just wonderin how you felt about that if you have 2 touring bikes in the garage? Sorry not meaning to hijack this thread!

[bellboy40]

Yes, I do have two 1500SEs in the garage. I sold the 94 to my riding buddy when he had an accident on his previous one and messed it up pretty bad. He kept it for about 9 months then decided he would sell the bike and travel with his wife in his travel trailer. I told him I would buy it back because I kind of hated to let it go when he got it. They are both in excellent condition. I love the 1500s. Wish I had bought one a long time before I did.

[Wingsconsin]

The following is my theory and my opinions -
I owned 2 GL1500s and put 100,000+ miles on them each over time

The fuel tank on the 1500 sits over the engine.
The engine generates heat -
When parked the engine heats up the fuel and causes it to expand and off vent fumes-
When the fuel tank is FULL this expansion can cause an overflow into the tray - a few drips and drops can smell up a garage without filling the tray -
When the tank is 1/2-3/4 full there is room for this expansion and the fuel has sufficient volume to absorb the heat without fuming.
When the tank is near empty - the fuel can boil if the engine is hot on a hot day - Our engines are liquid cooled but whe shut off - the coolant stops flowing and the engine heat sinks (gets really hot initially)

On my 1996 at 131,000 miles I did a new petcock, hose, fuel cap, gaskets, and fuel pump - it still did it occasionally.

By the way - a GL1500 will be able to nearly gravity feed fuel to the engine until about 1/2 empty -- then the fuel pump is needed to help-
If you fuel pump gets too hot on a low fuel run during a hot day it may not move enough fuel to keep the engine running well -
On really hot days - fill before you get near empty if you suspect your fuel pump is weakening.

[WingAdmin]

Warning: physics ahead

The coefficient of expansion for gasoline is 0.00095 per degree C.
The coefficient of expansion for air is 0.00340 per degree C.

So basically, if you heat the same volume of liquid gasoline and of empty air (including air containing gasoline vapors), the air will expand almost four times as much as the gasoline.

So if you have a tank full of gas, and it gets heated up 20 degrees by the engine, it will expand a little bit. If you have filled the tank right to the very top, as it expands, it will push up through the vent cap and drain overboard. Typically, you don't fill it right to the very top, so you have a tank that is 98% gasoline and 2% air. The air expands much more, but there is so little air, the pressure created by the expanding air is very little.

On the other hand, if your tank is almost empty and you heat it up 20 degrees from the engine, the air inside it will expand a LOT. The result is that the pressure inside the tank will rise a lot. At some point, the vent cap will allow some of that pressure to escape, to avoid over-pressurizing the tank and turning your bike into a bomb.

So let's look at two riders, Joe and Bob. They are both riding identical bikes. They go out for a ride together. Joe's gas tank is almost empty, but Bob's tank is almost full. After riding for half an hour, they come back and park in Joe's garage. The bikes are now heat soaked - all the heat trapped in the engine that was being sent overboard through the radiators is now just sitting there, because the engines are no longer running. That heat goes into the gas tanks, warming their contents.

Bob's tank is almost full of gas. Gas has a lot of thermal mass, and it takes quite a bit of heat energy to raise the temperature of all that gas. So his gas heats up say 5 degrees. It expands a little bit, creating a bit of pressure, but nowhere near enough pressure to trigger the vent cap, so nothing happens.

Joe's tank however is almost empty. Air has very little thermal mass, and it doesn't take much heat energy to raise its temperature, so it heats up, FAST - perhaps 30 degrees instead of the 5 degrees that Bob's gas heated up. As it heats up, it expands quite a bit - four times as much as the gas in Bob's tank would expand even if they were heated the same amount. Because of all this expansion going on, the vent in the cap opens up, allowing the excess pressure to bleed off. This fills Joe's garage with the smell of gasoline.

Basically, if you're smelling gas fumes after you ride, that's generally a good thing, as it means your vent cap is operating. If you don't want to smell fumes, make sure you fill up your tank before you park your bike.

Now if you are consistently smelling gas fumes when you park your bike, and your tank is full (but not overfull - fill to the bottom of the filler neck only), and you're STILL smelling fumes, then you have a problem, and you should probably start hunting down a potential fuel leak.

[cardinal]

Thanks Wingman,
A little thought, after the observation of the increased pressure in the tank when the fuel level is low, would lead to the fairly common thought that a gas (air) expands more than a liquid (fuel), therefore a pressure relief valve (fuel tank cap) will "relieve that expanded gas" and carry the odor of the gas vapors with it.
Some times an observation gets UNDER thought.

[ct1500]

so I think maybe the fuel cap is slowly letting the pressure decrease, thus the smell of gas from the fumes.
Whadda ya think?

That red hose from the fuel cap directs tank fuel vapors to be contained in a charcoal cannister, a closed system.

[ct1500]

deleted operator error

[WingAdmin]

so I think maybe the fuel cap is slowly letting the pressure decrease, thus the smell of gas from the fumes.
Whadda ya think?

That red hose from the fuel cap directs tank fuel vapors to be contained in a charcoal cannister, a closed system.

Only on California-spec bikes. All other bikes it just vents overboard.

[LucHam]

I also had that problem. If you change the gaskets of the carburator on your wing 1500 the smell will be gone. You dont see a gasoline leak because the gasoline is leaking on your hot engine and is vaporised instandly. I visited a goldwing expert and he changed the gaskets. I never had that smell again. And after that starting is much quicker because the carburator dont looses his fuell and does not have to pump up the fuell each time you wanne start the engine.

[lostfarmer]

I have a 1998 GL1500A that had the same fuel smell after riding and parking in the garage. The problem i had with mine was a leaking rubber gasket that goes between the fuel pump cover and the fuel tank under the seat. With the fuel level low there would be no odor. With a full tank the odor would come back. I removed the seat and you could see a little fuel seeping past on of the attaching studs and collecting below the fuel pump cover on top of the tank. Cheap and easy to fix this problem

Hope this will help someone with the same problem.

[shomann]

If the gas smell really annoys you, just remove the fuel cap, air out the tank a few seconds and put it back on before you park it in the garage. If the smell is not there after removing the gas cap and parking it is obviously was the smell of venting. If the smell is still apparent, could be petcock...

[AndyFromWI]

I have a 97 SE, that I have owned for 2.5 years, for my first year I never had a gas smell.
Last year I started getting the smell, I ended up rebuilding the petcock (auto fuel valve), that helped last fall. This Spring the smell was back and I'm currently rebuilding my carbs and doing a serious investigation (everything is torn apart)...


My point is that I'm not 100% convinced this is just normal.
I should be done with my carb rebuild next week and see if my smell is gone....
By the way, my wife also says I have a gassy smell!

-andy

[Stew]

so I think maybe the fuel cap is slowly letting the pressure decrease, thus the smell of gas from the fumes.
Whadda ya think?

That red hose from the fuel cap directs tank fuel vapors to be contained in a charcoal cannister, a closed system.

Only on California-spec bikes. All other bikes it just vents overboard.

If that is the cause of the fuel smell (mine does it too), then making a small charcoal canister should be easy enough using a small plastic jar filled with activated charcoal granules you can get at a pet store in the aquarium section, a couple vacuum fittings and a little vacuum line.

[LucHam]

I have a 97 SE, that I have owned for 2.5 years, for my first year I never had a gas smell.
Last year I started getting the smell, I ended up rebuilding the petcock (auto fuel valve), that helped last fall. This Spring the smell was back and I'm currently rebuilding my carbs and doing a serious investigation (everything is torn apart)...


My point is that I'm not 100% convinced this is just normal.
I should be done with my carb rebuild next week and see if my smell is gone....
By the way, my wife also says I have a gassy smell!

-andy

Your are right Andy, the fuel smell is not normal, after repairing my wing you dont smell anything of fuel.
Take of the left engine cover and have a light with you.
When your wing is cold an you start the engine and shut it down after a minut you should put him on the side support so the wing tilts to the left. When you look at the carb now you wil see that he is leaking fuel , this is normal for an old wing because the gaskets start leaking.


Luke

[Stew]

Just got done replacing the sub filter and while it was apart you can see plain as day like WingAdmin said, the gas cap vents straight to the atmosphere.

I know some said it's not normal but I can see how it is so common, the orange/red braided line from the gas cap goes straight down behind the alternator and terminates to an open line. Don't smoke while replacing your alternator!

[ct1500]

Just got done replacing the sub filter and while it was apart you can see plain as day like WingAdmin said, the gas cap vents straight to the atmosphere.
I know some said it's not normal but I can see how it is so common, the orange/red braided line from the gas cap goes straight down behind the alternator and terminates to an open line. Don't smoke while replacing your alternator!

Yes but the OP of this thread is in California and it would be a safe bet he has a CARB equipped machine. The spewing of gasoline fumes to fill a garage under normal operating conditions is not a design feature Honda would have built into any vehicle, just think of all the road tests done by potential buyers at a dealership and then bringing the MC back into the showroom, how would that have gone over having to evacuate the building?

The fuel tank and cap are designed to hold a slight build up of pressure within under normal and anticipated conditions. A very simple test for the OP or anyone else experiencing strong gasoline odors from their machine would be to stick a golf tee into the orange hose prior to bringing into garage, if gasoline smells persist then the fuel cap aint' the source of the problem and in the off chance was cured I would be looking for a new cap.