If you happen to have a California model or even just a CA tank, and the emissions cans and hoses happen to be missing, and you were wondering what to do about the nozzle in the front of the tank...
...do NOT plug it up.
It is a pressure release valve. It needs to stay open to allow the tank fumes to escape. Discovered today that quite a bit of pressure can build up if that nozzle is blocked—especially on a nearly empty tank. Luckily, my face wasn't hovering right over the cap when I opened it.
Quote from: silas on June 26, 2012, 11:26:19 PM
If you happen to have a California model or even just a CA tank, and the emissions cans and hoses happen to be missing, and you were wondering what to do about the nozzle in the front of the tank...
...do NOT plug it up.
It is a pressure release valve. It needs to stay open to allow the tank fumes to escape. Discovered today that quite a bit of pressure can build up if that nozzle is blocked—especially on a nearly empty tank. Luckily, my face wasn't hovering right over the cap when I opened it.
Then what do the flapper in the cap valves do???
Quote from: FJmonkey on June 26, 2012, 11:36:34 PM
Quote from: silas on June 26, 2012, 11:26:19 PM
If you happen to have a California model or even just a CA tank, and the emissions cans and hoses happen to be missing, and you were wondering what to do about the nozzle in the front of the tank...
...do NOT plug it up.
It is a pressure release valve. It needs to stay open to allow the tank fumes to escape. Discovered today that quite a bit of pressure can build up if that nozzle is blocked—especially on a nearly empty tank. Luckily, my face wasn't hovering right over the cap when I opened it.
Then what do the flapper in the cap valves do???
It let's air in as fuel is removed. The idea with the CA bikes (well, all of them now-a-days) was to force any fuel vapor in the tank to go to the carbon canister and NOT release it to the atmosphere.
Quote from: AustinFJ on June 27, 2012, 09:03:50 AM
It let's air in as fuel is removed. The idea with the CA bikes (well, all of them now-a-days) was to force any fuel vapor in the tank to go to the carbon canister and NOT release it to the atmosphere.
I am not so sure about that, after a run when all is hot and I park it it sings. While in motion air is flowing keeping engine heat moving rearward. When stopped the heat is trapped under the tank. My can casters we're removed and the tank plugged years ago. I think the flappers work in both directions.
The orange flappers in the cap are in the same circuit ahead of the nozzle in front. They appear to function as a venting valve. I'd have to tear everything back down again to be certain which way (and when) they control the flow. But since there are two flappers in the white plastic housing element, I'm assuming is a sort of switch... allowing air in to prevent a vacuum in the tank, and allowing excess fumes out to the emissions equipment.
My cap used to whistle too, until I tore it down and thoroughly cleaned every part. There was a lot of dry corrosion throughout the entire assembly. Used carb cleaner on the metals and WD40 on the plastics and rubber bits. The whistle must be the result of a partially plugged port or a leaking flapper seal.
Quote from: FJmonkey on June 27, 2012, 09:27:02 AM
Quote from: AustinFJ on June 27, 2012, 09:03:50 AM
It let's air in as fuel is removed. The idea with the CA bikes (well, all of them now-a-days) was to force any fuel vapor in the tank to go to the carbon canister and NOT release it to the atmosphere.
I am not so sure about that, after a run when all is hot and I park it it sings. While in motion air is flowing keeping engine heat moving rearward. When stopped the heat is trapped under the tank. My can casters we're removed and the tank plugged years ago. I think the flappers work in both directions.
If you plugged the normal vents in your tank, of course the flappers will sing. They are giving way before the metal of the tank. Doesn't mean they were meant to work that way.
And think about it. If you have a vent of fumes to atmosphere, why would you have (stock) charcoal canisters? Doesn't make much sense. The CA version even has a solenoid to close the vents for the carbs when the bike is off, so having a vent on the gas tank going directly to atmosphere, again, makes no sense.
Quote from: AustinFJ on June 27, 2012, 05:47:51 PM
If you plugged the normal vents in your tank, of course the flappers will sing. They are giving way before the metal of the tank. Doesn't mean they were meant to work that way.
And think about it. If you have a vent of fumes to atmosphere, why would you have (stock) charcoal canisters? Doesn't make much sense. The CA version even has a solenoid to close the vents for the carbs when the bike is off, so having a vent on the gas tank going directly to atmosphere, again, makes no sense.
Not trying to be difficult, but other non-CA bikes sing as well. Maybe I'm missing something...
Quote from: FJmonkey on June 27, 2012, 06:26:09 PM
Quote from: AustinFJ on June 27, 2012, 05:47:51 PM
If you plugged the normal vents in your tank, of course the flappers will sing. They are giving way before the metal of the tank. Doesn't mean they were meant to work that way.
And think about it. If you have a vent of fumes to atmosphere, why would you have (stock) charcoal canisters? Doesn't make much sense. The CA version even has a solenoid to close the vents for the carbs when the bike is off, so having a vent on the gas tank going directly to atmosphere, again, makes no sense.
Not trying to be difficult, but other non-CA bikes sing as well. Maybe I'm missing something...
Just free flow AWAY from your flapper valve. :yahoo: No worries! I do not believe the flapper valve is any different in the non-CA versions, just that it was used in them. Mine is a CA version and in the 110 degree heat, my flapper has been known to sing as well. All I was attempting to establish was that the flapper was not a 'vent-to-atmosphere' by design. It might have indeed been made to allow venting 'out' into the canister system as well as 'in' to the tank, but I have difficulty believing it would have been used in the CA system if it did not function as previously described.
I do not believe it was made to vent the tank to the atmosphere, that's all. When it is singing, I believe it is not functioning correctly in that it is (most likely) venting fuel vapor to atmosphere.
That's all I got. :flag_of_truce:
Anyone know how non-CA tanks vent off fumes?
Quote from: silas on June 27, 2012, 09:27:25 PM
Anyone know how non-CA tanks vent off fumes?
Directly to the atmosphere, via the flapper valves in the cap assembly..........Mine used to sing when the bike sat after being hot.
If they are singing, they are working properly........
In certain situations, like refueling while hot, while using my tankbag, the flapper valves wouldn't release pressure fast enough, and I would get fuel seeping up through the keyhole.
I have since removed the flapper valves, and have not had that problem since.
So, the exit point is the keyhole?
Non-CA bikes have a hose that attaches to a tube off the back of the tank, it goes down to below the engine and drains any overflow, I've always assumed the fumes go out that....
QuoteNon-CA bikes have a hose that attaches to a tube off the back of the tank, it goes down to below the engine and drains any overflow, I've always assumed the fumes go out that...
The CA tank has that overflow nozzle as well.
Never looked at a CA bike.... Maybe the GYSM has a section that explains the fume recovery system. RTFM?
Quote from: Firehawk068 on June 27, 2012, 09:43:03 PM
Quote from: silas on June 27, 2012, 09:27:25 PM
Anyone know how non-CA tanks vent off fumes?
Directly to the atmosphere, via the flapper valves in the cap assembly..........Mine used to sing when the bike sat after being hot.
If they are singing, they are working properly........
In certain situations, like refueling while hot, while using my tankbag, the flapper valves wouldn't release pressure fast enough, and I would get fuel seeping up through the keyhole.
I have since removed the flapper valves, and have not had that problem since.
The valve was not made to vent fumes to the atmosphere.
Quote from: AustinFJ on June 27, 2012, 10:32:23 PM
The valve was not made to vent fumes to the atmosphere.
Where do you think they go????
If you didn't have a tank vent, when your tank gets hot, you would overpressurize your fuel system, and your carburetor's inlet needle valves wouldn't be able to stop the fuel bowls from overfilling.
when the tank cooled, it would create such a vacuum, that it could possibly crush in on itself.........(Don't doubt this can happen. It's happened to someone on here)
The fumes exit through the flapper valves, and out around the top of the fuel cap, and out to atmosphere. Any fuel that comes out with it, flows down the little hole(gravity), down the tube and out the back of the tank, down the little hose, and forms a puddle under your bike.
Hope this helps.
Quote from: Firehawk068 on June 27, 2012, 11:03:36 PM
Quote from: AustinFJ on June 27, 2012, 10:32:23 PM
The valve was not made to vent fumes to the atmosphere.
Where do you think they go????
If you didn't have a tank vent, when your tank gets hot, you would overpressurize your fuel system, and your carburetor's inlet needle valves wouldn't be able to stop the fuel bowls from overfilling.
when the tank cooled, it would create such a vacuum, that it could possibly crush in on itself.........(Don't doubt this can happen. It's happened to someone on here)
The fumes exit through the flapper valves, and out around the top of the fuel cap, and out to atmosphere. Any fuel that comes out with it, flows down the little hole(gravity), down the tube and out the back of the tank, down the little hose, and forms a puddle under your bike.
Hope this helps.
They go to the valve at the front of the tank.
There are 2 vent/drain holes at the filler in the tank. There is a drain at the side to drain spillage and or rain/wash water. This is piped to the back of the tank and does connect to a hose and spills on the ground in a little puddle if you miss your filler hole or you have no gasket on your filler cap. There is also a vent hole at the back of the filler that when your filler cap is open you will/should see that it has a rubber grommet so that it seals to the cap when closed. This vent is piped to the valve at the front of the tank.
So if your scenario works on your bike, you are missing the rubber grommet the seals the flapper vent in the cap to the vent hole/pipe/valve at the front of the tank.
My statement has always been in this that the flapper valve does not vent fumes to the atmosphere. And by design it does not. It vents them to the valve at the front of the tank. On CA models, that valve is connected to charcoal canisters. In either case,the flapper was not made to vent fumes to the atmosphere.
Hope this helps and you get your bike fixed so it doesn't leave puddles under your bike.
Wow Tex.....
Thanks for diagnosing a problem that doesn't exist on my bike......
I was responding to Silas, where he asked "how do the NON ca bikes vent"
Mine is NOT a CA bike. I do not have the extra vent tube on the front of my tank.
My tank vents directly to the atmosphere, and works exactly as intended when they built it.
Sorry that you misunderstood my post. I was trying to help Silas.
Quote from: Firehawk068 on June 28, 2012, 09:03:57 PM
Wow Tex.....
Thanks for diagnosing a problem that doesn't exist on my bike......
I was responding to Silas, where he asked "how do the NON ca bikes vent"
Mine is NOT a CA bike. I do not have the extra vent tube on the front of my tank.
My tank vents directly to the atmosphere, and works exactly as intended when they built it.
Sorry that you misunderstood my post. I was trying to help Silas.
My apologies. I had commented earlier in the thread and with the subject still saying "California fuel tank nozzle", I thought we were still talking about the original subject. Missed the switch to non-CA bikes. My bad.
ok so my fuel cap leaks gas through the key hole after I fill it. How do I stop this? It doesn't leak when the tank is half full. Btw it whistles(sings) as well :).
A
I'd take it apart and clean it.
There's a tiny spring-mounted ball bearing that serves as a valve on one of the vent holes. Be careful not to lose it.
Big clear plastic bag is the best thing to take it apart in, anything that goes flying will stay in the bag..... Gallon ziplocs work good.