Gas Tank Vacuum Sealed?

I could not fimd any arrow on the rollover valve on my 06. Here is a shot of it mounted in case your is mounted the same way.


Since the rollover valve is supposed to let excess air pressure out of the tank. When the pressure inside increased it allows the air to escape. Likewise as fuel is used the valve allows air into the tank so it does not create a vacuum. The second function of the rollover vent valve (and what separates it from regular vent valves and lines) is to prevent gas from running out of your vent line during an accident. When the rollover vent valve is on its side or upside down, a check ball inside the valve will close to prevent gas from running out.

I am not sure if ours ahas a screen in it to prevent debris from going up it and in the tank. Also the line runing to it should run down hill like sewage plumbing. by all down hill I mean no part of the line from that tank to the valve and from the valve to the bottom of the bike is all lower then the line entrance into the tank. The Idea here is not to create a Piss trap like in waste water plumbing as it will close off the flow of air in either direction.

See if you can pass air both ways from the tank down. Sorry easiest to stick the hose in your mouth and blow and then inhale to see if you can pass air in both direction. Steady not hard as you do not want to suck up the check valve ball. Sound weird but I believe you do not want to over pressure it just simulate what happens in normal expansion and contraction of pressure in the tank.

Hope this helps

warp9.9 said:

I could not fimd any arrow on the rollover valve on my 06. Here is a shot of it mounted in case your is mounted the same way.

Hope this helps

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Thank you sir! That will help.

R3Rx118 said:

Thank you sir! That will help.

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I added to it so go re-read it in case I was typing while you were.

@R3Rx118 I just went down in the basement to check again and mine indeed is also a check valve as described above. blowing air into it you can feel some restriction but air flow fine. When I drew air thru the hose slowly it flowed fine draw hard and the check valve closes. I can not tell you how many times I have had the tank off but I can say there have been a couple times I forgot to put the hoses back on the tank after I bolted it back down. Now on the Rockets you can install and pull the hoses while the tank is down. You do have to remove the bear claw. I am not sure if the over flow bottle is in the way as it has been so long since I moved mine. I can say most likely I forgot to put them on while the bottle was still there its just been 8 or 9 years and well my wifey reminds me that I am aging

warp9.9 said:

@R3Rx118 I just went down in the basement to check again and mine indeed is also a check valve as described above. blowing air into it you can feel some restriction but air flow fine. When I drew air thru the hose slowly it flowed fine draw hard and the check valve closes. I can not tell you how many times I have had the tank off but I can say there have been a couple times I forgot to put the hoses back on the tank after I bolted it back down. Now on the Rockets you can install and pull the hoses while the tank is down. You do have to remove the bear claw. I am not sure if the over flow bottle is in the way as it has been so long since I moved mine. I can say most likely I forgot to put them on while the bottle was still there its just been 8 or 9 years and well my wifey reminds me that I am aging

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Correct me if I'm wrong...but if installed correctly it should flow if you suck in from the top, to allow for air to vent in as fuel is being used up. And if you blow into it from the top it should block the flow, as it would shut off the flow in the event of dropping the bike? And if that isn't happening, that could be where the vacuum in the tank was coming from. Or the valve is stuck or gummmed up? Yes?
Additionally doesn't it allow for venting the build up of pressure if say your bike is sitting in the sun?

(from the top) Yes to flow if you suck slowly, suck hard and you create enough return force to lift the ball and close the vale like if it was tipped over. Blow thru it from the top always ( so the tank don't expand and burst) it will feel some restriction ( because of the choke down point or restriction at the valve) but air will flow thru allowing excess pressure in the tank to vent.
Hope this makes some sense.

Also important to note is all my stuff is non Roadster so if yours runs thru some type of extra emissions octopus style crap I have to plead stupid especially without knowing the schematics and theory's.

warp9.9 said:

Also important to note is all my stuff is non Roadster so if yours runs thru some type of extra emissions octopus style crap I have to plead stupid especially without knowing the schematics and theory's.

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Yeah, it's apparently a California model with the evap can. I was told all the X models are. All that crap is probably gonna disappear in the very near future anyway. Not a requirement where I live.

Its unbelievably easy to remove, unplug, unbolt, replug, block 1 line with a small bolt, done lol.

Call me cwazy, but I recall mine doing that when new (2013) and I did some searching and found something about making sure the gas cap was pushed down tight. I don't know how or why, but for some reason I always push down hard when closing, and have not had the problem since.