AnyOne else - Vacuum in fuel Tank?

[Stig / Major Tom]

OK, back again with this question.
Is any one else finding a vacuum in the fuel tank when they open the cap?Symptoms are : sucking noise and cap stuck on filler neck a bit - when opening.
This happens nearly every time I open the cap after being parked - but only sometimes after being ridden.
One comment from a veteran scooter rider/mechanic is that this is due to fuel having over-flowed into vent tube - and now small PVC valve is clogged. Differing air temps causing fuel to expand and contract....and fuel cap cannot vent  air in....only out. My mechanic says venting out is normal. One remedy is to cut the vent tube from the filler neck and let it hang - so the tank can vent - in and out.
My concern is or course a scoot that cuts off or boggs in traffic from fuel starvation. This has never happened, yet.
Any ideas?
Thanks, Stig

[blue]

True this can happen all I did was take a gas line of and let a little air in the tank and the cap came right off.

[TroutBum]

Since you're still under warranty, take it to your dealer and let them fix this issue.

[08087]

I can't say it happens to me.

[Stig / Major Tom]

Since you're still under warranty, take it to your dealer and let them fix this issue.

Trying to sort out if it is an issue - or is it what happens when you ride a scooter.
Taking it to the dealer is a .....project in itself this time of year. They are knee deep in big bikes for spring riders.
If my scoot acted funny in the slightest way - I would be down there at sun-up. It runs fine - just wondered if another LIKE owner could pull his gas cap after it sits after a ride and see if the tank inhales?
Stig

[LidoCA]

 I finally had this happen. It was on Sunday morning and I opened the gas cap. Air rushed in, then gas came out. In hindsight, I am not sure if it was pressurized or in a vacuum. It did remind me of an answer from your previous post, about over filling the tank. I filled the tank higher than normal. Normally the gas pump shuts off at about three quarter tank.  I filled it over the cross bar in the tank. I don't know if that is supposed to be true cut off point. Since then, as the tank level has dropped, it has not happened. 

[donandrews]

Page 12 of the Like manual says not to over fill. "There should be no fuel in the filler neck." Don't think this will answer your question, Stig, but it may help LidoCA. We don't have self serve in Oregon so I just tell them to fill it to the bar and try to go the the same station all the time.
Peace and Ride Safe