I have been noticing when i open my tank to put fuel in the tank is under pressure!
Maybe i am just noticing this or has it always done this.
Does a yone else have positive pressure in the tank
Brogs

I'm not 100% but I believe there is an overflow vent that should keep the tank close to ambient pressure when it gets hot from the engine.

If you check the manual there is a dashed line from the fill arera I believe representing a vent line to a tube that exits the tank. Without a pressure vent/over fill vent I dont think the tank can flow fuel into the pump. Maybe that's clogged or pinched? Had the tank off rencently?

I'm not 100% but I believe there is an overflow vent that should keep the tank close to ambient pressure when it gets hot from the engine.

If you check the manual there is a dashed line from the fill arera I believe representing a vent line to a tube that exits the tank. Without a pressure vent/over fill vent I dont think the tank can flow fuel into the pump. Maybe that's clogged or pinched? Had the tank off rencently?

Mine has done it in hot weather. I don't ever notice it now but I am using an aftermarket cover that may not seal as tightly. Quarter turn caps only seal as tightly as the spring in the cap. I found a waxy glob under the two rubber lines on the LH side after a long hot ride. I was told that sometimes the factory sealant does not melt out for a long time....anyway, if you gas cap sqeals like a tea kettle when you shut down, that is an old issue. The tank is expelling air displaced by expanding fuel. i wouldn't worry about your fuel tank passing wind too much unless it's severe.

It's most likely a closed loop system, i.e., keeps the vapor inside sealed... which is a good thing. Look at the gas cap next time, but the bottom part. It shows two ball and spring chambers. It goes something like, one closes the gas from coming out upon tip over, the other seals when the bike sits static, but drops upon vacuum or the gas depleting in the tank.

I know on the 14R there is a vent thru a charcoal can that keeps the actic sea ice from melting and killing the polar bears

..at least in CA there is.

ahaha, you are very wise and knowledgeable, thank you for correcting me!

Just kept thinking about the vent lines on my ex-boat's fuel tanks. They would foul with corrosion and the engine would stutter under acceleration because of reduces fuel flow. PIA to deal with that problem.

Brogs,

This is typical for this bike (at least this model/year). There have been a few threads about this in the past and my bike does the exact same thing, its more noticeable in hot weather as Rook mentioned.

You may also notice a whistle sound coming from the gas cap (again more often during hot weather) this is just some of the excess pressure from the tank escaping through the vent. You can open the gas cap to relief the pressure but it'll just start whistling a few minutes later anyways.

Thank you all for your response.
Just seemed odd.
Brogs

Maybe it's the difference between thinking of it as the tank having a vent and the tank having a pressure relief valve? Open vent would be bad since combustible compounds in gas vaporize and separate from the liquid leaving behind essentially nonburnable liquid. Seems like it wouldn't take too long for this to happen really.