Fuel vapors...

[RUN666]

Every time I open the aluminum Monza cap, it's under pressure and the fuel comes out as vapor...

It's very hot here and my bike is in direct sunlight, and when I stop, I get this phenomenon every time.

So Triumph designed a black plastic vented cap and a sealed aluminum cap, and that prevents the former from venting? That's strange, to say the least, right? Or maybe I have a problem...

 

[Einar]

That sounds backwards. On mine, the aluminum cap is decorative and not sealed, so nothing happens when it's opened. The black locking plastic cap beneath it is the one that's sealed.

 

[dd14x]

That sounds backwards. On mine, the aluminum cap is decorative and not sealed, so nothing happens when it's opened. The black locking plastic cap beneath it is the one that's sealed.

Ditto - the aluminum cap (on a hinge) occasionally opens up when I'm riding too - so definitely not sealed.

 

[Protonhound]

Hmm, mine vents when opening the aluminum cap. It seems that releasing it allows the actual plastic cap to do it's venting, the aluminum cap is not sealed so it's not retaining any pressure by itself. I remember a thread talking about not laying the fuel cap upside down when fueling as this sometimes will prevent the venting mechanism to work right. I read that before I even got my '23R so when I fuel up I always put the cap right side up on a piece of paper towel.

 

[RUN666]

It's good, I solved the problem thanks to a member of a French forum... When I removed the canister system, I pinched the tank's air vent when reassembling it, which explains the high pressure in the tank in the sun. The problem will be solved tomorrow!

That being said, notice that you have, under the "Monza" cap, a small moving part with a spring that presses on the plastic cap and which apparently serves to maintain the pressure on this plastic cap. I think that, when I open the "Monza" it is actually the gases blocked by the plastic cap that escape!