The locked fuel cap opens by itself

[Martin_z_BA]

Hi, I have a question about the fuel cap, R3GT 2022.
I am driving a lot, filling up full to empty, the petrol level is as it turns off automatically, usualy about 2cm above the metal partition with hole for gas gun in the neck of the tank. I found 2 strange things. When I open the tank, I feel the sound of a strong vacuum. It's as if no air is going into the tank to equalize the pressure after the gasoline has been drained. The second thing that really pisses me off is that when I fill the tank and lock the fuel cap, it also spins out when locked and can be opened completely even though the lock is sort of locked. To close it, I have to unlock it and lock it again.
I don't know if it has to do with the amount of petrol or if the fuel cap is faulty. Has anyone had similar experiences?
Thanks.

 

[Rockatansky]

First part: that's normal - you have a bike with Euro 5, that means it's a closed system that does not allow steam to leave the system.

Second part: sorry, I do not get this - so you lock the inner fuel cap, but it's still open?

 

[Martin_z_BA]

I fill the tank. Then normally lock the cap. It is locked. After ride (we are on mototrip, so on the pause after 100-150km) is inner lock released and I can unscrew it even is locked. But if I want to screw it clockwise, I cannot hear the clicks, so I must unlock it, tighten and then lock again. Sometimes it holds normally till next filling, sometimes opens again.

 

[Martin_z_BA]

Fuel cap seems to be defected. Today it happened 2-3 times. Evening after ride I've locked it but even that I was able to unscrew it locked. I will contact the dealer.

 

[gadget_ho]

Fuel cap seems to be defected. Today it happened 2-3 times. Evening after ride I've locked it but even that I was able to unscrew it locked. I will contact the dealer.

Yep, seems faulty...

 

[MIG]

Fuel cap seems to be defected. Today it happened 2-3 times. Evening after ride I've locked it but even that I was able to unscrew it locked. I will contact the dealer.

Good call...
-MIG

 

[Vatoe]

I never lock mines - one less thing to do when refilling

 

[pica]

I never lock mines - one less thing to do when refilling

Same here...

 

[stingray]

I'll try locking mine for a while to see if it is defective. Living out in the sticks, gasoline theft has never been a problem for me.

 

[vsteel]

I think you are hearing pressure. I know I have had mine unscrew some when it built up a little too much pressure, to the point I don't need to unlock it to get the cap off.