Power loss

[MrPix]

I could be wrong as my English is not good, reading your description, I am thinking to this:
1) first case: tank full, air from outside cannot go inside the tank. The internal face of the tap is only facing gas.
2) second case: tank full, air from outside can go into the tank when you park as the internal face tap is facing air both sides. Then air pressure in the tank can quietly be adjusted during parking.

To check that you could park the bike case (1) with only 1 gallon in the tank and check if you have any issue when you restart.

That means for me, that it is good to check gas in the tank by opening the tap before any ride . You are sure that pressure is in equilibrium with outside.

There is no 'tap' on the 2020... just saying.

 

[JPHDT]

There is no 'tap' on the 2020... just saying.

I know that my English is not as good expected.
In order to use the right word, what is the name of that piece of equipment we have to unscrew from the tank of R3 2020 to fill that tank ?

 

[MrPix]

I know that my English is not as good expected.
In order to use the right word, what is the name of that piece of equipment we have to unscrew from the tank of R3 2020 to fill that tank ?

Sorry, ... 'filler cap'... on older bikes there was a 'tap' that needed to be turned to allow fuel to pass from the tank to the carbs... I thought you maybe referring to that, but it makes sense now.

 

[JPHDT]

Sorry, ... 'filler cap'... on older bikes there was a 'tap' that needed to be turned to allow fuel to pass from the tank to the carbs... I thought you maybe referring to that, but it makes sense now.

Thank you @Mr Pix, you made my day . I know now, that my old HD has a tank tap that needs to be turned to allow fuel to pass from the tank to the carburetor, and a tank filler cap.