fuel burps when throttling, Gas Cap gas tank vacuum lock?

All...

1983 Yamaha XJ 550 Maxim

I've had some issues with my XJ-enstein, but engine wise it's been pretty nicely restored.

so, my mechanically inclined friends have told me that it may be an issue with the vacuum lock on the gas cap.

When I replaced my tank, and procured a new cap, it was cheap and easy.

1) can i possibly work on this piece, get it to 'breathe' better?
My cap is essentially 3 months old, much rather wait to 'trick out' my cap needs due to already too much $$$ spent

2) should i simply by an OEM or more substantial part?

Pictures to follow.

 

like i mentioned it's brand new, can i alter this in any way to aid in improving my vacuum?

 

Have you tried running it with the cap opened?

 

Have not due to my extreme ignorance. I thought that would be ‘bad’

 

I did after I saw this. No definitive change. One run had zero burps, making think that it was fine. The other was burpy again.