More gas per fill up for our wimpy 3gal gas tanks?

Hey guys I had a little thought while thinking about our tanks. I know it has been noted that the filler neck stops us from accessing the full capacity of our tanks, and removing that would be difficult....

My idea is to take a punch and just "push" a hole high up on that metal sleeve, allowing me to fill it up higher. No shavings with a punch versus a drill. My only concern is I know it's been said that area is used to allow for expansion, but if I only fill up on my way out of the house and don't let it sit with a full tank, it should be okay no?
Just a thought, curious to see what y'all say...

 

1. Don’t.
2. Which model XJ do you have?
3. Most have 5 gallon tanks, and almost none have less than 4 gallon tanks.

 

I've got the 1985 maxim x 700. Last time I got to reserve with only 110 miles on the clock... From what I can tell there aren't many options out there for getting any increases....

 

No good/simple/easy/inexpensive options.

The 700 tanks are pretty small. And they don’t interchange with anything.

Are you or any friends a master fabricator?

 

Unfortunately no, just wanted to see if any of you more experienced fellas had any thoughts. From what I can tell fabricating up a new tank would be the only way, apart from my hairbrained idea .

 

I expanded the bleed hole at the top of the fuelling tube inside my GS tank. Took it out to about a 1/4" or so. Main reason I did it was to hurry up the last gallon of fill, as it took an age to bleed through the 1/16" hole. Like yourself I never filled it up without going somewhere so the bike never sat with a totally full tank.