I'm in the middle of designing and figuring out my custom tank. I'm trying to figure out what to do for filler neck and cap. What are some ways you guys have solved this? One option is to buy another kit tank to cut the stock filler neck.
The rubber o-ring might give a bit of trouble. That rubber isn't fuel resistant. But they might make some someplace that are. Or maybe a fuel-proof gasket the same size.You could make the tank out of aluminum and use the butt end of a maglite. maglite has an endcap with an o ring seal.