Gas Cap does fit on new tank's filler tube

[BillD]

I just installed a new fuel tank (Canadian manufactured via eBay) on my '60 Bug Eye. Every thing was going fine, including the dreaded fuel line fitting, until I tried to put the cap on the filler tube. The filler tube inner opening is 37mm and the center part of the cap (with the ears) is 38mm. I'm thinking about using an exhaust pipe expander to widen the opening to accept the cap but am open to suggestions. Thanks in advance. I've been lurking and have already benefited greatly from this group!

Bill D.

 

[Rut]

I bought the same tank and just tried my original cap. It fits perfectly...I'm soooo happy!
Rut

 

[BillD]

That's reassuring. I'm thinking that the previous owner may have replaced the cap with one that fitted the slightly larger mouth of the original BE Sprite filler tube. The vendor tried a standard Sprite/Midget replacement cap on one of his tanks and it worked so I've ordered one and hope that fixes the problem. {The plastic cap from a paint spray can that is temporarily serving as a replacement works surprisingly well but just doesn't look historically correct.}

Are there any tricks for installation of the top grommet?

 

[leecreek]

grommit goes in before the gas tank.

 

[BillD]

Thanks. That's probably the right answer but not the one I wanted to hear. I took off the grommet because of alignment problems in installing the tank. Looks like I have another adventure ahead of me.

By the way, I measured my original fuel filler opening and it was 38.8mm. The replacement tank's opening is 37mm and my "original" cap's width is 38mm. Close but no cigar.

 

[BillD]

I got a more modern gas cap to fit the filler tube of my replacement tank but just out of curiosity I tried expanding the mouth of my old tank with a tailpipe expander {Powerbuilt 940377 Small Tailpipe Expander - Amazon $13.64}. I was easily able to increase the diameter by 3mm with no impact on the cap's ability to lock. This would have been an alternative way to solve the problem and use my old gas cap.