Help Desperately needed with leaky fuel cap 1977 gs400

[Guest]

Hi, as the title suggests I am not a very talented mechanic and desperately need to figure out how to stop my gas cap from leaking. I bought a new genuine cap from Everett Powersports because the PO misplaced it and I am in the middle of derusting the tank with evaporust, but to finish that I need to flip the tank over and I can't do that if all the evaporust just drips out. I scraped some of the crud off where it seals but that didn't seem to help and I am still confused on how to fix this. If anyone has any recommendations on what to plug the tank with to finish derusting it let me know, I couldn't find any rubber stoppers that would fit cause of the weird notches in it.

[Big T]

Is it pouring out, or dripping out?

Dripping would be the vent in the cap

[Guest]

I would say dripping. Could it also be that there is an uneven mating surface on the filler cause of the chipped paint?

[alke46]

You need to get creative with some large stoppers and the use of something like this. I'll be back after a short visit to find what I used and post it on flickr and then here.

Stay tuned.

I have used both of these at different times. The one on the right is available in the plumbing dept of Lowe's or Home Depot. Hope this helps.

IMG_20220812_202445056 by Larry Alkire,
on Flickr

IMG_20220812_202438718 by Larry Alkire, on Flickr

[alke46]

After going back to look at your photo, I'm not sure that cap will ever fit right. Something about the details of the cap and the holes inside the tank where the cap seats just doesn't look right to me.

[alke46]

Can you post a photo of the cap on the tank? It's just my curiosity.

[1978GS750E]

I've always used aluminum foil tape. Can be found at a good HVAC supplier.

[Guest]

Can you post a photo of the cap on the tank? It's just my curiosity.

Thanks for the advice on the rubber stoppers. And i will post a photo of the cap on the take later today. It fits fine but just leaks a tiny bit if i hold it upside down for a while

[Guest]

I've always used aluminum foil tape. Can be found at a good HVAC supplier.

Thank you! I will try this

[1978GS750E]

Thank you! I will try this

Maybe you should try some Gorilla tape? (Sorry, could't help myself!)

[Guest]

Maybe you should try some Gorilla tape? (Sorry, could't help myself!)

Have considered this so may happen if all else fails

[Guest]

Can you post a photo of the cap on the tank? It's just my curiosity.

[alke46]

Thanks. Does appear to be the right cap.