Gas tank breech!

Hey all,

So, my Moby is leaking gas at an alarming rate and I'm pretty sure it's due to a small breech in the gas tank. I've yet to pinpoint the location, but when I do, how can I fix it? I don't have any welding equipment, nor do I know how to weld. What about that "welding" putty stuff? Could I use that as a long-term solution or would it be more or less temporary? Could I use it until I have time to take her into the shop?

Re: Gas tank breech!

Patrick Keaton /

I used JB Weld on a Tomos, but have not tested it yet to see if it will work. I use JB Weld on lawnmower gas tanks

Re: Gas tank breech!

Make sure that the tank is leaking and not the fuel tap. The original ones will leak after 40 years or if you try to clean it with carb cleaner it will leak. Best way to find the leak is with blue power chalk that they sell in the hardware store for chalk lines. Not expensive at all. Basically dry the tank as best possible and powder the area where you think the leak is and look for the dark spot forming as the chalk gets wet.

Trouble with monocoque mopeds is that the tank is an integral element of the frame. If it is perforated or cracked at the base of the tank where it connects to the base of the seatpost it will need grinding and welding to restore the frame to full strength. You would also probably want to add the upper stress bar to the bike.

Take it to a place or a good person that does welding and see if they can fix her up for you.

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