Gas tank repair advice......

[bobbyboy]

I've got the tank off and have cleaned most of the paint from it. The inside was washed a while ago with muriatic acid and water then rinsed and a light oil spray to keep the rustworms away. My problem is that I noticed a crack from the filler neck to the nose of the tank. The metal here is very thin and I am remise to weld it for fear of a massive burnthru. Various cranks at work have suggested TIG, J-B weld, Belzona, two part epoxy. I suppose any of these will work, but, what do you fellows suggest I do, keeping in mind that that I want to retain the originality of the bike as much as possible. I am open to any and all reasonable methods to fix this crack.
Thanks for your input, and have a care.
Bob

 

[bluebikerblan]

Bob...I'm an old lifelong biker and a retired inorganic chemist rather experienced with de-rusting (reducing agents/acids used to clean and derust metal gas tanks)

Muriatic acid is a 30% solution of HCl (hydrochloric acid in water). Frankly, it's way too aggressive/corrosive on gas tank metals and hazardous to the worker, to be used for the purpose you describe. Much more appropriate would be more dilute solutions of phosphoric acid such as is commonly used in the dairy industry as milk stone remover, radiators and such. There's a lot on these techniques like electrolysis on this site and others.

But whatever you do....please reconsider using muriatic acid on your gas tanks. There are just too many safe, suitable and economic ways to do this job. Best, Blue

It would seem likely to me that a good deal of metal has been dissolved and a signifigant amount
of damage has already occurred. I wouldn't worry nearly as much for "originality" as I would integrity of the tank in question as a gas tank on a motorcycle.

I suggest that you give serious thought to starting fresh with another undamaged appropriate tank. If you're stuck on trying to save it....try POR 15, it's a very strong epoxy based coating that can add some strength as a interior coating.

If the metal is that thin, you can bet that there will be some highly vulnerable seams as well and other spots of real concern. Blue

ps. What year & model bike/tank do you have? I may be able to help locate a reasonable good
condition used one?

 

[XSLeo]

I'm with blue on this. If it's to fragile to weld then it's to fragile to use. Lots of people bobbing and chopping and using non stock tanks. Some one may have a good tank they aren't using. Place a want add in the sale section of this site. Or any of the Chopper sites, other 650 forums, Ebay. Mike's even sells brand new tanks for a not to unreasonable price, they even come painted. Like old Henry Ford says "Any color you want, as long as you want black."

 

[bobbyboy]

Blue & XSLeo,
Muchos on the advice. My bike is a 73 model. If either of you know of anyone that has a compatible tank ,then I will certainly consider that route. My situation is that because i want to keep the lines, clearances and look of the original, I am apt to stay with a tank of the same or similar size and proportions. Nothing looks worse than a bike with a part on it that looks out of proportion to the rest of the bike. I will place an ad in the wanteds tho. Thanks again for your help.
Bob

 

[gggGary]

The only solution I would consider on a gas tank repair other than welding would be brazing. And I see your dilemma the early tanks are a lot harder to come by. I have 4 and not one of them is "without major issues". Typically big dents, rust, and bondo with who knows what underneath.

 

[bluebikerblan]

Blue & XSLeo,
Muchos on the advice. My bike is a 73 model. If either of you know of anyone that has a compatible tank ,then I will certainly consider that route. My situation is that because i want to keep the lines, clearances and look of the original, I am apt to stay with a tank of the same or similar size and proportions. Nothing looks worse than a bike with a part on it that looks out of proportion to the rest of the bike. I will place an ad in the wanteds tho. Thanks again for your help.
Bob

Just checking....they do come up....not that I reccommend this particular one. Is this one the type & color you're looking for?

http://cgi.ebay.com/ebaymotors/73-Y...rcycles_Parts_Accessories&hash=item3362b9e46e

Blue

 

[TwoJugs]

If it is a crack because of the metal being so thin from the acid wash then yes, another tank would be the smart move. If it is a crack from other causes, vibration, fill nozzle damage, fill tube repair, then gggGary's method of brazing should be good. A solder job might even work as a garage job if you want to do it in house but it won't be as strong as the braze. As usual, respect the fumes when working on used tanks and applying heat.

 

[bobbyboy]

It is indeed a vibration generated fracture as all the other seams are sound and there are no pinholes anywhere. I just talked to a dude at work this morning that has repaired tanks for some of the locals and he also suggested the Braze. I am going to take it into him this weekend and he can tell me better whether or not he can and will do it or if I should just pick up another tank. he suggested a nearby cycle salvage place just north of where I live in Peterborough. This guy apparently has everything including the famous Urals.
I would like to thank all of you great guys for replying to my post for help. You really are the best.
Have a care
Bob

 

[oldbiker]

hi,, this is only a pipe dream.. but if its rusted around the filler ,,,,you could easily look at fitting a modern alloy aircraft style pop up cap you can pick them up from wreckers at a reasonable price and they are not hard to fit ,, it would look brilliant... you could use an r6 fz1-6 or a gsxr 1000-600 hope this helps you regards oldbiker

 

[jamesgs4]

like totally barf man! a r6 cap on an xs? you guys really are upside down lol

 

[gentlemanjim]

I've repaired a few tanks with by brazing with a flame torch. and then seal with Red-Kote. And I have had great success derusting with the electrolysis process and a Evapo Rust soak both work well.

 

[gentlemanjim]

like totally barf man! a r6 cap on an xs? you guys really are upside down lol

I did that on a XS750 standard tank, but you have to install an external vent. Makes stunnding presentation.

 

[72XS2]

I had the same problem with my gas tank, mine is a 72. I bring it to a welder and he used a TIG welder to weld it and it worked great. I had to repaint it anyway.