Welding a Fuel Tank?

I am currently suffering from sticker shock concerning the cost of a new tank from a forum source and not enthused about spending around 150 to $200 on ebay. I have sent a few request out to "local" (withing 2 hours driving time) salvage yards that I've found and waiting on their response. In the meantime I decided to chip away whatever the previous owner tried to repair this tank with and found a number of small holes in the lower right corner of my current tank. See pics below. Do you think a fabrication shop could weld these holes up so this tank can be put back into service? Welded, smoothed, blocked and painted. If so, my next question will be, how does one go about removing a tank liner that was also put in about 16 to 17 years ago? If the tank gets welded the liner will be ruined in that area which will probably compromise it further as fuel get behind the liner in time. Thanks for your input.

How it looked! Is that Bondo??


Whatever it was removed from the lower right corner


Better angle


Same corner underneath the tank (backside)

 

what you have there is pretty much a basket case. the labor to repair will be more than the cost of a good replacement.

CN

 

Is that tank from an 85/86 xj 700 or X? If so, seeing that nipple underneath make me think it's a California Emissions tank......if that's what you have, then its even more rare.

Either fix the tank:
or
pick up a regular tank, with a regular vented cap, and then cap off the extra tubes going from the carbs to the canister under the right body cover.

IF you decide to go that route, I MIGHT be interested in the tank as a project myself.....

dave f

 

Well Hogfiddles, It's off my '85 XJ700N and according to my VIN I have a 1985 XJ700NC-R that came in Super Red. I can also vouch for the color since that's what I saw when scraping down the area around the problem area. The tank also has another opening just below the petcock. I assume it's for a fuel gauge sensor? If I can get this tank welded I might just consider installing one of those as well. Of course, if someone wanted to save me the time and hassle of repairing this "rare" tank and maybe offer a non-leaking decent tank of similar size as a trade, well.....

 

Yep, thats the California emissions tank. You should have a little charcoal canister mounted inside the battery box behind the right side cover.
Good luck getting it fixed up.

 

Here is a decent link on repairing a tank. I would agree with fiveofakind on his process to keep the cost down. Anyway, this was a very decent tank, and the cost was about $250 to have a like new tank. May be cheaper in Georgia compared to California to get some of it done, but the extra repair for welding may make it about the same. Add to that the unknown condition of the rest of the tank and there is some risk of a repair that will be money down the drain ...I think we are all good at that at times but that is how we learn.

As for the current liner it is already ruined. The fact that the tank developed holes indicates that the metal prep for the current liner was not sufficient and rust remained under the liner, and eventually rotted all the way through.

http://www.xjbikes.com/forums/index.php?threads/gas-tank-acid-wash-lined-radiator-shop.43984/#post-389457

 

It's not actually in he battery box--- that's in the middle of the bike. The canister goes in the smaller holder behind the right body cover-- the spot where the tool pouch would reside on the non-CA 85/86 700/750/700x/750x bikes.

 

Well ok yes not technically in the battery tray, but the molded compartment is part of the battery tray. I didn't realize thats where the tool pouch went, mine is in a plastic box beneath the main saddle.

 

Interesting.... I wondered where they put it for the CA models---- maybe that explains why some of my seats have that plastic box attached and others don't------ I figured they just get lost

 

Well the canister seems to have gone missing somewhere along the way. Now I know why the tool pouch is missing as well though. I guess I should have guessed that I had a CA model. The original dealer decal is still on the taillight from El Cajon.

 

How u make out with the tank. I just recently removed my liner. Acetone soak with bmx chains inside swish that around a few days. Fist I washed that gas out an welded the holes only 2 not as bad as yours.

 

Thanks for asking. I haven't done much of anything with the bike in a few months. Got it tore down, caught the flu which had me down for a few weeks, went on a cruise, holidays, and now cold weather. I don't do cold and anything below 55 is cold! I hope to get back to working on this in the next few weeks though. I'm thinking about buying a welder since no one really wants to do the welding for me.

 

Yeah, cuz they don't want to blow themselves up by welding on a gas tank.

If you think under 55 is cold, come up here..... It's been down to -18/-20 here---- yeah I know ..... Guys in Canada are are saying"if you think -20 is cold, come up here......"

Lol

 

-20°C is nothing. But when the wind blows, I wear a jacket to bbq.

 

welding a gas tank is dangerous, welding metal that thin is for a good welder, the seam area is the hardest place to fix a leak.
you haven't taken the holes out far enough to get to solid metal yet, when you do i think you'll be able to put your finger through them

 

No way I would attempt to weld a gas tank. Find someone who knows how to do it or find a new tank. Life's too short to take that risk in my humble opinion.

 

Well yeah, -20c. SOUNDS cold but that's only -4f. I'm talking -18 to -20 f to begin with. That becomes more like -27.7 to -28.8 c. That's cold.. You might put on a hat for your bbq

 

There ya go--- stick your fingers in the holes before weld... Keep the fumes from getting out.

 

i gas welded, braze really on a DR650 tank once. filled it with water and turned it so the crack was on top with a small bubble under it. all went well until i filled the tank and went for a ride.
on the way back i felt my crotch getting cold, the metal was stressed from the heat and cold water and cracked again. rode the rest of the way standing on the pegs and didn't stop. got home and laid it on it's side and went and took a shower. not a pleasant experience.
where the leak is, is important !
i bought a plastic tank

 

Welding a gas tank requires excellent preparation. Most shops will not weld a fuel tank because of the amount of time involved for preparation, and the cost to the customer for all of the argon that will be used to purge the tank.

You might consider filling those holes with lead. Leading is somewhat of a lost art, but the advantages are that you can use a hot iron to heat the metal (no open flame, no arc, but the ones for auto body work are hard to find). The teperatures involved are lower, and combustion is less likely.

 

Which is EXACTLY why I said:

 

I have XJ550 SECA tank with the same problem. Safety is the main concern. In my case, I have had the tank for three years and it was empty when I got it. I had it submerged in vinegar for a week a couple of years ago. So I'm pretty sure it is safe. I plan using a MAPP/Oxygen torch to braze it using silver solder in order to fix it. I saw plenty of replacement tanks on the net for around $100.00. I would be happy to purchase one of these tanks. However, the thing that bothers me is that these tanks can look perfectly fine with paint. With my tank, only after I stripped the paint did the holes become apparent. Just don't want to throw away $100.00 plus on a used tank which I know nothing about. Here's a perfect example of what I mean from ebay:

http://www.ebay.com/itm/1981-Yamaha...Parts_Accessories&hash=item20efb13bb5&vxp=mtr

At least this guy is honest and points out the holes. Still want's $125.00 for it.

Here is the damage I need to repair.

 

Another good option to seal up holes like that is to tape the outside of the tank with foil tape, and line it with an epoxy tank liner. Once the liner cures you can remove the tape and use body putty to smooth everything over.

 

Know what you're saying K-moe. Thought about that option many times. Just a bit leery about going with just a liner. Especially with investing in a professional paint job afterwards. Just don't want to end up with a leak underneath an expensive paint job. I looked at that ebay link again. He wants $125.00 plus $92.40 shipping, $217.40 total. Insane!