82 KZ/GPz gas tank repair

OK. I finally decided to tackle my fuel tank problem by working on the rust first. I still had 3 gal of Evapo-Rust, so pour that thing in the tank and...........................PINHOLES! Yes, hole with S! Guess tank decided to work on it's rust on it's own. I never had the tank sitting outside after I got back from the paint shop. it was either sitting in my car's back seat or was inside the house. Anyway, some on the side, some at the bottom. Side wasn't too bad. Tape them off for now. I counted three of them. It's really pinhole in size. But the bottom.

Started with 3 pinhole size holes. Clean them with brass wire brush, light sand with fine emery cloth and use JB weld until I finish with Evapo-Rust. But more I clean the tank, more pinhole(s) emerges.So at this point, I stop using JB weld and tape it where it leaks. It's working for now. stopped the leak while I work with Evapo-Rust. My next move, use some kind of tank liner.

As I mentioned before, we can't get any of the good stuff you guys mentioned. I drove all over the island, looking for treasure called POR or Caswell, but all I can find is Kreem. So I bought that just in case, but I really don't want to use this stuff. 25 years ago, that was the only thing available. Today, we have lot more other stuff. I just bought this just in case I don't have any, or ran out of option. it's sitting in my living room right now. Still need to have the Evapo-Rust work it's magic.

Send several e-mails with pictures attached to those that work on fuel tank and they all said my tank is gone. I hope this is not the case as it's very hard to find these tank. I have never seen one on ebay to this day. Found couple in Japan, but buying one is problem itself (auction), shipping that big of the stuff is another. Don't want to sell my Kidney for a gas tank.

 

Any thought? And don't worry about the paint. I have decided to swallow my tear and repair the tank first. And I am still looking for either POR or Caswell.

I think you are doing well with your approach.  Patch the holes as they appear and keep going.  I'd get that level senor out of the tank because the evaporust will eat all the zinc plating off the steel parts.  For sealing I'd use Caswell's.  It's super thick so it will reinforce the metal that's been thinned by the rust.

I did de-rust and sealed my Z1 tank with a POR15 kit more than 20 years ago and i am very impressed till today of the inner tank surface shown up now. POR15 tank sealer is the best you can get for your money. You can try to solder the pin holes with tin, flux and a big electric soldering iron but this need a good clean to bare metal. You run into the risk to open up your pin holes and the tin flow and disapeard into holes.

If you need a POR15 sealer kit, it´s not a problem to get one here in Europe (Germany).

www.por15.de/Fuel-Tank-Kits:::15.html
  
 

From my experience, Caswell appears to be nothing more than a thick liquid epoxy. Maybe a hardware store would have that?

Thanks for the info guys. And Nessism, don't worry about the sending unit. That one is toast and using it as a lid. I have functioning unit sitting in my parts bin.

I'm still on the hunt for POR or Caswell. For some reason, every online store I go to, they just don't have surface shipping option and tells me I need to input different address where they can ship it ground. I know for a fact that most of the online shop, when you buy other stuff, you can choose shipping method from ground/surface mail to next day air, but for some reason, pretty much everywhere I went to, when you choose a HAZMAT, it won't even give you that choice. All it say is they're unable to ship it to my address. Same with tires. Believe me. I just tried. 

Anyway, I'm still working to get the rust off from inside the tank. Every time I tried to turn the tank around, keep finding new pin hole to seal.

I have shipped from Caswell Canada.   www.caswellcanada.ca/shipping.html

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I have shipped from Caswell Canada.   www.caswellcanada.ca/shipping.html

--- Yes, I tried their US site as well and when I go to check out, I don't have any shipping option.  Pretty much any site I go to said I need different address. Also, that Canadian site said they will not ship it outside of Canada, so that is that.

I'm on ebay right now. Trying to get seller to ship using ground shipping but so far, no luck.......................
 

So today, I had to help one of my friend get his car from towing yard. I won't go into details about this, but I had my gas tank outside the front porch, still working to get the rust off. Today's menu was do the front of the gas tank. I already had top and bottom of the tank treated with Evapo-Rust, so it was time to treat the front side of the tank. The reason I'm taking so long and doing it day-by-day is that I keep finding new pinholes to take care of. Using JB weld for now just to seal up the holes so I can treat it with Evapo-Rust.

Anyway, most of the pinholes were taped off as when I clean the area with brass wire brush, new holes keep emerging. so instead of cleaning it, I just wipe the area with acetone and tape with 3M duct tape.

After I came home, tank had big enough leak that I decided to just JB weld that whole area. Hopefully, this will do the trick and hope I can finish treating the front area of the tank. The actual area was little less than half of what you see, but oh well................Opened up the Pandora's box, I guess................

I just want to coat the tank.................................

I'd cut that whole area out and have it patched, make sure the tank is extremely clean first, no fuel residue at all..

Yeah, I was gonna save the tank but more I work on it, I was thinking about that too. I do have that low-temp Aluminum welding rod, so was gonna tried that first. But at the same time, if the pinhole is this bad, it's almost gone at the bottom..............

The tank went through Kreem process about 20+ years ago, then it was cleaned using acetone, I coated with motor oil before storage but put it on the bike (covered) and got rusted again. Hence the Evapo-Rust procedure. So there's no trace of gas.

We just don't have any good motorcycle shop other than Harleys. I did make several calls, but they all doesn't want to work on any Japanese bike. Period. I used to know couple good guys who works on Japanes bikes, including welding, but they're all gone now..................... 

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Yeah, I was gonna save the tank but more I work on it, I was thinking about that too. I do have that low-temp Aluminum welding rod, so was gonna tried that first. But at the same time, if the pinhole is this bad, it's almost gone at the bottom..............
 

You can´t welding or soldering steel with aluminum. Your low temp solution is tin. Ask you local plumber shop, they should know how to fix your fuel tank.

Radiator shops are worth as look too for tank repairs...