Saving a '81 KZ750-E

I have been doing some further research into the POR15 tank sealer (reviews mostly). They claim it bonds to lightly rusted metal. It would solve the flash rust issue. I still need another Phosphoric acid wash though to get after what was under the last areas of fuel deposits. A lot of bad stories with other brands of sealer out there. Makes me leery of using a sealer. If I do use a sealer I plan on doing the leak repairs first

I was able to get the solder to wet pretty good around the buckle pin hole. The blob on the left rolled down and stuck there.


The rear mount bracket is another matter, though. The bracket and tank get hot enough to melt the solder, but it won't wet to either surface.

Cleaned up, but the mount bracket just won't take the solder.
A good TIG welder with some silicone bronze filler rod is probably where I'm headed for this leak. I just need to find a local welder good enough to pull it off.
The tank wall is thinner than the bracket, and thinner than it originally was.

Your soldering looks like you didn´t use any kind of flux and to much heat . Flux did help to de-oxid, flow and penetrate metal with tin.

Yes, I used flux... too much heat? Maybe, but a propane torch is the only heat source I have to use. I don't have a solder iron with enough power to get the tank hot enough to flow the solder. The area that covered the leak looks like it wetted fine imho.

Check out Caswell tank sealer kit. Its a superior product as its a two part epoxy. I have lined two tanks with it and both have been fine for years.

The tank is currently being TIG welded. It should be done later today. I am having the welder use silicon bronze filler rod, or known by Everdure as a trade name. Good ductility, with less hardness that other filler rod alloys. Strength is not what this weld is for, only sealing the perimeter of the rear mount bracket. I picked up a gallon of alcohol for leak testing, but could not find enough quantity of isopropyl alcohol, so I will be using denatured alcohol. I should be able to post some pics of the welding later tonight or tomorrow.

Scirocco wrote: Your soldering looks like you didn´t use any kind of flux and to much heat . Flux did help to de-oxid, flow and penetrate metal with tin.

Just to be clear, this is the leak repair (circled), the blob to the left ran down the flux prior to the area wetting at the leak.

Got bit by the spring cleaning bug today since the tank welding is taking a bit longer than the welder thought it would. I actually rolled the bike of the stand for the first time! The bike lift got a thorough wipe down and cleaning. I'm really liking how the stance is coming out. It will change when the motor goes in, but I am liking the new rake.

Looking good

I finally have a leak free tank. I put the welder through hell with this job, but he finally pulled it off. Chasing pin holes that would open up, and a few small cracks in the tank wall right next to welds. It took no less than 8 leak tests using the alcohol before he got it leak free. Each time draining and drying the tank to get all of the alcohol and fumes gone to be able to weld a little more. It's not pretty, but when you are chasing leaks the welding process gets complicated.

I can finally see the light at the end of the tunnel on this tank. I have one more rust treatment to do, followed by the sealer before it heads off to the paint shop. The sealer is arriving tomorrow afternoon, so I plan on doing both remaining steps on Saturday. I will apply the sealer immediately after drying the tank from the rinse.