Saving a '81 KZ750-E

Hope it all works out on Saturday! It's been a bit of an ordeal with that tank - you, sir, have shown some serious perseverance!

The chassis looks good with that front end. Looks like a nice riding position and quick on those corners... looking forward to the first ride report.

You and me both!!

I had to test fit the tank after welding, right?

What sort of sealer are you going to use?

I ordered the POR15 Tank Sealer, and it had shipped by the time Caswell was recommended by DoctoRot. I certainly don't want to do it twice, but on the other hand I don't want to wait for a different brand to ship, and spend twice as much. So I figured I would run with what I bought. Everything is taking longer to ship with the pandemic affecting warehouse labor. More bore scope inspections are in order after the next treatment. I am hoping to minimize the flash rust by rinsing a second time with alcohol after the water, and before drying with compressed air. Once dry and fume free I will run the heat gun through it as insurance no moisture of any kind remains. I think the performance of these sealers relies heavily on the prep work. If I can get the inside flash rust free, I think the POR15 will work as designed.

Por-15 sealer is good. It's thinner than Caswell's and easier to apply. I think Caswell's is better for seriously damaged metal but your tank should be okay with the Por-15 stuff.

Stir up that Por-15 stuff and dump the full can inside your tank. Move it around for a good half hour then dump out the majority through the petcock hole. Put your plug back in and look inside the tank because there will still be a good size puddle moving inside. Move the puddle around and coat the tank again. You will be able to get a couple of extra coats inside the tank before the sealer fully kicks off and stops flowing. Don't put the tank down until it stops flowing. It takes about one hour. Just get yourself a cold beverage and take your time and focus on getting that sealer to coat the entire tank several times before it's all done.

The phosphoric acid solution is in the tank for the last time, I hope! I am going to try and rinse with the alcohol instead of water this time to try and prevent the flash rust. I will dry with no heat, just compressed air. I am leaving the tank open this time to let the bath out-gas (learned THAT lesson the hard way!). I am only going to leave it in the tank an hour per side before draining it for a check. Hopefully the tracking is correct and the sealer arrives by the end of today.

It looks like rinsing with alcohol solved the flash rust problem! Finally a rust and leak free tank!! I will run a heat gun in it for a while to make sure it's dry, along with letting it sit overnight, before I use the sealer.

I’m impressed with the persistence and focus on completing a task. Good job. You have my respect.

First time using a tank sealer product. Time to get this sealer party started! Process seems pretty straight forward. Just going to take my time and hope I get full coverage...

After rolling the tank for 30 minutes, I drained it, and rolled it around another 30 minutes. Pulled all the cover plates and filler plug, then coated the top of the filler with a brush. Instructions call for a 96 hour cure before putting fuel in it. Yeah, I still have to get it painted, and do the motor as well. So that won't be a problem.

What it looks like before stirring.


After 15 minutes of constant stirring. I guess it never achieves a solid color.


Filler neck coated.

Nice job! You should be good to go now! I think that a lot of tank coating failures are self inflected injuries. Getting rid of all the old rust like you did and making sure the metal is clean is the key to success.