Saving a '81 KZ750-E

It looks like the Evapo-Rust didn't do a very good job. I suspect it has lost potency after using it for 6 months. I will dry the POR15 degreaser, and then the POR15 rust remover. The bore scope was well worth the money ($40 shipped). I can't post the video until it's converted from mp4 to one of the allowable formats.

I had the best results with POR15. First degrease with POR15 Marine Clean, so the acid can fully penetrate the rust surface. Grease or fuel residude put a layer/barriere over the rust an acid could not go through. Some heat will accelerate the acid reaction.

Here is a still from the bore scope. This is the top side of the tank, near the front.

The Evapo-Rust worked on the lighter rust areas, but clearly did not fair well on the heavier areas.

www.homedepot.com/p/Klean-Strip-1-gal-Co...-GKPA30220/100406369

SDS says 35-45% phosphoric acid. You can cut it with water and it will still work, just a little slower.

I finally got some custom spacers made and painted. One set positions the ignition switch.


The other set positions the headlight bracket.



I wanted to see how the new speedo looks from the rider's viewpoint. Still need to design a mounting system for it, but it looks pretty good.

Nice.

I decided to go with the POR15 brand of treatment to clean out this tank. I will use the Cleaner/Degreaser first, in case more old fuel residue remains. Then I will use the Rust Remover to get after the remaining rust. It is water based, similar to the Evapo-Rust product, Since it will be at full strength, I expect better results than using something that has been used for close to a year.. Again, the bore scope will tell. Now I need to wait for it to get here as no one has any locally, I got word from the upholstery shop that my seat is finished. I will have to wait until Monday to pick it up. Using a replacement seat cover from Z1 Enterprises over the pan I repaired. Really hoping it came out okay. The foam on the used seat was in a lot better shape than the original, but still almost 40 years old.

Still dealing with nasty fuel system parts. How does the screen frame come off? Is it just a mild press into the petcock body? I was thinking it should be removed before soaking in carb dip, but I don't want to break it. The rebuild kit from Z1 Enterprises looks like the small o-ring isn't included.

Looks like you've got some work to do
The rebuild kit that I got came with the small o-ring already installed: www.bts-motorradteile.de/images/product_...es/bild2_7243827.jpg

The large o-ring didn't fit well and the tap was really hard to turn. This seems to be a common problem with the rebuild kits so I ordered a couple of OEM ones. Haven't tested them out yet but it's quite high on the list (as long as it stays too cold to paint). I'll let you know.

The large o-ring didn't appear to be the right size in the picture, so I already suspected that. I'm wondering if the screen and screen frame will withstand the carb dip. It will take a good 24 hours to eat all that gunk away. I am sure the frame is brittle, and certainly don't want to break it.

Yeah, I'd want to get the screen off first as well. Unfortunately (or fortunately for me ) I can't help you - the tank and petcock on my 750 were in really good nick.