Saving a '81 KZ750-E

Skidmark wrote:

650ed wrote: Was that engine painted when it was new? I ask because my 1977 KZ650-C1 was not and it has been very easy to keep it looking fresh. I've seen many painted engines (including the cylinders on my old BSA) that very quickly looked pretty bad as the paint failed. Ed

Yes, the cases where painted black at the factory. Clutch cover and sprocket cover were clear coat. Other two covers were half paint, half clear coat. I have not decided on what parts will get which finishes yet. Still looking for a high temp clear in the US, but haven't looked real hard yet. EU has paint that cannot be shipped to the US. One thing I do know is that I don't want to be doing much polishing on the engine. I may black out the entire engine, except for the fin edges on the head. Still undecided...

are you looking for rattle cans or will you be using a spray gun?

I bought the PJ1 Fast Black Engine and Case Paint, in aerosol cans. I have heard good things about it, better than some of the other high temp spray can products on the market. I intend on spraying it right over the bead blasted metal surfaces.

Getting the tank prepared for another round of chemicals to get rid of the rust. I made some block off plates from some 1/4" x 1" flat bar I had in the shop.


After reading the safety precautions on the POR15 Cleaner Degreaser, I was surprised at how "human unfriendly" this stuff is. Avoid skin contact, clothing contact, eye contact, vapor/mist/fumes contact or inhalation. Geez!! The rust remover was touted as water based, but it is a diluted phosphoric acid solution. Both present issues with disposal after use, more so the Cleaner Degreaser since it needs to be diluted at 4:1 ratio with hot water for use. More fluid to dispose of than the original container will hold once it's mixed. At least I can get the Rust Remover back into the original container. The Cleaner Degreaser is labelled as containing potasium hydroxide, butoxyethanol, and alcohols. A call to the county disposal may be in order.

Use rubber gloves when you working with the POR15 Cleaner Degreaser, you will lost your finger prints as quick as possible!!!

2-1/2 gallon mixture was put in at 140 deg F. Shook and rotated the tank for several minutes, then placed it back end first into a 5 gal bucket. Let it soak for a couple hours. When I took it out for another shake and inversion, a small sign of weepage on one plate. I can live with that!


It's now soaking for the second half. I will drain and rinse it tonight. Tomorrow it will get the Rust Remover treatment, a rinse with water, then a flush with a gallon of WD40. Once the bore scope reveals all the rust is gone, and it is sufficiently dry, I will bead blast the entire outside and take it to the paint shop. That is, providing no pin hole leaks show up! Fingers crossed!

What went in clear, came out, well, not! A good bit of sediment at the bottom of the bucket.



Using a heat gun to dry the tank. I will see how it looks inside in the morning. The cleaner had the same color and smell as the inside of the float bowls. So I guess it did what it was supposed to do. Hopefully no more evidence of old fuel gunk.

No need for a gallon of WD-40. Just coat the inside of the tank. An alcohol wash would be useful before the WD-40...however IA is hard to find these days.

I have to say I am thoroughly impressed by the POR15 Cleaner Degreaser. Despite the cautions needed to handle it, and dispose of it after use, it certainly did the trick. All I can see inside the tank is orange rust spots. No more blackened areas. Time to move on the the POR15 Rust Remover.

Before the cleaner


After the cleaner



Before I add the Rust Remover, I cleaned up the sealing surfaces removing all of the old paint and grunge.

Don´t use any WD40 inside the tank. Any kind of oil coat the surface and no acid will penetrante the bare metal or rust!
This is the reason why you have to use the degreaser first.

My intention was to use the WD40 after the final rinse, after the rust removal, to get rid of any residual water. I wanted to avoid any flash rusting once the inside is finished. I wasn't going to use it before the Rust Remover.