To coat or not to coat

Satin black. Just do PJ1 engine case black or satin black. That stuff is the shit. I used it on hubs last year. They came out sweet. And you can powdercoat them if it doesn't hold up for you. Mine have been fine

Agreed, should work fine. I'm in the process of doing some parts now too. I'm using the VHT stuff. They make all types from wheel paint to epoxy. Local auto parts stores, like Autozone have the black in stock, Amazon for the other colors.

Light coat of aerosol or go with powder coat. Mag is a weird animal when it comes to painting.

Yup. Particularly mag. Definitely do not leave it bare; stuff oxidizes almost as fast as a naked chamber after a wash. And it really needs to be clean, of dirt and oxidization.

Duplicolor makes a satin black wheel paint that is really good. it stands up to pressure washing also, you can get it at Orielly auto parts for 7.99

I know this Alodine....

I wouldn't overthink the primer and magnesium. Whats tbe worst that can happen? Each plate is a few sq inches. You will have to give them another shot out of the can in 3 months. Is your fromtend from a 82 yz?
Have rhem powder coated when you have a bunch of things to get done. I just painted mine to mimic tbe bronze/copper Kawasaki color

2 cents here... I've been painting cars, motorcycles, boats, planes for 30 years.. The best you could do beside powdercoat is sand them with a 180 grit paper, even if they're already bare.. then apply 1 good coat of Axalta 615 Vari-prime self etch primer. As soon as that tacks up (about 10 minutes), don't sand it but immediately apply a satin black automotive paint (I prefer FP1004 Spies Hecker). It uses a hardener and that's key.. hardener. Anything else is just soft and porous and will eventually degrade. I did the side cases of my old 79 RM and it is very durable... Oh and yeah, it's expensive.