Zambia wrote:
Silly question - if a fella was to aggressively sand out the "corrosion pitting" would your vapour process be able to bring back that "not polished" factory look?
Yeeeeaaaaahhhhhhhsortof. For sure, just like repairing a gouged sidecover, if you sand or file these off, I can refinish it with the process and your work will be blended perfectly in, inasmuch as you were able to do a smooth job of it. But the vapor blasted finish is not as flat/fine as the factory finish, it's more of a fine lustrous satin. It looks great, perfect on many parts just as is, but if you're trying to replicate the original finish exactly, in some cases you will end up doing some hand or DA buffing work to do it. In my experience this comes into play mostly on side covers, and not on engine cases though.
That pitting is a thing though, for sure. The 70s were not the golden age of Japanese metallurgy, and a lot of sins were hidden under paint and clearcoat on engine components of the era, and not just by Kawasaki. The metal can vary quite visibly on a single side of a single part when you strip all that coating and oxidization off, and you can see streaks, color differences, and pits. It depends on just what they tossed into the metal vat that day.
This is the second set of triples cases I've done in the last month and both sets had some good pitting on the area above the transmission, and vapor blasting it is a great way to make it more noticeable
, especially when it's first done, and shiny and clean. The good news is that when you put the motor back on the bike and install carbs and snorkels and whatnot, it's not as much of an eye-catcher as it is when the part is in your lap, or on your bench.
Any aluminum that is laid bare by this or a similar process starts to oxidize though, the instant it comes in contact with oxygen, which is not a bad thing per se, it's hard and forms a protective 'skin' on the soft metal beneath. Over time this slightly darkens and dulls the aluminum. But that's gonna take a while after vapor blasting - years I'm told.
You wanna find a medium-sized part and fix it like this, then send it to me? I'll process it for you gratis in the name of science and technology, just take good before pictures before you start your repair, and we will see how well it works for your purposes.
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. For reference, this project was three hours in total, plus $30 return shipping to California, net $180 at 2015 rates ($50 per hour). 48 hours in-shop. And this is what I do, same as you, fix and restore old Japanese motorcycles, and I love them as much as you do. I will treat your parts as if they were my own, I promise. 
