Watch RestoCycle vapor blast a Z1 engine!

You guys will enjoy this I think

We have a great customer that is giving his beloved 75 Z1 some TLC and that includes a spa day for his engine. Will walk you through some of the process as we go through the project, and will update with new photos as we go.

Here's the patient: a 75 Kawasaki Z1 engine. In great shape overall, just showing the signs of a life well lived.

We have most of the engine here, although some side covers are being finished differently or replaced. Vapor blasting results in a beautiful lustrous satin finish that looks about perfect to my eye for the biggest and hardest to clean parts of the engine: The crankcase, the cylinders, the head and the valve cover. It can be a very useful prep step for the higher-polished parts like the points and generator covers, and the clutch and sprocket covers, but those can also be finished with chemicals, abrasives, and polish, and look closer to stock. We discussed this with our customer before he sent everything in and the customer opted to do those without vapor blasting first. Informed customer, happy customer, etc .

Here are some close-ups of the crankcase, just for fun:

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We've also got the valve cover, sump, oil filter cover, and some of the inner covers...

Along the lines of 'what could possibly go wrong" take a quick look at that inner cover for the points at the left. See that gnarly black crud to the left of the seal? Hang on to that thought.

We also have the cylinders, and the head to work on. In this first photo you can just get a peek at a nice crosshatch in the bores - these were either bored or honed before we got them, and so they will be masked, as we want to do our thing to the gasket surface and get it spotless for reassembly, WITHOUT touching the bores at all. We very slightly prefer to do our thing before machine work, but we do it both ways all the time, no big thing.

Look as well at the white powdery stuff on these fins. When you see white powdery crud on old aluminum, you are usually looking at the remnants of what is now a pitted area beneath. We won't know for certain till we process these, but I am betting that there is a bit of pitting on these fins. It's the best possible place for this to happen in fact, will not really show very much, but it's something to know.

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Here's our cylinder head. In great shape, not a mark on the fins or anything at all, just ready for a reset.

Close-in of the gasket surface and the combustion chamber, before we clean and vapor blast it:

And the top side - this has been through the solvent tank and the heated aqueous parts washer by this point, and is about to get plugged, masked and prepped for vapor blasting. ALL the oil passages in the head have been cleaned out and flushed with solvent and hot parts cleaning solution. EVERY threaded passage will have a stainless socket head cap screw threaded into it to protect the threads and blind holes from media contamination. This thing will look like porcupine when it goes into the vapor blast cabinet.

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The crankcases get similar prep: If they come in oily like these did they will get a soak in the solvent tank for starters, and the oil gallery plugs will be removed, thoroughly cleaned out with bore brushes, solvent gets flushed through them, then they get closed back up and the other entries are plugged. All the threaded passages will get bolted, and any direct bearing surfaces will get masked with special tape. We spend more time cleaning, preparing, clearing and rinsing then we do vapor blasting, and that is a critical part of good process at this work. We do not vapor blast dirty or oily parts - that is a recipe for trouble.

Back to this upper crankcase for a moment though: We slightly prefer to have the studs removed, and it definitely makes it easier and cheaper to ship these that way, but sometimes those can be a bear to remove, so it's no big deal if they aren't. We will however clean and then mask those studs before we do our thing to prevent any damage to the plating, which can be getting funky 40-something years later.

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So at this point we are about halfway done with our pre-cleaning and prep, which we will resume on Monday when we're back to work on this. We did pick off some of the smaller parts to get them done and done though, and those are always fun to see before and after, so here we go with those:

Crankcase sump cover:

Oil filter cover:

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Inner covers:

Valve cover:

I have to admit, it is very fun doing this work sometimes . Love these KZ engines - great metal.

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One more thing, just because there is always something to be learned, and to understand.

Remember that gnarly black crud on the inner points cover? If you look where the grommet slots are you see that the crud is at the bottom of the seal, at 6:00 when installed on the bike. The seal was weeping just a bit for all those years and used oil is corrosive as we know. Especially if it never gets rinsed or flushed by clean hot oil out here underneath the points and advancer, unseen.

Here is what lay beneath that. This photo was carefully taken to show the pitting in the most obvious way, just to show you what we sometimes discover, Obviously nothing we can do about this, and this will again be unseen beneath the points and advancer, but it's a useful example of what can lay under crud.

OK, that catches you up for the moment with this engine - we will resume next week and I will post up those photos as we go. Thanks for checking it out, and feel free to ask any questions you may have as you look at these.

N.

OK we are all done and packing up today. Here's the second half of this project:

Here's the head, all prepped and plugged and clean, and ready for vapor blasting.

...and done:

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Lower crankcase:

...and the upper:

Better, yes?

...and finally, some fun before-and-afters:


Head: