Engine detail: Paint or media blast?

scott s

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On a STOCK engine ('75 XS650B in this particular case) would the head and cylinders be painted from the factory?
I know the case halves (usually) came with silver paint, but what about the jugs?

I plan on doing some serious engine detailing soon and have an opportunity to media blast the cylinders and head. Should I just leave them bare?
 
Far as I know :confused:, there was no paint on any of the engine (crankcases, cases, barrel or head) from the factory until much later on the Heritage Special which had a black painted engine as standard
 
that is correct.. I did have a stock 75 at one time. the engine was left in raw form with a clear coat to help aid in the prevention of oxidation.
 
Far as I know :confused:, there was no paint on any of the engine (crankcases, cases, barrel or head) from the factory until much later on the Heritage Special which had a black painted engine as standard

On my 79 special II there is no paint on the engine but on my 81 special just the cylinders and the rocker boxes are painted black. The head is bare. I bought both these bikes from the original owners and they said thats the way they came from the factory........BG
 
I've found that if you strip the clearcoat off the engine cases and wet sand with 600# and then take a polishing wheel to it they shine p quite easily with a nice luster. I bought a flex shaft and hooked it up to a drill motor works very well. The cylinder and heads may reespond well to media blasting (be certain everything is well sealed up first) and then pain them. Duplicolor has some very nice engine paint that holds up well. IMO cast aluminum heads and black cylinder barrels.
 
I'm not going to paint mine. They look so pretty after bead blasting. :D
crankcases.jpg
 
yeah... i was too lazy to blast 'em... i painted 'em black.

i think it should be specified, that while the cases looked like they aren't painted, they usually are clear-coated. you will probably have to strip them before trying to polish.
 
I have cases from a '74 and a '77 and thought they were both not painted; however, I was using aircraft stripper to speed up the gasket removal process on the upper crank case of the '74, and a thin layer of some kind of paint or coating began to flake and peel off! I took a look at the '77 and it has the same finish.

Now, I understand the default reaction is "well these bikes are 40 years old, a PO could've painted them," but the '74 and '77 come from different owners in different states, each with the same finish. My conclusion it HAS to be from the factory, but if it's not paint, what is it?
 
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