Corroded Cases

I have attached pictures of the cases off of my 1979 CR250 (2065). I am worried that the corrosion in and around the crank area have rendered the cases unserviceable. I had mentioned it to a moto mechanic friend of mine and he said not to worry, but I think I might have failed to explain how bad it was. What are your options on it? I have seen cases sold pretty cheap and would rather replace them now if they need it than put the motor back together and mess something up it if fails. Thanks in advance for the help.

That does not seem too awful bad as I have seen worse. I know people that have soda blasted the effected area and sealed it with epoxy. As long as the sealing surface is ok I think you would be good to go.

A light Sand blast might work ok.
Mike

I will second the soda blasting idea. This very effective at removing the oxidation without touching the remaining good metal. Don't glass bead or sandblast as it will ruin the magnesium.

How about the crankshaft? I can't see how a crank from that would be useable. You could put a listing in the classified section for an engine core and see what you get offered. It doesn't look totally scrap metal but I sure am not positive. Some guys take those things and list everything on ebay starting at ten dollars or so, some guys there do also earn it flebay name.

Fran

The crank looks fine, but I did pretty much buy someones unfinished project with this bike so who knows if it was the original one. After looking more at the sealing area there is some pretty deep pitting there as well. I think I will look for a cleaner set of cases. Thanks for the input.

The magnesium most likely acted as a sacrificial anode for the steel crank. That's probably why the crank was in good condition.