case sealant

Bottom End (crankcases and crankshaft)
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case sealant


Post by 55FL »

Looking for guidance re a case sealant to use to prevent oils seepage through the pores of the case.
An epoxy base paint ?


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Post by Cotten »


I have encountered certain epoxies, and an isocyanate urethane, that survive modern fuel well enough to trust within a motorcase.
I don't think either is available from retail sources.

Our OHV's have the carb on the wrong side: It points upward when leaning upon the jiffystand. Thus, a pesky petcock (or just forgetting to use it...) can allow seepage to drain down into the combustion chambers and past the rings to contaminate the oil.

A sprocketshaft seal can even let it fill the cases far enough to create a dangerous situation.

Legend has it that the original coating was Gasoila. Until modern times the industry standard was Glyptal.
Neither survived my tests with P4gas, even when baked.


old bob


Post by old bob »

Check Knowledge Base Page 11 Engine case seal

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Post by panhead »

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Post by Panacea »

Panhead, thanks for posting the link, I looked for an hour yesterday for page 11, my curiosity amazes me. My last two rebuilds(different bikes) did use Yammabond, although I don't know which formula, with good results. Mike

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