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Fake vlave covers for oilheads

dan cata

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A colleague of mine dropped his r1150r and wanted the R/H side valve cover replaced.

I purchased locally a used cover for the 2 spark model. When I got it it felt pretty light, but it said MAGNESIUM after all... :D


I had to sand blast all 3 covers and then powder coat them. I sent them all to some guys that do both the jobs.


I got the bike's OEM covers painted and the replacement cover like this:




I guess it is a copy like the ones you can find cheap on ebay. Note that the OEM covers were sand blasted the same way as this one and did not have this kind of issue. Regarding the material it is made of, I think it is what we call "zamac", an alloy that is easy to pour into modls but cannot weld, like what old bike carburetors are made of.


If you plan to purchase a used cover, I recommend asking the seller the weight of it, compare to what yours weight, it should be a decisive parameter if it is OEM or crap.




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Zamak is a zinc die casting alloy, but it's density is over 3x that of a typical magnesium casting alloy.  If using the same volume of metal, it would be heavier.  Though I'm sure it is some kind of "mystery crap alloy".  More likely, it's the result poor casting techniques yielding a much more porous casting (more voids) and variable wall thicknesses, as evidenced by it's condition after blasting.


Either way, a good warning to the wise.  That part is horrible.  Thanks for the "heads-up" (yes, that was intentional)... 

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