As Rob says, we rebuild cranks, and have bearings in stock. As you pointed out however, the problem point is the unobtainable centre seal. That being said though, we have found that more often than not, the 87~88 (MC16 & MC18 Mk1) centre seals have been good enough to reuse.
As a caveat to the above though, modern fuels appear to be taking much more of a toll on 2-stroke crank seals, and as such, I expect to see fewer 87~88 cranks suitable for rebuilding in coming years. The last two MC21/28 cranks for example, have had the centre seals literally disintegrate as the cranks were pressed apart!
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Andy.
NSR-WORLD.COM
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