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Discussion Starter · #1 ·
I'm not too friendly with 500 twins....I have what appears to be a late 60's 500 twin crank and rods in a set of damaged cases.Serial number PCXXXX. I also have a set of nice cases,they appear to be earlier,serial number HXXXXX.The earlier cases look like they have a timing side bushing similar to BSA. The later cases have a ball timing side bearing.I assume this later crank and rods will not fit into the earlier cases by using any combination of bearings? Thanks
 

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A beefed up boss was added to the right side case castings, in 1968 or 69 I believe, to make room for the right side crank bearing. I don't think there is enough material in the older cases to machine out for a bearing retrofit.
The photo below shows a set of the later model cases with the added "double chin" of the right side bearing area.

 

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Discussion Starter · #3 ·
Thanks,that pic looks like the same thing on the 650 twin when they went to a larger timing side bearing around 1954.
 

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Discussion Starter · #4 ·
I split the damaged cases on the later engine and for sure the swap is not going to happen.And while the later case has a roller bearing,there's no "eyebrow" like on the one you have shown.But the whole inside casting is different and no way to machine it I would say.
A pile of scrap,more or less.
 
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