Expansion was a polite work for total disintegration.
That picture (and others) was posted on ADV Rider from a bike that was recommissioned, maybe a member here, Robert ?.
I think one of the inner primary stator mount pedestals was also broken off at the base. (replacement inner primary, stator and rotor)
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Steve, I can not remember how much my new 'Lucas rotor cost (I bought the new 3Ph Stator / Rotor / Podtronics off Rex's Speed shop in the UK as a package - The POD replaced now with a Tri Spark Mosfet)
I see no reason to screw around with parts that could fail, there looked to be nothing wrong with the original 1973/74 parts but replaced them anyway.
I have no inner shims, the inner spacer is reduced in thickness, the key is new, the rotor is modified (OD) , the stator is modified, the outer retaining nut is modified, the inner primary cover is modified.
It has no large OD Belleville washers.
View attachment 85881 View attachment 85879 View attachment 85880
Detect some movement in the rotor, not sure, throw it in the bin.
If I was closer post wise the OP could have had my original rotor which seemed fine. (round with a hole in the middle)