Is it 5083 that you are on about in sheet form? I once spoke to the guy who used to make all the Kenny Roberts gp chassis' and that's what he used. Only problem is 5083 work hardens over time so might be ok for a season of racing but not sure how good it would be on a road bike.

I think you might be right on on having to machine/ream bearing housings after fabrication.

I thought that dram looked like the spondon on. Those rotaries were awesome bikes.

Do you manage to make all the billet bits from 7020 too? It just seems so hard to get hold of.

How did you go from fabricating bike frames to all this cnc machining? Amazing stuff though and hopefully Mk motorsport will be a success for you.