I recently saw for sale an Ariel VB600, a model I'd not heard of before. A bit of digging on the Internet revealed a 598cc SV Single, manufactured between 1947 and 1958. Would it be correct to think that this was just a badged M21?. I know BSA and Ariel were part of the same group but just how much crossover was there regarding communality of components etc?.
I would say that the only commonality between the VB600 and M21 would be Val Page who designed the VB engine and had a hand in re-designing the BSA singles (SV and OHV) just before WW2. As far as shared components go, the post war Ariel Huntmaster 650 had BSA A10 engine underpinnings but different outer covers and rocker boxes plus a Burman rather than BSA gearbox. Also the Ariel Colt was a re-badged BSA C11G but with lower capacity (200 rather than 250cc). If there's any more to add from other posters, please feel free.
Good info, thanks.