Stroked version of the 600, improved (as in less self-destructive)in 1960 with new cylinder head and lubrication system; plus duplexframe with better steering, though it wasn’t until ’63that they had the Roadholder forks (and 12V electrics). Lots ofearly bikes retro-fitted with later equipment. CSR version had45hp engine that could be a touch fragile. Beware, again, of bodgedengines with non-standard parts. Also Matchless G12.