I think the cb650 uses cdi ignitin rather than points in which case I'd doubt they'd work. Most assesories / parts dealers will carry points suitable coils that may be possible to fit, david silvers for brand new coils that are 'correct' but my 500/4 came with a brand new set fitted and had cost the PO almost hundred quid. Anything off a pionts ignition bike should work. It is possible to glue new leads into the 500's original coils but it's a pain to do and I've never been completely happy to trust the results.