BSA A50 early RM19 alternator part numbers

[Schaefer]

According to my parts book and other sources like Lucas fitment lists my BSA A50 of 1965 requires a Lucas RM19 alternator with stator 47164A and rotor 54213901. I've been looking now for these parts for over a year now, mainly on eBay.co.uk, and although I stumbled over a stator occasionally for the life of me I couldn't spot a rotor. I find it hard to believe that this particular rotor should be such a rare bird so I'm wondering if Lucas really did stamp "54213901" on the part or if I'd have to look out for something different. Any ideas? What other (aftermarket?) rotor could be used instead? I definitely want it to be a 6V system, by the way...
Cheers
Carsten

[DAVE BRADY]

Hi Carsten,

Have look on the Paul Goff website and if in doubt contact him.

Dave.

[chaz]

yes, they were stamped up, usually the coils were stamped on the outside, the laminated outside so can be hard to read.
most rotors had a number on them.
what you have to remember is that if you cant find them its probably because the rotors ally body can move on the steel taper or the magnet gets weak even the key slot wears all making it a reason for changing.
likewise the coils can wear due to vibration and hot oil, the wires get hard and crack or break at the joints.
remember they are 50plus years old and if 6v many owners take the opportunity to change to 12v (also possibly neg earth) in order to get better lighting  and even electronic ignition as opposed to originality.