You can rub them down smaller, on sandpaper or a file.
Thatès what I did TT
You do the experiment and tell us how it went ?
Ah too late it's together again, but if the brushes stick again I'll try it
Unregulated voltage was way over 12 at times 18 even, 21 was seen but fleetingly probably an unsteady hand on the voltmeter probe
Tomorrow I'll try the meter between battery and negative lead to see how my Vreg is working and think about a voltage indicator of some kind (maybe a LED that goes off at 11v or similar).
Thoughts regarding electronic ignition
1. quite amazed how well the bike started considering the low voltage (7.3)
2. although obviously not going properly it did go at this voltage
3. had I not had electronic ignition I could have been caught out if a ride went into evening with a flat battery
4. OTOH I nearly got caught out and away from home - still more than happy with it though