The 12 volt armatures are not as reliable as the 6 volt ones in my experience..The best results I've had are with a standard 60w dynamo running a regulator designed to operate at 12 volts....However, nothing is for nothing and the dynamo won't produce maximum wattage until it is running faster than it would be with the standard system...
I ran this set up successfully on an M21 I owned for about 8 years until I sold the bike...I used non LED bulbs of moderate wattage and the lights were fine for riding over Dartmoor, which has no street lights....As an aside, the 12 volt Altette horn I fitted also lasted longer than any of the many 6 volt ones I've had...Ian
Jon Cull or anyone else with relevant info: Can you direct me to a source for a 6v LED bulb that will "light up half the parish" and will fit the DU142 headlamp assembly? I hear that there are such bulbs that give more than 3000 lumens, but have not been able to find one. The best I found on Amazon and Ebay is 800 lumens, which is only a little brighter than a standard automotive incandescent bulb.
This is where mine came from ; http://www.norbsa02.freeuk.com/goffyWhyNotLEDs.htm
