Sorry Martyn, that is not correct. There are somewhere between 70 and 80 Walkernaters out there and with one exception, of more which later, they all have Iskra alternators, which are made in Slovenia. These alternators are intended for use on small Citroen cars such as the 2CV and the Dyane etc. On these cars, which have air cooled twin cylinder engines, the alternators are mounted on the exhaust manifold where the only cooling is that from the air passing over the engine. I thought that if they could withstand that sort of heat then they would survive sitting behind a Vincent engine. They can give up to 30 amps at 14+ volts I.e. about 400 watts. These alternators require an external regulator. Last time I checked these were about £15 each. Either I can supply them or Vehicle Wiring Products, or similar can. They are a three wire system and do require a switched 12 volt supply. (Sorry Vibrac, one just has to remember or fit a switch which combines an earthing switch from the magneto and the 12 volt supply to the regulator/alternator.) As far as I know none has yet war out a drive belt although some people have asked for a spare in case it ever fails. Replacement belts are also about £15. They are known as a J section belt for any one who wants to order independently with six chords (grooves and ridges). I was told by the manufacturers design engineer that three chords would transmit one horse power reliably so they are well over speced for longevity. The only problem with the design has been that on three of them one of the bearings inthe dynamo replacement have had the drive shaft turn in the and wear the drive shaft. The solution to this was invented by father and son Appleton and consists of a steel tube over the drive shaft which is trapped against both bearing inners, ensuring that everything has to turn together. Please note that the bikes involved gad all done many tens of thousands of miles before the problem occurred and the modification was built in to all the last kits sent out.
The one exception to the kits being supplied with Iskra alternars was a one off for Peter Holmes. He had access to a supply of Nippon Denso 40 amp alternators, which have the regulator built in. It proved possible to fit this to the rest of the parts with only minor modifications. Having not sol any kits for several years I have now had two orders come in in the last few months and theses will be dealt with once September is over. It has not proved possible to source Nippon Denso , now known as Denso, alternators so I have obtained some sold as Kubota, although I believe they are made to fit a variety of engines. By total chance I have one of these fitted to the three cylinder diesel engine in my ride on lawn mower, which has lasted for several years but with only a small number of hours compared with a car or bike.
If anyone wants any spare parts then I should be back in the UK next week.