Some simple checks first:- Make sure your dynamo is properly earthed onto the crankcases. Make sure your battery is properly earthed onto the frame and the frame is earthed to the engine and dynamo body. Check your dynamo output where it connects to the DVR2 (not where the leads exit from the dynamo) by disconnecting the yellow and green lead, joining them together with a bridge and measuring the current between bridge and earth with a voltmeter, give the engine a bit of a rev and you should achieve 15 - 20 volts easily. Make sure your dynamo polarity is correct with regard to the DVR2 and battery. If all is well, reconnect the dynamo to the DVR2, disconnect the battery live lead to the ammeter and connect the DVR2 so that it is delivering directly to the battery (not via the ammeter). At this stage you have the dynamo, DVR2, and battery all connected up exactly as they should be except that the DVR2 'A' lead is connected to the battery, and nothing else is connected to the battery. Make sure the DVR2 earth connection is good. Before starting the bike again check your battery state which needs to be reasonably satisfactory, low charge is OK, but not completely dead. Start the bike and you should see about 13v or slighly more at the battery. You should also see the lights brighten when revving. If you have no luck it might be worth fitting a 6v battery and wiring the DVR2 for 6v (use both output leads connected together - if I remember correctly) and seeing if it will provide 7v to a 6v battery. I don't know what the static resistance readings are between the various DVR2 leads but I could find out as there's one in the workshop. Let me know how you get on.
