Whilst in the process of fitting a Garmin satnav cradle to my D Comet (replica) I discover that it is wired for +earth, is this a particularly good thing, what are the pros and cons if there are any, and if so what is involved in changing to -earth, it is running a Lucas dynamo, everything else is pretty much standard, I don't think it is relying on the headset bearings to provide an electric path, a cable has been run to the headlamp.