Check you have a damn good earth at your regulator btw, as that could give false readings when you have current flowing - any resistance will give a volt drop !
Hello phil_h
The regulator that has failed is a Electrex RR51, this has never been earthed to my knowlege over the passed 3yrs, saying that my old Duc regulator had an earth.
attaching an earth now, are you saying would give different readings?
Many regulators use their chassis mount as an earth point, so they can flow high current easily - which sometimes gives problems if you have the frame sprayed ! So to avoid this many have a dedicated earth wire so its obvious, but its not as good a method. I'll go and have a look at how mine is earthed and offer some more specific advice, but you can trust me, it wont work without some kind of earth
Right, I've been in the garage and taken the fairing off to see whats its all like and get you some pix ... and there is no direct earth bond from the regulator to the chassis. I've got a 98 SPS, and the regulator is fixed to a rubber mounted heatsink.
the yellow wires are the ac in from the alternator, the 2 green wires are the earth connection from the regulator which connect to 2 black wires going to earth somewhere via the loom. This connection is very important at both ends, so clean the connector block if it looks corroded. From the wiring diagrams, earlier models look to have just one earth connection and a red/white charge light wire. 2 red wires then feed the rectified, regulated voltage into the wiring loom. (in the pic i'm holding my external charger lead out of the way) The second pic is there to remind us all that there is a stupid metal connector that can cause faulty readings fitted on either end of the battery. The terminal you fix the wires to is just a swaged-fit into the metal plate and can be pulled through if you overtighten the nut trying to get a 'better' connection - which makes it a worse connection. I've welded up the backs of mine.
Steve, hope this helps. Just looked looked at my 916 and taken this pic. I have a earth wire going from the regulator/heatsink bolt to the main harness.