916 alternator/regulator
 

I've got a 1997 916bip, I bought it about 2 years ago, I was told that it had had a new japanese regulator fitted. After about 1 month it stopped charging and I bought a new regulator (RR51) and fitted it, no problem, But in october this year it stopped charging again, I touched the regulator and it was red hot (hot enough to burn my fingers) so I ordered another (RR51) Sadly I have only just got around to fitting it, But no joy, still not charging and the new one gets really hot as well, I tested the output and it's only 8.5 Volts, I have tested the alternator output and that puts out about 80 volts AC at 6000 rpm, Any body know whats wrong?

Charging Problems
 

You need to replace the stator wires from the engine cover to the connection to the regulator. Better still, relocate the regulator for better cooling.

Here's the full story:

http://www.ducati-upnorth.com/tech/chargingfailure.php

Thanks,
 

Yes that may be the problem, I noticed that the yellow wires did look a bit worse for wear, Does that mean I should take off the alternator cover and solder new wires to the stator directly do you think, or just join them outside the cover? do you think that it could have damaged the stator its self (the're quite expensive), I guess I'll find out.

Thanks again, I've googled the problem but not found an article as helpful as that one.

Matt

Just join them outside the cover. They stay separated inside the cover so even if you have heat-damaged insulation they can't short together in that area. Shorting together inside the sheath will often damage the regulator/rectifier but usually not hurt the stator windings.

Thanks again
 

Thanks, I'll Do that This afternoon, I'll Let you know the outcome. :)

How did this work out for ya?
I have the same problem. I'm on my third RR in 2 years. I relocated the last one as per Shazaam's recommendation. However just realised she aint charging again. Done the un-regulated voltage test and got 80V @ 6k RPM.I'll replace the wire with heavier stuff. Is it likely this is after taking out another RR?

Ok well I cut the alternator wires back to within a couple of inches of where they exit the engine case the wire looks in good condition. I took an ACV reading from there and got the same 80 ACV @6K RPM. Thats 60V short of where its supposed to be. From this reading I have to assume the stator is faulty. Electrex do a replacement unit, anyone any experience with these? Im pretty sure the RR is dead aswell so gonna get em both from eletrex. Have a new Yuasa battery to go in too so hopefully it'll be the last time I have to strip this system down. Have also learned that I might have contributed to this failure by allowing my last battery to discharge. Then jump starting the bike and allowing the charging system to revive the battery. I have learned(thanks to Shazaam) that the single phase 350watt system is not really up to this. So from now on Its gonna be replace all wiring with 10guage, solder all connections, install a voltmeter, relocate the RR and pay special attention to my battery condition. If the battery dies i'll get the Odessy unit Shazaam recommends.

Ok well I just fitted a brand new Generator and RR to my 916. The old Gen turned out to have burnt wires inside the case. So burnt in fact that the insulation had fallen apart exposing bare contuctor. When I installed the new unit I tested the unregulated voltage and I was only getting 95VAC @ 6000 rpm. I'm gonna try a different meter when I can get hold of one.
One odd thing I noticed when I was doing final checks. I measured the redulated voltage across the battery and at idle I got 14.2 volts but as I revved the engine the voltage dropped to 13.4 at 6k rpm. Now I have read that a dirty fuel filter will cause the pump to draw more current. Since the pump is working harder when I rev the engine I'm hoping its just a dirty filter. I have a new one but ran out of daylight today. Question: Is it usual for the voltage to drop when the engine is revved or should it rise/stay the same?

as the pump is running at idle I would have thought a dirty filter would have put a load on the battery even at idle and pull the volts down not let them sit up at 14.2V.
I have no experience of the RR51 so not sure of its regulating characteristics so have no idea how it behaves

To be honest I'm just clutching at straws now. I have replaced the filter with a new one from Ducati. Gonna butcher the old one and see how bad it is. I measured the battery voltage this morning, it read 12.55 volts, acceptable as far as I know for a battery 12 hours rested. I started the bike and allowed to idle @ 1200rpm. The meter read 14 volts. Now here is the problem as the revs rise the voltage across the battery drops to just over 12 V @ 6K. This is not right. I also have an R1. To get a comparason I checked it and got 14v at idle rising to almost 15 @ 5k rpm. To me this is how the ducati should act with a new RR, generator and battery. The only other component is the flywheel. Im not well briefed on magnetism but is it possible that a potentially 13 year old flywheel could have lost some magnetic power. As mentioned it a previous post I did check the unregulated voltage after installing the new generator and only got 95VAC where I should be reading at least 140VAC. Since there are only 2 components (generator and flywheel) interacting to produce the unregulated voltage, is it reasonable to suspect the flywheel is duff? Anyone with any insight please let me know. Im 400 quid out of pocket so far and still none the better for it.