Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Sorry few electrical problems

[Braai Boy]

Hi peeps
I've just finished rebuilding the wifes 748 (1996) and have a couple of questions.
1 After connecting everything back together there was a lead that I couldn't remember where it came from. I think it connects to the battery neg but not sure? Please see photo.


Also the battery isn't holding charge, now I've taken readings and I think it's the alternator as the readings are @1500 25VAC @3000 45VAC and @6000 85VAC.
These all seam a bit low to me. By the way the voltage across the battery doesn't go over 11.75 VDC.
Now I know on later models a 3 phase system was used, does anyone know if this can easily be installed onto my wifes bike?
I think that's all for now.
Thanks in advance for any help and I hope you enjoy the weekend.

[Shazaam!]

The voltage levels are OK. Unless that's the output lead from the regulator, the low charging voltage means that your voltage regulator/rectifier has failed, a common problem on early superbikes. A three phase conversion isn't practical but you can take steps to avoid future failures.

http://ducatisportingclub.com/contro...d.php?tid=2042

[Derek]

Looks like you are probably right about the location of the wire. If your battery volts aren't exceeding 11.75V then it isn't charging. With the engine running at 2,000 rpm or more this should be about 14.0V - 14.5V. If the unconnected cable is from the regulator that might explain it.

[Braai Boy]

The unconnected cable disappears into the wiring loom along with all the other relay cables. I have run the bike with and without the cable connected without any noticable differance. If you think it's just the regualater then I'll get one tomorrow.

[Walenut]

Just had a look at mine and that looks like the earthing strap off the regulator, goes onto the left side of the regulator as you look at it, and is secured by the bolt that goes through the hole that secures the regulator. You can just see the securing hole in your picture and it looks like the bolt is missing? If that’s as clear as mud let me know and I'll take a picture.

[Braai Boy]

Walenut thanks for that. Makes sence as to why the regulater doesn't work. I will try it tonight and see how I get on.