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

[Wulfie]

Hi Guys,
I don't post much, but do keep an eye on the boards so that's why I'm here as I need a little help. I first started having problems with my 748 SP charging circuit shortly after purchasing it 18 months ago, i'll also add the only problem as well.
I read most of the stuff that Shazaam has posted on the subject so I have a little knowledge and consequently tackled the problem thus.
Firstly, last year I had initial problems, so I inspected the wires from the alternator connectors to the RR, they were found to be brittle and corroded so I replaced the wiring from the altenator connectors to the RR by soldering uprated wires (30A capacity) to the original ones from the alternator which looked OK. Then the replacement wires were individually covered in heat shrink and then both fed into a heat protective tube and the covered in heat shrink to tidy them up. This cured the problem for last year.
This year after winter the bike was slow on the starter and popping etc so I bought a new Bosch battery, at the pricely sum of £70 too but that sorted that out. this was about 3 months ago. I went out on the bike 2 weeks ago and it broke down again, incidently the bike has had weekly use at least since the battery replacement with no problems.
I suspected the RR would be U S as the current provided from the alternator, which is a single phase alternator was measuring OK, and the measurement across the battery with the engine running was only 12.5v with no increase to the voltage upon increasing the revs, so I have replaced the RR with one from ebay ( I know, I know but we'll get to that later) upon fitting the replacement RR and checking the current again I have found that when the bike is idling the AC current from the alternator is @ 70v, when you increase the revs to 6000 rpm @ 120v, a substantial jump from the last measurement ? (just to confuse the issue I have bought a new better meter in between the measurements so I am assuming that the new measurements are correct. however I have no proof at this point.) however the regulated voltage is still about 12.5 v.
So here are the questions....and thanks for reading so far
1 Are there any circumstances that the alternator would dish out more AC voltage than the RR can handle thus knackering it, and explaining why the readings are the same with either regulator fitted ?i.e both been cooked.
2 Are the AC voltage readings acceptable at those levels, as the upper one is ball park with the manual, however the lower readings seem high ?
3 What sort of fluctuations in voltage are normal when testing the AC current ?
4 Would a gunged up fuel filter cause a low rectified voltage reading and potentially if replaced could this solve the problem.
5 Would you still get a voltage reading of @12.5v from the RR conectors back to the loom, i.e after the rectifier if it was not working at all ?

Of course I am aware that the RR I bought from ebay could be goosed same as the original one, and of course it stands to reason that this is probably most likely, however I am reluctant to spend £70 on a new one just to have something else render it useless as soon as I fit it, if you follow. It's a bit rambly I know but thanks for reading anyhow.

Cheers

Wulfie