Ducati Sporting Club UK > Model Specific - Discussion, Technical Problems and Help > 998 / 996 / 916 / 748 > Generator light

[two dukes alan]

Been out this morning for a short run (light rain & drizzle). A fter about 30 miles my generator light flicked on and off 4 or 5 times in about 3 miles. The bike ('95 748sp with 36,000km) runs fine, no unusual sounds etc. I turned around and came home with no problems and am wondering if I just have a loose wire?
This is the first time I have been out for 3 weeks when I had a weekend up Scotland and did 800 trouble free miles.
Anybody got any thoughts?
Alan.

[bostrom998]

I used to have a '95 748 BP and a few miles after that happened it caught fire, simple lack of charge in battery and a steep learning curve, so hope that's not what your issue is all about!!!!!!!

[Shazaam!]

Don't ignore it and keep riding without checking/replacing the stator wire insulation and in-line connectors. The light is warning you that the charging voltage is intermittently low. If the stator wires are shorting together it'll damage the regulator/rectifier.

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

[two dukes alan]

Thanks guys. I am going to check out the wiring tomorrow evening, thanks for the tip about the stator insulation and connectors. I fitted a new r/r 2 yrs ago just after I bought the bike so hopefully that is still ok (the symptoms are different).
Alan.

[748mart]

I'm a bit confused with this. I understood the new type r/r dosn't have a wire for the generator wire. In which case you must have replaced the rr with an old type one if the light is coming on. I'm sure Shazaam will correct me in a mo.

[Shazaam!]

The early 350W single-phase (two wire) charging systems had a charging light. The post-'99 520W three-phase (three wire) systems eliminated the warning light circuit. The updated regulators for the three-phase system are installed on the single-phase bikes using a short wiring harness kit supplied from Ducati.

[two dukes alan]

Well I checked the wires and the insulation on the end of the alternator output as it exits the sheath is putty, that would explain the light I think. Tomorrow I will make up a new heavier gauge replacement and report back.

[Shazaam!]

At first glance it may appear that the high current being carried by the wire had just overheated a few inches of insulation next to the high-resistance bullet connectors. But when you remove the common sheath that the wires run in back to the left engine cover, you likely find that overheating (from the current, not the engine) has softened the insulation to a degree where you can damage it with your fingernail. A multimeter will say it's continuity is OK but at the higher AC output levels at higher rpms the insulation can’t prevent the wires from shorting together. Remember, the wires are held in physical contact along the entire sheath length.

You don’t really need to remove the engine cover. Inside the engine the wires don't touch each other. The approach that I took was to replace the damaged wiring (with a larger gauge to reduce electrical heating) up to where it exits the side cover. I pushed a piece of shrink wrap tubing over each of the wires and into where they pass through the seal in the cover and left the internal portion of wiring alone since they are separated inside the engine. Again, the main problem is where they touch each other along their length where they run in a common sheath. Discard the sheath.

I also took the oportunity to relocate the regulator itself to the licence plate holder to get it away from the engine and exhaust heat.

[two dukes alan]

Yes thats what I had in mind when I make up the replacement, good advise though. The relocation will be the next step if this does not cure it, I intend to reroute the wires into more air flow to help but the new regulator wires look fine..maybe it's damage from the first burn out that I didn't notice! They say you pay to learn. Looks like we all become experts to some degree when you fall in love with a Duke.

[two dukes alan]

Well just to finalise, I did a 350 mile run on saturday around Dumfries & Galloway(I live in south Durham) and the bike was fine despite some really (for up here) hot conditions.
A question for Shazaam, do you have any problems with water with the r/r on the number plate? (and don't tell me it never rains in CA).
Alan