'94 M900 - Not Charging - FIXED!

[Howley]

Hi All,

So as I mentioned in a previous topic, the bike is not charging my battery. It charges fine on a tender. I have checked the following:

- Voltage across battery terminals with bike warmed up at 3000rpm - 11.81V (too low!)
- Stator coil resistance - 0.4ohm
- Wires from stator are melted (could be old melting, only just noticed as insulation has started falling off) on the stator side of the white connectors.

QUESTIONS
1. Main question is the stator. If something was wrong, how far out of the recommended 0.2-0.4 ohm range would the resistance be? I checked it alongside a new and another second hand stator and the readings were the same. It took a bit of jiggling with the probes to get a good reading, was getting in the range of 0.5-0.3ohms on all three units. This was tested at the connectors.
2. What does the melted stator wires suggest?
3. What else could be causing the battery to not charge. How do I isolate the problem?

Thanks in advance!

[garryc]

If you haven't seen this before read
http://www.mad-ducati.com/ShowPage2.php?PageName=Technical/ChargingOrNot/ChargingOrNot_1.html

[suzyj]

The melted stator wires are likely due to a short or a dead rectifier/regulator.

[Howley]

Thanks for the great article garryc! I did those checks and the stator checked out fine. Only thing is the article said the max voltage shout be 1/4 the wattage of the system. I was getting 124v~ at 7500rpm which suggests I have at least a 480w system. This seems too high. Should I be worried? Also do I need to load test the battery if it charges on the tender and starts the bike?

[garryc]

I followed the article and found my stator to be fine.I knew battery was good  replaced rec/reg and all has been good since. 98 M600

[Howley]

A question about the crispy wires...

The wires on the regulator side are fine. The connector itself is dirty on the outside, maaaaybe a little melty although I don't remember it being any different, and not corroded. On the stator side the wires were crispy, the terminal not corroded and like the other side a bit dirty and maybe a little melty. I've repaired the insulation on the regulator side, and since I'm checking the stator at the terminals can I assume that bit of wiring, the connectors, and hence the connector to regulator wiring is ok?

Thanks!

[zooom]

I've always used this fault tracing for charging issues...

http://www.electrosport.com/technical-resources/diagnosis-center/fault-finding-guide

I ended up sectioning out pretty much the entire wiring from the RR to the stator on my 99 Gran Canyon due to this and the lovely small wiring Ducati supplied to the charging system that crispified over time....which was a much less simple job than what you'll have for to deal with....

[Howie]

The connector that connects the stator to the regulator is cheesy and with age can become problematic.  High resistance at that connector will cause the wires to overheat from that connection back to the stator.  Cut back from the connector until you get to good wire, a little more is you can.  Solder new wire of proper gauge or heavier in place of the old crispy wire.  Replace the old connector with a new one of good quality able to carry at least 40 amps.  Pack connector with dielectric grease.  Some folk used to totally eliminate that connector.  I prefer not to eliminate the connector since having one makes diagnosis much easier.  Your choice.  Check the regulator again to make sure it didn't fail.

[Thermite]

The melted stator wires are likely due to a short or a dead rectifier/regulator.

+1.  Have you removed your R/R and inspected the bottom?  Defects in the potting like bumps, lumps, cracks or discolored ares are a dead giveaway.

CA Cycleworks sells an aftermarket RR that's doing just fine on my monster.

Your stator numbers sound okay.  Don't go nuts trying to read to much into them.  The values jump around a lot and that makes them problematic for a digital multimeter.

[Howley]

From the numbers I've got now, would you say I should be ordering a new RR, or should I fix the connector and check again?

*Edit* Bottom of the RR looks great, no cracks, melting or anything. It looks a little wavey but it looks like normal resin. In fact the whole RR side of the circuit looks in great condition.

[Howley]

OK so I carried out the Electrosport tests found here:



I got down to the first test of 'B', where I was getting 0.09V to 1.1V depending on how I connected the probes. It was probably more like 1.1V.

On page C the second test failed.

What do you think?

According to my results from: http://www.mad-ducati.com/ShowPage2.php?PageName=Technical/ChargingOrNot/ChargingOrNot_1.html
I "can be assured that the rectifier is faulty".

[Howie]

Yes, you need a regulator. 

[Smokescreen]

I'd say, for safety, you should get the magnesium left side case cover from Ducati Corsa, and a regulartor, and whatever fixes the thing? But mostly a magnesium case cover, because that's awesome!!!

[Howley]

I'd say, for safety, you should get the magnesium left side case cover from Ducati Corsa, and a regulartor, and whatever fixes the thing? But mostly a magnesium case cover, because that's awesome!!!

Hmmmmm. My side cover IS dirty....

Thanks Howie, I'll order one.

Thanks all of you for your help, I'll let you know if it sorts my problem out!

[zooom]

Thanks all of you for your help, I'll let you know if it sorts my problem out!

IT SHOULD...and make sure you repack the contacts with plenty of dielectric grease!!!