rectifier or stator?

[ctadams21]

Hello all,

After combing the internet and Ducati Forums, I'm still not able to diagnose my charging problem.
The bike (2000 Monster 900S i.e.) does not ever show over 12.5 volts at the battery at any rpm (Battery fully charged prior to test).
I checked the three yellow stator wires for continuity across all combinations and they were all very close (0.6-0.7 ohm).
I've checked the three yellow stator phases against the battery ground and none are grounded.
I've checked the two positive and two  negative wires coming out of the regulator for continuity to the the battery + and - terminals and all checks well.

Here's the kicker:
When I unplug the stator and check VAC across the three yellow stator wires(all combinations), the reading increases to 50-ish VAC as I rev to around 5000 rpm.
But.....
When I plug the stator in and check the same three yellow leads the VAC is less than 12, does not increase with rpm and on one phase, decreases as the engine speed is increased.

I'm leaning toward a bad rectifier but would like some feedback before I purchase.

Thanks in advance.

Clayton

[ducpainter]

One of the smart guys will come and correct me if I'm wrong, but the stator check has to be done with the R/R disconnected or you're reading the R/R voltage. Sounds like a bad rectifier to me.

[koko64]

+1. A search will reveal Howies wisdom.
What you can do is look at that Rec/Reg and try and spot any goop that may have melted out back where the potting sealant is. Look for signs of heat damage to the unit or wires to it at the alternator connector.  I repaired the burned wire connector on an SS and found the reg ok, so you may get lucky. The alternators are generally very reliable while the rec/regs are a known issue.

[ctadams21]

I did have to replace the electrical connection to the reg/rec due to corrosion. The unit itself looks fine...no seeping or visible heat damage.

[Speeddog]

They nearly always look fine from the outside.

[Howie]

Stator is good.  Before changing the regulator make sure the 40 amp fuse is good and the black wires from the regulator are well grounded.

[ctadams21]

Thanks Howie. I didn't realize there was a 40 amp fuse on the bike. I found it by the ecu under the tank and it looks good. I'll check the ground wires .....

[ctadams21]

grounds check out ok. Looks like I'll be ordering a R/R. From what I can tell, most are updating to a mosfet Shindengen FH020AA and using the Triumph adapter harness.

[Howie]

Or  https://ricksmotorsportelectrics.com/Hot-Shot-Ducati-Rectifier-Regulator-10_009H

[booger]

The Rick's Hotshot is more of a plug & play than the Shindeningendeningenden but the Shenanigans is probably a little better in quality. Not sure. I got the Rick's and it is doing fine.

[ctadams21]

Been riding with no issues for a week now. New rectifier did the trick!
Thanks all.

[koko64]

 

[DuciD03]

- you guys are awesome -