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Discussion Starter #1
On my second stator on the bike. First one lasted till "05, new one is now barely maintaining the charge. I am not sure if the "silent recall" was done or not but due to the fact I got a new stator in '05 for free, got to believe that was done. My question is, I understand the 916 had a similar charging issue, 2 phase system that the company put out a modification kit to correct the draw back. Fact or fiction? Will it work on an ST2? Gets old worrying about wether its going to leave me stranded....anyone have any other know ways to correct the design flaw??
 

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Charging

I think the recifiers are the problem. I have re-wired a couple of these using the new 3 phase recifier and mounting them where they can get good air and haven't had more problems.


On my second stator on the bike. First one lasted till "05, new one is now barely maintaining the charge. I am not sure if the "silent recall" was done or not but due to the fact I got a new stator in '05 for free, got to believe that was done. My question is, I understand the 916 had a similar charging issue, 2 phase system that the company put out a modification kit to correct the draw back. Fact or fiction? Will it work on an ST2? Gets old worrying about wether its going to leave me stranded....anyone have any other know ways to correct the design flaw??
 

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Charging Numbers

On a cold start, voltage shows around 12. At idle, it slowly creeps up to 14.1 or thereabout. Once rev'ed or crusing, it drops to about 13.3/13.4. All this without lights on. Was told that this is normal for the '97 ST2. Can anyone shed some light.

Cheers:)
 

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There's a lot of good reading in the Halls Of Wisdom...
Basically, above idle and/or when cruising, the voltage should stay close to 14.5VDC (with a known-good battery). Here, in the USA, our lights are on all the time, so we're always feeding close to 5A into one of those elements. So I read a lower voltage here at idle...around 12V.

Bobsst298: Don't know about any "mod kit" other than the Ducati Campaign that placed an updated spacer/washer on the crankshaft, which dispences more oil to the stator windings, which aids in cooling of the stator. While they're in there, Ducati also replaced the stator, assuming the the original one might have been over-stressed.

To troubleshoot the stator, you should have low Ohms (around 0.5) between the 2 yellow wires. Do it with the wires unplugged (behind the radiator). Also check integrity of this plug. Next look for infinite (very high) resistance from either yellow wire to engine ground. If all this checks OK, I would CAREFULLY place a voltmeter into the yellow stator connector, making sure the leads don't touch, and don't touch gnd. Start engine.
Around 2000rpm, you should see 30 or 40VAC. As you rev engine to 4000rpm, this reading should double. Be careful of ELECTRIC SHOCK, because at high rpm, this can and will go over 100VAC. turn off engine.

If all this checks, plug in the RR again, and re-check battery voltage at idle, and then at 2000 or 2500rpm. At 2500, the reading should approach 14.5VDC (as the batt. charges).
 

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Chilehead
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On mine, with a good regulator and charged battery, 14.3V at:

2000 RPM no lights
3000 RPM low beam + running lights
4000 RPM low + high beam + running lights

Tom
 

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Old Wizard
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3,006 Posts
Replace the stator leads and remove the common sheath.

The stator windings don't often fail but if its leads short together the regulator is history.

If you relocate the RR to the tail, the stator wires are no longer routed inside the hot fairing, so with better convection and conduction cooling, PVC-insulated AWG 12 gauge from Radio Shack is all that you really need. 10 gauge is even better.



The environment that the wire sees is important, and this is where Ducati engineers screwed-up. The stator wires run first internally to the engine, and then are enclosed on a sheath that passes over the engine and internal to the fairing. So the insulation on these wires don’t see adequate cooling, they exceed their performance rating, and loose their insulation properties. If a high resistance develops at the in-line connector the heat generated is conducted along the entire wire length and the electrical insulation fails. Don't just replace the discolored portion, replace the entire length of wire back to the engine casing.



The portion of the stator wiring that run in the sheath is where insulation failure is critical. The stator wire are held closely together and insulation breakdown from heat causes them to short together at the higher output voltages at higher engine rpm. You can't just use an low voltage ohmmeter to find the insulation problem, the shorting occurs at higher voltages.

Most regulators fail because they get too hot inside the fairing, but this intermittent shorting together of the stator wires is the other cause of regulator failures.

You don’t even need to remove the engine cover. 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.

The wires inside the engine don’t come in contact with each other until they exit the cover. Even if the insulation overheats it can’t damage the regulator, and because of the hot environment, a larger gauge wire inside the cover isn’t going to reduce insulation operational temperatures much in this section of wire.

The regulator itself is sealed against rain and grit but it's a good idea to make the lead connections up inside the tail unit and seal the wire penetration with silicone sealant.
 
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