Checking and Replacing a Stator on a KTM 690

So there I was, nowhere exotic, not in the middle of a fabulous trip – just running errands around town when…

UGH! I was just over a mile away from home and it was all flat so I just started walking the dead bike down the sidewalk home. Technically it could be any one of a bunch of things but it’s usually related to the last thing you did – except I hadn’t done much of anything. Because I had texted the Moto Buddies in a group chat, as I was walking we all tried to diagnose the issue.

These three things were right on the money. It was most likely either the Battery, the Stator, or the Voltage Regulator Rectifier (VRR) – and yes, it could be a terminal, connector or wire too.

As for Tomm’s thought

I had a good quality AGM style Battery that somehow broke a plate connection on the inside of the battery (see https://aufroad.com/the-norcal-bdr-part-2/) and luckily I had Tomm’s BDR rescue and Recovery come to save the day.

I’m not sure why but I seem to document things via text and images. The next day I got a chance to look at it and

No Problem? So I thought. So I took it for a short ride around the neighborhood. i watched the voltmeter drop from it’s 12.4 to 11.8 and down to 11.4. Still no Battery light, but obviously I still have a problem.

I parked it back in the garage, put it up on a stand and started taking things apart.

While I was doing that, Charles was way on top of it all. He’s fast like that.

Here’s that link he referenced: https://www.ktmforums.com/threads/charging-issues-16%E2%80%99-690-duke.140465/

I found my old post here: https://aufroad.com/charging-system-diagnosis-update-1/ that had pretty much the same info.

HOW TO TEST YOUR KTM VOLTAGE REGULATOR RECTIFIER

I know this isn’t anything to do with the Stator – but you need to know if one or the other is broken, right? I don’t know diddly squat about electrical so if I can do it you can too! I started with the VRR just because it was something I had done on my 950. I took off my seat, took off the right side panel and then removed my canvas tool pouch that sits in front of my Rottweiler Intake. If you have a stock airbox you’ll have to remove it and it should then look similar to this.

The Green Arrow is pointing to the connector between your Stator and VRR.
The Red Arrow is pointing to the Positive connections for your VRR.
The White Arrow is pointing to your VRR bolted to the side.

Unplug that big brown connector (carefully). They like to crumble if they’ve been neglected and old.
Next unplug the Positive Connector – you’ll know it’s the right one as it has two red wires going into it.

Next pull out a multimeter. Mine is a Harbor Freight Special that costs less than $10.
Set your Multimeter to this setting. I don’t know what that is or means but just do it.

Next with a piece of paper, draw a matrix. We have a red and a black wire coming out of the multimeter and we’re going to connect it to all the different variations we can. This is really easy.

Start with the Positive Lead (red wire) of your Multimeter and connect that to one of the Positive terminals in your Positive Connector.

Next let’s touch the Negative Lead of your Multimeter (black wire) to one of the terminals in the brown connector block coming from your VRR and make note of the number.

Now move on to the next terminal in that same plug (there are three) and write that down and then do the same for the final terminal. Mine were all “1” on this multimeter but my old multimeter showed them at “0”. The point is that they are all the same.

Next, we’re going to connect our red multimeter wire to the Negative Connector coming out of your VRR. No, I didn’t unplug mine. I found it buried and saw that the wires coming out of it were grounded to the frame. I have a big relay right there but this is looking from the center line of the bike our towards the right side. That Zettler thing is a relay that powers up my Nav stuff but that’s the bolt you need to touch.

So, Red Multimeter to the Ground, let’s do the same thing. Touch the Black multimeter to each of the terminals in the Brown VRR Connector and write each of those down.

Next we simply reverse those two steps. So Black Multimeter wire to the RED wires in the Positive Connector. Then using the Red Multimeter wire – test, test, test.

And finally, Black Multimeter wire to the Ground – then using the Red Multimeter wire – test, test, test.

You should have a matrix that looks similar to this.

IF one of the brown connector terminals gives you a whacked out reading (looking at the horizontal lines) you have an issue with the VRR. I had either all “1” or something in the “500” range for each of my three terminals so I was thinking that there was nothing wrong with my VRR.

Back on my 950 when I did this very same test – it was the VRR that was bad and my chart looked like this:

Here’s the video I had seen years ago.

That’s how simple it is to test a Voltage Regulator Rectifier.

So, if my battery was newish, and my VRR checked out, it was now time to test my Stator. This is the thing that creates power in your bike, kind of like your car’s Alternator.

That post that Charles had sent has three simple sounding tests.

• #1 Internal resistance check: With the bike off and the stator connector disconnected, test each of the 3 leads from pin to pin the meter on resistance. Test pin 1 to pin 2, pin 1 to pin 3 and pin 2 to pin 3. Meter reading should be less than 1 ohm. 0 ohms is ok, open or infinite is not and requires the stator be replaced.
• #2 Ground check: With the bike off and the stator connector disconnected, test each of the 3 leads from pin to ground with the meter set on resistance. Each reading should be open or infinite. If anything else the stator needs replacement.
• #3 Voltage output check: With the bike running and the stator connector disconnected, test the output voltage from pin to pin with the meter set to AC volts. Test pin 1 to pin 2, pin 1 to pin 3 and pin 2 to pin 3 with the engine RPM about 3K. Meter reading should be above 15V AC and go up as RPM’s go up. If they are lower than 15V the stator needs to be replaced.

That also checked out with my Workshop Manual.

Here is Test #1 from above (Internal Resistance Check)…

And here’s the Ground Check (Test #2 from above):

Remember, I am The Voltage Idiot, but I’m pretty sure that when they say “resistance” they are talking about Ohms. Working first on the #1 Internal Resistance Check I set my multimeter to this:

I was getting consistent readings across the three pins.

With the same setting on the Multimeter it was now time for the #2 Ground Check. Following the instructions I did not come out with a 1 or zero, open or infinite – at least not for all three. One of the pins gave me a 74!

So that meant I probably should crack the case and look at the Stator. This was verified by my highly trained and highly knowledgeable team of text-perts.

So next, I pulled off the shift lever, then the 7 or so bolts that hold the stator cover on. With those out and oil running into the drain pan I pulled off the cover and turned it around to see the stator.

That one black node (not sure if that’s what it’s called) was the issue. All of these windings, all of this copper wire should be bright and shiny, not black and ugly.

I posted up on ADV to see if anyone had a better stator than stock but the general consensus was to use OEM. So I ordered one from Rocky Mountain and it was here in a few days. I ordered the Husky version as I heard they spun slower and I figured I wanted slower Swedish electrons.

Kidding of course. But I also had to order a new gasket for the side cover.

I then followed the wire from the dead stator up under the frame back up to the airbox removing all zip ties holding it in.

With the Stator and Cover free from the bike I moved to the workbench. I looked in my shop manual for anything covering Stator Replacement and there was nothing. I checked YouTube for the same and still nothing. It turns out, it’s easy enough to do.

There are 3 bolts holding the Stator to the side cover. I removed the three bolts (all the same size) and noticed they were pretty gunked with threadlock.

I looked for anything clocking the stator in a particular position but didn’t see anything. I did notice that the incoming cable was at about the 1 or two o’clock position. This is the backside of my new stator.

I took a small pair of needle nose to the spring that looked to be holding the cable out of the way and made sure to take a picture of it’s relative direction as it came out.

With that, the whole thing popped easily out of the side cover. I cleaned up everything I could of the side cover and then figured out where and how the stator went back in. I cleaned the threads of the three bolts and used a bit of locktite putting them back in. Torque was just 10 nm.

Next was the spring. With everything clean, I could see how it sits down in the slot and then the tabs lock into the case holding the tension. Here’s a picture of it before I took it out. You can see that it slides down that grove and then into the locked position. The matching engine case side will essentially trap the tab when you put the case back on.

I did put a little dab of Permatex 80017 around where the rubber plug met the aluminum. That worked great sealing my gear position sensor.

Turning to the bike side, I was working in the full sun and it was hot and glaring so I decided to work smarter and gently tossed the bike on it’s side. Much easier to see and work on stuff. I could never have done this with my Hayabusa.

I cleaned up the old gasket and in particular this small section where the two cables get in and out via rubber plugs. They have one slot in the engine case side and one in the stator cover side. You can see I had a small bit of old green gasket that was hanging on there.

Oh, and speaking of that other wire. I saw something in my manual about a crankshaft position sensor? Not sure what it is but I checked mine and it was not – so I then adjusted it to the .70 mm.

With the case side cleaned and ready to go I placed the new gasket on the case, verified I had the two collars still in the case and then put the bolts back in. The are all the same size EXCEPT for the two that go through the collars. Locktite all and torqued to 10 nm.

I then routed the plug and cable side up under and alongside the frame to plug back in with the VRR. I then did a full change of my oil with all new filters, screens and seals. I always change the filters with the oil – but I don’t usually go with new screens and o-rings but all that fried stator insulation was probably in my oil – hence my apprehension.

With the oil changed I then started it up and had a solid 13.8 volts! It was getting dark and so I figured it was a good time to have a frost adult beverage. For the record, in this case it was a Very Dry Costco French Vodka Martini with a spicy cherry pepper stuffed with cream cheese.

Mileage for this latest incident was 27,857

I’ve been asked how long should a Stator last, how long should a VRR last? There’s no correct answer. Your mileage may vary. But if you pull anything from this, just know that checking and replacing either your VRR or Stator is easy even if you have zero experience.

*Oh and if you ever have a VRR go bad always replace it with the much much better MOSFET kind. Always.