This UTV (Side by side) came into the shop about six months ago for a no start. We were cranking the engine to try to get the unit to start and the ground wire for the stator started to smoke!

After I tested (with a meter) each leg of the stator, leg to leg and also to ground...the stator seemed to test out good so I figured that maybe the ground wire became weak over the years so I removed the stator and replaced the ground wire with the same gauge wire and reinstalled. The machine seemed to run just fine for a few days of subsequent testing so we called the customer and he picked it up and was happy with the repair.

Just this week it came back for the same problem as we found out. So naturally we used it as an excuse to get the Pico out and I have attached a waveform for you all to see.  :)

I think what is happening is a failing leg on the stator that is leaking to ground causing the ground wire to get hot due to the short. I believe that is what I am seeing on the scope but this is my second job with the scope so I am all ears to your thoughts.

Thanks in advance!

-Russ

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I saw in the first waveform I attached that I did not have my stator settings setup right, I had them on DC instead of AC.

The ground should read zero right? It shows that I am getting about 1.8 amps on the ground for the stator. It is currently not smoking or getting hot and I think that when it does smoke this amperage goes way up.

Sorry I am so new to this!  ::)

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Added a cranking waveform.

Channel A: Stator Leg 1 voltage AC

Channel B: Stator Leg 2 voltage AC

Channel C: Amp clamp on ground

Channel D: Voltage to ground

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This waveform is revving the vehicle to roughly 2000 rpm (no tach)

Just trying to give you guys all the angles.

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Redline, dropped a screen print from a KLR, and this stator if it is the old or new is putting out good voltage as it appears, not familiar with this unit the only ones I have tested are 3 leg.

Do see signatures on the ground appear to be coil timed, but that noise might be on any system, ? what does a good one look like..?

Did a lot of testing as of late on shunt typ verses Mofsett and shunt work the stator 100% as apposed to Moffset. Would also look @ what is coming out of the RR if this system employs that type of thought. Is the RR working the Stator too hard, don't know. My captures I did not have a ground channel.

See almost 4 volts hit to ground on these events, and almost 2 amps, but momentarily. The volts might be higher as it looked like it was capped and rotated down, just a hook up issue.

StitchB

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According to the capture that I first uploaded, the AC output only seemed to be about 10 VAC.

That does not seem like enough. Maybe I am interpreting the data wrong but thats what it looks like to me.

Also this, to my knowledge, is not a waste spark system due to it being a single cylinder 500cc engine.

I was seeing a bunch of stator leg irregularities between each leg on my initial capture like I had pointed out in the JPEG image that I uploaded.

What do you think of those?

Redline, that  is the beauty of this thread, you can get many opinions.

Sending a JPEG, when I stated it looked good I was looking @ the total sine wave, which is about 25 volts.  That said the captures I sent of the KLR are the wave and all of them show from 0 volts up on the sine wave, recorded using DC voltage setting. All leads were on the Stator side of the R/R not on the Battery side.

I have the setting on DC which is where it should be even though recording an AC signal, might not be true for the amp side, maybe need some feed back from other players here.  Also, talk to Tom and Such on this  when testing AC in other things none automotive AC can be dangerous if exceeding the limits, just speaking what I have been told.


I asked if a waste spark which see no reason why a single cannot be. If you notice every other signature is smaller meaning on a wast spark system there is less resistance in the Jug on Exhaust (no fuel) so takes less voltage to jump the Gap, it was just a thought and the RPM for every other hit gave me the 2,000 RPM.

Also an interesting test on alternators is have nothing on the other end such as a regulator, it is surprising what they will put out with no target voltage on the Battery, can be up to 75 volts I have seen on a car, also a nice test just playing around to see what is what.

The legs on the signatures I tend to view as noise, but not always the case.  See it a lot and becomes a gut feel after while. If you want to see if the capture is actually significant click on filter on each channel and see what is left. I did this on yours and the Volts and amps still are there on the ground line which is wrong IMO.

Also this is the first Alt I have seen in bike or car with only 2 legs, usually 3. Think it is done to create a steady line of voltage and not have any drop outs over 360 degrees, JMO.

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It could still be wastespark, just from an academic point of view; with one cylinder on a four stroke engine and only a crank sensor to measure piston location...but is it a two stroke engine?

Fisher, not sure but pretty sure is a big 500 4 stroke, but have been wrong before, but yes agree with your view on it.

Sorry guys was out of town for a little bit. I see that you bring up a good point that it could be a waste spark system but the charging system should work the same whether it is or not correct?

It is a single cylinder 500cc 4 stroke polaris engine. The ground wire is burning up on the stator wiring harness like I had mentioned before. I have a theory that the charge coil of the stator is partially grounding and causing current to go straight to ground causing the ground wire to get hot.

Thoughts on this??

Also do you know of a good way to test/prove my theory with the scope? I am all ears as I am still learning how to use this equipment. I am happy to provide any new waveforms you guys request!

Thanks guys!

RedlinePowersports wrote on Mar 7^th, 2017 at 8:23pm:

I have a theory that the charge coil of the stator is partially

Redline, not sure on this but assume ( I know dangerous) when you say charge coil we are talking a capacitor.

Still find it interesting the volt and amp jumps are in correlation to what I feel is firing of the coil. For giggles do another test and run a channel on the igniton could primary and see if the 2 correlate. 

Stitch, I was referring to the stator coil that produces ac voltage to go to the regulator/rectifier.

I suppose anything is possible except the signatures on the ground wire are always @ ground except during these suspicious spikes which seem (not sure) to be tied to ignition firing. 

The stator wires put out a cycling voltage but no where during thier ups and downs of the sine way does this show on the ground.  I was thinking about this and discussed it with another mechanic, ??? does this unit have a CDI.

If so it is triggered by a second winding (on my KlR) much like a CPS which signals the firing of the coil. But my main thought here is the CDI bleeding back ignition signatures into the ground wire one the stator through the CPS.

The only energy that I see on the ground wire that could make it hot is these signatures which seem to (IMO) time with ignition.  Would be curious to see a known good unit. The problem with the motorcycle section is there are very few players but like diesel will be more all the time as you and a few others are the first to by them for motorcycle specific needs.


StitchB

Redline, go to your PM box, left something there for you, might help.

StitchB

Gotcha. Now I see what you are looking at. Yes this is a CDI ignition system. I PM'ed you as well, I will be doing further testing mentioned in the PM and I will keep you all posted. I'll post my findings tomorrow or the next day.

Thanks and talk to you soon!
:D

Stitch, your buddy you PM'ed me was absolutely right. The engine is rubber mounted. The customer had been working on this unit himself and had hooked up the ground wire that would normally go to the engine back to the battery. The ground wire coming off of the battery goes to the frame and then from the frame to the engine. The wire from the frame to the engine is the one that he put back to the battery, thus, causing the engine not be properly grounded.

When cranking the next best ground was the stator ground. With the Pico I was able to prove what was happening. The stator ground had 370 amps running through it on a 14 gauge wire! That's why it was burning up.

I grounded the engine properly and the stator wire now only has a 21 amp draw on it on start up.

Thanks again guys for helping me solve this one!

Way to go Larry(aka StitchB)!  [smiley=thumbsup.gif]

RedlinePowersports wrote on Mar 18^th, 2017 at 3:57pm:

a 21 amp draw on it on start up.

Redline, hope you meant MV and not amps. 

All the credit would have to go too james as he came up with the fix, but who cares...........a win is a win.

As I say, even a blind squirrel finds a nut sometimes ;D :D.

But you are just beginning to see the real value of this tool, it is for when nobody can fix it, and it does take some time.
Have a nice day.

StitchB  AKA Larry

StitchB wrote on Mar 20^th, 2017 at 9:17am:

All the credit would have to go too james as he came up with the fix

That would be our very own James H (CDN EH!)

http://www.autonerdz.com/cgi/yabb2/YaBB.pl?num=1480261201

Great Job  8-)

Mick wrote on Mar 21^st, 2017 at 5:07pm:

That would be our very own James H (CDN EH!)

And the winner isssssssssssssssssss CANADA. I hate it when that happens ;D :D ;)

Yup, same James, and nice enough to take time out of his busy day to research this, a true gentleman.

StitchB  AKA Larry

StitchB wrote on Mar 22^nd, 2017 at 3:59am:

Mick wrote on Mar 21st, 2017 at 5:07pm: That would be our very own James H (CDN EH!) And the winner isssssssssssssssssss CANADA. I hate it when that happens ;D :D ;)

Ahhh, no worries! There are some good guys in Canada. A real good friend of mine is an automotive instructor just outside of Montreal. Was on the phone with him last night for over an hour. 


StitchB wrote on Mar 22^nd, 2017 at 3:59am:

Yup, same James, and nice enough to take time out of his busy day to research this, a true gentleman. StitchB  AKA Larry

Thanks for the input James!   [smiley=thumbsup.gif]

Spence wrote on Mar 22^nd, 2017 at 5:11am:

Was on the phone with him last night for over an hour.

Spence, did not know you could hold a train of thought that long ;D ;D ;D, guess I will have to reevaluate that.

StitchB wrote on Mar 22^nd, 2017 at 3:59am:

And the winner isssssssssssssssssss CANADA. I hate it when that happens

Its not about winners its knowing who is "james"

It seems to get the fingers moving on the key board though EH! :o

StitchB wrote on Mar 22^nd, 2017 at 8:55am:

Spence wrote on Mar 22nd, 2017 at 5:11am: Was on the phone with him last night for over an hour.  Spence, did not know you could hold a train of thought that long ;D ;D ;D, guess I will have to reevaluate that.

I may need you to expand on that... What were we talking about?    :-/

Spence wrote on Mar 22^nd, 2017 at 9:19am:

StitchB wrote on Mar 22nd, 2017 at 8:55am: Spence wrote on Mar 22nd, 2017 at 5:11am: Was on the phone with him last night for over an hour.  Spence, did not know you could hold a train of thought that long ;D ;D ;D, guess I will have to reevaluate that. I may need you to expand on that... What were we talking about?    :-/

Even I got the joke and I am Canadian :o

Mick wrote on Mar 22^nd, 2017 at 12:07pm:

Spence wrote on Mar 22nd, 2017 at 9:19am: StitchB wrote on Mar 22nd, 2017 at 8:55am: Spence wrote on Mar 22nd, 2017 at 5:11am: Was on the phone with him last night for over an hour.  Spence, did not know you could hold a train of thought that long ;D ;D ;D, guess I will have to reevaluate that. I may need you to expand on that... What were we talking about?    :-/ Even I got the joke and I am Canadian :o

Maybe you missed mine...   8-)

Spence wrote on Mar 22^nd, 2017 at 12:37pm:

Mick wrote on Mar 22nd, 2017 at 12:07pm: Spence wrote on Mar 22nd, 2017 at 9:19am: StitchB wrote on Mar 22nd, 2017 at 8:55am: Spence wrote on Mar 22nd, 2017 at 5:11am: Was on the phone with him last night for over an hour.  Spence, did not know you could hold a train of thought that long ;D ;D ;D, guess I will have to reevaluate that. I may need you to expand on that... What were we talking about?    :-/ Even I got the joke and I am Canadian :o Maybe you missed mine...   8-)

You lost me  ::)