So I soldered the stator

[mh]

Last year I melted my stator, and in fact, the connector had also melted and shorted two of the stator wires together.  So, following the advice around here, I soldered the wires together when I replaced the stator.

Fast forward to a night a month ago- I'm sitting at a signal about ten minutes away from where I started the bike.  It's a cool evening, the air is fresh, except for this smell of something ionized.  "Hmm, it almost smells like something electrical is burning...  Damn," I think, "those sprinklers can't have gotten things that wet, could they?"  Well, it turns out that the instrument light bulb I just replaced a few months ago had blown out again when I wasn't paying attention.  I was hoping that was the casue of the thing I smelled.  Actually, I was wishing it was just coming from a car near me.

But no, a couple of weeks ago, I was changing my oil and decided to put a little more Yamabond on my left engine cover since I was guessing that's where my oil leak was coming from.  No, it looked all right (but I messed up my gasket, damn.)  But I also noticed a very charred bit of insulation on the stator, right on a corner where the wire bends into the mass of windings.  In fact, a lot of the insulation looked a bit darker than the fresh blue color that stator had when I bought it.  Maybe that was due to the oil.

But the charred bit was pretty definite- a bit brittle and it scraped off easily enough- actually a charred blister with the bare wire right underneath it.

This leads me to believe that there was something causing a short from the charred stator wire to either another stator wire, ground or the battery.  This makes the regulator and the wiring prime suspects in all these cases.  Looking at the symptom (melted insulation), I would almost be tempted to put some sort of self-resetting circuit breaker on each of the stator lines to prevent such a burnout in the future.

Thinking it through and checking that the wiring is not at fault (shorting somewhere), I'd assume that the regulator is the problem and replace that (finances permitting- I may just start from scratch, the 2003 SV650 is now fuel injected.  *sigh* no more carb problems....)

Interestingly, my battery still charges, so I may have been lucky enough that the insulation only melted in one spot and did not short one stator wire to another (or ground), or I may just be getting by on only two stator windings.

The moral of the story is that the failure of a stator is just one symptom of a problem.  Replacing the stator and soldering the connection isn't going to fix the problem, it's just going to delay recurrence of the same or worse symptoms if the problem becomes big enough.  To fix the root cause of the problem, you're going to have to fix whatever is pushing too much current into the stator windings causing them to overheat, which I think is the regulator.

[Lucky]

Initaly the thinking here was that corroded connections in the stator-R/R caused the stator to burn up, and this is still true, but, and like mine, this is a BIG BUT, it must be kept in mind that these bikes are now 20 years old, and the regulators are now failing due to age.  I've always advised that BOTH the R/R connections should be cut & soldered.  Recently I've amended this to 'the system should be TESTED first, THEN the connections soldered', I plan to make these changes on my website as well.
--Lucky

[mh]

Lucky,

I still don't buy the line about the corroded connection causing the stator to melt.  As I mentioned before, the corrosion increases the resistance, which for a given voltage, decreases the current flowing through the wire (I=V/R).  Putting a power resistor in line with one of the stator windings isn't going to burn out the stator, it's just going to cause your battery to charge slower.  The only way to burn out the stator wire is to pump too much current through it and overheat the wire.  You can do that either by increasing V (higher RPM) or decreasing R (cause a short).

So, it's either too high RPM creating too high voltage (but you'd hope the stator was designed for your speeds), a short in the wiring, or a fault/short in the regulator/rectifier.

Okay, the corrosion may contribute to the problem in a different way.

The connector may be vibrating around, intermittently opening and shorting the line at a high frequency or the connection may have so much corrosion on it that it's normally an open circuit until the voltage across the wires is high enough to cause a spark to arc across, again at a high frequency (sort of like the lightning sparks you can get with a Van de Graff generator but at a lot higher frequency since the air gap is so much smaller).

Making and breaking the connection, or switching instantaneously from zero volts to, say, minus 50 volts, is a bit hard on a rectifier- it's designed more for a smoothly oscillating sine wave.  Once the diodes start getting instantaneous voltage swings, who knows what they'll do.  Maybe they'll let a bit of current through in the wrong direction and short a couple of stator windings together.

Yes, the diodes could degrade with age- accelerated by the high frequency noise they see- and cause more problems the older the bike is.  

But the point I'm trying to make here is that the R/R is, and has always been, the cause of the stator burning out.

All the other culprits are contributory: high ambient temperature is not a conclusively proven cause, it just means that the temporarily-shorted (read: hot) stator wires have less air cooling, but the short has already occurred, now you're just trying to pull heat away from the wire to keep the insulation from completely burning away.  It might actually be the elevated temperature of the R/R that's contributing to the shorting.

Interestingly, one common fix for the Honda VFR's notorious R/R problem is to put a bigger heat sink on it- and keep the connections clean.

Okay, it's actually more of an overall system problem- bad connections, heat and age all help contribute to the intermitent failure of the R/R.  The problem is that the R/R isn't permanantly damaged, it's only in operation and not during a static (DC) test that this failure mode occurs and takes out the stator.

[George R. Young]

With an alternator, the open-circuit voltage goes up as RPM and the inductive impedance goes up as RPM (i.e. frequency) so the thing acts, to a first approximation, as a current source. It puts out 20 or so amps AC into the bike/regulator load, or into a short circuit just as happily.

So, I agree stator failure isn't caused by connector corrosion, I've had 3 stators die independently of the recent connector death. And I don't think the regulator causes the problem, as shorting the AC output doesn't really harm anything.

I think the stator is underdesigned from the thermal viewpoint and its normal current output and the resulting high temperature eventually causes insulation breakdown.

[Dan_Byers]

Please please everyone read my reply and LISTEN WELL.
 The last time my stator fried I replaced it with an Electrex model, and ALSO replaced the R/R with an Electrex model as well. Also make note that I ran a sep. ground wire as per Electrex's instructions. Also note that I soldered the stator wires directly, eliminating the supposedly problematic connector. After the fix, everything was great and charging was right around 14V. Early this riding season, after slowly allowing my confidence level in my V to return to full strength, the V died. Dead battery (btw, the battery as near-new and tests fine)...NOMINAL charging (if revved up it slowly climbs to about 13V)...now my confidence in my V is shot. My wallet, even if fat enough to justify another Stator, say forget it. Whatever causes the overheating/fried stator syndrome, NONE of you has hit the nail on the HEAD. I love you guys for all you've done, but I don't think any of you has done more than solve a little piece of the puzzle. It isn't the connector. it isn't the R/R. It isn't the stator itself. (btw, for those asking, my bike's running temp was fine) What it is, or what combination of things it is, I wish I knew.
Now the V sits next to my bassboat in the garage, silently mocking me everytime I see it. Such a shame.

Dan

[Lucky]

Dan,
The Question begs to be asked: What failed? did you retest it? You could have a bad part from Electrex.  I had to return a R/R to them, it failed and the bottom was all melted out.  as with any electrical part shit happens.  in the case of the r/r I just returned it to them and they exchanged it. it was 13 months old (their warrenty is one year) no questions asked.  my faith in electrex or my vision is not shaken.

My point is this:  the connectors on these bikes corrode with age.  corrosion causes resistance which = heat. causing heated & burned wires and melted connectors.

No one said this is the main cause of the problem, only a common one we have identified.  It's entirely possible you have a poor connection in the key switch or somewhere else along the supply path.  have you checked all that as Electrex reccomends?

Some food for thought.
--Lucky

[QQBS]

An open question.  If you take a piece of rectangular iron and wrap copper wire around it and then quickly and repeatedly pass a permanent magnet by it in close proximity, what will be the result?

[Ken_Williams]

I am sorry to hear that your charging system has gone bad again mh.  Your second occurrence of the failure in such a short time is worse than most of us experience.  Replacing stator and regulator certainly eliminates the vast majority of charging problems existing on the typical Vision.  Assuming you don?t find some chafed insulation, my best guess is that you have experienced an infant mortality problem.  Even the best manufacturers of electronics will ship some percentage of product that fails after a short time in service.  I also noted your idea of inserting circuit breakers in the stator to regulator wires.  I agree this is a good idea.  In the event of a stator short to ground, a large current is likely to flow between the regulator and ground.  This large current can damage the regulator.  Circuit breakers or fuses would keep a shorted stator from damaging a regulator.  Those who eliminate the stator to regulator connector probably increase their chance of regulator damage in the event of a stator short.

I believe, as George Young states, the cause of most stator failures is a lack of robust stator design.  The combination of high temperature at normal current output and likely the deteriorating effects of the oil bath, eventually causes insulation breakdown.  The last sentence was a lightly modified version of a sentence in George?s post.  As George states, the first order approximation of the stator is a current source.  This approximation should be good through the normal operation region of 12-14volts.  I must point out though; this approximation has limitations at the extremes.  I have not shorted my stator wires with the engine running.  However, if I did, I would expect stator winding overheating and damage from the excessive current flow that would result.  

[Rick G]

Hi All,  The Yamaha Venture and the V-max , both had stator problems early on, Yamaha tried the oil spray thing probably because it was cheap) but that did not solve the problem either. eventually they started using wire with a higher grade of insulation ( read, more expensive) to solve the problem. This makes me wonder  what grade of wire Eletrex stators  use , we occasionally hear of a failure on them . what about Rick's stators, anyone have any experence with them? For me the answer is to rewind my own with wire with the  highest  rated  insulation I can get. maybe it will solve the problem, if not at least I can afford "roll my own"
My  V had recieved a new staytor shortly before I bought it, and I have put 15000 miles on it ,  so  far so good. I wish every one had recieved the same reliability, I have gotten from this old bike.  I've done a fair amount of prevenative stuff, but I think I been lucky. (maybe in another life, Pete. LOL )

[slower]

WHAT about the CONNECTOR BEHIND the REGULATOR? going to the BATTERY? could I solder that one as well? would it make my v charge any better.. how do I find out WHERE to put those EXTRA GROUND WIRES on... I am getting about 12 barely above the peg up on the meter... it  ain't chargin the batt.. I have to charge the batt every time I get on it..  I take a chargin' box with me in a back pack and when I get off  the bike I unhook and charge the batt up.. when I leave I wait a few minutes for the bat to STOP COOKIN'.. It cranks right up...I push it less that way... 8)

[George R. Young]

I like the idea above regarding high temperature wire, see
http://www.mwswire.com/inschar.htm for insulation characteristics.

Also, suzuki has some documentation on howto rewind, see
http://www.suzukicavalcade.com/Maintenance/stator.htm

So when my next one fries, I'll be skinning my knuckles winding the high temperature wire.

[Lucky]

Your probably past just replacing the connectors.., but yes, eliminating both connectors on the r/r is the reccomended procedure.

before you do that though, you must test both the r/r and the stator per Electrex's flowchart.  if by some chance they both prove out good then follow the advice and procedures in the rest of the flowchart concerning supply wires, switches, connections and grounds.

then, after replacing parts and/or repairs are made RETEST EVERYTHING.  too often we have been finding a fault, correcting it, and going on our merry way without bothering to retest the system for additional or "hidden" problems.

the additional grounds reccomended are from the r/r mounting bolt to frame or battery. also be sure the harness ground located on the left ignition coil mopunting bolt is clean, as well as the battery ground wire.

remember, your bike and all the electrical connections on it are 20 years old, so you will have some resistance at every connection on the bike.  the more resistance, the more strain on the charging system.  make EVERY connection on the bike clean, shiny and tight, and you will be well rewarded with a trouble free system.

[Cdnlouie]

I have recently replaced my stator with one of Rick's units. ?I am still using the R/R that does not pass the Electrex tests (at least with my Radioshack 1.5volt diode tester) and the jury still seems to be in deliberation about this issue. ?I've got about 700km of trouble free charging so far this year.

I concur with the combined list of stator hazards agreed upon by most:

Age - Corrosion - Heat all combine to threaten the life or reliability of the stator.

My most recent thoughts gravitate toward the R/R heat issue. ?I believe that one could install one of those fancy little CPU fans on my rectifier to improve idling cooling. You know that you can burn your hands on this unit worst than the engine ?:o. ?This has to be the place where heat is going to affect its performance and who knows how many more years we will keep throwing something at the wall on this issue and something may stick.

The R/R is placed in the worst possible location for cooling. ?Closed space (almost) and additionnal radiant heating from rear exhaust. ?I would think that a heat shield would also be a great addition in this compartment.

All the heat in the wrong places Eh!

Louie

P.S. Bad News! Watch the rear exhaust some guys have shorted out their stator by not ensuring the conector and wires are properly stowed away from it.  :(

[Rick G]

Hi Louie,   I moved my reg/rect from that hot box behind the battery, to the location under the t stem  ( Truimph located thier zener diode and heat sink in the air stream in that same location.
I wonder if  installing a gutted heat sink from a bad R/R )with some heat sink compound  between them ( on the back of the R/R heat sink would help? amy be I'll temp readings on my heat sink, wil some one take readings on one in the stock location, You will need  a digital themometer like HVAC tech's use, there about 10.00 .

[Mark LeBlanc]

I've owned a Vision since 1984, now on my second one, bought the day Earnhart died, with 34,000 miles.  Did anyone think of replacing connections, using dielectric silicone/grease?
I had a friend give me electrical connectors used by Catepillar, (very well sealed/watertight) and will use the grease on them.  I also plan on soldering the connections from the stator.  I've been blessed, never had stator problems on either, but listening to you guys has me paranoid.  The heat on the r/r sounds familiar, same problems exist on computers (more my speciality).  Cooling seems the way to go.  Thanks for your imput.

Mark