how many agree that stator failure is caused by vibration ?

[rm97]

  I'd bet that  finning the whole case, would make a big difference.  Just think how important the finns on the r/r are.

That is basically what I'm going to try. I plan to cast an aluminum circle with fins, to completely cover the circular area on the stator cover. The fins will bolt on where the cover that says Yamaha on it usually does. I'm also going to try to get the fins to conform to the curvature of the cover, and maybe I will even use some of that heat conductive grease suggested. Since I'm not worried about my foot having to fit next to, or behind the cover, the fins can be about as big as I want them to be.

[Walt_M.]

Why didn't Yamaha improve the insulation heat risistance? They did! Read my first post on this.

[George R. Young]

Why didn't Yamaha improve the insulation heat resistance? They did! Read my first post on this.

I bought a stock Yamaha replacement stator in '89 and '94 and they both failed, so it does not appear there was any better heat resistance in later parts. Mine failed like clockwork, every 25000 km, 5 years.

[YellowJacket!]

Most of my driving has been "around town" at less than 60mph for short distances and a lot of sitting at traffic lights.  I have a digital thermostat and rarely get dangerously hot.  I'll occasionally get out and do some longer riding with highway but that has been rare since I started my clinical rotations.

I also use the sidestand almost exclusively lately.

A lot of the talk begs the question, "what causes the heat buildup?"  Is it the stator internally overheating and the epoxy breaking down causing a short?  Is it poor heat dissipation of the Vision motor causing the stator to overheat which in turn causes the breakdown?  A combination of the two?  The list goes on....

What would be interesting would be for one of the guys with chronic stator problems to periodically remove the side cover and look at the stator to see what kind of condition its in.... time consuming, yes... either that or sombody CNC an acrylic sidecover so we can look at our stators and see whats going on.

David

[Rikugun]

I bought a stock Yamaha replacement stator in '89 and '94 and they both failed, so it does not appear there was any better heat resistance in later parts. Mine failed like clockwork, every 25000 km, 5 years.

Did you re-use the same R/R both times?

[Kenny]

 I have 106,000 klm on our 83 with the same stator,most of my driving is crossing North America, on the earlier 82 Hannigan Faired Vision I had 78,000 klm with three stator failures -this was a mixture of long distance and stop and go traffic.
   Other than soldering all charging related wire connections, my biggest change is Synthetic oil.  I have a laser thermometer and pointing it at the engine stator cover I have noticed a temperature reduction of 8 to 12 degrees.
   Interesting thoughts about vibration but I would discount it unless the stator mount Hdw was loose,old chev engines had a form of scoop on each rod cap which flung oil around the crankshaaft area for lubrication.A friend of mine rebuilt one in the late 50's and didn't install them .... Seized solid !!
     My thoughts
         Cheers Ken S.   

[Rick G]

That was Chevy;s old "dipper rod 6 . If the oil was bit low and you hot rodded it around right hand corners, all the oil would be thrown up  the  side of the block and starve it for oil, then BANG went a rod or two.

[jefferson]

Hey Kenny,

Any chance you spectated at the WSB races at Brainerd back when they ran there. That was the only place I ever saw a Vision with a Hannigan on it. Was it yours?

Jeff

[George R. Young]

I bought a stock Yamaha replacement stator in '89 and '94 and they both failed, so it does not appear there was any better heat resistance in later parts. Mine failed like clockwork, every 25000 km, 5 years.

Did you re-use the same R/R both times?

Yes and it worked fine. The stator is approximately a constant current device. The purpose of the R/R is to change from AC to DC and to dissipate the excess current produced by the stator as heat. The R/R in my bike delivered DC and limited the output voltage to about 14.5 volts to keep the battery happy.

The fundamental problem is that with this R/R design, the stator is delivering full output all the time, heating the wire insulation to crispy, with resultant insulation failure.

I can think of two ways around this.
1) Different R/R design which only draws current from the stator as needed. Haven't seen one like this for the Vision yet. I have this type of operation on my Concours, and had it on my Yamaha RD350, and Bridgestone 350GTR, because they have excited field alternators instead of the permanent magnet/full output all the time kind in the Vision.
2) Stator rewind with teflon insulation, the stator still puts out full current all the time, the wire still gets hot, but the insulation doesn't break down. Haven't seen this either.

[Rick G]

There are two problems with excited field  charging systems,  #1 is cost , its a much more expensive system. #2 room , its a much larger system  and would result in a very large laft hand case . If it were mounted on the top of the trans , behind the cylinders there might be room.  Its a dry system as far as I have seen , IE, does not run in an oil bath.

[admin]

ok, well at this point it seems our main goal is to eliminate or reduce the amount of time
and money that we need to spend on the charging system, period.

while we don't have 100% definitive answers on why the failures happen so often on many if not most of our bikes,
we do know that there are tens of thousands of other bikes that use this charging system.
let me repeat that, tens of thousands of other bikes use this charging system. 
we know they all also have various problems whether it is the stator, the reg-rec or the melting plug syndrome,
they are all having issues.


What we need to do is come up with a list of the steps that should keep the problems to a minimum.

1.  make sure your battery is in tip-top shape, replace it every 3-4 years.
      the reality is that this may be the elephant in the room.
2. pitch the stock regulator and put a larger, heavier duty unit, ie newer style mosfet.         
      on a side note: has anyone looked closely at the stock regulator harness ? 
      are those wires aluminum ?
3. ditch the stator plug and solder those wires permanently.
4.  what else...     run a honda stator ?     :'(

comments ?

[Kenny]

  Hi Jeff,
    I haven't been to the races at Brainerd, but had travelled from B.C. to Windsor Ont. once across Canada and the next time across Hwy 2 from Grand Forks to Minot and Colville, somewhere around 83-85 or near that year.
  Hey Ron don't forget about the Synthetic Oil. ;)
          Cheers Ken S. 

[The Prophet of Doom]

Ricks Electrics would agree with you Ron...

"Heat and vibration break down the insulation on the copper wire inside the rotor, resulting in a "short" of the current from one coil to the next.  This prevents the electro-magnetic rotor from providing sufficient magnetic strength to produce a strong charge in the stator.

A failed rotor can also result in a secondary problem.  When the internal "short" occurs, the resistance in the rotor goes down and current flow increases.  This puts a heavy load on the rectifier/regulator and may burn out the regulator unit.  Simply replacing the rectifier/regulator because it looks bad will yield the same results – the bad rotor will continue to burn out new rectifier/regulators.  When the rotor fails, always replace the rectifier/regulator to prevent future problems."

They also note that their rebuilt Honda rotors are the company's biggest seller

[George R. Young]

. . . A failed rotor can also result in a secondary problem.  When the internal "short" occurs, the resistance in the rotor goes down and current flow increases.  This puts a heavy load on the rectifier/regulator and may burn out the regulator unit.  Simply replacing the rectifier/regulator because it looks bad will yield the same results – the bad rotor will continue to burn out new rectifier/regulators.  When the rotor fails, always replace the rectifier/regulator to prevent future problems." . . .

This part gives me problems. The stator puts out a constant current, about 20 Amps. If there is an inter-winding short, some of this current is shunted internally, and LESS is delivered to the regulator/battery/bike load. If the short is from winding to ground, the output current drops drastically.

In neither case would there be additional load or stress on the regulator.

I think this claim is because they are in the business of selling stators AND regulators.

The only way a stator could harm a regulator is if magically all the magnets became stronger and the output increased.

There is no way I know of that a faulty regulator can harm a stator.  If it fails open, the DC voltage would go up and the lights may blow and the battery may boil, but the stator doesn't care. Even if it becomes a short circuit, the stator is quite happy delivering its 20A into a short circuit, but the battery will stop charging and eventually the lights will dim and the bike will stop.

The stator failures and the R/R failures are in my opinion independent.

[fiat-doctor]

George I believe you are right on all counts 
notice however the website refers to rotor not stater they are talking about the type of router that is controlled by the regulator  not the permanent magnet type of rotor if we have 

[Ken Williams]

In a correctly functioning charging system, stator output voltages range from a diode drop below ground to a diode drop above battery voltage.  When a stator winding shorts to ground, stator voltages are directly referenced to ground at the short.  This causes voltages to alternate above and below ground in at least two of the stator output wires.  IF the regulator semiconductors were not adequately specified for the reverse voltage caused by this abnormal operating condition, I believe it would be possible for a shorted to ground stator to damage a regulator. 

[pinholenz]

Last year there was a lot of talk about Mosfet R/R's from R1's and the hope fitting that these would contribute to the longer life of stators. For those who have gone down this route, is there any evidence that there  has there been an improvement or otherwise?

[fret not]

In my correspondence with the fellow (d'Ecosse) who wrote the MOSFET article on the eviltwinsbk site, he stated he had never seen a failed MOSFET RR unit.  I was having difficulty testing the ones I had bought and they didn't pass the test for our original RR units.  I first thought they were no good and contacted him for more information only to learn they don't test the same way.  Actually, I don't know how to test a MOSFET unit other than plugging it in and trying it.  So far all the ones I have had work well.   It seems they are significantly more robust than the silicon gate type that came with our bikes.

The MOSFET units with two 'pig tails' like the original RR unit from the XZ come from Honda CBR600RR '05 and later and CBR1000 '07 and later I think.  There may be some from other makes and models that fit this description but these are the ones I am familiar with.  The pig tail configuration makes the adaptation to the XZ much easier than using some of the many other MOSFET RR units that only have receptacles in them which require you to make up wires and plugs for them.

[Rikugun]

Last year there was a lot of talk about Mosfet R/R's from R1's and the hope fitting that these would contribute to the longer life of stators. For those who have gone down this route, is there any evidence that there  has there been an improvement or otherwise?

When I got my 82 it had 6k miles and a faulty original stator. Around the same I bought a parts bike with 16k and it had a replacement stator that was on it's way to the grave and only lasted several thousand miles. Unfortunately I have no way to know if that replacement was it's first or how many miles were on it.

I replaced the stator with a new one and the R/R with a low miles used MOSFET from a Honda.  The R/R runs relatively cool even mounted in the stock position. The stator is still going strong but I've only accumulated maybe 8k since then. A success to me will be in excess of 50k so I'll keep you posted.  :P  :)

Regarding fret nut's comment regarding lack of failed MOSFET units it will be interesting to see if that changes over time. There are significantly less units in service compared to "conventional" types so the incidence of failure is not surprisingly low.

[mdskinner731]

ok from what i kno...  wire connections corrode under the right conditions. aggreed?? (im going to assume you all agree)
SO with that said... corrosion=resistance; resistance=amp-draw; amp-draw=heat; heat=toasted stator

someone correct me if im wrong.. :o