Burnt Stators

[gti20vturbo]

How many burnt stators have we had on this board or have you heard of any from owners not on this board? Is Kawasaki helping at all in regard to warranty? Did you have any warning signs of the issue?

[hikewithmike]

I had no warning signs other than intermittent electronic failure--the Stator or Regulator being the cause of it. The only thing you can do is periodically check voltages on the battery, espcially while it is running.

[kiwi 41]

Is there a faulty R/R on these machines, would be interested to know what year the stators are failing and did they all come from the same factory?

[invader]

The regulator/rectifier part # change to 21066-0705 (replaces 21066-1127) is listed for all model years. No idea if and how it's any different.
The regulator/rectifier firstly rectifies the AC coming from the stator back to pulsating DC using a set of Diodes (allows current to flow in one direction). The rectifier then limits this voltage from the 50-60V pulsating DC by "wasting" power using zener diodes. More current draw after the reg/rec increases current flowing in the windings of the stator, which will increase the temperature of the stator and the reg/rec as well.
Stator failing from burnt shorted winding wires is primarily caused by heat, mostly with stock shunt type R/R in favor of a more expensive series type R/R, and vibration damage to the winding wires' thin varnish insulation... Engine oil does provide some cooling to the stator. Oil temperature is a bit lower with synthetic oil, and also provides more cooling to the stator when kept at the full mark.

[kiwi 41]

Thanks Invader, I am learning all the time, keep oil up to full mark and synthetic oil will reduce risk of stator failure. A R/R failure increases current which increases temp of stator which can result in a BBQ stator. Just repeating what you said so i get it through my Kiwi brain

[invader]

Originally Posted by kiwi 41

A R/R failure increases current which increases temp of stator which can result in a BBQ stator.

I never said that... More current draw after the reg/rec increases current flowing in the windings of the stator, which will increase the temperature of the stator and the reg/rec as well.
In other words, as you increase current draw to power lights, heated gear, and electric powered accessories, current flowing in the windings of the stator increases thus raising its (and the R/R) operating temperature.

EDIT: With stock shunt type R/R, stator is always operating at maximum output and shunting any unused current to ground... Compu-Fire's series type R/R #55402 draws no more current than neccesary from the stator, thus reducing its load and operating temperature... More info further in this thread in post #13+.

[kiwi 41]

Okay and you will forgive me as trying to get my head around this stuff. If The R/R does fail my lights will get very bright and eventually cook stator

[invader]

The regulator is protecting your bulbs, etc from overload. Bulbs would burn out and stop drawing current before stator overheats... A sound battery with a high cold cranking amp rating kept well charged up with a battery tender reduces load on the stator which has to recharge the battery after operating starter. Stators run cooler with a sound and well charged battery, and also from less current drawn. If the battery is not building up normal resistance as it accepts a charge, the generator keeps charging battery at higher than normal rate. Stator then overheats and eventually fails. Battery charging current should gradually decrease and taper off to acceptable level after engine starts.

Stator failures from winding wires shorting out on the core through their insulation are caused by a combination of age, heat and vibration.

[invader]

The regulator/rectifier connectors can oxidize and corrode from water and salt exposure. Keep the connectors clean and protected with dielectric compound/grease. A rear wheel hugger or mud flap/splash guard also helps. R/R should also be well vented for cooling.

Batteries degrade from sulphation buildup on the lead plates, as sulphur seperates from water upon discharge. Lead-acid batteries discharge more quickly when warm and in higher ambient temperatures. Keeping it fully charged without overcharging it maintains its efficiency while extending service life.

[invader]

The Versys isn't bad compared to many Honda CBR's and Ducati's stator for example. Some burn out a couple stators per season, having to replace it at every couple thousand miles.

[kiwi 41]

By good maintenance such as keeping engine oil full, keeping R/R clean and well vented, looking after our battery and replacing a battery that is failing before it puts to much load on system we can minimise stator failure.

[CanadianFZ6]

I will eventually be replacing my stock R/R with a Shindengen Mosfet from these guys http://roadstercycle.com/index.html
The advantages of the Mosfet is that runs cooler (so that means it can be located just about anywhere on the bike) and if it does over heat, it just shuts down until it cools... It also provides a more consistant voltage across the batter terminals especially at low rpms....

I had one on my V-strom and it work flawlessly...

Richard

[invader]

Actually, a series type R/R does not require the stator to flow as much current, and has 1/3 of the power dissipation compared to shunt type (like OE or MOSFET based) R/R.

http://www.posplayr.100megsfree3.com...R_Tutorial.pdf

Cooler running stator: http://badweatherbikers.com/buell/me...tml?1312566505

Lowest price I found for a Compu-Fire 55402 R/R (40 Amp 3-stage charging system):

http://www.powersportparts.net/Compu.../tr60-3337.htm

http://www.debrix.com/Voltage-Regula...f55402-mca.htm

[twowheeladdict]

This is the first I have heard about it and have been on the Ninja 650 forums since '07. There are several guys with '06 -'08 bikes with over 30,000 miles and one guy just reported 70,000 miles without any major issues.

[miguelito]

I was going to post about this myself. I'd be curious as to what mileage the bikes were at when the stator failed as well. The people on the board who I know of who have replaced their stators are: 1. Myself at about 44k miles. 2. Steve Harrison at about 34k miles, (I think), and 3. Gary, (aka DBD34), AT SOME UNKNOWN MILEAGE.

Anyone else here who's had their stator fail, please chime in with the approximate mileage when it went out. thnx.

[invader]

The fried stator is also caused by a combination of a change in the strength of magnets used in the flywheels. 98-03 Aprilia's rarely if ever burn out their stators like this. The problem started occurring with 2004 and up models. Denso, the supplier of the flywheels, increased the power of the permanent magnets when the flywheel was redesigned in 2004. The increased magnetic flux creates more power in the stator windings compared to the previous rotor on the 98-03 RSV and 02-05 Tuono. They also had some flywheels with varying magnet strengths at different points which pulsed the stator causing excessive heat cycles.

The stock R/R on all years is a shunt type that grounds excess power, essentially creating a dead short, keeping the stator at full load at all times. This excess power being shunted to earth is dissipated as heat in the windings of the rotor, and to a lessor extent in the control circuitry of the R/R. The extra power of the newer flywheel creates enough extra heat in the stator to cause it to burn up over time. Denso also supplied flywheels to Honda and other Japanese (Kawasaki), some claim with out mentioning that the magnets were stronger. When Honda started getting burnt stators, they traced the problem back to the flywheels and issued a recall and refitted the affected bikes with a flywheel of lessor magnetic power. Aprilia has chosen to ignore the issue, perhaps because this does not usually occur until after the warranty has expired. One possible solution is to replace the R/R with a series type unit. Series R/Rs open the charging circuit to deal excess power taking load off the stator instead of shunting excess power to earth and fully loading the stator at all times. Opening the circuit and taking load off the stator reduces the heat produced prolong the life of the stator.

One of the common upgrades that you see on 98-03 Aprilias is using a Shindengen MOSFET R/R as an upgrade to the original SCR shunt R/R. While more efficient because it is MOSFET instead of SCR, the Shindengen R/R is still a shunt type (not a series) and still dumps all excess power to ground. Since it is more efficient than the SCR type and does not get as hot, that much more heat needs to be dissipated by the stator.

http://www.vfrdiscussion.com/forum/i...ies-regulator/

[DBD34]

Michael, My stator was history at 27,000 miles, I did not replace the regulator, still running the original with 57,000 miles on the Versys. Invader, great posts as usual, is it possible that the lack of an oil cooler contributes to the stator problems? I was riding hard in hot weather, anyone else?

Gary

[invader]

Originally Posted by DBD34

Michael, My stator was history at 27,000 miles, I did not replace the regulator, still running the original with 57,000 miles on the Versys. Invader, great posts as usual, is it possible that the lack of an oil cooler contributes to the stator problems? I was riding hard in hot weather, anyone else?

Gary

I don't think we need an oil cooler. A normal operating oil temperature of at least 212F is already hard to achieve without ThermoBob's radiator bypass... Are you running any additional electrical accessories, and are you still on original battery?
I really like the series type R/R to reduce current draw on stator and effectively lower its heat output, while wasting less engine power.

[miguelito]

Originally Posted by DBD34

Michael, My stator was history at 27,000 miles, I did not replace the regulator, still running the original with 57,000 miles on the Versys. Invader, great posts as usual, is it possible that the lack of an oil cooler contributes to the stator problems? I was riding hard in hot weather, anyone else?

Gary

FWIW, I was riding pretty hard in hot weather a lot of the time. I also have not replaced any other parts of the system, and actually had the stator re-wrapped rather than replacing it with a new one. I've traveled about 7k miles since the repair without any issues.

Originally Posted by invader

Are you running any additional electrical accessories, and are you still on original battery?
I really like the series type R/R to reduce current draw on stator and effectively lower its heat output, while wasting less engine power.

I'm not running any electrical accessories, (all stock electrical system).

[hikewithmike]

Originally Posted by DBD34

Michael, My stator was history at 27,000 miles, I did not replace the regulator, still running the original with 57,000 miles on the Versys. Invader, great posts as usual, is it possible that the lack of an oil cooler contributes to the stator problems? I was riding hard in hot weather, anyone else?

Gary

Mine went toast at about 33,000 miles. I am half speculating it is the heated grips I had installed with a new handlebar. The controller is acting correctly, it should allow me to select up and down temperatures, but I have to cycle all the way up, if I want anything down I have to turn them off and then back on. The indication LEDs only work for one temperature also. Don't get it, last set of Oxfords were rock solid. I suppose I should see what the warranty is on them now that I have a couple weeks of idle time.

Sorry, bit of topic, but yea, mine got mildly fried and went caput at 33k.