Going through a stator every year.

Purchased a 2003 VFR in 2019. I replaced the battery, installed new tires, and road about 4 thousand miles the before I encountered charging problems. Reading through forums I discovered the VFR stator was a common problem. Using that info I tested the R/R it was good, the stator failed so ordered and installed a new one as well as a voltmeter to monitor the charging systems. The new stator charging output was 15.2v at the battery R/R tested good so I finished out the riding season. About four months into the next riding season same charging issue. This time I installed a new OEM stator and R/R, and once again finished the season with no issue. 2021 and the same charging issue with the stator, about 3k into the season, and it's dead. This will be my fourth stator in as many years, has anyone else encountered a similar issue? Going through multiple stators on the same bike?

 

That must be a real pain to have to keep replacing stators. I have only replaced a stator on my Silverwing scooter. That one had an oil-cooling jet through an o-ringed/dowel join on the stator cover. Does the 6th gen engine have something similar and if so is yours blocked? Photo attached shows the inside of the cover with the oil feed and the oil jet circled, the oil jet ends up at 12 o'clock so the oil runs down from the highest point.

Otherwise, maybe you have an intermittent short in the stator wiring but I suppose that has been replaced when you swapped out the old stator and installed the new RR. Good luck with finding a solution.

 

Those old style RRs are rather Brutal on Stators. It accepts the voltage from the Stator Field, until it reaches design voltage, then, to keep the volts below14.4Vdc, it "CrowBars" or Shorts the Stator Field to GND. The excess energy is dumped as heat,,.. heat in the stator and heat in the RR. Maybe even some heat in the wires.
Stator is always running at full output (RPM dependent). Though it does warm the engine up faster.
Some newer models use MOSFETs that do the same thing but generate a little less RR heat.
The right ticket is to install a "Series RR". They use 2 banks of MOSFETs (rather than 1) and Open/Adjust the draw from the Stator.
Only the required power is drawn from the stator, rarely runs at 100% (unless ya gots a ton of accessories).

The 2015 V-Strom 1000 has one, (had one, sold it, too big for me) as do some Polaris Side/Side.
Pricey RRs, but ya might even make some $$$ back on less fuel used (more so on a smaller motor).
I ordered one (KIMPEX 225800), but it came "new defective" (some pins cast in wrong position, would not accept the connector shell), Return'd
It did meter out OK (nothing on any pins, on low ohm scale). But it also means RR was NOT Function Tested after manufacture.
Series RRs run much cooler, as does the stator.
I'm putting one in my 2015 V-Strom 650 ADV (it still came with shunt/short style RR). Stator there is about 400W max.
In colder weather (+2'C last weekend) I use power for Heated Boots, Heated Pants, Heated Jacket & Heated Grips, about 11 amps.
In good weather, and with LED Headlamps (2 amps) I can save maybe 200w,,.. Bike already gets 500km/tank, now even better.

SH775 & SH847 are also Series RRs as is the Polaris 4012941
Kits are available with connectors/harness. https://roadstercycle.com/
I'm building a Test Jig to test ALL RRs (uses a bunch of 100W 0.1 ohm power resistors, a Scope and assorted connectors).
Mid 80s Suzukis were notorious for RRs that shorted internally, then burnt the stators.
Also SOLDER all the brass connector/wire Crimps, from Stator to RR, they corrode over time, problem is worse with older bikes (copper strands corrode).
Actually, if its a heavier wire, anywhere, Solder those connectors too.
Fix'd a bunch of these connectors, will be doing another in a few weeks.

 

I can only speculate the first stator went due to the regulator, a charging voltage of 15.2 is very high and an indication the R/R is not functioning properly. Re-using it likely cause the second stator failure, etc. All I can recommend in addition to using a mofset R/R is to install a voltmeter so you can see when charging voltage exceeds ~14.5 or is excessively low.

 

Hi Robert and welcome to the Madhouse.

When you get time please visit the introductions part of the forum and say Hi to the rest of the folks on here.

It really sounds like the stators are being wrecked by a faulty RR. 15+ volts is too high!!!!!

You are not alone - as there is an enormous thread on charging system issues which affect so many 5th and 6th gen models. ..

https://vfrworld.com/threads/how-to-fix-common-regulator-stator-failures.39277/

The heart of this is if you want a reliable option go for one of the Shindengen series RRs like the SH847 - they run cool and do not over stress the stator.

Good luck let us know how you get on.

SkiMad

 

Thanks for the feedback. Question about the charging voltage. My Honda manual states the charging voltage at 5000 rpm with the high beams on should be 15.5v. What are you seeing for charging voltages at that rpm?

 

interesting. let's wait to see what GRUM has to say.....................

 

I can only go by my own experience, for many years and well over 200,000km my 6th gen sat happily between 13.5 and 14.5 volts, except for a few seconds just after start up. I realise those numbers were based on a cheapo Chinese voltmeter which I had wired onto an ignition on circuit so they might have been higher.

As for information in the Honda manual it is important to realise that, that is simply a permissible range and your RR should only operate briefly in the highest output range straight after the engine is started, so that it rapidly replaces the energy drained from the battery during start-up, but after that the output voltage should drop down - typically to numbers in the above range - on mine it was a pretty constant 14.3 volts .

(By way of comparison on my 6th Gen the highest number I ever saw was 14.8volts straight after starting up the engine which is why 15+ volts looks like a warning sign).

If your RR is operating continuously at 15+ volts it either implies there is a short in the system or the battery is struggling or the RR poses a risk to voltage sensitive components which may result in bulbs failing prematurely and you may end up buying yet more stators.

OK that is my just 2p but perhaps you might want to see what a RR & stator manufacturer says :

https://ricksmotorsportelectrics.com/blog/how-to-test-a-motorcycle-rectifier/

Take care

Skimad

 

Thanks, Skidmad for the info.