Stator on borrowed time?

[Dostoy320]

Hey guys,

Last spring I tested the voltage on my GS450 at the battery terminals. With the engine @4000K, I was reading over 16v, which I believe indicates a bad R/R, as it shouldn't being sending that much voltage to the battery.

Anyway, I didn't replace the R/R because I was just being stupid and lazy. The bike ran all summer but then an extended ride in the fall managed to boil off all the water from the battery, destroying the battery.

This spring I did the popular upgrade to the SH775 R/R and installed a new battery. I'm reading right around 14v @4000K now, which I think is about right.

My question is, should I replace the stator even though it seems to be working fine? Did that summer of riding with a bad R/R put stress on the stator and make it extremely likely to fail soon?

Thanks

[posplayr]

The old r/r was apparently broke and not regulating which stressed the battery not the stator. However no way to know if the stator was not having an issue without going some tests . Look for revised phase. B tests. Doing the leg to ground.

[Guest]

I did the same thing and now my battery doesn't lose water hardly at all. I've got 13.9V which is my idea of optimum. The SH775 is just a must do mod and way cheaper than boiled batteries and fried stators.

It's not hard to pull the cover off and have a look at it. If it's looking cooked you may be wise to just replace it, but once you have a series regulator the heat will be less and further damage should be avoided. One of the nice things about a 450 is that the oil capacity is huge for the displacement so it runs relatively cool.

To my thinking, the voltage having been way high would indicate the R/R being unsuccessful at dumping excess to the stator thus frying the battery instead. If it's working in spec now, you could probably wait until the winter to pull the cover off - fingers crossed, no guarantee.

[geol]

Unplug the stator from the R/R and start the bike. Put a multimeter set to a lower VAC scale and measure voltage between a & b then a & c then b & c. There is probably a spec on what the voltage is supposed to be but it is likely 35-45 VAC for each test. If that is what you are getting (DO CHECK MANUAL), leave the stator alone. If you are getting significatly less, then stop the bike and you can put the meter in Ohms lowest Ohms scale and check the legs again the same way. You have continuity on any of the checks, stator is fried. I doubt the stator is bad if you are getting 13.7 VDC at higher rpms. That seems to be a bit low but what do I know?

[posplayr]

Unplug the stator from the R/R and start the bike. Put a multimeter set to a lower VAC scale and measure voltage between a & b then a & c then b & c. There is probably a spec on what the voltage is supposed to be but it is likely 35-45 VAC for each test. If that is what you are getting (DO CHECK MANUAL), leave the stator alone. If you are getting significatly less, then stop the bike and you can put the meter in Ohms lowest Ohms scale and check the legs again the same way. You have continuity on any of the checks, stator is fried. I doubt the stator is bad if you are getting 13.7 VDC at higher rpms. That seems to be a bit low but what do I know?

I realize you have been doing this for years and the manuals have been around for years but there are improved methods of checking the stator. Certainly I agree in using a voltmeter and doing leg to leg tests as you describe (80 VAC at 5000 RPM) are part of the standard course.

The best tests however seem to be the Leg to Ground tests which should be 0 VAC.

The ohmmeter tests is worse than useless.

http://www.thegsresources.com/_forum/showthread.php?223164-FIRST-and-SECOND-LAW-of-Stator-testing&highlight=Phase+B+tests

[posplayr]

I did the same thing and now my battery doesn't lose water hardly at all. I've got 13.9V which is my idea of optimum. The SH775 is just a must do mod and way cheaper than boiled batteries and fried stators.

It's not hard to pull the cover off and have a look at it. If it's looking cooked you may be wise to just replace it, but once you have a series regulator the heat will be less and further damage should be avoided. One of the nice things about a 450 is that the oil capacity is huge for the displacement so it runs relatively cool.

To my thinking, the voltage having been way high would indicate the R/R being unsuccessful at dumping excess to the stator thus frying the battery instead. If it's working in spec now, you could probably wait until the winter to pull the cover off - fingers crossed, no guarantee.

Certainly the excess oil capacity might do well to extend the stator life causing the R/R to fry first. With a Shunt R/R the two are pitted against each other with seeing which will fry first from the shorting of the windings. It is usually the stator on most bikes.

[Dostoy320]

Thank you gentlemen. I'll do voltmeter tests now and if the stator holds out until winter, I'll do a visual inspection as part of a long list of work I have planned for this bike for the winter.

[tom203]

Thank you gentlemen. I'll do voltmeter tests now and if the stator holds out until winter, I'll do a visual inspection as part of a long list of work I have planned for this bike for the winter.

For what it's worth.... I upgraded to the SH-775 three years ago using a 33 year old previously used stator- no problem ,good output still. If you get good numbers, you should be fine. Consider mounting an onboard voltmeter to keep you informed- you'll likely get warning signs if stator is suffering.

[Dostoy320]

For what it's worth.... I upgraded to the SH-775 three years ago using a 33 year old previously used stator- no problem ,good output still. If you get good numbers, you should be fine. Consider mounting an onboard voltmeter to keep you informed- you'll likely get warning signs if stator is suffering.

Yeah, the voltmeter addition is something I've been meaning to do to both my bikes... Advance warning is nice....

[Nessism]

I'm going off memory but seem to remember that the 450 is one of the GS models that ground the R/R through the battery box, which also happens to be rubber mounted. The ground path goes through the little tubular metal bushings in the middle of the rubber damping grommets. In other words, it's an epicly crappy grounding method. I strongly advise you 450 guys to review this situation and jumper the ground over to the battery. Once the grounding gets crappy the bike can over charge which can burn out your ignitor. Burned out ignitors are very common on the 450 for the reason mentioned, and since so many have burned up over the years finding a decent replacement ignitor is getting expensive and difficult.

[Dostoy320]

I strongly advise you 450 guys to review this situation and jumper the ground over to the battery. Once the grounding gets crappy the bike can over charge which can burn out your ignitor.

I saw your reply yesterday morning after having to limp the 450 home on 1 cylinder the night before when I lost spark. Given my recent issues (including still having that crappy ground in place) I assumed I had burned out the ignitor. However it turns out it was just a bad spark plug, as the offending plug won't fire on either side but a good one works fine. Whew.... I took the opportunity to run the R/R ground over to the battery though. Thanks for the heads up on that.

BTW, I did the leg-to-ground tests (0 VAC) and leg-to-leg tests (~60VAC @ 4000RPM), so I'm assuming all good with my stator for now.

Again, thanks for the help everyone.

[posplayr]

Dostoy,
Counter to Ed's comments I have never seen any evidence of bad connections ever causing an overvoltage condition. It is possible for bad connections to stress an R/R causing it to fail resulting in over charging, but unless you have a failed R/R you will in all likelihood not ever over charge.

The one exception to this is some of the older single leg SCR SHUNT R/R (e.g. pre 1982 GS750E).