Can the R/R kill a stator?

[Guest]

I'm going through the stator papers now. I get as far as the measured output voltage on the stator, and one leg never gets above 17VAC (other two legs are above 100VAC). Tests that measure the resistance between legs were all within passing range.

It seems the stator is bad. (Presuming I checked it correctly, that is). Battery never reads more than 12.5V, regardless of RPM (12.25 @ idle, 12.5 @ 5-9K). This battery is a week-old AGM battery at 14AH, so it shouldn't be the problem.

The bike has 5400 miles on it now, and the stator looks great. No sludge, no melted anything...but still has the low output on that one circuit. I plan on checking it again just to be sure.

What could cause failure at such a low mileage? Could the famously poor R/R kill the stator? I bought a Compufire before I had the chance to go through ALL of the stator papers (impatience is my superpower, what's yours?). The implicit follow-up question is, of course: should I keep the Compufire?

(And because it can't be overstated....thanks to the members here that created the stator papers and BassCliff for that huge pile of info)

[mrbill5491]

If one leg on the stator is below what it should it, you have a bad stator and 17 VAC is not good. The other two seem a bit high to me (sounds to me you had a bad stator to begin with.) As for the Compufire, Test it as well. I have a Compufire on my bike and no problems. All I know is, when you work on the charging system, make sure you do all the tests. Me I did the tests and replaced everything new and upgraded to the Compufire with a new stator and battery though your battery should be fine. I also clean and replace any bad connections as well. One other thing, I use 3 grounds on my bike. battery to motor, R/R to frame and/or motor and R/R to battery.

[tom203]

You said resistance between stator leads was OK, but did you check resistance from leads to ground? -should be real, real high. Getting 12.5 volts from idle to > 6k is odd, but could be R/R trying to compensate for bad stator

[saucebox]

Stator leads to ground tested out as OL (over limit, right?....it's a borrowed meter as mine grew legs). I'm thinking that means that that particular measurement passes.

Second trip out to measure output—stator's toast. Still getting really high VAC on two legs, and almost nothing on the third (15-17VAC, depending on RPM).

The next plan is, of course, to go through and follow the wiring advice as far as grounding points, etc., replace the R/R with the Compufire I have on hand, and order a stator. Fix it once, and right...at least that's the hope.

After shirking responsibilities at work (hey, the GS is important!) and reading through a ton of the electrical threads, it seems the consensus is that the Rick's stator is the best. I was going to go ahead and order one, but I can't find anyone that has a Ricks for a 79 750. Is it the same as a 1980 (found tons of those)?

BassCliff mentions in a post (http://www.thegsresources.com/_forum...53&postcount=4) that it might be the same as other models...but it's slightly confusing which years of which models would cross over. Any ideas?

[laxton]

Resistance between the stator legs is hard to check as the difference between good and bad can be as little as an ohm or two. Just replaced mine recently after getting similar output to you. Two were OK and one was very low. BTW mine also looked good when I took it out but all you need is a short between a couple of overheated windings inside and its toast. You can rewind them but I decided not to bother. Got one from atxpowersports. Had to replace the R/R as well as I had been running on two of the three phases for about 15 years without a problem until I installed heated hand grips which pushed it over the edge. The battery decided to quit as well so the $30 I saved on the heated hand grips ended up costing me ~$400.

Phil.

[tom203]

The 79's had a 12 pole stator while the 80's had 18 poles- they aren't interchangeable (unless you switch rotors too )

[gearhead13]

Can the stator AC voltage be too high? I tested mine and was seeing 60vac @ 3k rpm, cant imagine what it would be at 5k+
All other stator tests were normal.

[saucebox]

Can the stator AC voltage be too high? I tested mine and was seeing 60vac @ 3k rpm, cant imagine what it would be at 5k+
All other stator tests were normal.

Didn't think of that. I didn't even check the lower RPMs...too hard to hold the two ends of the meter, the throttle, and try and keep the meter from sliding off the frame/tail.

How important is it to do the stator papers test at the prescribed RPM?

[koolaid_kid]

Extremely important. I use alligator clips to hold my leads. Just a thought, as I seldom grow more than 3-4 hands when testing.

[duaneage]

THe short answer to the posted question is yes and usually. A shorted diode will destroy the stator in short order, and that is quite common. Hot oil eventually wears down the stator's insulation to the point where it fails, that's a consequence of a wet stator design.

[Rich64N]

The short answer to the posted question is yes and usually. A shorted diode will destroy the stator in short order, and that is quite common. Hot oil eventually wears down the stator's insulation to the point where it fails, that's a consequence of a wet stator design.

My R/R failed, killing my stator 2 years ago (plus most of the electrical bulbs including the low-beam H4). I got one of duanage's last Honda R/R's and a Canadian (Quebec) stator.

Since then I've made a spider of grounds out of old auto wiring harnesses. It is overkill but about half the components now have 2 grounds (frame and battery). Electrical issues are our bikes downfall.

[tom203]

THe short answer to the posted question is yes and usually. A shorted diode will destroy the stator in short order, and that is quite common. Hot oil eventually wears down the stator's insulation to the point where it fails, that's a consequence of a wet stator design.

Here's a pic of my recently smoked stator- note that pencil is pointing at area that typically sits in oil. My SH-232 R/R tried to cope but stator output was too low. Switched to another stator and things returned to normal.

[haztoys]

Once a Suzuki stops charging and test show the stator or rec is bad ..Replace the whole works ..And NEVER start a Suzuki with a died or jumper battery ..Ever ....One of the big reasons for died charging systems on bikes ...

Just a mechanic's point of view ...

[saucebox]

Once a Suzuki stops charging and test show the stator or rec is bad ..Replace the whole works ..And NEVER start a Suzuki with a died or jumper battery ..Ever ....One of the big reasons for died charging systems on bikes ...

Just a mechanic's point of view ...

So then part (or most) of the problem in this case is the owner. Since I bought it, it's had little electrical quirks. I knew nothing about the stator papers, didn't look anything up, and replaced the battery (after jumpstarting the old one from....you guessed it...my truck). The replacement battery got me another month and a half of riding, but when the same problems popped up, I finally stopped lurking around here.

At this point, the whole works is on order. I'll go through and make the modifications to the grounding points as prescribed elsewhere, and go ahead and install the new stator (on order) and the Compufire.

Maybe I'll get lucky and get all of this back together and working and still have a couple of warm weeks to ride.

Thanks to everyone that's posted.

[saucebox]

Hate when threads are left unresolved...and still almost forgot my own.

The Rick's stator is working great, and the Compufire has super-stable output.

Hat tip to all who posted. Everything's working great, and all tests pass after taking the advice here and in other threads (clean/consolidate grounds, eliminate stator to headlight switch leg, etc.).