How to tell if your alternator is fried.

[dcstrom]

Short answer: look at it!

Long answer: the first symptom of a problem was a big connector getting hot enough to melt the connector and nearby plastic. I also got a code 46 on the dash at this time (charging system) and ABS fault but they went away and didn't come back. It was the one near the battery carrying power and earth from the regulator to the battery.

We first thought it was a regulator issue, and replaced it (only to later find the original regulator was still good). Then checked fuses, connections, cleaned earths (the cable that overheated was the earth attached to the engine block). We tested the 3 white wires from the alternator to the regulator, but didn't have a multimeter with the degree of accuracy required to check the readings as per the manual. However it was in the ballpark with all 3 reading the same, so though it was probably good. Voltage readings to the battery under different conditions were all correct, and we tried a different battery.

After going through everything the symptom persisted - everything was working fine but the earth wire from the regulator was still getting hot.Stumped, we took it to the dealer, and they did what we should have done much earlier on - pulled the alternator cover. It's obvious that the stator is fried.

Yamaha Germany and the dealer were both fantastic, getting me a part from another bike (no stock in Europe, 3 weeks from Japan), and getting her up and running again within a few days, and for the right price!

This whole thing has been a bit of a hassle, but I should have just given it to Yamaha from day 1. Not bad though, the only real electrical problem in over 120,000 miles. I know some BMW people than have stator problems frequently enough that they carry one in the spares kit!

Full story is over here http://www.yamahasupertenere.com/index.php?topic=20551.0

 

[WJBertrand]

Wow. Any idea what caused it?

 

[Checkswrecks]

Wow. Any idea what caused it?

It's typically breakdown of the varnish used as insulation, with results that look just like Trevor's photos.

 

[arjayes]

Saw that many times with motors and generators as an electrician in the Navy. I've been following your electrical saga, dcstrom. Glad you finally figured in out. And thanks for posting the process here. Definitely adds to the collective knowledge.

 

[Squibb]

We have been having a few summertime overheating R/R issues on the baby UKGSer Forum I also inhabit occasionally (F650GS is my winter hack), so I have been interested in following dcstroms threads.

I always wonder with alternator failures like this, whether they are the primary source of the problem, or secondary. The chicken & egg scenario. I still don't get why that wire from the R/R to ground ran so hot, if the R/R & the other charging circuit wiring were still good. Fuses & battery too. My first guess would be a failing R/R that was allowing too much current to waste, almost a short circuit if you like. Otherwise I have seen ailing batteries work the system too hard, but we normally spot this from seeing the lights flare as the revs increase.

As I understand it the standard reg/rec sees the alternator running at it's full output capability, OK revs dependent, with the R/R wasting away energy that is not required in the form of heat - hence the heat-sink around the R/R. The upgrade most folk turn to when they have R/R issues tends to be the MOSFET but, as I understand it, this merely operates in a more efficient manner, with greater voltage stability, yet still wastes away surplus energy. So both of these work the alternator hard &, I would think, any breakdown in the R/R components could easily lead to a failed alternator if left unchecked.

Some talk of using a Series R/R, which only calls on the alternator when required & sounds more efficient, if expensive. Other talk of it being far from the Holy Grail & prefer MOSFET. Would I be right to assume we are all running the basic R/R as OE on our S10s?

I admit my electronics knowledge is basic, so can anyone enlighten me?

......................... KEN

 

[trainman]

We have been having a few summertime overheating R/R issues on the baby UKGSer Forum I also inhabit occasionally (F650GS is my winter hack), so I have been interested in following dcstroms threads.

I always wonder with alternator failures like this, whether they are the primary source of the problem, or secondary. The chicken & egg scenario. I still don't get why that wire from the R/R to ground ran so hot, if the R/R & the other charging circuit wiring were still good. Fuses & battery too. My first guess would be a failing R/R that was allowing too much current to waste, almost a short circuit if you like. Otherwise I have seen ailing batteries work the system too hard, but we normally spot this from seeing the lights flare as the revs increase.

As I understand it the standard reg/rec sees the alternator running at it's full output capability, OK revs dependent, with the R/R wasting away energy that is not required in the form of heat - hence the heat-sink around the R/R. The upgrade most folk turn to when they have R/R issues tends to be the MOSFET but, as I understand it, this merely operates in a more efficient manner, with greater voltage stability, yet still wastes away surplus energy. So both of these work the alternator hard &, I would think, any breakdown in the R/R components could easily lead to a failed alternator if left unchecked.

Some talk of using a Series R/R, which only calls on the alternator when required & sounds more efficient, if expensive. Other talk of it being far from the Holy Grail & prefer MOSFET. Would I be right to assume we are all running the basic R/R as OE on our S10s?

I admit my electronics knowledge is basic, so can anyone enlighten me?

......................... KEN

I think you have a good theory, earlier in this thread some currents up around 50 or 70 Amps were mentioned, i am not sure if they turned out to be true but if so would be close to or above the alternators 600W rated output, much time at this level would give over heating and no doubt failure at some point.

 

[dcstrom]

I think you have a good theory, earlier in this thread some currents up around 50 or 70 Amps were mentioned, i am not sure if they turned out to be true but if so would be close to or above the alternators 600W rated output, much time at this level would give over heating and no doubt failure at some point.

My friend said he measured 70 amps, I didn't see it - when I tried to measure on my multimeter I found it couldn't handle more than 10 amps haha

 

[greg the pole]

Trevor, did Yamaha tell you what readings came back from the stator?
1-2, 1-3, 2-3?

I'd be interested in what readings it showed compared to the allowable readings

 

[dcstrom]

Trevor, did Yamaha tell you what readings came back from the stator?
1-2, 1-3, 2-3?

I'd be interested in what readings it showed compared to the allowable readings

Greg, no, I don't know if they tested it. I DO know that the most common multimeters don't test to the accuracy required in the manual. The manual quotes .162 ohm, or something like that, and none of the 4 multimeters I had access to would display more than one decimal place. So when they read .2 - I took that as possibly being .162, rounded up It may well have been, but without the right tool I know that is not a good test for a bad alternator... just look at the alternator, it's obvious then!

 

[arjayes]

We have been having a few summertime overheating R/R issues on the baby UKGSer Forum I also inhabit occasionally (F650GS is my winter hack), so I have been interested in following dcstroms threads.

I always wonder with alternator failures like this, whether they are the primary source of the problem, or secondary. The chicken & egg scenario. I still don't get why that wire from the R/R to ground ran so hot, if the R/R & the other charging circuit wiring were still good. Fuses & battery too. My first guess would be a failing R/R that was allowing too much current to waste, almost a short circuit if you like. Otherwise I have seen ailing batteries work the system too hard, but we normally spot this from seeing the lights flare as the revs increase.

As I understand it the standard reg/rec sees the alternator running at it's full output capability, OK revs dependent, with the R/R wasting away energy that is not required in the form of heat - hence the heat-sink around the R/R. The upgrade most folk turn to when they have R/R issues tends to be the MOSFET but, as I understand it, this merely operates in a more efficient manner, with greater voltage stability, yet still wastes away surplus energy. So both of these work the alternator hard &, I would think, any breakdown in the R/R components could easily lead to a failed alternator if left unchecked.

Some talk of using a Series R/R, which only calls on the alternator when required & sounds more efficient, if expensive. Other talk of it being far from the Holy Grail & prefer MOSFET. Would I be right to assume we are all running the basic R/R as OE on our S10s?

I admit my electronics knowledge is basic, so can anyone enlighten me?

......................... KEN

Good questions, Ken. When trying to debug a circuit (or design one for that matter) it's important to remember that current always flows in a loop. DC current will take the path of least resistance. AC current will take the path of least "impedance", which takes into account the effects of capacitance and inductance in addition to DC resistance. In this case my guess is that the stator insulation failed and at least one of the coils was grounded. The current that was being dumped to ground from the R/R had to go somewhere and return back to the R/R. My guess is that path was through ground (the chassis) back through the grounded stator and then back into the R/R.

Trevor - Did you ever measure resistance from the stator to ground with the stator disconnected from the R/R? That should have read basically infinite resistance. If not then the failure was likely a grounded stator. That's my best guess anyway. If the stator had internal shorts (which would result in lower coil resistance) I think the symptoms would have been very different, like lower AC voltage into the R/R, and possibly lower DC output voltage as well. But not massive over-current to ground.

 

[greg the pole]

Greg, no, I don't know if they tested it. I DO know that the most common multimeters don't test to the accuracy required in the manual. The manual quotes .162 ohm, or something like that, and none of the 4 multimeters I had access to would display more than one decimal place. So when they read .2 - I took that as possibly being .162, rounded up It may well have been, but without the right tool I know that is not a good test for a bad alternator... just look at the alternator, it's obvious then!

I do have a high quality meter, but I'm pretty sure I blew up the internal fuse, and it no longer functions properly.
Like I said before, mine was a bitch to take off. Maybe it's getting hot too, and fused to the connector. I'll have to do it all over in the next two months or so when I pull my motor out. I'll attempt to get a reading and even a visual on my stator

glad you got it sorted.
Regarding your voltage, book says 14VDC at 5k rpm. I think if you're within +/- .5VDC you're good to go