Another alternator hits the dust and not under warranty

Yes it is pretty typical to let the engine water warm to something like 185F before the "hot" water is cooled by the radiator.This keep the engine temps up for better consistant combustion and help emission.

I suspect..but do not know...that there is a similar, but smaller, thermostat in the oil gallery that does not let oil into the oil/water heat exchanger until the engine oil is also up to temp.. I would suspect this open at some thing around 225F.

Maybe some one who has access to BMW engine docs could confirm or correct.

Thanks for the additional comments on the stator and alternator. Yes it is my guess/bias that the regulator is the root cause. I'm not disputing the gentleman who makes the statement that regulators seldom fail. His experience is certain at least as valid as mine.

The problem is that I don't think anyone on this blog has really run this problem to ground yet....atleast not that I can wrap my head..sometimes foggy...around.

Still waiting for someone to solve this problem.

Lots or motorcycles have stator failures. I follow the Buell threads, they have the problem.
At first they thought it was the type of oil some users were running. It is well known that at higher temps, GL5 will plate the stator with the phosphorus that is in the oil
I have installed several in Honda street bikes. One thing they all have in common is the type regulator where the stator runs at full output all the time, with the extra voltage going to ground.

I believe it is heat related. I think I read many pages ago Joel saying he thought one thing that contributed to it was lack of oil for cooling.
Not sure I would use a cover that is an isolator. The pipes actually pass under the cover as well as the center case in the same area where the stator is.
I like the idea of taking a piece of sheet metal of some kind and make a heat guard that has an air gap on both sides of it. Weather it mounts to the exhaust or the engine depends on the convenience of mounting locations. This shield would catch a lot of the radiated heat, then be air cooled by the air passing between the pipe and shield as you move.

I am not an engineer, but I did stay at a Holiday Inn Express last night

So, this would go in between the stator and the power leads that go to the rest of the bike? How would this keep the stator from frying exactly?

Here it is on amazon, they might be able to do international shipping: http://www.amazon.com/Compu-Fire-Regulator-3-Phase-Charging-Systems/dp/B0035U7LRM

Here is the ones they are putting on the 3 phase Buell systems.
http://roadstercycle.com/Shindengen FH012AA Regulator upgrade kit.htm
http://www.compufire.com/index.php?option=com_content&view=category&layout=blog&id=2&Itemid=6
(about 1/2 way down the page)

Yes it happened again, the second rebuilt stator experienced that same fault again, one of the phases burned!
And again when I am 1200 km from home base!! At least the LED that I installed warned me with enough time that I could find a hotel.
I will buy a new stator this time, just ordered this one. http://www.electrosport.com/street-bikes/bmw/f650gs/stator-3-phase-102.html
This will take a few weeks to get here and meanwhile I have to ride about 2000 km to get to my place, so I purchased a car battery that I connected in parallel with the bike's battery. Together they gave me like 6 hours of riding today. Found an hotel, and a auto electric shop that will recharge both batteries tonight, so that tomorrow will need to make another 400km and so on for the next 4 days !!! That bike is getting a nightmare. because I also noticed that the valve cover is leaking on the left side, another known issue on these bikes. gee I bought this bike to travel, but wondering now with all these issues!
I don't know what could be the cause of this problem, I guess I will purchase the compufire regulator as well, in case the problem is related to the regulator, I would hate to burn the new stator

Wouldn't a BMW diagnosis using their computer be a lot cheaper than parts replacements to locate the fault?

Fred

There are no fault codes for the stator or regulator. We can see high and low voltage codes, but they don't tell us what is wrong.

BMW has no idea why so many stators are failing on the F800GS. The German colleague I respect the most has no idea whats killing them but thinks it's fairly common on bikes, which it is. The USA guy I respect the most thinks it is duff stators. The USA guy I respect the least thinks it is faulty regulators causing it, which it could be but that same regulator is used on other makes that are NOT seeing high failure rates. I think it is an oiling issue, i.e. the stator is not receiving enough splash oil to cool effectively and I now know there is no nozzle cooling it. ADV community seems to think it is radiant heat from the exhaust.

In short, theres plenty of guessing myself included but no certainty.

The average BMW tech doesn't know an ohm from a watt, though there are exceptions.

I'm sure this will get sorted, and hopefully soon.

My current best hope is that the stator can hold up to the high voltages series regulators create. Hopefully someone takes the plunge and tries one. Unfortunately the only quick news we could get is bad as it will take 50,000 miles to know for sure.

On a positive note, the vast majority of stators are making it at least 30,000 miles :)

The stator pictured is reported to be 20% more powerful than stock yet produces 300 Watts. BMW claims 400 stock. It is listed for the F800 so it should fit the GS. Whats up?

Joel, please could you explain how is the cooling of the stator? there is no oil bath because when you remove the cover, there is very little oil escaping. If not where and how would it return to the carter?

As for the fault, when the technician disassembled the 2nd stator, the one he rewinded, he said the fault was coming from only one phase and he blamed tthe connector between the alternator and the regulator ?!?! This 3rd stator also failed on one phase, I have 2 equal voltages between ground and these 2 phases and a much smaller one between ground and the 3rd phase, sorry i don't remember the numbers. So I would think that in my case the fault doesn't come from radiant heat from the exhaust, because all 3 phases would be affected then.
There is obviously a cooling problem, I am riding 90% of the time in 30-33 degrees temperatures, maybe it was calculated for northern hemisphere weather.

Evidently it is not very cost effective to find the fault changing components, but as the next stator will be the 4th one, if there is indeed a fault in the regulator, i would be very upset to loose that 4th stator. nThat is why I am thinking of buying that compufire one. Are the stators on Harley's so different that they withstand the voltage peaks of a series regulator?

Soon as my f650gs is out of warrantee I am going to switch out the regulator to a compufire.
But heh I got 2 more years till then. Maybe BMW will have a fix before then but not holding my breath.

I recently had my stator rebuilt and the company that did the work also cycle/stress tested the the reg/rect.
They were very amused when I told them I got 70,000km out of the stator, they recommend getting the next rebuild done between 30,000 and 40,000km, rather then waiting for it to die. So next time I do my spark plugs I'll be buying a 2nd stator and then just alternate between both of them.

After wrapping my exhaust the alternator cover temperature went from 230 degrees (not wrapped) to 185 degrees (wrapped) - this was after 100 miles of hard riding. My third stator is holding up pretty well. 1st stator (OME) lasted 50,000 miles, second stator - (OME but re-wound) lasted 200 miles. Now at 53,000 miles and so far so good. We'll see. I think the exhaust wrap will do the trick - and it is a cheap fix. Only another 50,000 miles will tell.

TheCowboy

Tks cowboy. looks like i should go this way as well. How much work did it require to do the wrap, did you have to remove the headers, etc... needed new gaskets? there are all kind of wraps, fiberglass, titanium, etc.. I have no experience whatsoever in exhaust wraps, anyone better than the other?

I wonder what the temp dif of the stator area is is with and without skid plate?

Random comments:

Gary: It might be the RPM at which the aftermarket stator is rated - 3500 RPM.
I would guess that max. output is not until much higher RPM, which is where BMW is getting the 400W max. output.

Cowboy: That sounds encouraging - how did you measure the temperature / temperature difference?

BudMore: Likely it will depend on the skidplate - note that the BMW version has some slots that let air pass thru, while some others do not have any slots. I'm not sure if the BMW design was an intensional addition for stator cooling or not... just my observation ... some skid plates pretty much block all airflow accross the engine covers... this can not be a good thing..........

a 10C degree temperature rise makes things happen roughly twice as fast...
http://www.chemguide.co.uk/physical/basicrates/temperature.html
e.g. insulation likely breaks down twice as fast for every 10 degrees C ..................

If oil were flowing into the stator area life would be much better ... alas, as Joel points out, there does not appear to be any provision for oil to circulate in that stator area ... thus ... it gets pretty damn hot when paired with a regulator design that runs the windings at 100% load.................

IMHO any and all methods that would reduce the average operating temperatue of the stator would pay huge dividends......

I gotta go now.............

I will make a CF/K shield...... It seems like good points have been passed on here.....enough for me to consider that radiant heat is at the very least a catalyst.

Erling

C5!

There is oil injected into the case at 2 points, just none directed directly onto the stator. It is cooled and in my opinion, not very well by splash only.

You will usually loose one coil only in the alternator, even if the problem is caused by external heat. The odds that all 3 phases age and fail at exactly the same time is remote and this particular alternator is wound with good separation between phases. Anyways when a phase finally fails, it does so by shorting at which point it cooks and turns black pretty instantly. At this point it may short to other phases and take them all, or if separation is good enough, only one phase will burn.

Just one phase being burnt is in NO way indicative that the voltage regulator has a problem, nor is it an indication that the voltage regulator doesn't.

Reducing the radiant heat directed at the stator cover can't hurt and should help, but I doubt it will help all that much.

No body is measuring the stators temperature but only the cover temperature and through various means. The stator is mostly hanging inside there and not in particularly good contact with the cover.

What would be REALLY interesting is if someone attached a thermocouple to the stator and read off temperatures. Hell, could add a gauge to the cluster and monitor it full time. "I ride a BMW, stator temperature is more important then coolant or oil pressure lol"

But seriously, I have a cheap digital candy thermometer. The sort u get at a grocery store. As it happens, It dropped into some carmel I was making and while I was tearing apart the kitchen looking for it, my carmel turned into hard candy. While chipping it out of the pan I found my digital candy thermometer but broken in half. The thermocouple, wire and display head all came out and still works. The wires are tiny and would squeeze under the rubber plug on the cover, RTV the junction to the magnet wire, tape the head to the cover and we would have real temperatures.

I.m in St Louis if anyone wants to come by and experiment :)

Did you notice in the link that C5! sent about applications:

BMW Street Bikes
F650 (97-01)
F650CS (02-11)
F650GS (99-11)
F650ST (97-98)
G650X (07-11)
F800S (07-11)
F800ST (07-11)

⇓ SUZUKI Street Bikes
VS700 Intruder (85-87)
VS750GLP Intruder (88-91)

Wonder what the price is for the Suzuki parts :)

Never mind, Bike Bandit, Stator assembly for 1990 VS750GLP = $331.56 but none in stock.

Yes, I had noticed that the F800GS is not listed.

Fred