Another alternator hits the dust and not under warranty

[Toadride]

Well, this one's certainly got my interest peaked. Altho my problems are "apparently" fixed as mine failed around 50000 and just inside of my warranty time. I posted it somewhere but cant remember. Thing is, Rick, my mechanic is an old timer with a lot of previous experience on Ducs and he said stators were always failing back ten or twenty years ago. He had no offering of why the Beemers' are failing but did what they used to do with the Ducatis. Which is, ground the regulator with an extra wire. Said it fixed the Duc problem. Don't know if it's going to fix future failures for me or not and with heat more likely than not seeming to be a contributing factor, I'll be looking into the wrap myself. As for the bashplate being a contributing factor, a big portion of the failures have been S models, haven't they? The road bike? Doesn't have a bash plate does it?

[TheCowboy]

It would be interesting to find out how many of the lower time failures had bash plates installed. My stator did not fail until I had accumulated 50,000 miles. I do not have a bash plate - so unrestricted flow across the pipes.

TheCowboy

[vtbob]

After reading all these posts and looking at a couple of other blogs Aprillia, rotax, Denso. I've come to the opinion...I stess opinion..that ambient engine heat, exhaust headers, skid plates etc have no effect on this failure.

The Aprillia fix seems to be a second ground on the regulator...implying if the regulator ground degraded it cause the stator to over heat.

Some stator failures show only a few coils are over heated, other show the whole stator over heated.

All this seems to indicate an age related failure of the charging system which manifests itself as stator failure.

Sure wish BMW/Rotax/Denso would speak up on this and put the speculation and all the wasted effort to a end.

[Cesar Serpa]

Mine only have 20000km and a stator burned. I don't know wen really happened i bought it two months ago but i can not prove it already damaged but now i need to resolve this problem. I send the stator to rewind but after that i read where i am afraid that will happen again soon :( One thing is true the exhaust pipe near the motor is not good, so i´m thinking to use the heat-shield in the exhaust. JRWodden do you already order it?

[JRWooden]

Originally Posted by Cesar Serpa

Mine only have 20000km and a stator burned. I don't know wen really happened i bought it two months ago but i can not prove it already damaged but now i need to resolve this problem. I send the stator to rewind but after that i read where i am afraid that will happen again soon :( One thing is true the exhaust pipe near the motor is not good, so i´m thinking to use the heat-shield in the exhaust. JRWodden do you already order it?

I have not ordered it yet ... to get the price down I have to order in bulk and need 10 guys or so to make it work...
The kit would be a piece of the insulating material 12" x 3" x 1/4" thick and four "zip ties" made from stainless steel.
Right now I only have 4 guys interested....

Cushman
GB
FredRyder
me

Let me just say going in to this, that I am reasonably sure that the header heat is not the "root cause" of our problem, but the added heat can not be a good thing ... it seems to me that for $20 it's a good idea in any event...

I have two questions for guys with failed stators:

1) were the fried windings at the bottom?

2) have you removed your R/R and inspected for solid (electrical) ground contact?
2b) If you have not done so, would you take a look and tell us what you find?

Thanks,
Jim

[JRWooden]

Originally Posted by vtbob

After reading all these posts and looking at a couple of other blogs Aprillia, rotax, Denso. I've come to the opinion...I stess opinion..that ambient engine heat, exhaust headers, skid plates etc have no effect on this failure.

The Aprillia fix seems to be a second ground on the regulator...implying if the regulator ground degraded it cause the stator to over heat.

Some stator failures show only a few coils are over heated, other show the whole stator over heated.

All this seems to indicate an age related failure of the charging system which manifests itself as stator failure.

Sure wish BMW/Rotax/Denso would speak up on this and put the speculation and all the wasted effort to a end.

VTBob:
I just took my R/R off the bike.... I'm stunned ...........
If there is supposed to be a ground ground connection from the frame of the bike to the regulatore ...
It sucks ... sucks real bad...

Let me count the ways:

1) the heatsink shell of the regulator is anodized (?) or otherwise passivated...
anodizing does not conduct eletricity well, so I hope it's something else...
anyway... it's a less than ideal "contact interface"

2) there are a pair of thick washers between the back of the regulator and the bracket
I'm not sure why they are there ... they are not mentioned in the Rev. 4 BMW manual...
Maybe for better heat disappaiton....
Anyway... add two more contact "interfaces" ... they are steel washers and conduct OK,
but ... add two more "contact interfaces"

3) The screws holding down the R/R + washers do NOT screw into threaded holes in the bracket,
rather there are two tinnerman clips on the backet and the bracket is painted.
No special preparation seems to have been done (masked off spot on bracket ...)
to enhance electrical conductivity... this is a very crappy "contact interface"

4) The bracket is bolted to the frame with two more screws and guess what ....
No special preparation seems to have been done (masked off spot on bracket ...)
to enhance electrical conductivity... this is a very crappy "contact interface"

Are we SURE that grounding is supposed to be done through the frame of the regulator???
Because if it is... well this is a serious issue...........
I'm going to go find the wiring diagram................

[ebrabaek]

[QUOTE=JRWooden;

Are we SURE that grounding is supposed to be done through the frame of the regulator???
Because if it is... well this is a serious issue...........
I'm going to go find the wiring diagram................


3)[/QUOTE]

It should be through the R/R..... with some heat dissipated through it.... Thus the cooling ribs..... There should be a GOOD ground through the R/R......

Erling

[GB]

Use a multimeter from the battery's negative post to the R/R and see if you get a reading or not. If you do, then my guess it's well grounded.. maybe

[JRWooden]

The BMW manual offers no schematic that I can find ...
The Haynes manual has a schematic and it does not call out a ground from the frame of the regulator to the frame of the bike...
it only shows that pin #4 (brown) goes back to the negative terminal of the battery............

I can assure that the ground from the frame of the regulator is crappy.............
but maybe that's because it's not needed?
If it is required ... somebody in Germany needs to be shot... then hung..........

[Toadride]

One thing my mech did stress was the stripping off of the non conducting anodized surface to get a good ground.

[JRWooden]

Originally Posted by Toadride

One thing my mech did stress was the stripping off of the non conducting anodized surface to get a good ground.

I'm wondering if that will do any good or if the case is even bonded to the ground side of the circuitry ???
I reckon I"m going to have to get the ohm-meter out and check continuity from the ground wire to the heatsink...
They sure didn't do anything at the factory to enhance the grounding I can tell you that much..........

[vtbob]

Originally Posted by JRWooden

The BMW manual offers no schematic that I can find ...
The Haynes manual has a schematic and it does not call out a ground from the frame of the regulator to the frame of the bike...
it only shows that pin #4 (brown) goes back to the negative terminal of the battery............

I can assure that the ground from the frame of the regulator is crappy.............
but maybe that's because it's not needed?
If it is required ... somebody in Germany needs to be shot... then hung..........

I also went to the Haynes manual and only found the wiring diagram. It shows two wires going to the battery return. this seems to imply the current is at least some times large enough to require two wires. ..and likely good connections on those two wires.

Battery connections are prone to corrosion. Tomorrow I'm going to check my battery connections...Haynes says they are the heavy brown(1.25) wires. The wiring diagram says there should be another very heavy (6) brown wire from the battery going to frame which acts as the starter return path, spark plug return etc.

In the wiring diagram there is no indication that the Regulator is chase grounded so JRWooden findings seem to confirm there is no chassie ground there.

[JRWooden]

Originally Posted by vtbob

I also went to the Haynes manual and only found the wiring diagram. It shows two wires going to the battery return. this seems to imply the current is at least some times large enough to require two wires. ..and likely good connections on those two wires.

Battery connections are prone to corrosion. Tomorrow I'm going to check my battery connections...Haynes says they are the heavy brown(1.25) wires. The wiring diagram says there should be another very heavy (6) brown wire from the battery going to frame which acts as the starter return path, spark plug return etc.

In the wiring diagram there is no indication that the Regulator is chase grounded so JRWooden findings seem to confirm there is no chassie ground there.

In my manual it shows two @ 1.5 wires -- I'll "assume" (yes I know) that the 1.5 means 1.5mm wire diameter...
1.5mm is roughly equal to 14 AWG and for the length of the run back to the battery 2 conductors @ 14 AWG or even two @ 1.25mm would be adequate ....

I'm not sure where all the ground wires get bonded together ... I don't think it is AT the negative terminal,
but wherever it is... as new as these bikes are, I would not think that this would be the problem....

... and ... I'll have lost all faith in German Engineering if I find out they were relying on a ground path being available thru the heatsink of the regulator .... so I'm not sure where that leaves us, but I think I'd rather be over here:

http://www.advrider.com/forums/showthread.php?t=163155

[JoelWisman]

Originally Posted by JRWooden

In my manual it shows two @ 1.5 wires -- I'll "assume" (yes I know) that the 1.5 means 1.5mm wire diameter...
1.5mm is roughly equal to 14 AWG and for the length of the run back to the battery 2 conductors @ 14 AWG or even two @ 1.25mm would be adequate ....

I'm not sure where all the ground wires get bonded together ... I don't think it is AT the negative terminal,
but wherever it is... as new as these bikes are, I would not think that this would be the problem....

... and ... I'll have lost all faith in German Engineering if I find out they were relying on a ground path being available thru the heatsink of the regulator .... so I'm not sure where that leaves us, but I think I'd rather be over here:

http://www.advrider.com/forums/showthread.php?t=163155

I do still have a factory wiring diagram, as well as the fact that I have pulled one of our R/R's apart that took impact damage from a fork lift. There is ABSOLUTELY NO electrical connection between anything in the R/R and the anodized case. ZIP ZILCH NADA NONE. Removing anodization serves absolutely no purpose but to waist time. It also does not particularly lower the temperature of the R/R to grind on it and use thermal paste because it's bonded to a part of the frame that gets hotter then the regulator. The regulator sheds heat by radiation and some convection. Further, I have yet to see or hear of a single regulator for the F8 electrically fail, so not sure why we would care anyway.

As to adding more ground wires or improving the ground path, (which is from the R/R to about mid harness, spliced to the brown wire between main ground from battery and brown wire that grounds engine near starter) why?

From a stator current perspective, if this did anything at all, the only thing it could do is increase stator current by lowering load resistance. If the theory is that a poor ground is causing voltage to climb in the stator, thats true. If excessive voltage causing partial discharges and flashover of the stator is our issue then a series regulator should kill the stator much quicker.

I suspect all the theories on other forums that regulator wiring is the cause of stator failures is 100% wrong.

The regulator portion of the R/R can cause stator failure by shorting one winding, but even this is super unlikely cause usually this type of failure would blow the diodes into outer-space long before the stator felt it.

The regulator reducing load resistance by pulling the voltage too low could cause problems but only if the stator / rotor is designed wrong and can't operate at full power output.

Open circuit connections to the regulator could cause it IF the stator can't handle open circuit voltages and certainly this is a hard thing for stators to cope with unless designed for it but with this would go flickering lights. Further, theres a lot of power going through these circuits. If theres a bad connection anywhere in the stator, R/R or R/R to bike wiring, that bad connection is really likely to burn up and produce somewhere between a cloud of smoke and a fire.

Interesting theories these other forums are putting forward but I'd bet a shiny penny that they are 100% wrong about this one.

[ebrabaek]

I think that if we are trying to blame the failure on a mechanical connection...ie...the ground path..... Then perhaps the people with failed stators....could have a look at the wires from the R/R to the battery ground.......( seems like this is the path...rather than a ground of the R/R itself).... I will not dispute the aging of the winding.....etc....since I have no clue in that regard... But.. If the wire/s from the R/R to battery neg and subsequently chassis gnd....is somewhat corroded.... It could cause the stator/RR not being able to regulate. There are several similar issues on other bikes..... That can be fixed by soldering....rather than crimp connectors. A multimeter might not tell the whole story...ohming the connection....as vibrations....and the tune of up to 400 watt of energy dissipation could make a mess..... But tracing the Chassis gnd path....and solder it...will at the very least eliminate one suspect....imho....

Erling