Fried F800GS Stator

m0ng00se

Registered user
Joined
Apr 1, 2009
Messages
90
Reaction score
0
Location
Kent
I recently had a problem with my F800GS ... post can be seen here:

http://www.ukgser.com/forums/showthread.php?t=276807

Charged the battery and bike ran fine for a few days and then it died again. Thinking the battery is almost 3 years old anyway, took me all the way through Africa, I decided to buy a new battery and all worked fine for a few days until last week Friday on our way to Dawn to Dusk down in Wales, sitting at a traffic light, the engine and display just died. Had to be pushed by two friendly guys to get to mates house.

In order for me to still do the race, I got a jump started, yes the BMW that had to be jump started every time down in D2D :) and quickly rode down to Cardiff to buy another new battery ... I should've tested first, but there you go.

Anyway, battery in and all went well, but that evening only 10 minutes into the first lap at the Big Bike Rally in Wales and all dead again, so I decided I had enough (was very muddy anyway).

... So, this evening I did some tests, while engine is running, I don't see 13+v on the battery terminals, so it's not charging. Checked for continuity on the 3 yellow stator wires and all seems fine, but I also got continuity between the yellow stator wires and earth (engine casing) .. which is not good.

I then started the bike with the stator unplugged and got good AC voltage on the first two wires (around 50V AC), but the third wire only around 22 volts, so I decided to open the alternator casing and check the stator ... and as expected it is absolutely fried ... you can even see burn marks on the inside of the flywheel.

The problem is, BMW only sells the whole unit at around £500 (I think), Motorworks don't have any second hand stators, but found a company in Essex, WestCountry Windings (http://www.westcountrywindings.co.uk/) and they can rewind the stator for around £120 using thicker wire as well which supposedly last much longer ... so I will drop it off there, pick it up next week and let you know how it works !
 

Attachments

  • SAM_1495.JPG
    SAM_1495.JPG
    93.6 KB · Views: 9,969
  • SAM_1496.JPG
    SAM_1496.JPG
    94.4 KB · Views: 7,958
  • SAM_1498.JPG
    SAM_1498.JPG
    82.9 KB · Views: 7,867
  • SAM_1502.JPG
    SAM_1502.JPG
    88.5 KB · Views: 6,870
  • SAM_1503.JPG
    SAM_1503.JPG
    89.1 KB · Views: 7,196
What a complete arse - but well diagnosed!

Any ideas why it fried in the first place?? I'm tempted now to have a look at mine!

Glad it's identified anyway and good find on the re-winder too - I'll file this for future reference lol..

G
 
What a complete arse - but well diagnosed!

Any ideas why it fried in the first place?? I'm tempted now to have a look at mine!

Glad it's identified anyway and good find on the re-winder too - I'll file this for future reference lol..

G

I was told it could be my voltage regulator/rectifier that was faulty that caused it, not sure if that rubbish, but I ordered a new one anyway and will replace just in case.
 
Hi,

I had my stator corroded on my 2006 F800ST in May 2010.
No coulance from BMW :mad: - so it costed me about 750 BP.

So, with my new F800GS, I will remember your solution. Great job indeed to find out.

Cheers,

Rob
 
Hi,

I had my stator corroded on my 2006 F800ST in May 2010.
No coulance from BMW :mad: - so it costed me about 750 BP.

So, with my new F800GS, I will remember your solution. Great job indeed to find out.

Cheers,

Rob

Took my stator to WestCountry Windings on Thursday ... phoned me later in the afternoon all done. They have cleaned it all up, nice thick copper wiring and all for only £80.

Put it back into the bike yesterday and all good, 14V+ on the battery terminals (also replaced the voltage regulator just to be safe).

Great service from them ... well recommended !
 
Hi, first post here!

As I commented at your YouTube video which describes the problem, I have exactly the same issues: bike initially didn't start with the first attempt, dashboard turned off and then did the check again, thought it was the battery so I replaced it and after some kms the issue started again until last night I had to walk home after it just refused to start.

I turned it on today with the old battery and checked the voltage on the battery terminals with engine running: 10.3V... :blast

I'm thinking of having the bike checked at the dealer next week. But before I go I wanted to ask if it is easy to open the side cover of the stator to check if it's fried. If so I will try to have it fixed with new wire. Do you have any updates 18 months after you had yours fixed?

Greetings from Crete!
 
Hi, first post here!

As I commented at your YouTube video which describes the problem, I have exactly the same issues: bike initially didn't start with the first attempt, dashboard turned off and then did the check again, thought it was the battery so I replaced it and after some kms the issue started again until last night I had to walk home after it just refused to start.

I turned it on today with the old battery and checked the voltage on the battery terminals with engine running: 10.3V... :blast

I'm thinking of having the bike checked at the dealer next week. But before I go I wanted to ask if it is easy to open the side cover of the stator to check if it's fried. If so I will try to have it fixed with new wire. Do you have any updates 18 months after you had yours fixed?

Greetings from Crete!

Since I had the stator rewounded, I never had a problem, not sure about now as I have sold the bike.

Taking the casing off is very easy, just unscrew the cover, and make sure you are careful to keep the gasket in tact if you do no have a spare gasket. Due to the magnetic force of the stator inside the flywheel, it's a little difficult to get off, but a little force will do. There might be a little oil inside, so if you wish, best bet would be to maybe put the bike down on the left side before opening.

Visual inspection should quickly tell you if the stator is knackered. You can also check for resistance with an ohm meter between the stator wires and the the casing, there should be no resistance.
 
Since I had the stator rewounded, I never had a problem, not sure about now as I have sold the bike.

Taking the casing off is very easy, just unscrew the cover, and make sure you are careful to keep the gasket in tact if you do no have a spare gasket. Due to the magnetic force of the stator inside the flywheel, it's a little difficult to get off, but a little force will do. There might be a little oil inside, so if you wish, best bet would be to maybe put the bike down on the left side before opening.

Visual inspection should quickly tell you if the stator is knackered. You can also check for resistance with an ohm meter between the stator wires and the the casing, there should be no resistance.

Thanks for the prompt reply! First I'll try to open the cover and visual check the stator. And I'll try to find someone here that can fix it. I also found in the USA somebody who sells only the stator for $165 but I'm not sure if it's OK to post the link here.

Some additional info: bike has 37.500 beautiful kms and I bought it 3 years ago.
 
Thanks for the prompt reply! First I'll try to open the cover and visual check the stator. And I'll try to find someone here that can fix it. I also found in the USA somebody who sells only the stator for $165 but I'm not sure if it's OK to post the link here.

any alternator/auto-electrical company should be able to rewound a stator. I just took mine out, dropped it off with them, it was finished that afternoon and back in the bike that evening. I replaced my rectifier as well, just in case it was the cause of the stator burnout in the first place.
 
I've just had similar problems with Denise's 650, eventually took the cover off and found her stator looks exactly like yours did! Took it out and dropped it off at a local shop who have sent it for rewinding, £75. Will let you know how it works when I get it back.
Mark
 
I've just had similar problems with Denise's 650, eventually took the cover off and found her stator looks exactly like yours did! Took it out and dropped it off at a local shop who have sent it for rewinding, £75. Will let you know how it works when I get it back.
Mark
 
I'd also point a finger at the rectifier being the possible cause.

Spot on Tim :thumb2

BMW advise Rectifier & Stator changed at the same time. Could be a faulty rectifier that cooked the windings :eek:

Happened to me some time ago while in Germany. Charged battery and got home OK. Changed both ..... no probs :aidan

85,000 miles now :thumb2

:beerjug:
 
I read a post some time back on a American forum where it was suggested that the rectifier was not earthing properly.The simple solution was to run an earth wire from the mounting screw to the frame.It might not work but hey its worth a go.
 
Mine was replaced under warranty for looking the same, although they had the engine apart for an unrelated issue.

I wonder if there is a common cause for the overheating failures, such as running hot (mine had been down through Africa too). Hard to believe BMW would have got something as basic as eatheing wrong - it's not like alternators are a new tech...
 
f800gs-1.jpg


f800gs-4.jpg

Does it look fried to you?
I've had a terrible week at work (thanks God at least I still have one in my country) so I didn't have the time to take the bike to my mechanic. At least I have a chinese-made moped bike...

Here's what I measured with stator plug disconnected:

Continuity between the yellow stator wires (1-2, 1-3, 2-3)

- Engine off (battery connected)
All tree between 0.6 and 0.9 Ohms

Continuity between the yellow stator wires and earth (engine casing)

- With battery disconnected:
Wire 1 - ground: 1.2 Ohms
Wire 2 - ground: 1.3 Ohms
Wire 3 - ground: 1.1 Ohms

- With motor running (4.000 rpm):
Readings went crazy but sometimes they showed numbers from 2 to 3 (ohms or megaohms? - it's a professional instrument but I guess I don't know how to use it and if I'm supposed to check for continuity with motor running)


Voltage

- Motor running idle:
Wire 1 - 2: 27V~
Wire 1 - 3: 26V~
Wire 2 - 3: 25V~

- Motor running @ 4.000 rpm:
Wire 1 - 2: > 75 V~
Wire 1 - 3: > 80 V~
Wire 2 - 3: > 75 V~

Your opinion?
 
This is what the stator from Denise's 650 looked like. The bike had 20K on the clock when we bought it, and with one thing and another, we hadn't been out very much on it. Once she did start riding more, the electrics started to play up, and after many other checks I finally pulled the cover off!

IMG00509-20130322-1551-M.jpg



So I took it to a local bike shop who I'd heard did stator rewinds, Pitstop Motorcycles from Lowton, Warrington. They send them away, and I was quoted £75 and one week turnaround.
Reading various threads on here and elsewhere, I decided to order a new regulator/ rectifier as well. Everyone who I spoke to suggested this was the best move, but no one could find me an alternative to the OEM part. With a new gasket, 'cos some heavy handed idiot ripped the original, this came to £103 from BMW Motorrad.

IMG00528-20130328-1802-M.jpg



I got a phone call on Saturday morning that the parts were in at Chester, then one at lunchtime to say that Pitstop had the rewound stator. They shut at 2.00 pm on Saturdays, but as they were putting up a new shop front, they were happy for me to call round anytime after that. It certainly looks the part now!

IMG00531-20130330-1806-M.jpg


So that evening I bolted it all back together, and yesterday we went out for a bimble. Despite the near freezing conditions, Denise was perfectly happy, as now her heated grips and jacket worked for the entire afternoon! Previously they would have only worked sporadically, and on one occasion we had to leave the bike at a petrol station and go home for the trailer two up, as hers was completely flat.
Off to give it a clean now. :thumb

IMG00532-20130331-1748-M.jpg


Mark
 
Last edited:
Some really useful info here folks so thanks all! :thumb2

I'll check the earthing of my reg/rec unit - it could explain the intermittent operation of my heated grips.

Hmm.....could there be some earth related electric trickery messing with the steering bearings as well?? :nenau
 
f800gs-1.jpg


f800gs-4.jpg

Does it look fried to you?
I've had a terrible week at work (thanks God at least I still have one in my country) so I didn't have the time to take the bike to my mechanic. At least I have a chinese-made moped bike...

Here's what I measured with stator plug disconnected:

Continuity between the yellow stator wires (1-2, 1-3, 2-3)

- Engine off (battery connected)
All tree between 0.6 and 0.9 Ohms

Continuity between the yellow stator wires and earth (engine casing)

- With battery disconnected:
Wire 1 - ground: 1.2 Ohms
Wire 2 - ground: 1.3 Ohms
Wire 3 - ground: 1.1 Ohms

- With motor running (4.000 rpm):
Readings went crazy but sometimes they showed numbers from 2 to 3 (ohms or megaohms? - it's a professional instrument but I guess I don't know how to use it and if I'm supposed to check for continuity with motor running)


Voltage

- Motor running idle:
Wire 1 - 2: 27V~
Wire 1 - 3: 26V~
Wire 2 - 3: 25V~

- Motor running @ 4.000 rpm:
Wire 1 - 2: > 75 V~
Wire 1 - 3: > 80 V~
Wire 2 - 3: > 75 V~

Your opinion?

I was testing a potential duff stator today on an F800GS

This one wasn't charging. I was getting a resistance of 0.04 between all the poles.

None of the poles should ground to earth.

I was getting 5V AC between 1-2 & 1-3.. 2-3 only gave 1.2V

At 5000 RPM the good poles were putting out about 17-20V while 2-3 never rose over 1.5V

DUFF STATOR !!!
 


Back
Top Bottom