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 !
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 !