Captain Beaky
Registered user
Fellow GS'ers, this may well affect you if you ride a 1150 (and possibly an 1100 and 850 too)
You may have read my last post :- "Bike just died".
I was riding last night when, without warning, the bike died.
I lost all electrical power and the engine died.
Investigating as best as I could in the dark, I found that the battery was roasting hot, so I lifted the tank, and disconnected the battery. Lickily my mate with a Transit got me home - Cheers Ian.
I have just found the root cause, and it's a little concerning.
The battery supply lead to the starter motor had shorted against the starter motor.
The battery lead is connected to the starter by a small stud and nut that is the terminal on the starter.
The wiring harness has a large crimp terminal on the end of the battery lead that connects onto the starter motor terminal.
This crimp terminal is bent through 90 degrees to allow the battery lead to travel forward along the starter motor and then up into the main wiring harness.
On my bike, this bend is either too sharp, or not far enough along the terminal (or both), so when the terminal is connected, it is pressing hard into the starter motor body.
There is some heat shrink insulation to stop a short circuit, but this has worn away on mine, allowing the terminal to touch the starter motor body and directly short out the battery.
It doesn't take much imagination to appreciate the power behind these lead acid batteries, and what can happen when you short one out. The damage on my harness appears to be limited to the melting of the insulation at the starter motor terminal, which shouldn't be too hard to fix - but it could have been much worse.
There is no fuse in the starter motor line (This is normal practice and not usually an issue), but this line is constantly live, and can (in theory) short at any time.
My bike is not that old, it's a 2001 MY with just over 12000 miles on the clock, so not a "Mega Miler".
It's really easy to check - just remove the side panel over the starter (The one with the power socket on it) and visually check that the starter motor lead is not pressed against the starter motor body.
I'll be posting photos when I get hold of a digital camera, and informing BMW GB about the failure.
Any response I get back will be posted here.
Get checking!!!!!!!
Cheers,
Mike.
You may have read my last post :- "Bike just died".
I was riding last night when, without warning, the bike died.
I lost all electrical power and the engine died.
Investigating as best as I could in the dark, I found that the battery was roasting hot, so I lifted the tank, and disconnected the battery. Lickily my mate with a Transit got me home - Cheers Ian.
I have just found the root cause, and it's a little concerning.
The battery supply lead to the starter motor had shorted against the starter motor.
The battery lead is connected to the starter by a small stud and nut that is the terminal on the starter.
The wiring harness has a large crimp terminal on the end of the battery lead that connects onto the starter motor terminal.
This crimp terminal is bent through 90 degrees to allow the battery lead to travel forward along the starter motor and then up into the main wiring harness.
On my bike, this bend is either too sharp, or not far enough along the terminal (or both), so when the terminal is connected, it is pressing hard into the starter motor body.
There is some heat shrink insulation to stop a short circuit, but this has worn away on mine, allowing the terminal to touch the starter motor body and directly short out the battery.
It doesn't take much imagination to appreciate the power behind these lead acid batteries, and what can happen when you short one out. The damage on my harness appears to be limited to the melting of the insulation at the starter motor terminal, which shouldn't be too hard to fix - but it could have been much worse.
There is no fuse in the starter motor line (This is normal practice and not usually an issue), but this line is constantly live, and can (in theory) short at any time.
My bike is not that old, it's a 2001 MY with just over 12000 miles on the clock, so not a "Mega Miler".
It's really easy to check - just remove the side panel over the starter (The one with the power socket on it) and visually check that the starter motor lead is not pressed against the starter motor body.
I'll be posting photos when I get hold of a digital camera, and informing BMW GB about the failure.
Any response I get back will be posted here.
Get checking!!!!!!!
Cheers,
Mike.
