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Discussion Starter #1
My radio hasn't been working so I have tried disconnecting the battery. Each time I do this when I reconnect the terminal(s) I get a big spark off the battery even though I have the ignition switch in the OFF position. What's going on????
 

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On the LT, off really isn't off. You didn't say if the handle bars are locked, but that is the position with the lowest current draw on the battery. Not sure if there is a difference in the sparking between the locked position and the off position. The battery will hold a charge much better if the handle bars are locked.

You really only need to detach the negative terminal to perform a reset of the radio. Some sparking is normal and is an indication of the high parasitic load on the battery. You will need to reset the throttle position sensor after reattaching the battery cable. Key on (let it go throught the startup procedure) but don't start. Move the throttle fully open then fully closed. Repeat. Turn off the key. Restart as usual.
 

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Discussion Starter #3
Thanks

That's more information that I've got so far. I'll try it. Thanks buddy.
 

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2005 K1200LT
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Actually it is not a high parasitic load that causes the sparks. That is the inrush current to re-charge the capacitors in all the electronics that you discharged by disconnecting the battery. That is why you disconnect it and leave it off for so long for all that stored energy to dissipate and force a hard "reboot" of the radio. It also wipes out the memory in the motronic engine control computer, thus the TPS reset propcedure. Perfectly normal.
 

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Just make sure you have no gas fumes around :histerica
 

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The clock is always drawing current, so some of the spark is coming from parasitic stuff like this. Not sure what else is on. I disconnected my battery for 30 minutes to reset radio and it still had stations in memory afterwards, so the radio memory isn't drawing current apparently. But the clock is. Possibly more?

Randy
 

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bgudmest said:
My radio hasn't been working so I have tried disconnecting the battery. Each time I do this when I reconnect the terminal(s) I get a big spark off the battery even though I have the ignition switch in the OFF position. What's going on????
Bjorn - I bet you know this, butt to be sure - when disconnecting/reconnecting the battery, the proper method is: negative terminal is first off, last on. I notice you said "terminal(s)", so thought I'd better mention the procedure.
 

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Hey Bjorn, and welcome to the site. I hope you find it to be as useful as I have. You did not mention what year bike you have, or what electronic equipment has been added. I don't know that the information would make any difference, but I am a tad worried about you getting a "big" spark. Of course, my notion of a "little" or "normal" spark may be the same as your observation of a "big" one, but when I've reattached the battery lead or leads (the latter only when installing a new battery) using the sequence that Dick suggested above, I get a perceptible but very small (entirely subjective description) spark. Now, my LT is a '99 (very few of the electronic gadgets that came standard or were options on '05+ models), so I probably have a small inrush current draw compared to other bikes, and a bigger spark may be entirely normal on other bikes. But I also wonder about a short in the system if the spark is bigger than "normal." BTW, what was wrong with the functioning of the radio that you wanted to reset it?
 

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Discussion Starter #9
Thanks to all for the replies

Bill,
I purchased a used 2005 K1200LT 2 weeks ago. When the seller demonstrated it to me the radio worked fine. When I got it home, the radio didn't even turn on. So I've tried all of the reset tricks that I read on this site. I called a BMW dealer service department thinking it might be a weak battery. I remember the seller demonstrating the electric reverse feature of the bike twice. I thought this might have excessively drained the battery, so I put a car battery charger on it for a few hours and then reconnected the battery and nothing happened. The battery has a date code stamped on it 04/06. If this is April 2006 the battery should still be good. If it is June 2004 then the battery might need replacing. Unfortunately the seller has been on 2 weeks vacation (left the day I picked up the bike) and I haven't been able to ask him these questions. I need to purchase a BMW service manual and schematics so I can get a better look at what makes this bike tick...........
 

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One other possibility is that your battery is bad. Sometimes a bad battery will reverse it's polarity even if only marginally. I've seen it a hundred times. A good and easy way to test if this has occurred is to see if there is any continuity between your positive pole and the frame of your bike. If so, you've got a bad battery. It's really quite an intriguing phenomena that can lead someone to believe that they have a short somewhere in their wiring when in fact it's the battery that's creating the problem.
 

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atrovarious said:
... is to see if there is any continuity between your positive pole and the frame of your bike.

errr....ummm.. what?

Does this have something to do with Doc Brown's flux capacitor?

 

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bgudmest said:
Bill,
I purchased a used 2005 K1200LT 2 weeks ago. When the seller demonstrated it to me the radio worked fine. When I got it home, the radio didn't even turn on. So I've tried all of the reset tricks that I read on this site. I called a BMW dealer service department thinking it might be a weak battery. I remember the seller demonstrating the electric reverse feature of the bike twice. I thought this might have excessively drained the battery, so I put a car battery charger on it for a few hours and then reconnected the battery and nothing happened. The battery has a date code stamped on it 04/06. If this is April 2006 the battery should still be good. If it is June 2004 then the battery might need replacing. Unfortunately the seller has been on 2 weeks vacation (left the day I picked up the bike) and I haven't been able to ask him these questions. I need to purchase a BMW service manual and schematics so I can get a better look at what makes this bike tick...........
The service manual is a very useful thing to have. You did not mention checking the fuse for the radio. Try this: switch on the map light there at the top of your dashboard. You don't need to turn on the key, the circut to the map light is always hot. If the map light does turn on it is not the fuse (both the radio and the map light use the same fuse). If the map light does not turn on, it's likely to be the fuse. If that is the case, and you don't have the manual or other documentation about how to get at the fuses, let us know and we'll try to guide you in.
 

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Discussion Starter #13
That's It !

For some reason I've been telling myself that "it can't be a blown fuse". Well, because of one of your reply comments, I checked the fuse and sure enough "it's blown"........ After slapping myself a few times I took the 7.5 amp fuse out of the seat heater fuse slot and put it in the radio fuse slot. The radio came on as soon as I put the switch in the "ON" position. Mission success.

This reminds me of how I learned over time how to trouble shoot my 4 Harleys. I've been riding Harleys for 30 years now. I did own a 1980 R75/7 BMW. I spent alot of sleepless nights working on it's ignition and carbs. I got so frustrated that I sold it 5 years later and never looked back............until now............. I'm back and I'm ready to learn everything there is about my 2005 K1200LT. I'm counting on you guys to help along...........Thanks in advance for your help :) !
 

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bgudmest said:
For some reason I've been telling myself that "it can't be a blown fuse". Well, because of one of your reply comments, I checked the fuse and sure enough "it's blown"........
Ayuh. Been there, done that too. :eek:
bgudmest said:
After slapping myself a few times I took the 7.5 amp fuse out of the seat heater fuse slot and put it in the radio fuse slot. The radio came on as soon as I put the switch in the "ON" position. Mission success.
:thumb: Congrats! Glad it worked out. Don't forget to swap out that 7.5 amp fuse for one of the right amperage (I think it's a 4 amp?) And don't forget to reset the Throttle Position Sensor as mentioned above.

. . .
bgudmest said:
I did own a 1980 R75/7 BMW. I spent alot of sleepless nights working on it's ignition and carbs. I got so frustrated that I sold it 5 years later and never looked back.
Well, I can promise you that you will not have to worry about carbs on the LT. Now you get to worry about the final drive, shift linkage, squeeling brakes, cowbell rotors . . . . ;)

bgudmest said:
I'm back and I'm ready to learn everything there is about my 2005 K1200LT. I'm counting on you guys to help along...........Thanks in advance for your help :) !
Great to have you with us. :D
 
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