For the past couple of years I've been having intermittent electrical problems with my 91 K bike. I traced some to a dirty starter motor, corroded grounds and bad battery, but this one stranded me yesterday. I was riding and the engine cut out like the kill switch had been used. This happened once last year. No lights, no displays, no starter. I managed to get it started again by cycling the ignition switch a number of times, and when I got to my destination, I stopped and restarted it several times successfully, but when it came time to go home, it turned over okay but with no starting, and then completely died except for a dim ABS light. The AGM battery is only 18 months old and starts it just fine. I am suspecting a dirty or bad key switch, which, of course, BMW doesn't stock anymore. Has any one else had this problem? Possible solutions?

You sometimes still find them available at the usual suspects. Further there are various 'repair guides' available that tell yu how to strip the part and clean the contacts.

The ignition switch is one of the more common places for that to happen.
With the switch on a 16v bike you can get the switch bit off the bottom of the lock and pull it apart. Where they are situated is not exactly kind to them so all sorts of things get in like dirt and water, I'll leave the rest to your imagination. New switches are available but check it out first as they are quite often repairable.

1 other item of electrickery is the kill switch, as some people dont use it much it has a habit of just sitting there gaining alittle corrosion each year till one day it all starts to intermittant and then be as touchy as the weather, perhaps ensure you have a clean contact on the kill switch too

K75cster wrote:1 other item of electrickery is the kill switch, as some people dont use it much it has a habit of just sitting there gaining alittle corrosion each year till one day it all starts to intermittant and then be as touchy as the weather, perhaps ensure you have a clean contact on the kill switch too

i thought he lights worked even w/ kill switch activated. they do on jap bikes but i never checked on my '91 16v. i had the same thing happen to me this past saturday. came to a stop and bike died.... no lights, no starter. only thing working was clock which had reset itself. had someone give me a jump start and all was fine. got home and checked the charging system and it was within specs. i had disconnected the battery last week to reset the tps and maybe i didn't retighten it enough. my key switch is a bit fussy as i have to wiggle it sometimes to take it out.

If your clock reset then you are losing all power. The battery is not connected to anything. Check the + connection at the battery and on the starter relay also the ground connection on the gearbox on the left side above the coils. There is also a red wire to the fuses from the starter relay which could be involved.
Wriggle the cables + and - to see if the connection comes and goes.

Rick G wrote:If your clock reset then you are losing all power. The battery is not connected to anything. Check the + connection at the battery and on the starter relay also the ground connection on the gearbox on the left side above the coils. There is also a red wire to the fuses from the starter relay which could be involved.
Wriggle the cables + and - to see if the connection comes and goes.

hi rick, because i lost ALL power, are you saying that more than likely the culprit is NOT the ignition or kill siwtch??? if the battery positive connection was not tightened enough, any possibility that would cause losing all power? funny you should mention the ground connection near the coil. last week i took them off (3-4 wire connections), cleaned them and retightened since they looked rusty and was easy to do. i took the side covers off this morning and tried wiggling the battery connections and ground wires (not much room to do a good wiggle end to end!!!) and i didn't lose power. but i suspect i need to remove the tank and do a better inspection. is the starter relay inside the relay box under the tank?

browe58 yes rick has picked up on the bit I missed if the clock reset itself it must be before the ignition switch and the kill switch, so once again check in the cable department from the battery both cables must terminate cleanly and tight, on clean terminals this is also true for the ground on the gearbox end. But also check for corrosion along the length of the cables, just as a clogged pipe wont let the water through, a cable that has a ring of corrosion around it wont want to let the power through, could be at a termination could be a spike in the length of the sheath (insulation) that has caused a reaction to start taking place. Usually if you start suspecting cables and you cant see if its crook inside its often smart to put a new one on to eliminate that as a possibility. If you still have the issue then you have removed one part as the suspect. they are big easy to get at and you can borrow one from someone to see. but for now just pull it off and inspect it fully

or ...if you suspect that a cable or assembly is faulty ....measure with a multi meter between the feed end and the load end ....on volts on the multi meter ....this will give you a reading .....if it is excessive ....you have prooved the fault