Author Topic: 1991 K100RS Electrical Mystery....  (Read 1879 times)

Offline 1991K100RS

  • Motobrick Curious
  • Posts: 22
1991 K100RS Electrical Mystery....
« on: December 06, 2013, 11:04:05 AM »
Hey all, long time lurker - first time poster

I have a 1991 K100 RS with 60,000 miles, 10,000 of which are mine.

Went out for a ride yesterday and during the ride I noticed that the green light that illuminates the speedometer was flickering. When I tried to use my turn signals it flashed green real quick on the speedometer, then immediately stopped blinking. When I came to a stop, speedometer was completely dark with no light. As I throttled up, the light on the speedometer became brighter. By the time I arrived at my destination, I was riding with no headlight and a dark speedometer. Checked all the fuses, all looked good.

1 hour later, turned the key and the speedometer lit up, but no headlight. With key turned and ignition switch engaged all I hear is a single click sound (I believe starter solenoid). Turned the ignition back and forth a few times and one time light came on. I hit the ignition and it started up with headlight no problem. Have not been able to reproduce since.

Iím thinking the battery is not being charged by the alternator. Checked the alternator, and itís plugged inÖ


1) Ground connection needs to be cleaned?
2) Starter brushes need to be cleaned or replaced?
3) Ignition switch contacts need to be cleaned?

Any thoughts on what could have been causing this pesky electrical problem?

Offline Inge K.

  • ^ Quintessential Motobricker
  • Posts: 1451
Re: 1991 K100RS Electrical Mystery....
« Reply #1 on: December 06, 2013, 02:06:29 PM »
If the background illumination in the cluster flickers/goes out, the LSR have a ground problem....clean starter commutator and/or
change the starter brushes.

If also the warning lights in the cluster flickers/goes out at the same time, the problem is most probably the ignition switch....
which can be dismantled and cleaned.

Inge K.
  • Norway