K100RT electrical problem

[Puccini]

My 85 K100 went dead as I pushed the starter button.

The battery is perfect and no blown fuses. Now all I get when I turn on the key is a glow from the battery light and not much else. No headlight, no fuel pump, no horn, Nothing !!!

Any ideas where to start with this problem???

[kioolt]

Do you at least get a light click sound?  That would indicate that your starter relay is working.  If so, my next suggestion is dirty or bad starter brushes.  Either could cause your headlight to go out and your starter to not work.

[Scott_]

I'd bet on starter brushes as well.

[Inge K.]

Hmm.........doesn't quite agree with the conclusion here................

It's mentioned that only the charge warning lamp glows.....then I assume that the rest
of the warning lamps still stays dark.

If so..........the power feed to the instruments isn't going through the LSR,
then the problem more likely is in the ignition switch.

[Puccini]

I'm making some headway. I took apart the ignition switch and it looked very clean and OK.
I put it back in the circuit and still got the same issue. Namely, glowing battery light, nothing else.

So, I cleaned all the contacts on every relay and connector under the seat with contact cleaner and dioxit. Still no response.
Then I tried the engine kill switch. Just moving it around. Surprize!!!! Dash lit up and headlight came on as if all was ok.
But, when I hit the starter, everything on the dash became dim and did not get bright again after I let go of the starter button.  Juggling the kill switch didn't produce consistant response. Sometimes dash would light and other times not.

NEW symptom,
It looks like theres some kind of drain on the battery.
When I turn on the key everything on the dash is dim and I hear a relay click but
theres not enought power to start the bike.
All this is without pushine the starter button.
Any ideas???
Gerry

[JamesInCA]

Load shed relay stuck? My cluster illumination ('87 K75) runs through the LSR; on the occasions when the starter relay sticks, I have no cluster illumination. I haven't noticed what happens to other warning lamps in these cases.

If lightly jiggling the kill switch is turning things on or off, it sounds like you have a problem there. It can get dirty, like the ignition. It also depends on some small springs (two, I think) to maintain contact. If the springs weaken, the connection can become inconsistent. If you disassemble the switch, you can pull on the ends of the springs a bit to stretch them back out so they press the switch's contacts more firmly together.

[Puccini]

OI, finally found the problem.

Starter was shorted. It still turned by hand but has a direct short to the casing.

Tomorrow I rebuild it.

I learned a lot about the K100 doing this.

Thanks everybody.

Gerry