Hi, I've just come across these forums while looking for some info.

I have a K100rt which wont turn over on the starter and wonder if anyone can help? Here are the complete symptoms:
With ignition in parking lights position, parking lights are on.
With ignition in normal "run" position, all the dash lights come on as
normal, but there are no headlights / tail light, the indicators only
work while you hold the button pressed in, the horn doesn't function
and the starter won't turn over. (when the starter button is pressed,
the relay clicks and the fuel pump runs but no starter motor).
The bike can be bump started, but if it is, the lights, horn and indicators still don't work.
So the question is, what can affect all of the above components at the
same time? I was coming back from Wales, and all was fine until I
stopped the bike only to find the above faults.

barnesst wrote:Hi, I've just come across these forums while looking for some info.

I have a K100rt which wont turn over on the starter and wonder if anyone can help? Here are the complete symptoms:
With ignition in parking lights position, parking lights are on.
With ignition in normal "run" position, all the dash lights come on as
normal, but there are no headlights / tail light, the indicators only
work while you hold the button pressed in, the horn doesn't function
and the starter won't turn over. (when the starter button is pressed,
the relay clicks and the fuel pump runs but no starter motor).
The bike can be bump started, but if it is, the lights, horn and indicators still don't work.
So the question is, what can affect all of the above components at the
same time? I was coming back from Wales, and all was fine until I
stopped the bike only to find the above faults.

I wish that I could help you because when I got my K75 in my shop for the winter I had a similar problem.
It was intermittent and then one day it stopped working for good, I thought that it would be easier to trace the problem. NOT!
I was getting power at the starter, but it wouldn't turn. The lights were no working and the flashers were only working on the left side even when you tried the right side.

This problem looked like the load shed relay was the culprid (#13 on the picture). This is the function of this relay: When you push the button, the lights are turned off to give maximum power to the starter.

I replaced the relais but it didn't change anything.

Then I thought that the brushes on the starter were gone (common on old K bikes). Easy, I replaced the starter. That was not the problem.
I then started to pull every relay and electrical parts one after the other and replacing them with a spare one. NO GO!
[I even replaced the water temperature sensor as apparently on the K bike if the engine is too hot (above the maximum temperature), the bike won’t start. I read this on another forum. I replaced the ignition and EFI computer, the air box,….. Every electrical component and still the same problem.
One day, out of the blue, the bike started again. WHY??????
Now, I am thinking that it maybe a problem with the kill switch as when you turn it off, the lights go off, but you cannot start the bike
Since then, I have not been able to replicate the problem and I am a bit scared to take the bike on the road. We just finished a very long winter and only had the opportunity to ride few times with the K100.

PLEASE let me know.

I recommand you to go to the download section of this forum and get my color electrical diagram. It may help you.

Good luck

Thanks for the info. I've been looking at the circuit diagram and the load shedding relay was going to be my next port of call tonight after work. Fingers crossed!

As an update, I found mention of the load shedding relay in an old 1997 post on a U.S. site. The guy's problem seems pretty much the same, and the reply at the bottom about the starter is interesting:

Bob asks:
====
Date: Tue, 01 Jul 1997 10:40:30 MDT
From: MF <markfNoSpam@NoSpamcol.hp.com>
Subject: BMW: k75 electrical problems

I'm having some problems with my 1991 k75, I'm hoping someone out there has
some advice. Here's the problem. I noticed the headlight start to flicker
(this included the instrument panel lights) when I went to pull off the
road
I noticed the blinkers operating erratic. No matter if I used either
blinker indicator or the cancel switch, all four blinkers went into an
emergency blink mode. After pulling off the road and turning off the bike
(by the way engine performance was not effected) I found that when I tried
to restart the bike the starter would not engage. I found that by putting
the bike in gear and rocking the bike(forward and back) the lights would
operate sporadically. With me rocking the bike to get the lights on I was
able to restart the motorcycle and ride home (with lights flickering).
I got home and pulled the tank and checked the ground. Everything seemed
OK so I got the Haynes Manual out. Not much help. After putting the bike
on the center stand I was able to recreate the problem. Again this problem
seems to manifest itself with the ignition turned on. There are no lights;
blinkers only operate in an emergency flashing mode; and, by rotating the
back wheel with the bike in gear the headlight (clutch out) comes on.
I then am able to start the motorcycle(but lights still flicker).

The bike has an alarm system. Thinking maybe the alarm CPU might be
affecting
the starter, I took the alarm out of the starter circuit loop by removing
the
wires from the alarm wiring harness that go to the starter relay, and
reconnecting the original brown and red starter wire back into the starter
relay. The same problem was still there(I also took the fuse out of
the alarm to make sure it was completly disabled). It said in the manual
a load shedding relay cuts all power except to the starter. I'm wondering
if that may have something to do with it. I figured the emergency blink
mode was some default in case of electrical problems? It seemed in the
manual that the blinker relay and load shedding relay sit side by side
so I swapped them(same Part #) with no effect. Anyone with any ideas? I
would appreciate a reply. Last resort is the Beemer shop, but I hate
to do that because this electrical trouble shooting is fun Right?

Sincerely, Bob Kinzel
====
Bob:

K bikes depend on a major ground connection THROUGH the starter motor brush
assembly. Long service can infiltrate the brush area with dust causing
intermittent grounding. I suggest you remove the motor and disassemble it
to clean out the commutator area and inspect for brush free length. This
is pretty easy to do...follow Haynes procedures. Brushes are available at
your dealer or through a alternator shop (if required).

This is exactly the same problem as I experienced. I forgot to mention that when the bike was not starting, if I put it in gear and rocked the back wheel the bike would eventually start again.
This was one of the reason why I switched my starter at the begining of the troubleshouting.
I will open the spare starter and check the brushes. Maybe I have 2 bad starters .

Now we are few people working on the same problem and we should be able to find a solution.

Bert

One other thing that sent me on a bit of a wild goose chase last night: The electrical diagrams in both the Clymer manual and your colour one imply that when the ignition switch is in the "on" position, all 4 wires are connected together. In fact, having pulled the switch apart last night, in the "on" position the red connects to the green and the grey to the blue/grey, but the 2 pairs do not connect to each other in the switch. The "accessory" position is correct though.

barnesst wrote:One other thing that sent me on a bit of a wild goose chase last night: The electrical diagrams in both the Clymer manual and your colour one imply that when the ignition switch is in the "on" position, all 4 wires are connected together. In fact, having pulled the switch apart last night, in the "on" position the red connects to the green and the grey to the blue/grey, but the 2 pairs do not connect to each other in the switch. The "accessory" position is correct though.

My color diagram is a copy of the one from the clymer manual. Since I mad it, i have read that they have an error on the diagram.

Bert

I did finally get round to swapping out the starter brushes, and lo and behold, all the front electrics sprang back into life. I can't understand why there's a major link running through the starter brushes, but that certainly seems the case. I've just done a couple of hundred miles on mine with no recurrence of the problem.