Hello K-bike gurus,
In an effort to convey all the pertinent information to you guys/gals, I may offer some seemingly irrelevant background details (like this particular statement). Just chalk it up to my inexperience in K-bike ignition diagnostics.
 
If you would prefer to skip the backstory altogether, just go down to the long line of asterisks. This is where I start the list of symptoms.
 
So, three years ago when I bought the bike, it was yellow. It was very visible, but ... yellow. I prefer, hopefully never to my detriment, a more stealthy appearance. I hesitated in painting it for a while because I had this feeling that just after it was looking the way I had envisioned, something mysterious and/or catastrophic would happen mechanically or electrically. Well, my nightmare appears to be in the act of becoming a reality. One reason for this background info is to hopefully explain why I have been operating the bike in a less than ideal (read: stupid) condition. It is also helpful to know - currently this is my only source of motorized transportation - creating the need to operate the bike in a, sometimes, vulnerable condition. Additionally, as the painting project required multiple, full un-dressings of all fairing components, I have been spurred to start all sorts of minor projects involving the elements uncovered in the process. At times I've wondered if I had essentially opened a can of worms that would not be satiated until I had replaced every one of the 30 year old parts - which is of course the entire bike. 


So, on with the issue -


While the bike 'appears' to have been garage kept in the past, soon after buying it I had trouble with the keyed portion of the ignition switch - namely that I could not remove the key. The key would turn and operate the switch, but I could not remove the key. In an attempt to understand how the switch operated, I noticed that the "real switch" portion was barely holding on to the back of the keyed section. It was so easily removed and brought out from behind the dash pad that I wondered how it had not become dislodged every time I rode over a speed bump. So, until I could get some graphite lubricant and remove the key, this is how I secured the bike. I'm ashamed to admit, I continued to operate the bike in this condition for far too long.


The key remained in the bike. When I arrived at my destination, I would turn the engine off by way of the stuck key, reach behind the dash pad, and pull the switch out so that the keyed section had no contact with the switch. Due to the astonishing ease at which these two parts were separated, I became quite proficient and lightning fast performing this maneuver. I felt this was necessary for the security of my bike, just in case someone I hadn't noticed was watching me. While this may seem to be an irrelevant bit of background, I want to explain the inordinate abuse and exposure this ignition switch has endured. 


More recently - after finding an adapter of nearly appropriate size, I decided to install some USB ports in the vacant slot of the dash pad. I removed the dash pad completely in order to make slight size modifications to the empty slot, fabricate a different switch blank for trim around the USB ports, and enjoy working comfortably from a plush chair under sufficient lighting in a warm room of my house. As a consequence, the ignition switch no longer had the protection from the elements offered by the dash pad. With the keyed portion of the switch removed along with the dash pad, the operation of the ignition switch was performed with my house key, which has a wide blunt end about the length of the slot in the switch. This had been the situation for the past week. I don’t recall getting much rain during that period, just a whole lot of cold. The bike is parked in a carport at my house, free from any precipitation.


Just yesterday the bike started cutting out while running, and coincidently only when driving. After the unexpected loss of power, I looked down at the gauges and noticed that all lights had gone out. I naturally grabbed the switch mechanism resting on the handlebars. As soon as I grabbed it, the connection was restored and I was able to continue with little loss of speed. The second, and all subsequent times this happened yesterday (around five times in total, maybe four), it took just a little more than grabbing the switch. A few times I had to jostle the mechanism in my hand for a second before the power was restored. There was no need to pull over and stop during any of these situations.


Then, on my way home to address this issue in the comfort of my carport, I decided to make a quick stop at the grocery store. When I went to start the bike and go home, I once again placed my house key in the switch and turned it. I hit the starter button. The engine turned over for a fraction of a second and then stopped. I noticed that the headlight and all dash lights had gone out. I wasn’t too worried; I was sure that a simple jostle of the switch in my hand was all that was needed – but it never did work like it had been. The proper dash lights were never restored (the sign I was looking for as an indication that whatever connection was faulty had been restored). A few times the proper dash lights made an attempt to illuminate fully but did not. They would occasionally illuminate, however faint. Pressing the starter button during those times effectively does nothing. 


[By proper dash lights, I mean the green neutral light and all the backlighting in the cluster, as well as the clock and the LCD gear indicator]


After further attention was given to recording exactly what symptoms the bike was expressing, I noticed that when I turn the switch all the way (passed the parking light/aux position) to the on position, the battery (charge) light makes a feeble attempt to illuminate, viz. appears as if less than the required voltage is being delivered.


This is when I removed the battery and walked home with it. I put the 8-month-old battery, with which I never had the first problem, on the trickle charger overnight. This morning the green light on the charger indicating a full or near full charge state was lit as expected. I carried the battery back to the bike.


Before re-installing the battery, I used sandpaper and contact cleaner to thoroughly clean all the connectors on both grounds to the frame (the one on the transmission next to the battery, and the one under the tank on the center frame rail). The symptoms were exactly the same, no change at all.


Further experimenting has led to some, I believe, strange symptoms. With the ignition switch in the on position and the kill switch straight up, the symptoms listed previously were witnessed. With the ignition switch in the on position and the kill switch to either side (in the “kill” position), the half-lit charge light goes out and a continuous buzzing emanates from one of the smaller relay switches under the tank. Judging from a diagram I have, I believe it’s the fuel injection relay. It’s on the forward side of the relay box and the furthest one to the left hand (clutch) side of the bike – one of the three similarly sized relay switches.


Honestly, as per a friend and long time Beemer guy’s advice, I haven’t really ever used the kill switch. He’s warned that they have a reputation for failure and advised I refrain from using it. So, I’m not real sure just how the bike is expected to respond to using the kill switch with the ignition switch on. But, these symptoms just strike me as probably not intended.


So, feeling that the problem is not the battery, I tried some further diagnostics.


********************


Again, when I turn the switch all the way (passed the parking light/aux position) to the on position, the battery (charge) light makes a feeble attempt to illuminate, viz. appears as if less than the required voltage is being delivered. All other instrument cluster lights (and both LCD units - clock and gear indicator), including the headlight, turn signals, brake light and horn do not operate when the switch is turned to the on position. And, of course the starter will not turn – no solenoid click – nothing.


With the ignition switch in the on position and the kill switch to either side (in the “kill” position), the half-lit charge light goes out and a continuous buzzing emanates from one of the smaller relay switches under the tank. Judging from a diagram I have, I believe it’s the fuel injection relay.
 
With the ignition key in the ‘off’ position – the red wire on the ignition switch has about 12.6 – 12.7 volts and the green wire has 0 volts.


With the ignition key in the ‘on’ position, and again not the parking light/aux position but the ‘on’ position – the red wire now has 2.34 volts! A very significant voltage drop. And the green wire registers a similar voltage.


This strikes me as unusual and completely WRONG!


I think I’ve conveyed all the symptoms that I have noticed or know to check for.


I’ve read some posts about measuring the voltage from the fuse panel but I’m not clear on what is expected and where. Additionally, I’m assuming that to properly measure at the fuse panel, I would place a probe on one side of the particular fuse slot (and only one particular side should register - because when you pull the fuse you break the circuit) and the other probe to ground on the frame. Is this correct?


Does anyone know of a good reference for what to expect at each fuse slot, and under what circumstances (key on or off)?


In my search of the Internet for anything that might shed some light on my problem and help with the diagnostics, I kept coming across Bertrand Vogel’s EFI/Electronic ignition K100 2v troubleshooting.

http://tomwade.me/motorcycles/technical/k100troubleshooting.pdf


While this is undoubtedly invaluable information every relevant K-bike owner should have, I believe I need help in the diagnostics that he mentions should be performed BEFORE consulting his troubleshooting guide. He starts his guide with this preface:


First, you have done all the basic troubleshooting such as: checking the fuses, ignition switch, kill switch, side stand switch (not applicable on early K100), transmission in neutral, clutch in, starter connection, Fuel pump connector on the fuel tank, and battery connections.


I believe I should start with these sorts of tests, in particular the ignition and kill switch troubleshooting. Does anyone know of a comparable guide that addresses these preliminary measures?


Thanks in advance for any assistance.

Hello!

I'll keep it short, others will follow.
Since the light goes of it has to do with the main electric.

My guess:

1.) 65% | ignition switch or Cable
Start and and shake/pull the cable at the right side of the steering, where all the cables are. To check if a cable is broken.
http://www.eilenberger.net/K75S/IgnitionSwitch/
http://technik.flyingbrick.de/images/6/6f/61_zuendschloss.pdf

2.) 20% | kill switch
http://technik.flyingbrick.de/images/f/f9/61_lenker_rechts.pdf

3.) 10% | all the connection under the fuel tank
Needs cleaning with DeoxIT® and after that with a tiny bit vaseline to protect.

4.) 5% | who knows

Cheers

Sorry to see your troubles but we will need some more info on the bike as there were changes made in 1985.

I have been through various issues with Ks too but the start procedure requires either the neutral green light on OR the clutch lever in. On mine the neural light does not work due to the gear position indicator switch being kaput. That's OK, BUT all the clutch switch does is enable the starter to be turned over. The switch at the clutch lever is identical to the front brake light switch and also the rear brake light switch to you can swap for a test but unlikely to be the issue.

Again, when I turn the switch all the way (passed the parking light/aux position) to the on position, the battery (charge) light makes a feeble attempt to illuminate, viz. appears as if less than the required voltage is being delivered. All other instrument cluster lights (and both LCD units - clock and gear indicator), including the headlight, turn signals, brake light and horn do not operate when the switch is turned to the on position. And, of course the starter will not turn – no solenoid click – nothing.

If these are feeble check the other end of the battery earth, its connected to a lug on the gearbox left side, above the gear lever. It too needs regular unscrewing and cleaning.

With the kill switch on the off position there should not be a buzzing from the relay. The electrical supply to relays is not fused and a faulty relay can power up when ignition is off and flatten a battery in a relatively short time.

If yours is early 85 the connection to the fuel tank is on the front left [tank is bolted down at the rear on this one] but if this is your problem it won't stop the starter turning the engine over, it just wont fire. This connection does go poor and need cleaning/tightening but it cuts off the power to the fuel pump  and if level is low the low fuel warning lights will not illuminate.

Cutting out while driving and an apparent loss of voltage [dim/feeble lights] could be suggesting a dodgy connection with the ignition switch/wiring arising from so much movement. So many lights going out could also do that. But poor fuse connections can cause problems, so just pull the fuses, clean and refit them.

Constant fiddling may upset the multiplug connection to the back of the clocks/instruments. If this is loose or poor contact you will also get issues especially when on the move and involves removing the clocks and cleaning the connection.

Given the situation  with the ignition I think that's no 1 on my list of suspects.

Chocolat has given you links very nicely.

dontb  afraid to ask any questions, a lot of us have gone through similar issues and lots of experience on the forum that everyone is very willing to share.

I'm adding

Replace fuse 1 (the top one)
Fuses can look good but aren't.

Cheers

Have you cleaned the ignition switch? 

http://www.eilenberger.net/K75S/IgnitionSwitch/

http://technik.flyingbrick.de/images/6/6f/61_zuendschloss.pdf

My apologies if you have.  I didn't have time to read the complete blow-by-blow.

I have checked all the fuses, but I'll replace fuse #1 just to be sure.
I've cleaned both ground contacts (trans & under tank).

I'm sitting down now to clean the ignition switch.
Thanks for all the replies!

Coincidentally, just yesterday I dismantled my ignition switch, as I was getting more and more frequent faint dash lights and no start. Been happening for a while, but only just got around to it.
Clean and deoxit the switch contacts. Also, the plug/socket where it connects to the main loom looked pretty grotty, so also cleaned and deoxited.
Seems good now, but haven't had time to check proper reliability yet.
Bill

Correction: it's the oil pressure lamp that is trying to illuminate when the key is on and I believe it's the load shed relay that is buzzing.

The load shed relay LSR disconnects the lights etc when you hit the starter. But if that's buzzing when the ignition is off it may be faulty. Anyone local with one to swap?

This is interesting. I have nearly 13V at the red wire on the ignition switch when the key is off. When the key is on, the voltage drops to around 3 at the red wire and the green wire. When I remove the switch and it's pigtail, and measure the voltage at the connection terminal for the red wire, it's around 13V. When I jump the red and green posts, again with the switch and pigtail removed, it falls back down to around 3V. F'n weird!!! I thought the voltage drop's cause must be in the switch or the pigtail but it's not. How is that possible? What's going on?

Matthew1971 wrote:
********************
Again, when I turn the switch all the way (passed the parking light/aux position) to the on position, the battery (charge) light makes a feeble attempt to illuminate, viz. appears as if less than the required voltage is being delivered. All other instrument cluster lights (and both LCD units - clock and gear indicator), including the headlight, turn signals, brake light and horn do not operate when the switch is turned to the on position. And, of course the starter will not turn – no solenoid click – nothing.
It may be an 8 month old battery, but if it hasn't been looked after then its likely been run down once too often and will now not hold a charge. Probably because your alternator is not outputting sufficient voltage due to a bad VR.
Charging the battery on a trickle charger will not guarantee that its up to the job. There's only one way to tell if your battery is ok and that's to use a meter to measure the static charge as well as the voltage under load.


With the ignition switch in the on position and the kill switch to either side (in the “kill” position), the half-lit charge light goes out and a continuous buzzing emanates from one of the smaller relay switches under the tank. Judging from a diagram I have, I believe it’s the fuel injection relay.
 
With the ignition key in the ‘off’ position – the red wire on the ignition switch has about 12.6 – 12.7 volts and the green wire has 0 volts.

With the ignition key in the ‘on’ position, and again not the parking light/aux position but the ‘on’ position – the red wire now has 2.34 volts! A very significant voltage drop. And the green wire registers a similar voltage.
What are you measuring here? Where are you probing with the black probe??
Sounds like you're measuring a voltage difference between 2 points.
Turning the ignition key 'ON' does not change the condition of the red wire at the ignition sw. It comes straight from the battery.
The black probe must be connected to a good earth like the engine casing or the Neg battery terminal

This strikes me as unusual and completely WRONG!

I think I’ve conveyed all the symptoms that I have noticed or know to check for.

In my search of the Internet for anything that might shed some light on my problem and help with the diagnostics, I kept coming across Bertrand Vogel’s EFI/Electronic ignition K100 2v troubleshooting.
This is the work of our own Crazy Frog (Bert) which you can find on the troubleshooting link on the Portal page of our forum site

http://tomwade.me/motorcycles/technical/k100troubleshooting.pdf

While this is undoubtedly invaluable information every relevant K-bike owner should have, I believe I need help in the diagnostics that he mentions should be performed BEFORE consulting his troubleshooting guide. He starts his guide with this preface:


First, you have done all the basic troubleshooting such as: checking the fuses, ignition switch, kill switch, side stand switch (not applicable on early K100), transmission in neutral, clutch in, starter connection, Fuel pump connector on the fuel tank, and battery connections.


I believe I should start with these sorts of tests, in particular the ignition and kill switch troubleshooting. Does anyone know of a comparable guide that addresses these preliminary measures?

If you intend to ride a vintage bike (your '85 K100RS is now nearly 32 year old), these are all things that should be attended to within your normal weekly/monthly routine. You can't expect these old bikes just to keep going and perform as if they are just out of the showroom. Rubber parts perish and metal parts corrode.

Thanks in advance for any assistance.

You may have a case of multiple malfunctions.

• Your ignition switch definitely needs some attention before you go any further. There is obviously a problem with this. This is a common problem with our K-bikes at this age.
  
• Your battery may not be up to the job and is not holding a charge due to a failure with the VR. The VR can be easily removed and simply cleaning the brushes and contacts can sometimes help. Take your battery to a battery shop to have it tested properly.
  
• Your earth connections need some maintenance. 
  * The GB earth and the earth under the tank on the frame, you've done.
  * You also need to clean the starter motor brushes and make sure they're within spec. This is an important earthing for the electrics.... yes, its weird.
  * Also (and this is a long shot), the continuity for the frame earth runs thru the engine mountings to the engine casing (GB) and back to the Neg terminal. If the engine mountings have not been undone and/or the bike has sat for quite a long time, corrosion can build up. Some K-owners install an additional earth cable directly from the Neg terminal or the GB connection straight to the frame connection under the tank, bypassing the engine mountings. This is more reliable.
  

As far as the fuses go.... just make sure the connections in the fuse holder are clean from corrosion and make sure your fuses are ok.

This is interesting. I have nearly 13V at the red wire on the ignition switch when the key is off. When the key is on, the voltage drops to around 3 at the red wire and the green wire. When I remove the switch and it's pigtail, and measure the voltage at the connection terminal for the red wire, it's around 13V. When I jump the red and green posts, again with the switch and pigtail removed, it falls back down to around 3V. F'n weird!!! I thought the voltage drop's cause must be in the switch or the pigtail but it's not. How is that possible? What's going on?

Just a guess but you're probably not probing it correctly. The green wire has a direct path to the LSR control coil which then earths thru the starter motor brushes.... so with the red and green bridged you are probably just measuring a voltage difference between the green to earth and the red to earth.
You seem to be getting good voltage on the red. That's expected as there's nothing between that and the battery. Repair and clean the ignition switch and retest.

Good luck 

I suggest a moderator move this thread to the Electrical category in the Technical, repair and troubleshooting section where it should have been posted in the first place.

In the Member's section I expect to learn whether a new member is interested in sunsets, sunrises, full moons or necromancy.

I just realized that I never did post what was exactly the problem. In the case that someone is experiencing similar symptoms, I felt I should post this information. 
The issue was with the frame ground under the tank. I eventually ran a wire directly from the frame ground bolt, into the relay box and out through the vacant fuse slot, to the negative post on the battery (as Holister suggested - many thanks Holister, and to all who responded). That did the trick!

That's great news that you got it fixed, and many thanks for posting what you found.  You have made an invaluable contribution to the data base.

Laitch wrote:I suggest a moderator move this thread to the Electrical category in the Technical, repair and troubleshooting section where it should have been posted in the first place.

Good point Laitch.
The topic has been moved.
Thank you.