After quite a while standing idle (several weeks) my K100 RT just about started so I took it out for a ride (about 20 miles) to charge the battery up. The next morning the battery was completely flat. I put the battery on charge whilst still in the bike on my driveway. A neighbour commented the next day that when he walked past the speedo clock appeared to be lit up. I have cheched this and he is indeed right. Even with the lights all switched off the speedo lights are on. I've had trouble in the past when starting the bike with an almost flat battery whereby the starter relay would jam closed and hence permanently energising the starter motor. Could something similar happen to another relay to cause this symptom? Or any other possible causes you may know of would be welcome.

TIA

Miamigo

Try to blow the horn and if that works then check out the load shed relay it may be stuck on.
Also make sure the key is turned off not just to the park position.

The horn works and the lights go out when I start the bike so I conclude that the load shed relay must be working. One other thing I've noticed now that I've fully charged the battery up is that the headlights main beam can be switched on even with the ignition off. I've managed to navigate my way around the K100RT wiring diagram in my Haynes manual and it leads me to believe that the ignuition switch is partially jammed closed causing power to the light swich to be maintained even when the ignition switch is in the off position. I can verify this with my K75. Quite useful having two machines of more or less the same type sometimes!

Possibly the ignition switch but also have a look at the right handlebar switch block, if it is falling apart that could happen when the park light comes on with the first ignition switch position.

Thanks Rick.

Quite bizarrely, whilst I was prodding around the back of the ignition key switch assembly, just to see how easy it would be to remove it, the fault went away. No doubt it will return quite spontaneously and run the battery down again.

yep your right ...it will return

Great news. When you pull the switch apart put the whole thing in a big plastic bag that way the bits that come out at a million miles per hour cant scuttle of to the corner of the shed and hide forever.

Here is a how to.

charlie99 wrote:yep your right ...it will return

It did today....in quite spectacular fashion.

As the weather in UK has been so good I took a trip down the A3 to The Isle of Wight to visit some friends. Parking up to go to a cash machine I noticed the speedo lights on again but after a short ride noticed they had gone out!

Whilst about to leave the second set of friends' house to come home a big plume of thich black smoke came out from behind the speedo down in amongst the loom between the forks. Luckily I managed to stop the smoke by just turning the handlebars. Upon inspection there was a black wire which runs from the r/h handlebar switch box and disappears into the loom. The insulation on this wire had metled in places and where it joins the loom had caused the loom insulation to break down too.

Once my friend had supplied a pair of wire cutters it was a simple matter to cut the wire off completely and after sepatating it from the damaged part of the loom I left that end floating in mid air .
After cutting this wire out everything on the r/h switchbox still worked perfectly (lights switch and engine cut switch and engine start switch) so I was able to ride home. Once back on the ferry, and hoping the whole lot wouldn't burst into flames on the car deck, I bought a cup of tea and had a little think. As everything still worked on the switch box it must have been the feed to the heated grips? So I decided to remove the fuse that feeds the heated grips, which isn't listed in the hand book that I keep under the seat but there is a 15A fuse which feeds "Optional Accessories" so I removed that fuse before heading the rest of the way home.

It was dark when I arrived home but I'll have a closer look in the daylight tomorrow. My suspicion is that the speedo lights were coming on because the overheating cable to the handlebar grips heater had melted the insulation on the loom and was putting 12v onto the feed to the speedo lights after the ignition switch.

You are going to have to investigate this well.
That black wire is an extra earth that is put there by the factory to prevent the throttle cable being used as an earth under some fault conditions to do with the indicator switch. If the black earth wire is not there then the throttle cable is the earth and overheats and melts the inner lining of the cable and causes the throttle to jam. Open or closed but it is jammed and I will leave that to your immagination what happens next.
This fault has very obviously happened and by cutting the wire you have put the heat so to speak back on the throttle cable.
I would say that the instrument lights comming on is just a symptom of a far bigger problem.
I know that 140mph can be exciting but when there is bumper to bumper traffic on a motorway that excitment is very easily forgone for a working throttle.

What I discoverd in the cold light of day was that the loom from the ignition switch had chafed through the outer black insulating sleeve and through into the wires within. At this point the feed to the lights in the speedo was intermittently shorting to the red 12 volt wire from the battery. Hence simply moving the handlebars caused the short to appear and disappear. The smoke was caused by the extra earthing wire to the handlebars, as identified by Rick above, also having its insulation chafed away at the same point which ultimately led to the earth cable shorting to the 12 volt feed and this causing the insutalion on both to be severely damaged. There are no fuses protecting the 12 volt line to the ignition switch so maximum current was able to flow down the two wires....limited only by the resistance of the wire itself ! Hence all the smoke.

Apart from the other cables from the ignition switch being damaged (these can be repaired) I shall have to run a new earthing cable to the handlebars and a new red cable to feed the ignition switch's 12 volts.
This is not a five minute job as it involves taking the tank off and some of the RT fairing.

It is difficult to see what had caused the cable chaffing. There do not appear to be any sharp edges in the vicinity of the damaged cable although the cables were quite tight at various angles of the handle bars and in places were held quite tight with tyraps against parts of the frame.

The picture is a bit blurred as my camera won't do "macro" but you can just make out the chaffed cable. This is just below the speedo and in amongst the loom between the forks.