On the way into work today My k100 died. Riding along quite nicely then everything went dead, dash lights, engine, everything.

This has happened before and I think it's a problem with the switchgear on the RH handlebar.
So with a bit of fiddling/shaking i got the hazard lights to function while i undid the screw holding on the cover.

After about 5 mins of shaking/pulling wires the dash lights come back on and all seems well, I started it up, no problem.
Just as I'm putting my gloves back on it dies again.

So, as I said, I'm pretty sure this is related to the rhs switchgear and maybe the ignition?

Just wanted to check if there's any known faults that match the above description, so maybe I can save some time fault finding.

Bike remains by the side of the road halfway between work and home...

Could be a connection problem with the cut-off switch in the RH switchgear.According to Bert's interactive electrical diagram for that circuit, the cutoff switch controls most major electircal circuitry, including power to the ignition componentry and instrument cluster. The RH cluster wiring is accessable under the tank. It may be possible to get going temporarily by jumpering Green to Green/yellow (Pin 9 to Pin 2)on the undertank connector, which effectively bypasses the cutoff switch. If that brings the bike to life, then the problem is the cutoff switch. If it does not, the problem may be a poor connection in the ignition switch, a stickier problem.

Caveat: If you don't feel confident with the electrics on your bike, I suggest you don't try this temporary solution. Check Bert's diagram on this site to see what I am talking about.

Morning Mook,

It sounds like you have got a dodgy connection somewhere, here is a quick link thats worth a look http://www.ukgser.com/forums/showthread.php?t=193313

A lot of people on here suggest using deoxit on all the electrical connections, I have currently got my bike apart to sort out all the electrical connections, and in the process have found a lot of "extra" wires that havent been terminated properly which have the potential to cause a short...

If you were a bit closer to me would have been able to offer a tow off the road....

Thanks guys,

will concentrate on the cutoff switch for now as the symptoms seem to match.

As for the starter motor... well I guess that may be my next stop. But from wiggling/playing with the wires to the switchgear and getting intermittant results I think that's where the problem is.

assuming it is the switchgear, I've been looking here, I'm not sure if it's the 8V or the 16V that i may need. any thoughts?

Forgot to add,
when the power goes off initially I lose everything, but moving the head light switch on/off a few times seems to give me hazerd lights.

Would this rule out main earth? (if hazard lights work but nothing else does?)

The main earth is more the main earth point where most of the other earths are bolted onto.

Having just been working on my hazard lights. They connect to the central indicator relays under the seat all the cabling runs back to there and it will override the indicators

I have just been down to my bike and disconnected the right hand controls under the tank (bike is stripped down at the moement) and i loose all control of brake lights etc from that side. I still have the left hand controls working horn, left indicator etc

Hmmm... never though to try the LHS switches... will do that when I get back to it.

thanks again!

mook wrote:assuming it is the switchgear, I've been looking here, I'm not sure if it's the 8V or the 16V that i may need. any thoughts?

An '85 K100RT would be a 8V machine (usually refered to as 2V). But I think it is a bit premature to be buying new switchgear at this point until you've identified the problem.

I think you're looking in the right area. If you get hazzards when you play with the wires to the switch assembly, that indicates a poor connection either in the switch assembly itself (corrosion / bad solder / broken plastic) or in the RH connector under the tank (corrosion / broken wire).

you didnt check any of the fuses ?

or give the starter a tap with a blunt object ?

Given that with some wiggling of wires earlier the bike started up I don't suspect A fuse issue.

I didn't consider the starter to be the culprit, as all power seemed to be lost to the dash lights...

The bike electrics ground through the starter so dirt in the starter will cause intermittent electrical problems in all systems. Rapping the starter might dislodge dirt and/or cause better brush contact and restore the ground circuit.

robmack wrote:The bike electrics ground through the starter so dirt in the starter will cause intermittent electrical problems in all systems. Put the bike on the centre stand, into 5th gear and try rotating the back wheel in both directions. If the electrics respond on/off, the problem could be a dirty starter.

Will try this... Thanks!

Read my update; I thought I read about the 5th gear trick on this board but may be mistaken. Rapping the starter may be more productive.

Ignition switch ??? The hazard lights work with the kill switch off.

ok.
update time.

Went back to the bike yesterday after work, and the problem was still there.
-No power
-after fiddling with switches a bit I get hazard lights
-opened up the switchgear (RHS) fiddled with wires/switches- Power on!
-start bike, put on helmet and gloves, sit on bike, Lose all power again
-Call breakdown recovery
-keep fiddling with wires in the meantime, -Power on!
-start Engine, Runs!
(this is where it gets wierd)
-turn off/on ignition to see how stable the connection is
-when engine powers off, (ignition off, Me not touching the bike) starter keeps cranking,
-turn ignition on, bike starts (on it own!) I rev it good,
-bike runs, I ride home and cancel breakdown callout.
-Bike starts this morning no problem, running like a top.

do I need an exorcist?

It is relatively easy to whip the starter motor out and de-dust it. As the others have mentioned, the carbon brushes as they wear cause all manner of electrical gremlins and if you've not done it in a while I recommend doing it anyway. It's worth a look, and might save you the trouble of twisting your head right round on your neck searching elsewhere.

yeah, not a bad Idea.

So to direct me to the right bit of fairing to remove... where is the starter located?
It's not easily visible from the outside.

Looking from the left hand side (shift lever side) view the back end of the starter motor just behind the ignition coils and in front of the battery. The underseat tool tray comes out, as does the ECU and the battery. It's held in by two screws and disassembled by undoing two long, thin screws. Slide the motor straight back away from the engine. Note the position of the brushes when you pull the end cap off. Have a can of contact cleaner and some clean rags with you. Sometimes the brushes are shot and it's time to replace them. Let us know how it goes. I reckon a thorough starter motor cleaning should be done every 30 thousand kilometres or so.

Some pictures is usually helpful when dismantling.

Inge K.

Tom Coradeschi Starter Cleaning Instructions

No pictures but a good description

Repair of a K100 Starter Motor

Nice writeup but in German. Use Google Translate to get the language of your choice.

UPDATE: I just wrote a tutorial on cleaning the starter motor and put it in the Tutorial Section of this web site. It has step by step instructions, with pictures, for removing, disassembling, cleaning and reassembling the motor.

So as an update, there's been no issue sice my last post. I've not had the time to get near the starter yet. ( our new 3 week old baby boy taking up a lot of my time at the moment).

I did give the switchgear a good soak in WD40. and *touch wood* everything seems to be running fine so far.

You seem to have your priorities right!

aye !...the young ones are precious