On a group ride my bike suffered a total electrical failure, the bike just cut out. The K Kronies sprang into action and after switching the ignition switch and kill switch on and off I turned the isolator switch on and off and the system sprang to life again. It behaved it self for quite a while but I did order another switch as a back up. It then played up a couple more times but it was an easy fix just turn the switch on and off a couple of times. Yesterday I decided to fit the new switch. An easy swap and once done I decided to pull apart the old switch and see what the problem was. Once apart there was very little to see the arrows point to a tiny bit of arcing and a little bit of discolourization.

So... fixable?

Dai already cleaned up and ready to bolt back together. I might use electrical contact grease on reassembly. However it might be another 15 years before I need it.
Regards Martin.

My K75 was suffering the same problem of cutting out. and turning key of then back on (or kill switch) it would start up again.

From this forum, advice was ignition switch needing cleaning. when I took the switch out to clean it I found it to be in good condition. I still cleaned it.
Bike went ok for about 300km with no problems but then started cutting out again.

Further investigation, I found the igniting box had the rubber cover partially dislodged. As I touched the plug came fully disconnected.

Now I have pushed that back and cable tied it to prevent any future unwanted movement.

I have not been able to go on any test rides as I have had surgery to do hernia repair. it will be some time before I am able to ride.

Kim the isolator switch is an aftermarket addition. Bricks can have a problem when you have low battery voltage and the relay points stick and the starter just keeps cranking over until it is totally exhausted. Turning off the kill switch or ignition switch will not stop it. The first time it happened to me was just after I bought the bike. I tried switching ignition and kill switches and it just kept cranking until it blew the side out of the battery. The end result was acid everywhere, luckily I had access to water and was able to dowse both the bike and myself. This seems to be at the upper end of the problem I don't think anybody else has had that happen  The best  way most owners have found is to disconnect the earth lead from the transmission. Owners have come up with various methods of doing this. I fitted a Narva isolation switch in the earth lead behind the lefthand side cover. 
Regards Martin.

Great idea. I made a new earth lead using a large spade fuse. Works great, easy to pull and refit. Also creates an excellent point for checking current draw. Found some picks.

Make sure that you are carrying a spare fuse or two somewhere on yourself or the bike. I have seen the terminals and the fuse link pull out of the fuse housing on a few occasions.

Thanks Dai. It's one of those huge 40amp large spade jobs. I soldered the ring ends on myself, I will have passed on before they let go. But yes I always had a concern over the manufacturers work at the spade holder. I keep the original ground cable with me on the bike just in case.

I am unfamiliar with the concept of an isolator switch. I see that it is aftermarket. Is it's purpose to cut all electricity in the event that no other OEM switch stops an undesired electrical event? Is it also used to obviate the need for disconnecting the battery for an electrical repair? Any other uses? Are the switch and the fuse in the battery ground wire two different solutions to the same problem? Thanks

The primary job of the isolator switch is to cut power when the relay sticks due to low battery voltage. It can also be used to cut power when working on the electrical system. And it can be used as a security measure as the power can be switched off and the red key removed.
Regards Martin.

Here's my quick disconnect. M6 knob. Allows ground disconnect without tools if starter relay sticks.

That's a good idea looks like most of us have come up with our own way of easily disconnecting the negative.