Hello and I hope this works correctly. I have a 15 k miles 86 K100RS that looks brand new. It was stored inside a dry heated garage for 25 years. Amazing, right! So did the brakes, coolant and all oils. Had a used battery and started and ran bike 3 weeks ago with everything doing perfect. It sat for those weeks and did not start when I tried again. So I got a new battery and installed it to have it not start. The dash light do not come on, brake lights do not work. Read the starter relay goes out so installed one. Same results. I jumped the relay and it started right up with still no dash or brake lights working. There is a load shedding relay but not sure what it does or which one it is as Clymer manual does not say. Fuses are checked and good, power to one side only on starter relay, starter button does not work or supply power to relay. Still starts quickly when jumping starter relay. I need more info on what this shedding relay does and how to check it. Thanks for your support.

Fixed bike! Stared going through things and checking fuses. The top and bottom 7.5 fuses checked open while they were good yesterday. Replaced them, bike fired up, lights worked etc. Ran it up and down, stopped and restarted it. 2nd time, starter stayed engaged. Took off battery lead, checked starter relay and it was closed. Swapped in old relay and all good again. Fuses showed good then open so will replace all of them tomorrow. Now have a spare starter relay, also. Used vehicles have many twists and turns but should work eventually.

could be in the kill switch circuit

Quite probably is the kill switch. If you've ever started the bike at night and seen the lights go out when the engine turns over, that's the load shed relay in action. It unloads ('sheds') all un-needed power to give the battery a better chance when starting the engine.