Hello I bought a bike from towing company lien sale. And I'm trying to get it started. Looked through some post with no start issues, but wanted some help on my specific problem. Had locksmith to make key which only goes to 1 position not 2. I'll take care of key problem with him later. So I short red and green wire to get oil, battery and neutral lights. On and off red switch is in middle position. Push green starter button but get nothing. Horn, signals, button to cancel signals, hi and low beam button work. All fuses are ok. Battery voltage on all fuses except 1, which is fuses 5 or 6. Counting from top to bottom. Not at home now to check. Pulled fuel tank, connector from right hand control has brown wire which i believe is from the start button. I see resistance change with multimeter connected at 9 wire plug/connector under tank when the start button is pushed. Not sure if that is the same wire on starter relay under seat the large black one with 2 heavy wire and plug on the side with brown/red wire and black/yellow. Also I can short the two heavy wire and starter cranks engine over. Wondering where to look next? Will get a service manual later. But don't want to invest too much money or time until I verify the bike runs. Thanks for any help. I think the bike is a base model also. And I also swapped the 2 blue relays.

Black/yellow wire from right combo switch getting 12V+ from the start button is what triggers the starter relay.

Is the green N indicator in the cluster illuminated when the bike is in neutral?  That circuit sends power to the start button.

Trying pulling in the clutch lever as that is the other way to get power to the start button.

I'll check the black/yellow wire this evening. I tried pulling the clutch lever in. And with the side stand up and down. Still starter would not turn over. Someone posted a wiring diagram I'll try to find that post and look at it again. Yes the green indicator is lite while in neutral.

85 K100 will not have a sidestand switch.

If you are getting nothing also check the plug on the fuel injection control unit FICU under the seat, make sure its correctly seated.

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Thank you very much Mr Duck It started. Guess i can tell you how dumb i feel. Just needed to pull in the clutch lever. Fired on the first try. Only spent $200 on it so I can’t complain. Will take ignition switch back to locksmith tomorrow. And i ordered the correct key blank off ebay.

Congrats on that. It's a great thing to hear that BMW start for the first time. It truly is.