Here's the issue I have.. When I turn the key to the first position I get nothing. Second turn illuminates the cluster and my abs light comes on as it should. I put the bike in neutral, hold the clutch, push the button, anddddd crickets. Nothing. Here's what I believe the problem is. The neutral light never comes on in the cluster. I know that light has to come on to complete the circuit and tell the computer to let the bike start. But also things like the oil light, choke light, fuel level sensor doesn't come on. So here's some more information to help me diagnose. 

• Clutch switch, kill switches, anything that can stop a k bike from starting has been checked and bypassed to attempt starting
  
• Bike has been dropped. Actually backed into while in a garage and fell over. (why its a project bike)
  
• Bike turns over fine when you jump the solenoid
  
• new battery
  
• gear selection switch was taken apart and "rebuilt" by me. (still consider it a culprit though, not my best work)
  

Here's what I think, and my bike mechanic disagrees on. I think the problem is within the cluster. I believe the fall broke an essential ground in the cluster causing half of it to not work. My mechanic is at his whits end and doesn't know what it could be. So what are my options? Can i tear the cluster open and search for the break? Can I get a super cheap cluster that will work properly for my bike and see if that fixes it? Or am I completely off and shouldn't waste my time with that fix? 
My bike by the way is 1991 Bmw K100rs with a RB "Luftmeister" competion turbo kit on it. The bike has 12,xxx miles.

YOU GUYS ARE THE GENIUSES HERE! HELP ME GET MY DREAM BIKE GOING!
Thanks in advance.

Have you tried pulling in the clutch and trying to start it?

That will start a K bike that has the cluster removed.

Yes I have tried that. I didn't know a k bike could start without the cluster. Are you sure a 91' isn't different. I know they changed quite a bit that year. From the looks of the schematic it won't start without it.

In that aspect they are the same, Pull the clutch lever in and that overrides the no start unless in neutral feature.
The cluster is quite easy to get apart to check the bulbs are working and replace them also check for corrosion on the connector pins inside and the pins at the main connector.

Either the N electronics in the cluster or the clutch switch feed 12V+ to the start button. When you press that it sends 12V to the starter relay via the black/yellow wire that goes to the starter relay to activate it.

If that isn't happening then I'd suspect the ignition switch might be the culprit.  Or maybe a ground come loose. Or that funky starter grounding thing.

Check fuse #1 it supply the clutch switch and all that doesn't function in your
cluster, and the your brake light shouldn't function either.

It's not the fuse. I've bypassed both the clutch switch and the starter button. I will check the cluster though for a bad light or two. Also why isn't the first turn of the key doing anything? What specific grounds can I be checking? The only ones I really know of are the 3 under the tank.

TurboBrick wrote: It's not the fuse. I've bypassed both the clutch switch and the starter button.

Did you check if it was 12V+ present in the clutch switch connector?

Does Your brake light function?

TurboBrick wrote: Also why isn't the first turn of the key doing anything?

It is park position, you should then have power to the small pilot lamp above the headlight and and to the taillight.

When you push the start button does the headlight go off?  If not, I would suspect the ignition switch may be dirty.  I had a similar problem with my K75 a couple years ago and it turned out to be the ignition switch.  Seems the design doesn't allow for a lot of pressure on the contacts to overcome any dirt that may be in there.

Even if it isn't the problem, in bikes as old as our K's it isn't a bad idea to sevice that switch. 

http://www.eilenberger.net/K75S/IgnitionSwitch/

No the headlight doesn't go off. I will try that.

The headlight doesn't go out as a result of that you got no power out of the starter relay, that is what breaks the LSR coil ground connection.

Ok. Sounds right to me. I'll see if I can fix that tomorrow. 👌🏽