new to me 1976 KZ 900, wires go where?

****UPDATE****
@F64
Mikaw and all, I have the wires secure. The longer black wire that was on the relay is now fastened next to the seat lock location. The taped loose wire with bullet end is now fastened to the engine block with the negative battery lead. I took apart the starter button handle and all looked good, clean and spring worked well, blew it out and have it back together.
When I turn on ignition, engine on run and press the start button the neutral light dims which tells me the button is working properly not stuck. Nothing else happens when I push start, no clicks, no odd sounds, starter not working. Should I check a few more voltage readings? Where should I check next? 

I’ll let F64 run you through testing. Do you know for sure you have a good fully charged battery? I would pull the heavy gauge black starter wire off the start relay. Test the starter with an auxiliary battery. Bike in neutral on center stand. 
 

Thanks @Mikaw,
battery tests out good, well charged. Testing the starter I put positive to heavy black wire and then ground to the bike frame correct?

Yes. Auxiliary battery positive to black starter wire and auxiliary battery negative to engine. I’d touch the negative to the engine ground bolt were the bike battery is grounded. It will probably flash and spark so you won’t want to ground it to anything that could get arc flashed. If you take the starter cover off you could also touch the auxiliary battery ground to the starter body. 

Yeah,
Check the starter relay again.

Key on/ ignition on
Meter DC V

Black probe on battery negative post
Red probe battery positive post
What is your voltage

Move red probe to starter relay terminal with the big wire from battery.
What is your voltage?
Press starter button
What is your voltage?

Red probe to large terminal with wire going to starter.
What is your voltage?
Press starter button
What is your voltage?

Red probe to small black wire at starter relay
What is your voltage?
Press start button
What is your voltage?

Red probe to black wire yellow stripe at starter relay
What is your voltage?
Press button
What is your voltage?

Turn off bike

good evening gents,
Test Results @F64

Black probe on battery negative post
Red probe battery positive post
What is your voltage - 12.11v

Move red probe to starter relay terminal with the big wire from battery.
What is your voltage? - 12.11V
Press starter button
What is your voltage? 12.0v , heard a click and neutral light went out

Red probe to large terminal with wire going to starter.
What is your voltage? - 12.08v
Press starter button
What is your voltage? - 12.08v

Red probe to small black wire at starter relay
What is your voltage? - 12.09v
Press start button
What is your voltage? - 12.09v

Red probe to black wire yellow stripe at starter relay
What is your voltage? - 12.09v
Press button
What is your voltage? - 12.09v

Let me know next steps and thanks!!!
going to test the starter next to see if it works.

The relay appears to be stuck closed. 

Trace the small black and yellow wire from the relay.That wire needs to go to ground.

Thanks for the measurements. You're doing a great job

I appreciate all the help indeed!! Thanks F64 and everyone, hopefully this helps others who might run into these issues.
That black and yellow wire goes back behind the terminal panel and into a wire loom, you want me to follow that loom till the black/yellow wire exits and make sure it's to the frame ground?
photo attached of the back of the terminal panel
 

Disconnect that black and yellow wire connector and take another reading.

DC V
Key on
Ignition on

Black probe on ground
Red probe on the black/yellow at the relay
What is the voltage?

Press starter button
What is your voltage?

My guess is someone tied that black/yellow wire to positive instead of ground.

 

good morning,
@F74
the terminal panel I unbolted to get to the blk/yel wire and disconnected at the bullet connector.
Black probe on ground
Red probe on the black/yellow at the relay
What is the voltage? jumps all over - Ghost v

Press starter button
What is your voltage? Same ghost v
No neutral light when I turn the key on.
I also checked the wires at the key and key 12.14v on all wires with key on.

Take the unconnected black and yellow that goes to the relay and ground that wire. You can use a spare length of wire. Ground it to battery negative.

Then try those readings again.

@F64, ok, blk/yel wire now grounded to the battery negative.
readings ...
Black probe on ground
Red probe on the black/yellow at the relay
What is the voltage? 0.0v

Press starter button
What is your voltage? starter relay clicks and goes to 3 - 5.5v, starts out at 3 it appears