‘81 gs550 all electrics working except starter, help!!

[Redman]

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........................and the 11.70v was when the start button was actually depressed at the same time with the clutch lever pulled in. So it seems like power is getting to the solenoid??.
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Yes!
But that is only a portion the of the circuit, the larger portion, but not all.
THe other part of the circuit is from the solenoid back to the battery negitive.

The solenoid is grounded thru its mounting, which is bolted to the battery box (notice it doesnt have a wire comming out of it for ground), ..... but the battery box itself is not well grounded to the frame.
So.... the battery box needs to have a ground wire from the bikes harness. And in stock config there is a blk/wht ground wire from the wiring harness connected to the solenoid mounting bolt (with a ring terminal).

In your pic, That thick black wire on battery neg looks to be something someone added. Okay, no probblem.
There can be all sorts of discussion about the best way to arrange the grounds, some ways may be better than others for various reasons.... but lets not get into all that now. Right now we are trying to figure why something doesnt work at all.

Your picture showing the big black wire and two other wires under a bolt on the frame : The big black wire seems to be the one that someone made up to batt neg... okay. The other two seem to be the blk/wht wires of the wioring harnesss. In stock arrangment one will be grounded to the frame like that.
You say there is no blk/wht wire on solenoid mounting bolt... I suspect the one that comes out of that harness with the grn/yel wire to solenoid should be what grounds the battery box at the solnoid mounting bolt. Does it reach?
Or add your own ground wire (if you got the ring terminals) from battery box solenoid bolt to that ground point.

Maybe in your testing and reassembly you did something, moved the battery box, or the ground wire tocuched the battey box or somehting, and that is why it worked for a while.

Other note: In stock config the R/R gorund wire is also grounded there. Were to ground that can be discussed, but forbasic concern it needs to be grounded somewhere.

Other note: In Imgur, when getting the share link, select BBCode, copy and paste that, will appear as the image.

[Redman]

Your picture . . . . .

[2BRacing]

Looking at your photos in post #9, the connections to the -ve battery terminal are a green corroded mess and must be cleaned up and who knows what is lurking under that insulation tape? The solenoid terminals could also be cleaned up to reduce resistance.

Solid, clean ground connections help a lot to eliminate intermittent electrical problems. As mentioned already, the solenoid's metal casing needs to have a good ground connection for the solenoid to work properly. Not sure if the solenoid on your bike mounts onto a side plate of the battery box, but usually the battery box is rubber-mounted to the frame. That is why one of black/white wires with the ring terminal was originally fixed under one of the solenoid mounting screws.

Has the black paint been removed from the frame point where the 3 wires in the photo in post #17 are connected?

[noaho]

Hey guys!

Thank you SO much for all of your extremely detailed help. Wasn't able to get to the bike for a few days, but yesterday I jumped the solenoid like Posplayr recommended and it did indeed turn over the engine. I took Redman's advice and wired the black and white ground wire back to the solenoid mount where it orig belongs. That solved it.

At this point, going to go through and clean up the corrosion on the electrics and start troubleshooting some carb and air/fuel mixture issues. In the future I will be doing more electrical work, and since I'm still learning the basics if you guys have any good resources I should look at to familiarize myself better w motorcycle wiring/GS specific wiring feel free to link them here

Thanks again so much for all your guys' help.