First time rehab of a 1976ish basket case

Should I cut down front fender or leave it?


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Yes, you won't get a proper ground for the start button in the right switch assembly until you install and plug in the left switch assembly. It has a ground wire running into the headlight bucket then to frame ground. It shares this ground with the right switch assembly through the handlebars. That means you will probably want to inspect that contact to make sure it isn't all rusty like the right side one was .....

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5t, Jim, and everyone else who was following along so intently and providing such invaluable information, I can only apologize for the disappearing act. Im back in the saddle (literally and figuratively) with little to show for my 6 month hiatus, aside from a clutch pushrod seal replacement and more wiring questions. My left side control assembly has no ground wire, and i can’t find any year wiring diagram to match it. Ill snap pics when I get home. Would it be out of the question wire in a ground from the control housing contact plates into the loom and just ground to frame from there?
 
I guess the early models didn't have a ground wire running out of the left switch to the headlight. Mailman just went through all this on his XS2 resto. It appears Yamaha may have relied on the ground to occur through the clutch cable, sketchy at best, especially if you keep it all greased up. I would add a dedicated ground wire. You could run it into one of the switch assemblies or attach it to the bottom of one of the handlebar clamps.
 
Yes, I went through all my handlebar controls and there were no ground wires. I was having intermittent problems with my electrical system, the horn and lights and starter.
What I did to correct this was I ran a black wire through my left handlebar loom that went from my left hand switch to inside my headlight bucket. Inside the switch I put a small eye terminal on the end of the wire and connected it to an existing screw.
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I also made sure to take some sandpaper or a small file and shine up the switchgear where it contacts the handlebar. Then on the inside of the headlight bucket, I found a black wire , wiring harness multi plug that had an open space and I put a bullet connector on that black wire I just ran, and plugged it into that multi plug. If you can’t find a multi plug with an opening, then just tie it into one of the existing ground wires.
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As soon as I connected that ground wire to the main harness ground, all my electrical gremlins disappeared.
Good luck to you!
Bob
 
Yes, I went through all my handlebar controls and there were no ground wires. I was having intermittent problems with my electrical system, the horn and lights and starter.
What I did to correct this was I ran a black wire through my left handlebar loom that went from my left hand switch to inside my headlight bucket. Inside the switch I put a small eye terminal on the end of the wire and connected it to an existing screw.
View attachment 136591

I also made sure to take some sandpaper or a small file and shine up the switchgear where it contacts the handlebar. Then on the inside of the headlight bucket, I found a black wire , wiring harness multi plug that had an open space and I put a bullet connector on that black wire I just ran, and plugged it into that multi plug. If you can’t find a multi plug with an opening, then just tie it into one of the existing ground wires.
View attachment 136592
As soon as I connected that ground wire to the main harness ground, all my electrical gremlins disappeared.
Good luck to you!
Bob
Thanks bob, I’ll be rigging something like that up in the near future. Your bike came with a real loom with multi connectors??? I had a dream my bike was that unmolested once.. but you get what you get for pocket change, in my case it was a rats nest fit for a king. Principal still applies though, I’ll run them straight to a frame ground or into the loom. Photos of controls and ignition coming at you in a few minutes
 
You should only need to ground one of the switch assemblies. The other should pick up that ground through the handlebars, as long as where both switches clamp is clean. That was another issue Bob encountered with one of his switches. It was new and painted too good. The part that clamped around the bar was painted and couldn't make good contact.
 
Ok, if this gets too confusing I’ll try to mock up a diagram but here goes. First image is ignition, with 2 brown, 2 black/blue, one red, one red yellow.
Red to fuse/battery
Red/yellow to starter button
In “on” position I have cont. from red to browns, and red to red/yellow
In “park” position, cont. from red to blues.
In better news, I’ve made some sense of the control wires
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below is shiny new right controls (shorted out old one and melted some stuff.. I’m that inept). Red/white to red/yellow on ignition loom (starter)
Brown to red on coils and to red/white on starter relay
Blue/white to blue/white on starter relay
This leaves a black/blue, blue, and red/yellow. I’m guessing one goes to hot, one goes to left control dimmer, and one goes to headlight.. but who goes where?
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Below is left control. To keep this short, I know what wires go where, just need to piece everything together and create a whole new bike-specific diagram since nothing matches any one (or any) diagrams in my clymer
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so that’s my novel. I’m just looking for any insight on how these puzzle pieces go together and the rest should all be really straight forward.. you know, like it always is
****edit*** it should be noted that I won’t be running any dummy lights or safety relay. The bike has only the necessary lights to pass inspection
 
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You should only need to ground one of the switch assemblies. The other should pick up that ground through the handlebars, as long as where both switches clamp is clean. That was another issue Bob encountered with one of his switches. It was new and painted too good. The part that clamped around the bar was painted and couldn't make good contact.
5t, I took a stone wheel on the rotary tool to everything under both control housings and at getting zero resistance! It looked like p/o (more like pos) had just scratched it up with either a screwdriver or his teeth to get some semblance of a ground
 
On your ignition switch, red/yellow is power out to the headlight on/off switch in your new right switch assembly. Connect it to the red/yellow coming out of that switch. The 2 blue/blacks are just plain blues. They power the tail light and I think the instrument illumination bulbs in the "Park" position.

On your new switch, the blue/black would run over to the hi/lo switch in the other handlebar control. It would send headlight power there when you turn the headlight on/off switch on. The blue is also from the headlight on/off switch and should be tapped into a blue running back to the tail light. Usually the blues coming out of the ignition switch have multi-connectors on the ends where you can plug that handlebar switch blue into. Brown would be power into the kill switch from the ignition switch and red/white would be that power out to the coils.
 
Blue/white should be the start button. It comes from the solenoid. It grounds that wire out when you push the button. Look up inside the switch and I think you'll see red/white and brown going into the kill switch. You should also be able to see the blue/white connected to the start button and the red/yellow running into the headlight on/off switch. At least that's how the factory did it. If your new switch is some aftermarket repop, who knows what color wire goes where, lol.
 
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Blue/white should be the start button. It comes from the solenoid. It grounds that wire out when you push the button. Look up inside the switch and I think you'll see red/white and brown going into the kill switch. You should also be able to see the blue/white connected to the start button and the red/yellow running into the headlight on/off switch. At least that's how the factory did it. If your new switch is some aftermarket repop, who knows what color wire goes where, lol.
My mistake, I misspoke!!
 
Blue/white should be the start button. It comes from the solenoid. It grounds that wire out when you push the button. Look up inside the switch and I think you'll see red/white and brown going into the kill switch. You should also be able to see the blue/white connected to the start button and the red/yellow running into the headlight on/off switch. At least that's how the factory did it. If your new switch is some aftermarket repop, who knows what color wire goes where, lol.
So, from right handlebar to ignition I’ve got red/white to coils, blue/white to starter, red/yellow to red/yellow, brown to brown, which leaves blue black (to go into hi/lo) and finally blue, which will go back into ignition and branching to tail light. Does power to headlight come from blue as well? Sorry I’m so bad at this. **edit** nope, it would come from the left side control housing via the hi/lo wires, right? Lot of learning happening here..
 
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On this diagram i have left the L/B, (blue/black), going to the reserve light unit.......Your loom seem to have a lot of bullet connectors.............This was a feature up to and including the 77D........As per previous posts it is easier to identify the year of the parts/looms ect..........
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On this diagram i have left the L/B, (blue/black), going to the reserve light unit.......Your loom seem to have a lot of bullet connectors.............This was a feature up to and including the 77D........As per previous posts it is easier to identify the year of the parts/looms ect..........
View attachment 136608
Thanks man! That should help to make some sense of things when I get back out to the garage tomorrow. There is nothing left of the factory loom, there wasn’t when I bought the bike. The right control i believe is a replica, and I think the ignition is nos. Left control might be original, but off of what I surely don’t know
 
Post some more pics..............Not so they are so close up, gives us a chance to see more and be able to help identify.........

without going back through the thread .........What year loom did you get from mikes.........??
 
Post some more pics..............Not so they are so close up, gives us a chance to see more and be able to help identify.........

without going back through the thread .........What year loom did you get from mikes.........??
I am not using a premade loom, I’m wiring everything from the ground up to force myself to learn how the system operates. Was it a mistake? Probably. But thanks to the support from everyone here it’s all coming together and I should be able to take this info and run with it and not bother anyone with questions for a while, just entertain with success photos. Time’ll tell!
 
Greasy, I just started watching this thread, I'd offer you some bits and pieces off a 1972 but Mailman has snagged most of the good stuff:D

I do have some odds and ends of other year bikes that may be of some help if you are not worried about being 100% original!

Just noticed you are in Spencer NY. Up till a few moths back I had never heard of the place. But a couple friends of ours bought an old farm house and barn down that way right on 34.
 
I am not using a premade loom, I’m wiring everything from the ground up to force myself to learn how the system operates. Was it a mistake? Probably. But thanks to the support from everyone here it’s all coming together and I should be able to take this info and run with it and not bother anyone with questions for a while, just entertain with success photos. Time’ll tell!

Gotcha.......yea that will make you learn........go to the "Tech menu"......"Electrical" ........"wiring looms"........and scroll down and check out the XS2 wiring diagram for a simple wiring loom.......Ask some questions pertaining to the safety relay set up...........Yamaha did an after thought on the wiring, to and from the coils to the safety relay when they introduced the Electric start..................
 
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