81 xs650 dies while cruising.

Battery is new this year, and I took it back and had it tested- it's good.

Keyswitch meter shows 12.3 idle, 11.9-12 with brake plus turn at idle
What should I expect to see at idle with brake + flashers?
I am a bit worried about that also.
I have a substandard wiring and have ground drawn directly to minus on battery via an extra wire.
I am at --- the TCI has not the right physics ,,power / ground
From where to where? Are saying you put a separate ground on the TCI box, or that you ran a wire from the main harness ground out to the battery ground?
 
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Battery is new this year, and I took it back and had it tested- it's good.

Keyswitch meter shows 12.3 idle, 11.9-12 with brake plus turn at idle
What should I expect to see at idle with brake + flashers?

From where to where? Are saying you put a separate ground on the TCI box, or that you ran a wire from the main harness ground out to the battery ground?

This is how I did it
I put mine on a Boyer Bransden box + 12 V Battery to ignition box outside the harness ...
Ground from minus battery to ground on Boyer ignition Box outside the harness ...
Be careful if you do it and feel free to upload the actual wiring so I / We can look at it
AND DON'T leave it there

The white down in the left corner --to frame earth negative --Instead to battery minus
The red going into the box from ignition switch and kill switch --- Instead from battery positive + 12 V
In my case it was the ground .that caused the problem ... so .I left that and pulled the red via the ignition switch so it does not have power on all the time


On Boyer http://www.boyerbransden.com/pdf/KIT00303.pdf

upload_2021-7-16_17-54-16.png
 
The tci module will work fine down to 11 volts. However there will not be enough umph to push out a strong spark through the coil. That said, the tci can have intermittent issues... usually funky solder joints. Take a close look with a magnifying glass. Sounds to me like you have more than one problem.
 
Last night I cleaned the slip rings and put an extra ground from where the RLU unit used to be to the battery strap. I also put in led taillights. It didn't make any difference in the charging voltage at idle. I also tried unplugging the headlight at idle. It didn't make a huge difference. 12.4-5 instead of 12-12.2.
My understanding is that i should be approaching 13vdc.
The i did some ground checking and found 0.5 ohms to the battery from the engine.
The meter didn't show a really constant reading from the handlebars to the battery ground. Sometimes it showed a low resistance, but it wasn't real steady.
How do the handlebars normally get to ground?
I'll upload some pictures of the harness connections when I get a chance. They seem good to me, but maybe I'm missing something obvious.
 

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I don't see much over 12 volts at idle on either of mine, and that can drop as much as a volt when I turn the lights on. I've never seen 13, but both bikes charge just fine once revving (low to mid 14's). I consider this normal. It's always been like this, early on when I had the old stock mechanical regulator and stock "open air" rectifier on my '78, really didn't change after the upgrade to an automotive VR115 regulator and Windy Nation rectifier. But what I like about the VR115 is it's output is more consistent and steady. The output from the old mechanical regulator was all over the place, bouncing up and down even at cruising speeds. I think the vibration was responsible, messing with the mechanical points inside the unit. My '83 still has the stock reg/rec but since it's solid state, it's output is nice and steady. I have no plans to change that out anytime soon but do have an automotive replacement should the need arise.

Normally, the handlebars get a ground from a ground wire for the horn run out of the left switch assembly into the headlight bucket. There it plugs into one of the available ground wire connections that run back to the frame. The ground wire connects to the left control's housing, effectively grounding the whole thing .....

I7OCZNO.jpg


The horn button picks up it's needed ground through the housing and the ground is also transferred into the handlebars through the wire retaining clip. This allows the wire retaining clip on the right switch assembly to pick up the ground and use it for the start button. This is why installing painted handlebars can often cause the start button to stop working. The paint blocks the ground from getting into the handlebars.
 
I don't see much over 12 volts at idle on either of mine, and that can drop as much as a volt when I turn the lights on. I've never seen 13, but both bikes charge just fine once revving (low to mid 14's).

The horn button picks up it's needed ground through the housing and the ground is also transferred into the handlebars through the wire retaining clip. This allows the wire retaining clip on the right switch assembly to pick up the ground and use it for the start button. This is why installing painted handlebars can often cause the start button to stop working. The paint blocks the ground from getting into the handlebars.
Ok. Good to know that 12.3 or thereabouts isn't unusual. I find varying amounts when I look through the forum. Since I haven't really had this bike running much, I don't have a great sense of 'normal'

Thanks! I'll check that clip on both sides and confirm all the grounds are good. I actually just ordered a new LH assembly because there's a 'weird' feeling when i pull the turn signal lever left. It kinda reminds me of when you have a bad light switch on the wall. It still works, but it's not crazy to think that the switch might be causing the issue I'm having with the signals causing the ignition to falter.

Also, 5twins, your buddy with the Mike's xs harness, do his gauge lights work? Mine don't, even before I made that harness change. I haven't really messed on fixing that much yet, but it's in the works. They definitely worked for me before the harness swap.
 
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Funny you should mention him. I told him about your similar "headlight always on" problem and directed him to this thread. He just got back to me. He tore into his harness but it's different than yours. He didn't find the blue/black tied into the blues like yours was so he hasn't "fixed" his problem yet. In fact, he said he didn't even see any blues, lol. I didn't ask him about his instrument lights but I will. So, he has issues with his MikesXS harness too, just not in the same spot as yours. His is an '80 SPII.
 
I thought I'd add a little update here - my buddy finally got his harness sorted. His issue was related to the light checker. There is a blue/yellow wire coming out of the key switch that carries tail light power to the light checker when the key is turned on. There is also a blue/yellow wire that carries headlight power from the RLU to the hi/lo switch. These two, even though they are the same color, shouldn't be connected ..... and his were. So he separated them and things now work as they should. His headlight doesn't come on with the key anymore, only after the bike is started.
 
I thought I'd add a little update here - my buddy finally got his harness sorted. His issue was related to the light checker. There is a blue/yellow wire coming out of the key switch that carries tail light power to the light checker when the key is turned on. There is also a blue/yellow wire that carries headlight power from the RLU to the hi/lo switch. These two, even though they are the same color, shouldn't be connected ..... and his were. So he separated them and things now work as they should. His headlight doesn't come on with the key anymore, only after the bike is started.
Weird. My RLU is bypassed, and it was before i replaced the harness so I've never looked at it in detail. I did figure out what was wrong with my gauge lights though. The blue gauge light positive wire was connected from the speedo straight through to the tachometer, with no other connections. So nothing would ever switch it on. I spliced it into the blue tail light circuit. That doesn't match the print, but the draw is pretty low for those (and I've since switched them to led) so it doesn't really matter. I attached pictures of the stupid loop for the blue wires between the speedo and tach, and the heat-shrink splice where i connected them into the blue tail light circuit. I'm pretty bummed with the quality and customer support on the Mike's xs harness, but it's not like there are a lot of vendors for this stuff so... What can you do?

I've ridden the bike plenty since then, and everything seems pretty good. I think I've got the electrical bugs all worked out.
 

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Normally, on the auto-on headlight relay bikes, the instrument lights get power from a split off the blue/black wire running from the headlight safety relay to the RLU. They come on with the headlight when the relay is tripped (bike started). Connecting yours to the tail light power means they will come on if you use the "Park" position on your key switch.
 
I'm pretty sure that it was the ignitor box for the ignition that was causing all the grief.
The ignition 'choppiness' was caused by the replacement rotor trigger signal.
The weak charging was probably grounding issues through the wiring harness, but I'm less certain about that.
 
Well the ignitor will cause problems as they wear out. Combined with charging and ground issues, you can end up with a lot of different symptoms. It was one comment about it failing above 3000 rpm that interested me. The active part of the advance curve/electronics peaks around 3000 -3300. I think there might be a clue as to what is wrong with the ignitor board in that comment. It would be interesting to look at it with a scope.
 
The ignition not advancing was what i mentioned above as choppyness. My replacement rotor was in, and it didn't trigger the ignition right. I put my old rotor back in, and the ignition timing advanced as it should.
 
I'm pretty sure that it was the ignitor box for the ignition that was causing all the grief.
The ignition 'choppiness' was caused by the replacement rotor trigger signal.
The weak charging was probably grounding issues through the wiring harness, but I'm less certain about that.
I read through the whole thread, and I am new to electrical issues, but you only mentioned the alternator once, if I remember correctly. You were saying you checked all these other electrical components but could a loose wire with the alternator lose connection with higher vibrations? Are any of these symptoms ever traced to a fault in the alternator?
A really interesting thread, beyond the frustration you experienced.
'TT'
 
It would great get to have a photo of it if possible.. The Gonzp project is (or may be ) having issues with non stock magnets so a photo of yours may provide a clue. Next chance you have that cover open would be great.
 
It would great get to have a photo of it if possible.. The Gonzp project is (or may be ) having issues with non stock magnets so a photo of yours may provide a clue. Next chance you have that cover open would be great.
Post #45 has 2 pictures of the rotor that was on the bike when I bought it. The rotor has a glued on magnet. Is that the photo you need?
Is there a thread in the forum about the non-stock magnets? I'd be interested to read it.
 
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