What the ??????

azman857

'80 XS 650SG Rider
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Fridays I have lunch date with the wife and I ride or drive over to her place of work. I took the bike today and after lunch I decided to take the long way home. Wellllll that was the plan....As I was at a stoplight waiting to cross over a bridge I The light change and I let out the clutch and it stalled or whatever and it just stopped running and no lights or electric power what so ever.. I get off the bike and get it over the side of the road so the traffic can pass me. I start checking things over and nothing obvious. Fuses seem good. Now it's 100*or so. Bright sunny and humid(for the desert) day. I take the headlight off and found a loose connection and put it all together again, turn the key and power for a split second. Checked fuses again and still none blown. Long story short, called the wife. She brings the ramps and we get it loaded up and home. I did even tried a spare battery, thinking the it had died. Nope. News as it develops.
 
And the adventure begins; no pun intended. Remember spark, air, fuel, combustion as you troubleshoot. Since you changed the battery I would assume it’s not the charging system, but it still may be. I would check the ignition system first. Maybe clean the ignition switch contacts and check your ignition coil, plugs, and wires. Check all the wires and fuses with a multimeter as well as the TCI box.
 
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Sooo, I sleep on it last night. Turn the switch and it's like I didn't. I have a voltmeter and it was reading 13.8V when it died, so I figure the alternator was doing it's thing. It reads low due to the thermal limiter in it. It's the Fiat one and I've had 2 and both did the exactly same thing. I'm wondering about internal breaking up. I'm going to test the switch next to see.
 
So on the fuse panel the red wire gets 12 V from battery. Then it feeds the 12 V to the switch. Once the switch is turned on it gives 12 V to the Brown wire. So if you turn in the switch and neither side of the brown wire at the fuse panel has voltage than trace it back.
 
Go back to the loose connection you found that gave you a split second of power on the roadside. Could be corroded, arced, burned. Use a 12 volt test light alligator clipped to the engine to trace your battery + paths. Sounds like you got a healthy battery & charging system but something came disconnected. Fuses only blow when + & - come together without a load...short circuit.
 
Well is seems when I re-connected the wire at the fuse box , I didn't do it well enough to it's liking(or she was just being fussy) and no power. Well I checked the battery first. 12V there. Iggy switch with the meter and seemed ok. Fuses checked good. Looked at the wire at the fuses and it was loose so I put it in right this time(between the plates) and cranked it tight. Switch on! The green "N" glowed brightly! OH yes, the engine run switch was checked too and it hadn't self destructed. I looked at the throttle cable and there was another unplanned roadside stop in the making so I'm presently looking around in the parts stash for a replacement. Hmmm maybe I ought to carry a cheap meter in the bag now?
The trouble wire was frayed but still connected. I guess my roadside refresh wasn't good enough at that moment. Ohhh well. all is good again.....almost...
 
Sooo, I sleep on it last night. Turn the switch and it's like I didn't. I have a voltmeter and it was reading 13.8V when it died, so I figure the alternator was doing it's thing. It reads low due to the thermal limiter in it. It's the Fiat one and I've had 2 and both did the exactly same thing. I'm wondering about internal breaking up. I'm going to test the switch next to see.
So you have a Fiat volt meeter installed on the bike? What is a thermal limiter?
 
My bad. I'm running a Fiat Voltage regulator. I believe it has a circuit with a temp regulator. The warmer it gets, the voltage drops.
 
My bad. I'm running a Fiat Voltage regulator. I believe it has a circuit with a temp regulator. The warmer it gets, the voltage drops.
Glad you got it sorted. Wait you have a Fiat voltage regulator? Where's the link for that on here? What was your reason for switching? I'm asking because I have trouble brewing in that area 12.6 running no issues yet but it's coming. this last one is just a smart a** question do you have a Lucas refrigerator?
 
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