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1980 Yamha XS 650 Charging system
- Thread starter RW198
- Start date
PM on the way.
So... you told me in our PM that you're reading 4.3Ω between rings. That should be good enough to charge. Let's start from scratch.
Comment #3 in my rotor ad is a copy of the TECH section troubleshooting guide with a few extra bits added by me. Have you gone through that yet?
A few questions:
Batt voltage with the ignition off.
Batt voltage with the ignition on.
Batt voltage with the engine at idle.
Batt voltage with the engine at about 3000rpm.
Length of brushes.
List of any (electrical) parts replace.
Give us some info to go on and we'll figure this out..... we always do.
Comment #3 in my rotor ad is a copy of the TECH section troubleshooting guide with a few extra bits added by me. Have you gone through that yet?
A few questions:
Batt voltage with the ignition off.
Batt voltage with the ignition on.
Batt voltage with the engine at idle.
Batt voltage with the engine at about 3000rpm.
Length of brushes.
List of any (electrical) parts replace.
Give us some info to go on and we'll figure this out..... we always do.
Hey Jim, I was going through your charging system by dummies list and when I jumped out the regulator the bike started working perfectly, 14.6 volts at 3k rpm at the battery. The battery voltage is 13.18 not running, 13.08 key on, and 12.79 at idle 1,300rpm (with the apparently faulty regulator) still plugged in. With the regulator jumped out at about 1,300 rpm it reads 12.9/13 volts at the battery. So as far as I can tell the regulator/rectifier is bad? Ground to any part of the frame, handlebars and engine comes back with zero resistance.
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By "jumped out".... you mean you ran the green wire to ground?
Yes. I also checked to see if I have a good ground anywhere on the bike and all tests came back with no resistance between the battery, frame, handlebars and engine. The slap test was also good. It pulled right into the case.
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So if you un-ground the green wire it goes back to not charging? If that's the case, yeah... sounds like the regulator is bad. Is it the original reg/rec?
No, it’s actually still working…. And charging. It is a new part, but I kinda cheaped out on that and got a Chinese one off of EBay. And I apologize, the stator is new from Mikes Xs, the old one was shorted out not the alternator.
That's good!! Maybe a dirty pin in the connector?
These old bike benefit greatly if you take the time to give each connector a good cleaning. There's over 40yrs of grime and corrosion buildup in 'em.
I redid the ground from the battery to the frame. I didn’t have that cleaned up very good. I’m going over all the connections and plugs again. But I am VERY happy that it is charging again. I’ll let you know if I find anything!
Yes... please keep us posted.
I checked everything out today again and everything is working perfectly! It purrs like a kitten a roars like a lion. Best of all the electrical system is doing exactly what it should and charging away! I am still a little concerned about the rectifier/regulator. Has anyone had one cut in and out like that? Or maybe the ground was a little iffy?
I have destroyed some regulators automotive parts ( pins not always in the same location ) connecting them the wrong way and they die Immediately
So my viewe is they work until they dont
The older mechanical type regulator can sometimes have a wide range
Rectifier usually can take e beating better .But everything is Possible
So I believe the ground is the problem
May I suggest install a Voltmeter They are not so expensive and can save the day and the night as well
So my viewe is they work until they dont
The older mechanical type regulator can sometimes have a wide range
Rectifier usually can take e beating better .But everything is Possible
So I believe the ground is the problem
May I suggest install a Voltmeter They are not so expensive and can save the day and the night as well
Look in TECH. There's articles in there to build your own reg/rec that's reliable and (much) cheaper than buying one.
Keep in mind that 4.3Ω reading means the insulation in the rotor is breaking down. Supposed to be 5.2Ω. Might last another year or two... or just an hour or two. No way to tell. You might want to consider a rewind this winter, rather than summer when you would rather be riding instead of waiting on parts.
Ride it 'till the seasons over. PM sent.
