Expanded charging system guide (In progress)

Thanks for update sounds like you know how to run the tester. That eliminates a diode as a problem, so the rectifier is good the regulator part does not have a "test" other than replace with known good and this; ground the green (outer lower) brush, do you get full voltage then? Voltage should go well past 14 volts when the engine is revved past 3K RPM.

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Edited; because I shot from the hip and 5twins (gently) corrected my aim!
 
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Thanks Gary. When you say "ground the green brush" do you mean attach a jumper to the screw holding the brush in place and attach it to ground? Or jump the green wire from the reg/rec to ground?
 
The green wire from your regulator is the green wire on the outer brush .....

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Your regulator is the ground switching type. It switches the ground on and off to the outer brush. That's how it regulates the charging output. If you ground that outer brush constantly with a jumper wire, the alternator should run full time and at full output. If it does then that would indicate the regulator isn't properly doing it's job. If it doesn't, the problem could be with the stator, rotor, or brushes.
 
Thanks both of you! I'll test this tonight when I get home. The brushes are brand new and the rotor tests at 4.6 ohms so it's looking like either the stator or reg/rec, yes? I've yet to clean the negative battery lead connection and will do that before I ground the green wire
 
Something to keep in mind is that the regulator reduces the charging output after the battery has been replenished. If you want to really see your peak charging output, electric start the bike then immediately test the charging output. If you go for a 10 or 20 mile ride then test it, you could very well see the peak output you got because the battery has been replenished and the regulator has reduced the charging output.
 
Thanks 5twins...that makes sense. I was planning on testing it right after it starts as you suggest. So now that I ponder this...it's entirely possible that my charging system is functioning properly given that when I initially tested the volts at the battery and was only getting 13.5v, possible the charging system was just "topping off" the battery.
So tonight my testing procedure will be: Electric start the bike and check volts at battery. If somewhere near 14.5v then I can assume everything is in working order. If it still hovers around 13.5v then I'll ground the green wire and test again. If it goes above 13.5v then I can narrow it to the regulator. Sound good?
 
Here are the results from tonight's test. I tried to electric start the bike but it wouldn't fire. The battery was reading 11.39v when I kicked it over. Started right up and the voltage only went up to 13.52v, just like my initial test. Even at 4000 rpm the voltage only went as high as 13.6v. I jumped the green wire from the regulator to ground and kicked it over again. This time the voltage stayed the same as the initial battery reading, 11.39v. Changing rpm did nothing to change the voltage. Reconnected the green wire again and voltage climbed again to 13.52v and stayed there. Well...it didn't "stay" there but it didn't go any higher.
 
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If I'm understanding you correctly, you removed the green wire from the brush and grounded the green wire. That's not what you want to do. You want to ground the brush itself.
 
5twins, I unplugged the green wire from the regulator/rectifier side, under the LHS side cover, and jumped that to ground. I did not disconnect the wire from the brush. If I'm understanding you correctly, I need to clip a wire to the screw holding the brush - the screw labeled Regulated Ground in your photo - and jump that to ground?
 
Yes you can just ground the green at either end without disconnecting, the Idea is to connect the brush to ground, making the alternator "ON" full time. wouldn't hurt to ohm out the green and red wire from brush to the 6 pin connector.
PS 4.6 is a low reading, the rotor is suspect, and likely has started to short out, low ohm readings are kinda hard to get right on meters and not always real accurate. I usually call 5 ohms the lower limit for a rotor. Take a look at the varnish on the rotor windings is it "dark and bubbled"?
Your 11.4 on the battery is on the low side also
 
Thanks Gary. I'll retest the regulator tonight. This weekend I'm going to pull the LHS cover and pull the stator so I can clean and inspect the rotor. I'll also test the stator at the same time. I know the rotor is testing low so I'm hoping that after the cleaning and with better access to the slip rings I can get a more definitive result. Regarding the battery voltage, it was down after cranking with the electric starter which, as I'm sure you're aware, sucks the power out of every battery within a five mile radius. ;-P
 
Tested the stator tonight and I got 0.7 ohms between all three white wires. Tested each brush wire to the connector and had good continuity between each. I cleaned up the slip rings on the rotor and am getting 4.5 ohms. The copper wiring all looks good as far as I can tell.
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I haven't used one of the rewinds but if memory serves (and it frequently doesn't) That company does use less but heavier wire. So that lower reading may well be normal. One of those; damn I wish I had recorded the ohms when the rotor was new moments LOL. I think the best course here is to try a different regulator. You know I went back to your original post Maico996 and with hindsight my question is how old is that battery and have you done load tests on it. I am beginning to think the issue is with the battery and or perhaps a starter that is drawing too much current. OR it could be a plugged or at least dirty idle or choke circuit. How's the fuel system. have the carbs been apart? Have you checked spark could be a weak or failing coil plug cap dirty plugs even a valve or cam chain in need of setting. I think the replacement rotor with lower resistance is a bi of a compromise, the heavier wire does make for a "bullet proof" regulator but at the expense of some efficiency performance of the charging system. Do you have any non stock electrical accessories that may be adding load? Also a check of the magnet for the pick ups is well worthwhile While picking a different rotor for my wife's upcoming "new XS" I did some ad-hoc testing I found a long arm 5mm allen wrench when held lightly by the short arm could be moved out to about 45 degrees or so before it would "unstick from the magnet" I need to do a bit more to "quantify" an easy pickup magnet test.
 
The short version is that I fell for answering your "what is wrong with my charging system" question instead of asking questions related to it not running well until fully warmed up.
Hint many of us like the security of the cheap and readily available small led volt meters that can be installed in or near the gauge cluster.
 
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Thanks Gary. The battery was bought last year but I haven't done any load tests on it. The fuel system should be ok...I rebuilt the carbs a few years ago and have had them apart more times than I care to remember when I was dialing in the jetting and balancing them. FYI I drilled out the plugs to access the mixture screws. I do not have any aftermarket electrical accessories installed. The coil, wires and plug caps were all replaced. Coil is a high-output coil from Mike's. Next on my list of things to check was the ignition. The bike really runs good once it's "warmed up" so I thought the starter was depleting the battery so much that it was causing a low voltage issue which the charging system wasn't able to overcome until the bike had been ridden for about 15-20 miles. I did pick up a starter off a bike that only had 60 miles on it so I have that to swap out. I'll go through the ignition and (ugh) pull the carbs and go through them too.
So based on the test results you feel the charging system is ok?
 
The only thing you could possibly do to put your mind at ease would be as Gary suggested (then crossed out). Try a different regulator. For electrical stuff, sometimes substitution is the best test.
 
Free test that get you in the saddle!
Top up your battery with a charger, unplug the regulator, then take it for a short ride how does it act?
 
"Unplug the regulator"...just unplug the green wire from the reg/rec connection? Mine is connected by bullet connectors (no factory connector). Or unplug the entire thing, all seven wires?
 
Unplug the green so the brush isn't grounded, will do it. This is a "weak pick up magnet" test.
 
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