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Discussion Starter #1
Customers 02 road star Silverado...
Did oil change n other misc items..
I always check charging at battery when looking a bike over. Bike wasn't charging so did typical tests n found bad stator..
Replaced stator n reg w oem.. Here's where it gets weird n I'm lost now..
Stator unplugged n it puts out 60+ ACV all day long..
Plugged in n it drops to 11 ACV n only 12.4v or so at battery..
I've spent a month or more trying to find the problem..
I've used 3 different regs now (OEM twice n a cheap Chinese) , I used a 4th one that is the mosfet type to bypass all factory wiring.. They all do the same thing.
I've pulled the stator n checked for pinched wires etc.. All perfect.. All ohms tests are perfect for stator , all wires to/from reg to battery ohm out perfect. Grounds are good, no burned plugs, battery voltage at red wires on starter relay.. Unplugged at reg gives me 60+ACV, battery voltage at unplugged reg...
Good battery
Only additional load are two lights up front..
So two key points ..
Lose ACV plugged into stator
Lose ACV plugged into reg
If I unplug either its good
Wiggling wire harness n plugs no change..

I'm n 04 MMI grad . been self employed for many years. (Normal day job plus working on bikes at home, now 4 yrs just working on bikes)
Any n all ideas appreciated
 

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Have you tried another battery?

can you ohm test the stator? If it puts out 60VAC with no load, but drops to 12.4V with the regulator & battery connected, it sounds like the stator cannot push any current: bad or wrong stator for the bike?

BTW, I assume you are rev'ing the engine off idle when testing the charging? Stator usually does not have enough output to charge the battery at idle.
 

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Discussion Starter #3
ave you tried another battery? YES, NO CHANGE. BATTERY IN BIKE CHARGES WELL N LOAD TESTS FINE

can you ohm test the stator?
NEW OEM STATOR N OHMS OUT PERFECT

If it puts out 60VAC with no load, but drops to 12.4V with the regulator & battery connected, it sounds like the stator cannot push any current: bad or wrong stator for the bike? IT WORKS PERFECT W EITHER THE STATOR UNPLUGGED
OR
THE REG/REC UNPLUGGED

02 xv1600a Silverado
4WM-81410-01-00TW
Looks to be right.. DONT HAVE BOX ANYMORE.. N DEFINITELY CANT AFFORD TO BUY ONE TO MAKE SURE..

I assume you are rev'ing the engine off idle when testing the charging? Stator usually does not have enough output to charge the battery at idle
YEP NO CHANGE ..
 

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from an electrical perspective, if a power source can put out its normal voltage, but it drops too low when the load is applied, there is a high resistance in the voltage source. Im not familiar with the stator on that bike, I assume its at least 3 phases (three wires coming out?).

If the stator is wired in a Y configuration, with a center ground, if the ground connection has high resistance or worse if its only coupled thru capacitance, then you would get a good voltage reading with no load (no current flowing) but it would drop when you connect the regulator and battery. To visualize this, thats what would happen if you took the ground connection off and put a 100,000 ohm resistor in series with it. With no current (load) the voltage would still read 60VAC.

Is it possible to measure the voltage on the stator side of the regulator, and then connect it to the regulator and still measure the stator voltage? If the stator wires stay at a high voltage, but the regulator is only putting out 12.4 V, that would indicate the stator is good.

I would be inclined to wire the stator to the regulator and that to the battery, with nothing else connected to the bike, unless it uses the ECM as part of the voltage regulation circuit.

Its easy to get stuck trying to debug something like this because you are sure the stator is good, the regulator is good, the battery is good, the wires and grounds are good.. but it doesnt work, so you keep trying it thinking "but it has to work!" If all those components are good, then the fault has to be something / somewhere else.

If the ECM is part of the regulation circuit, or the ECM tells the regulator to turn on after the bike has started, make sure the ECM is also grounded solid, and any enable signal to the regulator is working.
 

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Did you check it when the engine is running at 2-3k rpm?
Normally at idle an alternator will not produce enough power to charge a battery.
New alternators with the mosfets adjust so they do work at idle, but general rule is you need to be running at speed to get a charge out of it.
 

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Discussion Starter #7
Yep it's 3 phase.. Typical 3 wires from stator to reg.. Unplugged it tests out exactly as it should
30+ACV at idle (60+ACV at 2k)
OFL to ground

It puts out 60+ACV if isolated (unplugged) at stator plug
It reads 60+ACV at reg plug when unplugged from harness (shows good wiring from stator to reg)

I have tried a mosfet style reg to bypass the factory wiring all together.. Does the exact same thing.. All good till ya plug in the regulator.

Highly unlikely I bought 4 different bad regs (OEM n Chinese)

The only extra part in the system is the starter relay (yes the engineers ran the battery voltage through it) , they both show battery voltage n perfect continuity..



from an electrical perspective, if a power source can put out its normal voltage, but it drops too low when the load is applied, there is a high resistance in the voltage source. Im not familiar with the stator on that bike, I assume its at least 3 phases (three wires coming out?).

If the stator is wired in a Y configuration, with a center ground, if the ground connection has high resistance or worse if its only coupled thru capacitance, then you would get a good voltage reading with no load (no current flowing) but it would drop when you connect the regulator and battery. To visualize this, thats what would happen if you took the ground connection off and put a 100,000 ohm resistor in series with it. With no current (load) the voltage would still read 60VAC.

Is it possible to measure the voltage on the stator side of the regulator, and then connect it to the regulator and still measure the stator voltage? If the stator wires stay at a high voltage, but the regulator is only putting out 12.4 V, that would indicate the stator is good.

I would be inclined to wire the stator to the regulator and that to the battery, with nothing else connected to the bike, unless it uses the ECM as part of the voltage regulation circuit.

Its easy to get stuck trying to debug something like this because you are sure the stator is good, the regulator is good, the battery is good, the wires and grounds are good.. but it doesnt work, so you keep trying it thinking "but it has to work!" If all those components are good, then the fault has to be something / somewhere else.

If the ECM is part of the regulation circuit, or the ECM tells the regulator to turn on after the bike has started, make sure the ECM is also grounded solid, and any enable signal to the regulator is working.
 

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Opps, misread that somehow.

Assuming the stator ohms out correctly (not even sure what it should ohm out to, but normally if all 3 are the same, it's unlikely all 3 are bad).
Can only thing that something else is going on, magnets damaged/missing? If this was the case I would imagine it would be noticeable when you replaced that stator.
 

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Customers 02 road star Silverado...
Did oil change n other misc items..
I always check charging at battery when looking a bike over. Bike wasn't charging so did typical tests n found bad stator.. ...
I have to point out that this is an odd situation. Was the bike running when the customer brought it in?

The reason is it would be statistically odd if the bike was running ok, and being used, he brought it in for an oil change and other things, and you happen to notice the charging circuit had failed. If the bike was not charging it would drain the battery dead while riding with the headlight on in several hours, so from a probability perspective, you just happened to catch it right after it failed, but the battery had not gone dead yet.

This raises the question: is it possible your volt meter is not registering, its internal battery is going dead. Ive seen that happen on Fluke meters, the voltage reading starts running way low, and then after an hour the low battery icon lights up, and the meter shuts off,

Or maybe the point where you are measuring the voltage itself is just a bad connection, or you have a bad ground, or the meter is sticking on AC volts and not switching to DC volts.... It would suck if you went thru the work to replace the stator, and you are still getting the same readings, if it was a bad volt meter, probe wire, or connection point the whole time. Ive torn things apart when I thought they were not working right, but they actually were. like I said before, if the components of the charging system are all good, then something else is not right.

One other mistake I have made, Im getting far sighted and have to wear reading glasses to read a meter up close. A few times I had a Fluke auto-ranging on me, and I was reading milli Volts instead of hundreds of volts, the circuit was off, and I did not notice its range was mV instead of V. At times like that, when impossible things are happening, I expect to wake up and realize it was a bad dream.
 

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Discussion Starter #10
Had cover off again the other day.. Flywheel had good magnetism, no damage,
I am curious how close they run to each other (flywheel to stator) .5mm , 1mm, 2mm gap ... I measured both n had a couple mm gap..

Opps, misread that somehow.

Assuming the stator ohms out correctly (not even sure what it should ohm out to, but normally if all 3 are the same, it's unlikely all 3 are bad).
Can only thing that something else is going on, magnets damaged/missing? If this was the case I would imagine it would be noticeable when you replaced that stator.
 

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Discussion Starter #11 (Edited)
I sure as hell hope not. 😕. Meters worked fine on every other vehicle through the garage.. (Recently)
Definitely showed a bad stator after testing when I found low charging. Would think if meter was at fault I would get same readings w new stator etc..

Customers 02 road star Silverado...
Did oil change n other misc items..
I always check charging at battery when looking a bike over. Bike wasn't charging so did typical tests n found bad stator.. ...
I have to point out that this is an odd situation. Was the bike running when the customer brought it in?

The reason is it would be statistically odd if the bike was running ok, and being used, he brought it in for an oil change and other things, and you happen to notice the charging circuit had failed. If the bike was not charging it would drain the battery dead while riding with the headlight on in several hours, so from a probability perspective, you just happened to catch it right after it failed, but the battery had not gone dead yet.

This raises the question: is it possible your volt meter is not registering, its internal battery is going dead. Ive seen that happen on Fluke meters, the voltage reading starts running way low, and then after an hour the low battery icon lights up, and the meter shuts off,

Or maybe the point where you are measuring the voltage itself is just a bad connection. It would suck if you went thru the work to replace the stator, and you are still getting the same readings, if it was a bad volt meter, probe wire, or connection point the whole time. Ive torn things apart when I thought they were not working right, but they actually were.
 

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Discussion Starter #12
Customer is gonna take it as is since he's heading home in a few weeks (new Zealand) .. So out here putting it back together n figured.. What the heck ill put in the new battery that I fully charged last night...
Its smaller but starts bike fine.. Weird tying is it actually charges at 12.7-13v .. (Fully charged Old battery stopped at 12.5v) .. So not fixed but might work ok for riding around a bit.. I told him to keep a back up plan in mind if bike won't start or shuts off on him....
WTF... Omen of a bike..
 

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Discussion Starter #13
Lmao.. So first start up w headlight fuse pulled n it charged perfectly @ 14.5v or so... Messing around trying to track down exactly where the problem is n voltage just kept getting lower n lower till back to square one (even w headlight fuse out) ...
New battery it would atleast charge close to 13v.. Old battery back in n it goes to 12.8v or so (w headlight fuse pulled) ..
Maybe just getting to hot sitting here idling..
 

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Im not sure how it works in a motorcycle, but in a car when you first start it up, the regulator drives the alternator to output up to 14.5V, to quickly recharge the energy you just used to start the engine. Then it drops the output and the charging voltage will slowly ramp down to 12.6 to 12.8V after several miles.

A really smart regulator will drop the alternator out for a fraction of second to see where the battery voltage settles with no charging, and then either bump it up harder if the voltage drops, or back off if the battery holds its level.

That is why an old battery puts a big drain on the alternator, you can charge it and charge it, then when you stop charging (or turn the engine off) instead of holding at 12.6 to 12.8 volts, it drops down to 12.0 V or less. Sometimes you can see this at night, you stop your engine with the headlights still on, and the brightness noticeably drops.

A motorcycle regulator must be doing to the same thing to some degree - if it kept hitting the battery with 14.5V all the time when the engine is rev'd up, it would boil the water out of the battery when you are on the interstate. After its been running for a while the alternator/regulator voltage should drop down to around 12.8V... maybe a bit more, once the battery is charged.
 

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I am sure you have does this. But, better to be said then not.

All grounding wires on the bike are good?

I ask because I troubleshot a starting issue on a buddy' car many years ago. Turns out a bad ground near the rear lights was causing it. (I know odd. But, as soon as a took off the ground. Cleaned it and the area up. Reconnected. No more starting issue. Well, at least not until another friend wrecked it a few month's later)
 

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Discussion Starter #16
I am sure you have does this. But, better to be said then not.

All grounding wires on the bike are good?

I ask because I troubleshot a starting issue on a buddy' car many years ago. Turns out a bad ground near the rear lights was causing it. (I know odd. But, as soon as a took off the ground. Cleaned it and the area up. Reconnected. No more starting issue. Well, at least not until another friend wrecked it a few month's later)
Yep grounds cleaned n tight.. Perfect ohms to ground ..
 

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...Turns out a bad ground near the rear lights was causing it. (I know odd. But, as soon as a took off the ground. Cleaned it and the area up. Reconnected. No more starting issue. ...
instead of using a separate wire for each light and turn signal, some cars use a power wire and a data bus, that tells each light when to turn on and off. The bus runs to each light and some also to sensors. Its possible if one light connection was messed up it could lock up the data bus, and cause problems somewhere else.
 

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Discussion Starter #18
...Turns out a bad ground near the rear lights was causing it. (I know odd. But, as soon as a took off the ground. Cleaned it and the area up. Reconnected. No more starting issue. ...
instead of using a separate wire for each light and turn signal, some cars use a power wire and a data bus, that tells each light when to turn on and off. The bus runs to each light and some also to sensors. Its possible if one light connection was messed up it could lock up the data bus, and cause problems somewhere else.
Not one of those on this bike that I've seen or shows on schematics..
 

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yeah, I have not seen the automotive bus used on a motorcycle. A big car can have a lot of wires on it, with all the windows and locks and power seats.. might end up costing more if they put the bus and smart lights on a motorcycle.
 

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yeah, I have not seen the automotive bus used on a motorcycle. A big car can have a lot of wires on it, with all the windows and locks and power seats.. might end up costing more if they put the bus and smart lights on a motorcycle.
They do put a collection of grounds all in a special plastic cannection on some bikes.. Usually they end getting a bunch burned together n cause havoc..
 
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