Rotor, Stator, Voltage Regulator - Harley Forum

Tbone · #1 04-15-2009, 12:14 PM

I talked to one of my new co-workers from another part of the state this past weekend when we both were assigned to the striped bass hatchery for Easter weekend. He has (If I can remember right, it was a long weekend) a 1984 FXR. He was asking me if I knew anything about the electrical system on this bike. It seems that he changed the stator/rotor a while back because the battery was dying and it wasn't being charged while riding. Once the new rotor/stator was changed, it still was doing the same thing. He bought a new voltage regulator from the dealer and no joy, same thing.
I asked him if he had checked for voltage out of the charging system to the regulator and he had and there was voltage present. I asked if he had checked for voltage out of the regulator and he had and there was no voltage. I concluded that the new voltage regulator he bought was no good. The dealer won't accept returns (probably like everyone else) on electrical parts.
Is there anything else that could cause this condition like a bad ground or something like that?

aceharleywrench · #2 04-15-2009, 04:09 PM

Quick rule of thumb for 22amp charging system (most Evo's) The stator should produce 18-20 AC volts per 1,000 RPM (Thats AC voltage not DC) so at 2,000 RPM you should read 36-40 ACV,3K 54-60 ACV,etc.The best way to test this is to clip the lead off an old regulator so you can plug it into the stator & hook your test leads to the protruding wires after you strip some insulation off the end.If that tests ok check for continuity between either pin on the stator plug & ground,there should be no reading on your multimeter (set on ohms) between either pin & ground,if thats ok check the continuity between both pins it should be less than two ohms,if you fail any of these checks the stator needs to be replaced. At the battery set your meter for DC volts & check for a reading ABOVE 12.6 VDC with engine running above 1500 RPM.The last part of the charging system is the main circuit breaker (on FXR's under the left side cover) it's usually not the main breaker if the bike will start & run,but it is part of the charging system.I realize the specs I've given may not match the H-D service manual exactly,but these are "real world" specifications that take into account some variances caused by age & manufacturer.

Tbone · #3 04-15-2009, 05:18 PM

Thanks Ace.
I will pass it on and check back with more information.

aceharleywrench · #4 04-15-2009, 05:26 PM

No problem,let us know how he makes out.

Tbone · #5 05-07-2009, 10:40 AM

Oops.
I have confirmed that I can't remember anything.
The bike is actually an '83 shovelhead.
Are there different specs for troubleshooting or the same?

frisco-rigid · #6 05-07-2009, 02:15 PM

Hey T

Most spec's are the same..

I would add that for that system you want .2 - .4 Ohms betweeen the stator pins..

I briefly touched on this in that other thread with NP------ you must take into account whatever resistance (Ohms) are already in the meter wires..
Some meters allow you to adjust to zero before doing the check, in that way you see Only the actual resistance of what is being checked..

BUT, some meters do not have an adjustment for that so before performing the test you gotta see what the resistance is Just in the meter and subtract that from the reading..

In-other-words----- my digital meters show .4 Ohms Just by itself then when I test the stator Pins I get .6 Ohms----- I simply subtract that .4 Ohms (from the meter) and see that my stator pins reading is correct at .2 Ohms..

In my experience if the stator checks out and if there are no other shorts, broken wires, faulty Circuit breakers etc etc etc. then it's either the Batt OR Regulator..
A load test on the Batt is usually enough to eliminate the batt,,, then it will prob be the VR..
Relay to your bud that the VR ground connection Must be Good, either VR body to grounded mount or a separate wire from VR body to ground..

And definately do what Ace mentioned about clipping off the old VR Plug leads to perform all stator related tests in the future..
Clip one wire a wee shorter than the other and put covers on them, the reason---- you don't want them to touch each other or ground while motor is running..

frisco-rigid · #7 05-07-2009, 03:10 PM

Just figured a photo is worth a thousand words to back-up Ace's sugg..

This shows the .4 Ohms that must be subtracted from the correct reading of .2 Ohms...

This shows a 32 amp on top,, a 22 amp center and a 17 amp female plug for a 17 amp stator male.. A guy really needs one of these tools for that one..!

Tbone · #8 05-07-2009, 07:10 PM

My thanks to you Ace and Frisco. I appreciate the help. This may take a while. I'm e-mailing the thread to him and will let you know how it turns out. I hope he tries this and gets his bike running.

skullking · #9 08-02-2009, 03:21 PM

Help !!!!
We have a 2000 ultra the bike was running great then when we shut it off it just clicked and was dead! we thought it was the battery so we bought a new one and drove the bike home the volt gauge only showed 10 volts and while we had it at 70 miles an hour it would read 12 volts, any way when we got home and turned it off we went for another short ride and turned it off again it would not start. what do we look at next?
Thanks for any help you can give.
Bruce

frisco-rigid · #10 08-02-2009, 04:54 PM

Hi Skull

If it were my sickle I would first check the stator out-put..

Came back to edit cuz I see it was described earlier also..

Do you have a Volt/Ohm/Amp meter.?
If not,, better get one,, I carry one with me in the bags..

Put the meter on Lowest Ohm setting, remove the Volt Reg plug, insert one meter pin into one stator plug female hole, touch the other meter pin to ground, motor case will suffice.. There should be NO READING at all at the meter.. If there is there's no reason to continue cuz the stator must be replaced..
If there is NO reading then insert Both meter pins into both stator plug female holes, there should be about .2 - .4 Ohms..

If all is cool up to that point put the meter on AC Volts..
Get the motor running again and slip the meter pins into both female holes in the stator plug.. You should get about 20 AC Volts per 1,000 Rpms up to approx. 3K Rpm, about 60 AC Volts total..

If all that is good then most likely the Volt Reg is bad..

All these instructions are in your manual, ah, you do have a manual don't you.?