Greetings all,

New here. Hoping somebody has some insight on a problem.

2010 Iron 883 Sportster.

About a month ago I had a check engine light and battery light come on at the same time, but went off so I thought nothing of it. then a couple weeks back it started coming on and staying on. I looked up the problem and turns out I have a low voltage. I checked the voltage at the battery initially and it read 13.5 until I would drive it for a while and the light came on and it would drop to 12 volts. At first when revved the voltage would increase from the stator. I checked the stator per the instructions listed in several threads on these forums and the resistance and voltage both check out that the stator is working fine... so I replaced the voltage regulator. But even with a brand new voltage regulator, that is grounding properly (checked that too) I still have the same problem, except now testing at the battery, the voltage isn't increasing when revved. So it seems the stator is functioning fine, but the power just isn't getting to the battery. And the battery seems to charge and hold a charge fine. If anybody has any ideas or ways to check possible grounding problems, please let me know... My bike has been down for weeks now and is my primary transportation. Thanks guys

James

 

The voltage at the battery doesn't change a lot when revving the motor. With the motor at a fast idle, you should get 14.0 - 14.8 VDC across the battery. With the bike turned off, you should measure 12.7 - 12.8 VDC across the battery.

What do you measure for those voltages?

You may have an intermittent (stator?) failure. In that case, your stator measurements need to be checked when the battery light is lit (while the charging system isn't working).

 

With the bike not running, battery at full charge was about 12.5. with the bike running and revving there was no change at all. When I first had the issue it was increasing when i'd rev, but has since stopped entirely. no change in voltage at all. i'm getting voltage off the stator itself at all times, increasing as the rpms increase, so it's at least functioning. I would think with any current at all it would show at least a little fluctuation at the battery when revving, but there's no change at all. So all I can figure is there is a break somewhere between the stator and the battery? but again its a brand new regulator and from what I can tell all my connections seem fine. No corrosion on either battery terminal or the negative cable at the primary, and all seem tight. Any idea what the reading off the regulator should be and how to test them properly? I checked for voltage from the regulator body to ground and got 0, so it seems to be grounded fine... check from pin to pin off the regulator output has given me some readings that (to me) seemed unusual, but I've not yet come across anywhere what said how to measure regulator output or what it should be.

Thanks

James

 

What does the AC voltage from the stator measure, and does it climb (approx) at a rate of 20VAC for each 1,000 rpm increase?

You can't reliably measure the regulator output unless it's connected to the battery. If you get a good continuity check from the battery to the appropriate regulator output pins (pos & neg), then what you measure at the battery should be the same as the regulator output.

 

Yeah I just saw a video talking about the main fuse to the regulator and measured at that harness and voltage matched the battery exactly... so that's fine too.

as for the stator, it's about 35vac at idle and increases to between 65-80vac under mild revving all the way up to over 100vac under heavier throttle... about verbatim to what I had read it should be, though it does vary by a few volts either way at times, but I figure with any voltage output at all, it should definitely show at the battery, even if it weren't sufficient to charge it.

also double checked resistance across several different grounds and everything seems to be grounded fine... as well as both pins on the stator check out with infinite resistance to ground... so i'm really at a loss, man. What do you think the odds are I got a bad regulator? I have to assume the one I just bought is good and that the problem has to be elsewhere. is there anything else between the stator and battery that could be a possible culprit for shorting? with my luck it's gotta be something stupid i'm just missing...

with an output from the stator, but no fluctuation at the battery, there has to be something between them not working properly, right?

Thanks,

James

 

James,

Tricky electrical problems can really open up Pandora's Box. You said the battery was good not trying to upset you farther then you already probably are but you must fully charge (not from the bike) and load test your battery first. All of the tests and checks work off of a known and tested good battery. I really can't stress that enough. If that is proven and you still have problems my suggestion is to take it to a good HD dealer. You have already replaced the voltage regulator and probably did not need to. It could easily be something small and almost impossible to find without their resources. Hope that helps at least some.

 

Not upsetting. I get it. The battery charged fully and showed 12.8 volts when it had fully charged. Then she started fine and ran for quite a bit while I took measurements, so the battery ran the bike fine plenty long before finally dying again. I get what you're saying, but I do feel pretty confident the battery isn't the issue. My only concern with taking it to a dealer would be them going "oh it's definitely your voltage regulator or stator" and "fixing" one or both of them... just to find out that neither of those were the problem to start with.

My confidence in Harley dealers is pretty low to start with as right off the showroom floor, my fuel light came on with a full tank, took it to the dealer under warranty and they told me they had no clue what the problem was..... to this day my fuel light is still on, three years later...

So I always prefer to fix things myself, but this is frying my brain. If it comes down that I absolutely need to take it to a dealer, I guess I have to, but I already know they are going to try to tell me it's the stator or regulator... and from every test I can do, those seem to be fine.

But, you're probably right. i'm sure there are some things they can check on their end that I can't...

 

when my stator went bad it started to emit a very distinctive and nasty odor. Like it was burning the trans fluid.

 

yeah I read that elsewhere. I opened the primary and looked at and smelled the fluid... it looks normal and doesn't smell nasty/burnt really... just smelled like old primary fluid.... definitely needs to be changed, but doesn't seem burnt...

there have been times while riding I smelled what I thought was an electrical burning smell, so when I changed the regulator, I figured that burnt up and was what the smell was... but i'm unsure now.

How bad did the primary fluid smell? was it faint or potent?

 

It was very noticeable. Not faint at all