| Author | Message | ||
     Finnman |
I replaced the stator (Accel) a year and a half ago (about 10K miles) for not producing power. I did not replace the voltage regulator. Stator is not producing power again. Per the manual, resistance is ok at 0.4 ohms. It's not shorted to ground. AC voltage output is 0.8V - bad stator. I've recently heard if the stator is bad and requires replacement to also replace the voltage regulator - the HD regulators are supposedly notorious for taking out the stators. Any truth to that? Any recommendations before I dig in? Appreciate the help. | ||
| Blake |
I'd not heard that. Before deciding, check to see exactly what failed. A broken wire isn't likely to be caused by any problem with the voltage regulator. A melted winding, maybe? | ||
| Reepicheep |
Well, I can see how a bad battery could take out a voltage regulator. Instead of a nice big battery absorbing extra power, the regulator has to shunt it all and it over heats and fails. And I can see how a bad VR could kill a battery by over charging it, or by letting it discharge completely too many times. I guess a VR could hurt a stator if the VR goes into "perpetual shunt" mode. That would mean more power (heat) being dissipated by the stator windings. But if that was the case, the bike would not have been charging the whole time. We don't have much information about the Accel coil... I know it was a lot cheaper then the HD unit. Wonder what kind of quality reputation they have? The XB's seem to have problems with the connector between the stator and VR as well, so that is probably worth checking... though it sounds like yours is fine (you got the right resistance readings, but no voltage out). Are you sure the meter was set on AC Volts? I would expect a "no output voltage" situation to also fail the impedance checks... unless you lost all your magnets (which you would definitely know about). | ||
| Finnman |
I failed to mention I recharged the battery and it seems to be holding a charge. It allows the engine to run off of it to the 2K RPMs the manual wants you to run at to check stator output. I checked output several times with the battery hanging on at about 13V by the time I was done. I doubled checked the the meter settings several times since it seemed strange for the resistance to be fine, also meaning I have continuity through the stator. And as I mentioned earlier, the darn thing is not shorted to ground. Puzzling. The stator/VR connector appears to be in good shape and not chafed between it and the VR. I'll double check its condition again. If we're stumped, I may bite the bullet and chuck a part...the stator and VR. The VR since this is the second stator to the bike. Any other circuits I should inspect? What's interesting is the OEM stator saw about an 11K life and this second stator saw about an 11K life as well. | ||
| Reepicheep |
What primary fluid are you running? I guess the way a stator normally fails is that the insulation on the windings is compromised, and they short to something. The "something" could either be ground, or could be an adjacent winding. If it is an adjacent winding, you would still get some low ohm reading, so I guess that would be a fairly plausible way to explain your reasonable resistance measurements on the stator. Is "one of these three not like the other"? They should be pretty much identical... so that could be another hint. Measuring really low resistance is tricky, you end up measuring the resistance of your test leads and associated wiring. I oughta work up a system for bench testing voltage regulators... I don't think there is one in the service manual. Maybe there is one in that big fat "electrical service manual" Court was showing off.... | ||
| Finnman |
Primary fluid...I'm running Mobil 1, 75W-90. | ||
| Xcephasx |
a possible reason a bad stator would knock out a VR is because its output is not consistent, and the VR is working double or triple time to "regulate the voltage" as it's name would indicate. a crimp-on connector i used to install some fog lights worked itself a bit loose. the lights never blinked out on me or anything, but the connection was weak. this caused a "high resistance" connection that was unstable. played hell with my voltage regulator. killed 2 VR's and a stator before all was said and done. after i went through that, i installed a voltage meter on my gages. look for intermittent shorts, poor connections (dielectric grease does wonders), loose wires, etc. just my .02 kind of a hard one to chase down. good luck! | ||
| Finnman |
Thanks for the input. I plan on hitting the connections pretty hard this weekend while waiting for parts. I'll pick up some dielectric grease and slather it on. I appreciate everyone's help. | ||
| Reepicheep |
Xce... it took me a while before people finally explained it to me, but this is a shunt regulator system with permanent magnets, not a variable field strength alternator setup. So every time that engine rotates, each leg of the voltage regulator (probably a zeener diode tripping an SCR) switches exactly once. More or less load will make the switch trigger later rather then sooner in the cycle, but ultimately, it is one switch per rotation. And any power not "used" by the bike will be dumped straight to ground by the voltage regulator, turning the stator windings and VR into a little space heater. So more load is actually easier on the regulator and stator. I'm not saying I understand everything going on, there have been an awful lot of cascading failures that have not been well explained. I have some reading to do... That Mobil gear oil, if it was the full synthetic, seemed to shorten the life of stators. I would recommend the Formula + now. | ||
| Buford |
Have heard bad things (Buell Tech) about running the M1 gear lube...something about a phos additive that corrodes things? | ||
| Reepicheep |
I was one of the ones arguing that it was fine to run Mobil 1 Full Syn Gear Oil.... And I am ready to declare defeat. It won't instantly destroy your stator, and it is not the only reason stators die, but it does seem to help  The reason we said it is not a problem is that while it *does* react with yellow metals because of the sulpher and other additives, everything on the stator is coated in epoxy, or should be anyway. So the copper should never have been exposed. But perhaps there are pinholes in the epoxy, or the epoxy itself reacts with something. I don't know, but I am no longer comfortable recommending it. I admit I was wrong. Before, you had to run sport trans (non synthetic) or Mobil 1 gear oil (synthetic). My tuber shifted day and night better with the Mobil 1. But now, you can go to your dealer and get formula+, which is full synthetic, is a real gear oil, and won't hurt your stator. So that is the obvious choice. Normal engine full synthetic 20w50 would not be bad either, but real gear oil can have some additives that you can't put in engine oil that hold up much better in a transmission. Did I say "I was wrong"?  | ||
| Bluzm2 |
Bill, I may have to agree with you after closely looking my recent stator failure on my S2. The failure was at the joint of the lead out wires, where they attach to the stator windings. The solder joint is imbedded in the epoxy, I think the oil MAY wick down the wire and start eating away at the copper wires. I've switched to the Formula+ stuff. It stinks FAR less too! Brad | ||
| Bad_karma |
The resistance reading is fine for check continuity but it is less than ideal for testing insulation resistance to ground. To get a better assessment of this measurement you will need a megger. Caution if you should purse this direction, only megger not electronic devices, like stators, extension cords or such, do not megger things like voltage regulators, ignition systems or speedometer sensor that contain active components. One thing that I'm sure that plays a big part in these failures is the constant max current draw of the voltage regulator. I would thing that you need to determine the failure mode of the stator before you assume the voltage regulator is bad or is the cause of the stator failure. Joe (Message edited by bad_karma on May 04, 2008) |
