Evo Charging System Problem
Harley EvoDiscuss Evo Charging System Problem in the Motorcycles forums; I stopped by a movie gallery around four or five days ago on my 1994 FLSTC and when I came out the battery was dead. I jumped the bike, started ...
I stopped by a movie gallery around four or five days ago on my 1994 FLSTC and when I came out the battery was dead. I jumped the bike, started the engine, and rode home (where’s that kick-start when you need it?). On the way (about 17 miles of country roads) I lost the horn, turn signals, and eventually the engine started misfiring as I accelerated away from stop signs. I managed to milk the bike home. This is the classic symptom of a faulty voltage regulator.
The following day I replaced the battery since it was the one in the bike when I got it (and was a watercraft battery anyway) and I didn’t know how long it had been in the bike. Further, this bike had been a garage queen for several years before I got it, so decided to replace the battery to be safe (I don’t like to be stranded). I also installed a new voltage regulator and everything was just fine for the next 150 miles or so. This evening about half way home from a meeting (around 25 miles away), the turn signals quit working, the horn ceased to work, and the bike wanted to stall when I pushed the horn button. Sure enough the bike started misfiring as I accelerated away from stop signs. I barely made it home before the bike decided it didn’t want to run anymore. Again, this is a classic voltage regulator failure symptom, but the regulator isn’t the problem, unless something else is causing it to fail (my worst fear since these things aren’t cheap).
I only have a Clymer’s manual for this bike and no resistance specs for the alternator stator windings or anything else like that. The Clymer schematic for this year and model shows that this is a very basic charging system consisting of a circuit breaker, alternator, voltage regulator, rectifier, and the battery. I take it that the rectifier is contained in the voltage regulator housing, yes? I’ve checked the connections and they seem good, although the alternator connection on the front of the crankcase feels mushy, but it seems like that’s the way it is supposed to be……..or is it?
Has anyone else experienced this sort of problem with their Evo? Common connection problems? Grounding problems (Moto Guzzis are notorious for this problem)? Does anyone have the resistance specs for the alternator stator windings? From what I can see in the manual, the rotor is a permanent magnet type. Is that correct?
Update to my last post: I found the stator resistance readings in Clymers. They were in the troubling section, not the electrical section. Sometime I can’t see the things that are right in front of me. That said, I am still interested in any experiences anyone has had with this or anything close.
Remember the kiss principle? Even though it's a classic symptom of a faulty voltage regulator it's also a classic symptom of a loose or broken ground wire. check your ground wires before doing anything else.
It's almost identical sysptoms to a dying batt, a bad VR and a dying stator..
You didn't say if you checked the DC charging at the Batt..
My bet is the stator..
After installing the new batt you were running mosty on the batt cuz the stator is dying/dead.. With some RPM's there was perhaps just barely enough charging to get home..
The OHM's between the stators female plug holes should be about .2 to .4..
There shold be NO continuity between either stator plug hole and ground..
With the meter set at AC volts and both probes in the stator plug holes you should get about 20 volts per 1,000 RPM's up to 3000 RPM's ===60 AC volts..
Remember most meters have a wee resistance of their own between the probes, so, if it reads .4 OHM's touching the probes together and the reading between the stator plug hole reads .6,, subtract the Meters .4 and you got your .2..
Really very easy tests,, but certainly check batt ground as per MYT's sugg too.. All this should be in any manual worth it's ink..
Yeah Baby..
Ooh yeah---- if it turns out to be the stator don't bother getting the rotor too, don't need it unless you can see some kinda damage..
__________________ "Fill your hands you son of a bitch"
Rooster Cogburn
Last edited by frisco-rigid; 08-20-2008 at 04:27 AM.
You guys are spot on and I will do all those things as you suggest when I get a chance to begin troubleshooting the bike (maybe this weekend). But what I was really seeking is any Evo-specific knowledge you might possess concerning the charging system on my bike (kind of like some of what you gave me frisco-rigid). I understand charging systems fairly well and the Evo's is a very basic one. More times than not vehicles have common problems that are unique to just that vehicle. I’m sure Evos are like that (e.g., the inner camshaft bearing I have been reading so much about). Moto Guzzis, for example, are notorious for grounding problems and I can usually tell you exactly where the problem is likely to occur. My Bassa had a charging problem that was a direct result of a corroded ground connection that seems to be a problem on most (all?) Guzzis. In fact, over the years I have traced more charging problems (motorcycles, cars, boats, aircraft) down to poor ground connections that any other cause (myt evo, you’re right on this score). frisco-rigid, is there a common problem with the stator on these bikes? I could believe a stator is the culprit as you suggest, but I will test everything on the bike before I get to the point of R&Ring a stator. Yes, if the rotor is a permanent magnet--which it appears to be in the illustrations--then I’ll probably not replace it if I get to the point of opening the alternator up (this makes me long for the old generator bikes when the generator was in front of the crankcase and very easy to R&R).
After I R&Red the battery and voltage regulator, the charging system went through at least 10 start and recharge cycles and did what it was designed to do before failing again yesterday. I really thought the problem was resolved. However, it failed again either as I started the bike for the last time or on the road home shortly thereafter. It’s as though either I’ve got a loose connection somewhere (maybe) and even more as though something is killing the voltage regulator (I’ll check this out as well), or more specifically the rectifier (diode bridge?), which I suspect is collocated with the voltage regulator in the same VR housing (I’d really like a schematic of the VR with pinout). Do Evo stators have a tendency to develop shorts to ground? Knowing whether this is a problem common to Evos or not will focus my troubleshooting and hopefully, lead me right to the problem.
If it is a stator, how much effort is required to R&R the stator? Have any words of wisdom in this case?
MPH,
I'm almost 100% positive that if you pull your stator & check the point where the wires leave the stator you will find bare wire where there is supposed to be insulation(or stiff,cracked insulation),unfortunately this is a common problem,even worse,this could have ruined your new regulator as well.
There is no need for a schematic about the VR, they are NOT fixable..
I've taken one apart, it is destroyed by doing so..
Do make sure the VR is grounded WELL either by it's mounting surface or by the ground wire that some of them come with..
Like AHDWR says, the wires he speaks about will very likely be at fault if it's the stator..
I've spliced on another plug a couple times over the years with thousands of extra miles gained but you gotta have a spare plug/wires to do that with which I suspect you don't have soo, you'll need another stator..
When you say permanent magnet I'm not sure I know what you mean.. The rotor slips on the motor shaft and spins around the stator, maybe that's permanent.. It slips off the motor shaft to access the stator, it should be an easy job for you since you speak of alota mechanical experience.. It is very simple..
If you determine, via those tests, the stator must be replaced then here tis---
Pull outer primary after draining fluid.. You might have to pull the complete inner drive--motor sprocket and clutch assembly but sometimes you can get by just removing the motor sprocket if chain slack allows..
Then pull off/out the rotor and Walla, the stator..
Replace and re-assemble..
Once you know the stator is correct in all ways via tests, and you still have charging probs then the next culprit will be the VR..
That's all there is to the system..
Of course all wires to and from the system must be intact with no shorts..
Have a ball.. Yeah baby..
__________________ "Fill your hands you son of a bitch"
Rooster Cogburn
Ya know, when it rains, it pours. Yesterday evening my wife and I went grocery shopping in our pickup truck. On the way home from the grocery store I pulled into a gas station to get a little go-go juice. After filling the truck up I went to start the truck and the battery was a dead as it could be. It had started the truck’s engine just fine at the grocery store less than 10 minutes before. I suspect the battery internally shorted immediately after starting the truck at the grocery store. In any case, my youngest son came by and jumped one of my vehicles for the second time in a week. Once started, the truck ran just fine all the way home (around 26 miles). I just had to ensure I didn’t stall the engine!
The info you both provided me is exactly the type of info I was looking for. Thanks guys! The faulty insulation on a stator wire seems to fit the symptoms exactly. I also suspect that my worst fear is also true.......that I lost the new voltage regulator in the process, but I’ll check this out as best as I can before putting another $107 down for yet another one. I’ll also see if I can open it as well. After all, what do I have to lose if it tests bad? I’ve opened other potted electrical devices before and fixed them. Maybe I can fix it and maybe I can’t, but I won’t know if I don’t try.
By permanent magnets I mean that the rotor uses magnetized iron magnets for its magnetic field as opposed to an electrically excited rotor (to create a magnetic field), such as most automobiles use. Motorcycles typically have very low current requirements compared to automobiles, so simpler permanent magnet alternators are usually sufficient (these types of alternators are low current devices). I have one bike in my stables, however, where this isn’t the case. My old 1984 six-cylinder Kawasaki Voyager. It has so many electrical devices on it that Kawasaki actually installed a second alternator to support the load. With a properly-sized inverter I probably could use the bike as an emergency generator for my house......... That bike is also the largest and heaviest bike I’ve ever ridden or owned (with gas and oil it pushes 1,000 pounds). In any case, electrically excited alternators have brushes that serve to transfer electrical current to the rotor coils--also known as field coils--to create the necessary magnetic field. Therefore, the “magnets” used in the automotive alternator are electro-magnets. The Harley alternator doesn’t use brushes, so must be a permanent magnet alternator by default.
Electrically excited, Yeah baby...!!!
Gads,, I love it when you talk like that..!!
I know a girl that takes great advantage of electrical excitation and if ya got the properly sized inverter -----Whoa,, cut er loose 'n let er buck cowboy..!!
__________________ "Fill your hands you son of a bitch"
Rooster Cogburn
Evo Charging System Problem 
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Linear Mode
