Page last modified: 05/07/13
The Stator Papers V
Why do charging systems on bikes fail at all,
and why is it so hard to get them fixed?
by Peter Huppertz
(with updates by the current editors)
The GS Resources' 1st Law on Faulty Electrics:
Most any electrical problem starts with defective wiring or dirty connections. As a result of this, one by one the more expensive components will fail. Only then you will notice that something's wrong
We do get a lot of email on charging issues. I mean, nary a week goes by that I don't receive email on charging issues. So I'm bound to hear what's wrong most of the times, trust me. The text below tries to clarify that.
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Sometimes, someone brings up an issue that raises my eyebrows. I happen to have an example at hand:
The stator was just replaced before I bought the bike but it will now blow the main fuse after driving for 5 minutes. The fuse box gets really hot, the connector going into a heat sink looking device is molten. Any suggestions?
Seems like the guy who replaced the stator didn't do his job.
Part of the job of fixing a faulty charging system -- and in fact the very first thing that you should start with when attacking ANY electrical problem on a bike -- is to check all electrical connections. Then, and only THEN, you start checking the components.
My second objection would be that it appears to me that, if a GS doesn't charge, some shops or so-called "specialists" look at the stator, see that it's at fault, replace it, check whether the voltage has gone up and then say "It's done, here's the bill".
They should have looked further, though, because in many cases a failed stator is a clear indication that there is something badly wrong elsewhere in the charging system. Only replacing the stator will, in the best case, lead to the problem popping up soon after, leaving you with another broken stator.
This all boils down to the point in which I suspect that some proficient automotive engineers and workshops and dealers who know their way around carburetors and gearboxes and cams and valves way better than I do, are on hostile ground when electrics and electronics are on the menu.
But we've seen it happen. Incidentally, in September 1998 I got an email from a Canadian fellow who got himself a 1982 GS1100E at the price of scrap metal. The shop that sold it to him was unable to fix the charging problem. He bought it, checked our pages, sent two emails, got two answers, and lo and behold, the bike charges OK and judging from the email that I got, it appears he's now a happy man. Currently we're emailing on barbeque issues.
The molten connector is clear evidence of a job screwed up. Connectors don't melt if you don't heat them. The heat sink equipped device would almost certainly be your regulator/rectifier. The fact that this connector is molten may indicate that:
- your regulator/rectifier has died;
- there is a wiring problem somewhere, meaning a conductivity problem or shortage.
Mind you, this is not an exclusive OR, it's very likely that both problems exist. Most any charging problem starts with defective wiring, and then one by one the expensive components start to fail. That's usually when you find out something is wrong. But do not make the common mistake of replacing the faulty component and leave it at that!
That's one of the reasons why our fault finding chart starts with checking whether there's proper conductivity.
I know it is rather a comprehensive job, but when you do it this way, you would end up attacking each and every problem that you might come across. Remember that any faulty component in a charging system can screw up quite a few other perfectly good components, so there is no "I'll fix this now and look at the other ones next month". Unless you decide not to run it in between, of course.
If you don't feel comfortable working on electrics, grab the fault finding chart and have a knowledgeable person (uncles, nephews, brother-in-laws, neighbours, riding buddies, what have you) help you with that.
Oh, and one thing: don't call your local Suzuki dealer in order to order OEM stators and regulators/rectifiers; they're horrendously expensive and not as good as some aftermarket stuff I've come across. If you do need replacements of any of these, check out ElectroSport Industries. They make stators and regulators for most bikes that are cheaper than OEM units and are designed significantly better and are much cheaper than Suzuki replacements.
Here's their web site, just click on the logo:
The Stator Papers I: APrimer on GS charging systems (youshould've read that first, it explains the theory referred to in this Q&A)
TheStator Papers II: FAQs
The Stator Papers III - The Solution, detailsabout the availability of the Electrex unit.
The Stator Papers IV - The Fault Finding Chart,a comprehensive, step-by-step fault findingprocedure.
The Stator Papers V - Cause #1 for failingcharging systems: bad conductivity!
The Stator Papers VI - How to rewind your ownstator