atomic_fungus (atomic_fungus) wrote,

#5644: Definitive answer at least

Okay, let's review how the day has been since I last posted.

1) Dug into the Jeep. Had to remove the electric fan to get at the steering box, broke a bolt in the process. Adjusted the preload, went to Ace to get more bolts, everything's back together and the wobble is slightly better. There's less room in the steering linkage for shudder, but it's still shuddering at certain speeds. I'll probably have to do the control arm bushings next. That's $80 plus tax for the bushings, plus at least a day's work and a front end alignment afterward.

2) Dug into the bike.

Got the bolt out of the replacement flywheel by carefully grinding away munged threads. After examining the spare motor I realized that there's a shoulder inside the crankshaft which the flywheel removal tool is meant to push on, and my bolt should work, so I pressed the flywheel off the bike.

Could not thread the flywheel bolt in. Said many bad words. Looked things over, said more bad words, and then realized that I'd have to go get a tap to clean up the threads inside the crank. Tap cost $9 and change at Ace--to my surprise they had exactly what I needed, 12mm 1.25 thread--but at least I was able to fix the munged threads and get the flywheel bolted down. Because I had no way to keep the crankshaft from turning, I put the bike in gear, got on it, held both brakes, and with my free hand torqued down the flywheel.

Reassembled and tested. 12.5 volts at battery regardless of RPM. Worse, it would occasionally drop to zero! Contemplated suicide.

Instead, I went inside and got the good DMM, and it reported exactly the same result, but without dropping to zero.

So I got the test jig and set out to test the stator again, reasoning that I never did do an unloaded test with the test jig. And when I started the bike, I got maybe 6v out of the stator at 5k RPM, and most of the time it was below that.

With the good DMM, I measured the coil resistance, and it was 0.9 ohm. That is much lower than the other (Harbor Freight free) DMM says it is but it's still not out of spec.

Here's the thing, though: I have tried two different rectifier/regulators, and two different flywheels. The only possibilities I have left are the battery and the stator. I can get the battery tested (hope to do that tomorrow) but I've done the no-load test twice now; the no-load test takes every other component out of the system and tests just the stator's ability to generate voltage, and it's making less than 10% of what it should be. And that means that the stator has to be the problem, here. What else could it be? Since I get that reading with two different flywheels? (And no one--none of the sites I've looked at or YouTube videos I've watched--has ever mentioned the flywheel as a potential trouble spot.)

Stator costs $150 from these guys. $120 from here. Or this one for $110 but I have the least confidence in it fitting.

Well: with the insurance refund I got, and the generous birthday check from my mother-in-law, I can afford to buy the part, and I expected to do this. So I suppose paying a little more won't kill me.

It's just annoying that it's got to be the most expensive part of the charging system that's failed. The rectifier is like $20-$40 depending on where you get it. I'm worried that replacing the stator won't fix the problem, but I have to keep reminding myself that the no-load test is showing 10% of proper voltage and that means bad stator.


Well, lessons learned: dealing with my improvised flywheel removal tool was such a pain in the ass I've resolved never to do that again. The flywheel removal tool for the GS450 costs $12 and I spent more than that in time and money on my improvised tool and then cleaning up after using it. I'm intending to keep the bike a long time; why not invest in the tool? I was just impatient, but the fact that I had to schedule a day for working on my bike indicates that I could have waited for the tool to come in.

If the troubleshooting steps for a failed charging system don't mention the flywheel--if no one ever talks about it--it is probably not the issue. (Admittedly I wanted to be sure before committing to buying a $150 part.)

And finally, RTFM, because the service manual will point out everything you need to know.

So I'm dejected and kind of pissed off, but there's not a lot I can do about that now. Wife is home and I need to go make dinner, so I might as well do that.

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