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Discussion Starter #1
Hi all... it's been a while. Please don't mind the long winded post. I'm in a bit of a dilemma.

Recently found the paperwork for the '86 I rode around on before I got my BMW. With that in hand I serviced the bike (all fluids, splines, carb clean and sync, cleaning, new agm battery, aside from some other longer term stuff I've done over the last few years) and sold it last night...

then 60 miles later the stator failed... I think. I met the buyer on the side of the road today a few miles out of town. 12v at 4-5k rpm. Went back to the city where the other two bikes are in boxes, and brought 2 other R/R's to the side of the road. Both of these also rendered 12v at 4-5k rpm.

I didn't check the regulator. Had a test lamp with me... but the link to the diagram in the verses was bad so I was kind of at a loss there. I find it hard to believe all 3 could be bad. I didn't test the stator. Haven't ever had to do it, wasn't entirely sure on what to check, and as I was kind of rushed to go help the guy out...

Jumped it again and told him to keep the revs up and followed him home. So here's where I'm at:

1) I checked the voltage at the battery when I was bringing the bike back up to snuff, after I put in the new AGM battery. Voltage was correct. Could it be that the 100 degree heat killed it today? Coolant needle would swing up to about 3/4 at a standstill before the fan would bring it back down. Didn't overheat though. Coolant was done about 1-1/2 years ago. Stator is sitting in a fresh bath of Rotella T, and I was good about changing the oil.

2) Also, since it's a permanent magnet rotor, could it be that when he zinged it up to 8k on the test ride that loaded up the windings with more juice than they could take? Not that it shouldn't be able to take it... but these are a weak link on the Vulcans and I'm thinking along the lines of "the straw that broke the camel's back" What is the proper procedure to check the condition of the stator?

3) I did move the R/R back to the clutch side helmet lock mounting hole a couple years ago for the obvious reasons. Never had charging problems. I replaced the battery recently because I had let the old one die while the bike was sitting. The old one was a flooded battery, but I was good about keeping the levels proper. What is the proper procedure to check the R/R? I'm thinking more along the lines of the test lamp procedure. I know the multimeter one is pretty useless.

I had offered to buy the bike back from him for the selling price (1450, 150 less than asking). He's into it for $200 in registration and taxes, so I don't think he wants to. Thing is, I know that the bike was charging the last time I had it running, which was to sync the carbs a couple weeks ago. I don't wan't to screw this guy, but it just seems like bad luck. I have a used stator off my last 86 I would give him for nothing... but why spend all that time to put in a used, failure-prone part?

I suggested that if the stator is bad to replace it with an aftermarket one, and probably do the balancer gear bushings while the stator is out for good measure (26k on the clock). I'd kinda eat it at $350 for parts and labor, but that's what I'm thinking of offering if he wants me to do it. I've thought about kicking him back a few bucks, but I checked that bike inside and out before I put it up for sale... and I gave up $150 on the phone before he came to buy it.

So... thoughts, advice, vindication? I'd welcome it all.
Thanks for staying tuned,
-Luca
 

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If the stator is replace with a cheap aftermarket it want last long. Tim Parrot rewire would be the best way to go. Does this guy know how to do the replacement? A shop will hit him $750+ in labor alone. He probably ain't gonna be a happy camper either way. 27 year old bike, something is gonna let go.
 

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You offered to buy it back. That's all you can be expected to do. Chance we all take buying older bikes. JMHO
 

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I agree... either buy it back from him at the price you sold it... or its on him. If you feel bad enough... and can change out the stator... change it... but make him pay for parts.
 

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Discussion Starter #6
Thanks for the procedure, Slim

provided it is the stator (Sure does seem like it) I could do the tuxedo mod and give him a used stator one from one of my other bikes. Or he could do the tuxedo mod or have one of his friends do it. I know there is some controversy about cutting the cover on the engine... his call.

At least with the tuxedo/used stator he could do another replacement easily.
 

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Discussion Starter #7
and thanks for the kind words guys. I feel bad, but it just seems like bad luck. I helped him out the other day... I can help him out a little more... but it is his bike now unless he wants to sell it back.
 

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Giggity!
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Yeah, bad timing is a bitch. But you did everything except force the money into his hands.
I'm sure he'd be up for help changing it out.
I know I'd appreciate a previous owner who knows the machine
Helping me out.

Besides, a bad stator isn't really something you could hide.
 

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It would have been an as-is sale unless you specifically guaranteed something. But since you are dealing in good faith, if it were me I would let him have the other stator to send to TPE for a rewind. That's the best way to try and make sure the stator works well and is reliable.

I'm not sure I would offer to do the Tuxedo mod for him, you may be putting yourself on the hook for any problems that could arise from that, oil leaks, misalignment, etc. I am not a lawyer, just giving you another way to look at it.

You're going the extra miles for the buyer, many would shout caveat emptor and end the phone call. I'd give ya a plus 10 seller rating if it were me.

The stator tests aren't really complicated, they just look that way on paper. Really, you are looking for a consistent ohm reading between each lead (withing the given range), consistent AC voltage on each (within the given range), and absolutely no continuity from each stator lead to ground. All done with the stator leads disconnected from the R/R and/or harness. I only know this because I tested mine so many times.

Almost 2000 miles on the TPE rewind/MOSFET and it's doing fine.
 

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Discussion Starter #10
Thanks for the simplified explanation. Makes perfect sense. For the AC current on the stator leads I just ground the other multimeter probe?

yes, the sale was as-is. I did offer to buy the bike back in good faith, and I've got myself up on CL for maintenance work (obviously I need some brushing up on ignition and charging) so I'd like to make a good reputation for myself and see the new owner go off happy.

But you're right, now it's a liability to go cutting apart the engine on a bike I don't own.

I think I'll toss him a spare stator no matter what. That way he could stick it in, have a running bike, and send the other one out to get rebuilt.

If I can recoup the $150 I lost on the sale price, I'll do the tuxedo mod and he will have an improved motorcycle and a spare stator. Seems fair and reasonable to me... especially given the usual alternative (click)
 

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Correction: The AC volts test is done between each stator lead combination. (see the next two posts also)

You would be looking for 50-70 volts ac, with all three relatively close to each other. I would do the AC volt and stator lead to ground test with the engine cold, then check it at normal operating temp also.
 

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Sparky!!!
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That's correct on the AC test, ground the negative lead. Most digital meters will simply read a negative number if you reverse the leads, but still a valid reading.

You would be looking for 50-70 volts ac, with all three relatively close to each other. I would do the AC volt and stator lead to ground test with the engine cold, then check it at normal operating temp also.
No don't ground the negative lead.

Positive leader to A1 negative lead to A2, then positive to A2 negative to A3. Then positive A1 negative A3. Record those the readings. They should be within several hundredths of a volt of each other. But don't worry about the results until all of the tests are conducted, other wise it's like looking at a picture of a tree and missing the bull moose standing in front of the tee.

Sent from Motorcycle.com Free App
 

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Oh chit, I thought there was something wrong with that last post of mine.

Only go to ground for the stator to ground test, should be no continuity.
 

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Discussion Starter #15
Well, I headed over to the hobby shop and then stopped at his place which was a few blocks away.

The stator resistance seemed ok. There were no shorted or open circuits. The AC voltage was a bit off when testing between two of the leads.

As per the last time I checked it, I didn't get anything close to proper for the R/R. Pretty sure I had checked all 3 I had at one point and went nowhere with that.

The ground bullet connector for the R/R wasn't in all the way... DOH! Must have dislodged it putting in the battery. That helped voltage at idle, but it was still a bit low higher up.

Had him take it around the block and bring it back. Voltage got lower. Resistance in the stator increased a bit over spec... but heat adds resistance so that could be normal? R/R was a bit warm. Suggested he clean all the electrical contacts... including the R/R spades and harness. Also suggested he check the soldered joints on the R/R harness extension. Offered one last time to take it back, but he wants it. I can't poke around indefinitely on a bike I sold... and I can't spend the money with the offer up to buy it back.

So, left him a spare R/R, suggested he buy a new, better one anyways, and I'll give him a spare stator in the next few days that he can send out to rebuild. It's out of my hands and off my conscience. He should be on the forum soon.

Thanks again everyone. I appreciate the help,
-Luca
 

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Sparky!!!
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Well, I headed over to the hobby shop and then stopped at his place which was a few blocks away.

The stator resistance seemed ok. There were no shorted or open circuits. The AC voltage was a bit off when testing between two of the leads.
How Much Off?
As per the last time I checked it, I didn't get anything close to proper for the R/R. Pretty sure I had checked all 3 I had at one point and went nowhere with that.

The ground bullet connector for the R/R wasn't in all the way... DOH! Must have dislodged it putting in the battery. That helped voltage at idle, but it was still a bit low higher up.

Had him take it around the block and bring it back. Voltage got lower. Resistance in the stator increased a bit over spec... but heat adds resistance so that could be normal?How hot was the engine? did the cooling fan come on? And any thing over spec is bad... even iof its .01 ohms over. R/R was a bit warm.Normal (unless you have a MOSFET R/R Suggested he clean all the electrical contacts... including the R/R spades and harness. Also suggested he check the soldered joints on the R/R harness extension. Offered one last time to take it back, but he wants it. I can't poke around indefinitely on a bike I sold... and I can't spend the money with the offer up to buy it back.

So, left him a spare R/R, suggested he buy a new, better one anyways, and I'll give him a spare stator in the next few days that he can send out to rebuild. It's out of my hands and off my conscience. He should be on the forum soon.

Thanks again everyone. I appreciate the help,
-Luca
Like I posted earlier... You have to look at the whole picture while doing the Charging system test. Do each step in order, recording every peice as you go along. if not you won't see the whole picture at the end and will be chasing ghosts. Start with a fully charged battery that is known to test good by a load test. then fallow the steps in order. even if something tests out bad record it and go to the next step. then once its all done, show me the results because your high resistance might be seen even on the cold test, because I know what to look at when looking at the numbers. Then using your data, I can show you what your Charging system is in fact doing or not doing, and help you get it back on the road quicker.
 

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Discussion Starter #17
Yes, the cooling fan works and came on. The bike is not overheating.

The battery is good. DMM load tested and fully charged.

The alternator leads were .5 ohms cold, .6 hot

R/R was hotter than I ever felt it. Not scalding. Contacts looked pretty cruddy, so, as I said before, I told him the first thing to do is clean all the electrical contacts up and make sure they are solid. Clean contacts are the first thing to check in diagnosing a poor electrical system. getting the R/R ground good and tight improved things

Didn't write down the AC volts (they were off by several volts) because I told him today I'd either take it back or he could keep it and deal with it. He chose to deal with it. I'm sure he will be on the forum soon.
 

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I echo the +10 rating mentioned before. You did the right thing. :smiley_th:smiley_th
 

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I've never had a stator failure on a Vulcan 750, so I never looked into the technical side of it. But you offered to buy the bike back, and he doesn't want to do that. Not much else you can do. I wouldn't spend any money, or do any free work on the bike. You'll wind up almost giving it away. He bought a used Vulcan 750, and to the best of your knowledge everything was ok, so you didn't cheat him. He will just have to deal with it the way all other Vulcan 750 owners do.
 
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