Stator Installation: Things to look for

[IanDMacDonald]

I've used this thread as reference: http://www.xs11.com/forum/showthread...ght=brown+wire.

I see almost 12v @ field coil brown wire on two alternators (key on) on the green wire I see 1v on one alternator, 12v on the other alternator.

For the Impedance tests:

Each alternator checks-out between .4 to .7 ohms between the white wires. Brown to green, one is 3.6 ohms, the other is 3.8 ohms.

As far as the R/R testing goes, I'll call the first one toast. One I bought yesterday is so-far checking-out as far as diode tests.

Here is what happened: I put old alternator on, new R/R. I saw charging voltage @ battery. A few minutes later I check, no charging voltage, staying steady @ 12.4v, revving makes no difference. Swapping alternators makes no difference.

Alternator cover is magnetic.

R/R shows almost 12v from black to brown, but little increase as revs increase.

Not sure if it matters, but in-between all of this, I swapped batteries for a full-charged battery. The battery is good as far as load tests are concerned.
Jumpered field coil green to battery negative. No increase in voltage across battery.

[IanDMacDonald]

Is there any connectors elsewhere on the bike that could affect the charging system? Headlight bucket?

[IanDMacDonald]

One more crazy thought, but would using a S/S bolt as the replacement for OEM engine grounding bolt cause any grounding issues?

[motoman]

Is there any connectors elsewhere on the bike that could affect the charging system? Headlight bucket?

Have you actually taken apart and cleaned the stop switch? Checking connector ends on both sides of that associated plug-in on right side of frame under tank will show any voltage drop assocciated with stop switch.
Your grounding bolt choice shouldn't be an issue. If base mount and all are shiney-clean, after bolted up, give it a shot of clear battery term. sealer at that connection.

[D0wn5h1ft]

Measure from each white wire on your alternator to the engine cover it sits in. I almost guarantee that it's shorting to ground. You should read infinite resistance on each of the three white wires to ground. Happened to me twice already, easy fix (buy a new one, pretty cheap).

[IanDMacDonald]

So, if I don't read OL, I need to replace the stator?

[IanDMacDonald]

Okay, I'm really confused!!! I don't understand why I should see OL as readings from white wire to stator cover (I'm not, seeing 1 ohm and less on both alternators). I mean isn't the stator windings connected to the cover, which is in-turn grounded to the engine, which is grounded to battery? According to Gabe, if I don't see OL, my stator is shot?

[crazy steve]

So, if I don't read OL to ground, I need to replace the stator?

Yep... This part of the charging system is AC and cannot go to ground anywhere. But make sure you're reading your meter correctly; I've seen meters that read '1' if the resistance is too large to measure, and if it's an auto-ranging type make check the scale display to verify it's 'ohms', not Kohms or Mohms. If yours reads 'OL' (open line) when there's no continuity, a Mohm (millions) display is acceptable, even a large Kohm number (30K and up) would probably still work. But if you're getting any ohm-scale readings to ground (the alternator cover if it's removed from the bike), either the windings are internally shorted (in which case it's toast) or the leads are damaged and shorting to the cover (possibly repairable, but you'll have to remove the winding from the cover to check this).

[D0wn5h1ft]

I've lost two alternators to the enamel breaking down and shorting to the case. It sucks, you can't fix it (unless you have one of the old timers on here that knows how to rewinding 3-phase stators), and the stators are getting rarer as more of them break.

I would like to try my hand at rewinding them as a few years ago I had my college electrical engineering mentor (one of those "old timers") teach me how to do it. So if anyone has a broken one lying around they'd be willing to sell me for cheap, I'd give it a shot and if it works out ok offer a little rewinding service. I've seen a few really old posts about members doing it but I don't know if any of them are still around. There are small mom and pop shops that do it but they usually charge through the nose because it's a dying art.

I have one extra good one but I'd hate to rip a working one apart seeing as I'm probably going to end up giving it to mac.

[IanDMacDonald]

Stator Installation: Things to look for

Gabe (Down$hift) was gracious enough to give me a good-working stator. Before I install it, I want to know if there is anything I should look for prior to installing? I did notice drag marks on the rotor from the stator I bought used.

[D0wn5h1ft]

Just an idea, you could tape off your rotor and do a really light coat of black spray paint on it. When you go to install the new rotor give the starter a few hits without actually starting the bike. Take off the cover again and see if there's any long scraps in the paint. If it's all still there you know that it's not rubbing anymore.

[IanDMacDonald]

https://dl-web.dropbox.com/get/Publi...sjk_4xmPegmCQ/

That is the results of Gabe's test. Not sure if the cover I got from Andreas is not holding the stator in properly, or if my rotor is fubar. Ideas?

[IanDMacDonald]

For those whom are just dropping in, here is what happens: I see charging voltage for about five minutes, then nothing. I think I shut the bike off before any damage was really done to the stator, as I still see OL on the leads to ground. I chalk off the rotor and pulse the startwe, resulting in the stator rubbing on the rotor. So, either the stator , stator cover, or rotor is warped is my guess.

[crazy steve]

If you're installing the stator winding into a cover, it can be very tough to get it in square. Pull the winding back out and look for signs at the recesses it fits into for interference or 'cocking'. The winding fits tight, you might smooth the edges some to aid in fitting.

Also make sure the locating dowel sleeves for the cover are both present and undamaged.

[D0wn5h1ft]

If you're installing the stator winding into a cover, it can be very tough to get it in square. Pull the winding back out and look for signs at the recesses it fits into for interference or 'cocking'. The winding fits tight, you might smooth the edges some to aid in fitting.

Also make sure the locating dowel sleeves for the cover are both present and undamaged.

I'll second that suggestion of making sure it's square. The tolerances are REALLY small. It took prying all over your broken one you dropped off to get it out and with the corrosion I don't think I could have gotten it back in. When I replaced my stator I put a small piece of plywood on top of the stator and tapped around the outline of it with a mallet. I made sure not to get too crazy with it and damage the stator. However, if you don't want to take a hammer to it I'd suggest taking a scotch bright pad and cleaning the outside of the stator (if/when you get it out) and the respective parts of the case. Add a little bit of oil to smooth the replacement back into the case and you're done.