I want to repair this alternator for an ST1100 and your're invited

Well, being air-cooled the 40A unit is prone to environmental influences like water, dust or sand...
In the UK some packed due heavy corrosion on the stator, actually seizing the engine.
Sand and road debris can abrade brushes and slip rings, humidity and water are an enemy of the rear/aft sided ball-bearing.

So the sealed, oil-cooled unit was not such a bad design to begin with.
 
Time for another update. I pulled all of the blue rtv out of the stator that leaked after I installed it. I wanted to inspect it for how it leaked, I was gunning for it to be able to retain oil.
I have discovered the field coil has a rubber insert that goes over the two prongs, pictured below. Mine is still flexible, but I'm wondering if I shouldn't remove it and allow the rtv to adhere to the two leads in case the oil is able to leak passed the two metal leads.
I might as well try, the stator won't be useful otherwise so I might as well experiment. That rubber piece is 25 years old and it just might not be able to seal oil anymore, but rtv...
IMG_20161011_165146.jpg
 
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flying couch said:
ive got a28 amp alt cap you could have also . im so glad i am putting in a new 40 amp. just looking at those photos sends shivers down my spine.
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Thanks for the offer for the 28A alt cap, I'm interested. To date, no one I know is able to repair the leak, with a functioning stator and field coil wire after disassembly. It would be useful to some if I'm able to do this who would still like to run a 28A alt, whether it's a cheaper solution or due to the climate they're in, salty roads.
I am working on a stator right now (the 2nd time) after I attempted a repair and it leaked after install. I later found out I rushed a cure time before I assembled the two parts and am attempting to do it again after I clean up the parts. I intend on putting 200 degree oil in the stator as a leak test, before an exorbitant amount of time is spent installing it only to find it leaks. Big time downer. So, I will report back my findings and techniques, having tried the 2nd time, after this weekend.
 
i just verified 14 volts at the battery tonight !!! what a good feeling .
yes paypal me the shipping cost and you can have.
now all i gotta do is re assemble everything with cleaning and lube
 
hi. i sent a response to the email. not sure if you got it.

my bike is together and im so glad i cleaned and lubed the shaft! the couch really glides now . all i need is a far away destination .
i dont know how to do PM on this site yet, but the alt is yours .
 
You can PM by left clicking my handle, a menu pops up with what you'd like to do. Since I sent you a PM, a flag at the top of your screen should say you have a new notification.
You can also email me at maverickmoddy@gmail.com, it would be the easiest. I appreciate the offer. mod
 
At long last, 2nd attempt to seal the 28A stator components was a success. An alternator refurbisher mentioned he used Ultra Blue Permatex, so I gave it a go, following the directions this time. Last time I rushed assembly and didn't wait for an hour after finger tightening to allow for a cure time, then do a final tighten. Not this time.
I also used a carb and intake spray to remove the oil residue for good surface adhesion with Permatex.

So far, 18 hours later, my leak test has proven negative.
How do you do a leak test for a stator that isn't mounted to the bike? You make it up, that's how.
Suspend your heat gun over a bowl lined with aluminum foil and put a cup and half of motor oil in it. You can use a thermometer, but it took about 5 minutes to heat it to it's temperature, so you could do it that way.
IMG_20161201_165759.jpg

IMG_20161201_165833.jpg
Heat to 200 degrees and serve.
IMG_20161201_170225.jpg
By pouring the oil evenly inside the field coil and outside would insure the best chance for oil to get out if I didn't seal it well enough.
The bowl is where it could collect if my technique didn't work.

At 18 hours and no oil residue is a good chance this stator is leak free and ready for installation.
The wires are long enough to solder them directly, bypassing the P2 and P3 connector. You can also shorten the wire to include the connectors.
I have to say, with the effort of refurbishing a 28A stator, if you were intending on upgrading to a 40A would be better to do it at this time.
I also believe it would be better to have a 28A stator ready to go rather than the wait time to clean out the resin, disassemble the stator, solder new wires, seal it, then install.
Lastly, I really wanted to drive this home to put many of the 28A stators not in use, back in use. There is a place for them.
A 40A isn't for everyone, especially those in a climate or road conditions that corrode the exposed areas of the alternator. A 28A is sealed, protected from these elements. As long as you don't lose a leg in the stator, a 28A is fine. I know, I rode with one for 45k miles before I got noticed my voltmeter reading low at idle. I'm upgrading to a 40A, should be getting the rebuild back in the next couple of days. I will be getting into my original stator that failed soon. The one pictured here is from DaveS, properly tested before I got started, just needed to be rewired.
I'm hoping my stator just needs to be rewired externally, where the short is. Til the next time..soon.
 
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Good news. With a recent upgrade to 40A service out of the way, I was able to take a look at the original stator I purchased the bike with.
For a recap, right after I'd done some shim work and tightened a leaky coolant hose, relieved it wasn't a leaking water pump, I noticed 11.5 volts at idle ( totally recommend a voltmeter you can reference on your bike. I would have been stranded wherever the battery finished running out of juice, so for $8 bucks..)
On initial testing from the P3 connector to ground revealed one of the 3 legs from the stator was dead. Dang, all that I'd read about people having charge issues was happening to me.
The short story after placing a couple 28A stators to bide time for putting together the needed 40A components, I explored the leaky stator to see if I could "properly" seal it the 2nd time and it was successful.

Today, I removed the resin, covering the nuts to disassemble the stator like I've practiced before, tested the stator once I separated it from the field coil and it passed.
3 leads of stator had continuity and measured .5 .5 .6 ohms, within tolerance. I also noticed the wires going into the back of the stator were in the same condition as DaveS's stator.
One could conclude, over time, eventual leaking oil and weather, the insulation of these wires becomes cracked and exposed, causing it to short before an internal failure. Will know more after I solder new wires and seal it "properly", then some one uses it for a while, for the definitive.
 
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Long story short, I was able to rewire, leak test and bench test the alternator. Now to find a home for someone who want to run a 28A stator.
 
moddy said:
Long story short, I was able to rewire, leak test and bench test the alternator. Now to find a home for someone who want to run a 28A stator.
Click to expand...

By rewire I mean used new wires externally. I am not setup to rewire a stator, the coils needed to be intact for what I did to work. In my opinion, what fails, is the soldered connection the stator wires make internally. The black insert that all five wires come from the outside, are soldered on the other side of that. Having disassembled the stator, cleaned and re-soldered, revealed a good connection again. You won't know if a stator can be soldered again, until you have the stator off the bike, desoldered from its internal connection and tested separately.

This is inside the stator where the field coil fits inside the stator coil. Normal disassembly is loosening the seal between the stator housing and the black plastic electrical hub. They both come out together as a unit, the stator is soldered to the insert.

IMG_20170309_123201.jpg


In this case, it wasn't hard to pull the stator out as the points of solder had failed. Three leads to test are sticking up from the stator coils. This is tested for ohms in the same manner as the p3 connector when separated. No more than 1 ohm between any two leads.
This tested at .4 to .5 ohms between each lead.
This particular stator had one leg fail, as mine did. It is common for this failure if it isn't the VRR.
Thanks to Pat (sirepair) for sending me this to study, I will clean it, solder new wires and re seal the plastic spacer in place.

IMG_20170309_123146.jpg
 
Howdy,

I have a leaky alternator myself. How much play is there behind the black resin cap that all the wires go in? Is there enough room to pull it out so I can clean it and get a good seal? The alternator tests out fine.

Thanks!
 
iwriteiwrite said:
Howdy,

I have a leaky alternator myself. How much play is there behind the black resin cap that all the wires go in? Is there enough room to pull it out so I can clean it and get a good seal? The alternator tests out fine.

Thanks!
Click to expand...
zero play. Unhappy to report that to you and to remove it to work on it is probably second to the work it takes to remove the engine. Behind the rubber cap is where the wires are sealed in resin. After having researched this issue plenty there is not other alternative to pull the stator after removing the swing arm to clean it out and reseal it. Now it begs the question if you are going to spend the time to work on the 28 Amp stator, why not do the alternator upgrade. I had more time than money and that is why I not only disassembled my stator, but have come into a couple more from donors who have upgraded. Hope this information helps, I know it's not the best news.
 
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