28A repair? 40A purchase from where?

Joined
Jan 5, 2013
Messages
191
Location
Ipswich MA
Bike
1994 ST1100 ABS
I have concluded that my 28A has seized. That said, can anyone with the knowledge answer these questions?


  • Can a Stator seize causing the engine to not turn? imitate a seized engine?
  • To remove the alt cover do you still need to pull the swingarm?
  • If the Stator has seized, do you repair them? can it be repaired? or do I purchase a new one?

If I have to pull the alt all together going through that whole procedure of removing the swingarm, then of course why not perform the "40A upgrade".


  • Where do you purchase the 40A alt? is there a part number? or is there a list of parts?

I enjoy wrenching but honest, just want to ride. Im totally bummed at the repair that I am going to have to perform. I have searched the site, all the sites.. I have read how to do this to the point that I am beginning to mix things up.

Thanks
 
Howe, there is a small bearing in the stator that could seize, I suppose, but the main loading is on a large bearing on the rotor end which is bathed in engine oil and would be unlikely to seize. I would guess that engine power driving the rotor would cause the stator bearing to spin in its housing before actually causing the engine to seem to seize. A burned piston or stuck valve would be a more likely cause, IMHO. (did you adjust valves recently? a mis-timed cam will cause the engine to not turn before it bends valves)
You can remove the stator without removing the swingarm, but be sure to leave the rotor in place, as the spring-loaded gear drive requires a special tool to reengage it, if you inadvertently back it out. I would not trust a used stator and would buy a new Honda replacement before having yours repaired-- a costly, risky proposition. Remember also that low alternator output can be caused by a wiring problem or a defective regulator rectifier. So, after all that work to replace the stator, you may still have an electrical problem.
I just completed a 40A alternator upgrade which is not easy and I would consider major surgery. I bought all-new parts from Partzilla and am thoroughly pleased with the results. I would not attempt this project without borrowing the upgrade kit from John Oosterhuis , however.
 
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CGRed. I don't do PMs here and you don't email so I'm asking you via post to remove my email address from this public forum. Thank you. I'll delete this post then.
John
 
Im going to pull the stator and see what it looks like.

What happenned is this... Bike started up for the first time this season. Alt made a grinding noise. A quick ride and it went away. I assumed a little winter time rust. Next day I wen to start it again and it made a MUCH greater grind and instantly stopped. Nothing.

Ill poke around... see if I see anything.
 
John, Don't know if CGRed saw your message but I've taken care of it for him.
 
I slid the stator back to see what I could see. First thing I noticed was the chip in the mounting bracket ...

Alt 1.jpg

Also, the orange gasket sealer... suspicious. Makes me think this has been apart before.

Anyway, a chip in the alt could bind up the rotator and the stator which would cause an engine seize type symptom. I took a large flat-head screwdriver and pushed the rotator to see if the engine turned freely... she did

I havent condemned the alt yet. I dont have tons of farkles so Im not jumping into the 40A upgrade. I just want to diagnose and fix this issue.
 
Looks like the o-ring that sealed the Stator to the Alternator Shaft Assembly had failed (not unheard of) and a repair was attempted with liquid gasket or sealant.

If you remove the spark plugs the engine can be turned over by putting the transmission in gear and rotating the rear wheel.

I think you're going to have to pull the swing arm and then the stator/alt shaft assy.

John
via iPhone 6
 
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Ok John... Glad you chimed in...

you say "I think you're going to have to pull the swing arm and then the stator/alt shaft assy" I have never seen this alt apart so bear with me. Will the alt shaft assy simply slide out? By taking the stator off exposing the alt shaft assy I can then put my hand on it and slide it out for inspection?

Like I said before, I have had no real issues with my 28A alt. Im hoping I can remove it, inspect it, clean it, and put it back. Im sure Ive read somewhere how to bench test the stator.

Thanks
 
Is that picture taken with the swingarm still in place?

Just wondering if that o-ring can be replaced without completely pulling off the stator/swingarm? Is there room to wiggle it off/on.
 
I asked if the stator can be removed without removing the swing arm. Ill take a closer look but Im skeptical.

Alt 2.jpg (Un-cropped picture)
 
Look, I don't think the alt is the cause of your reported 'engine seize' problem. I'd suspect the starter.

As to the alt, now that you've pulled the stator partway off and broken that seal, if you're not going to take this opportunity to do the alt upgrade, I think you are going to have to order the stator o-ring, pull the swingarm and alt shaft assy to inspect, clean and R&R the o-ring. For peace of mind. You'll have to make a Lewis-Pin (or borrow the STOC upgrade kit) to reassemble. Swingarm special tool also. Anyway, this will give you a chance to inspect/service your drive splines (final drive and driveshaft) and swingarm bearings.

Assume you disconnected the neutral switch when you took the picture.

John
via iPhone 6
 
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John,

Would he really need to pull the alt shaft assembly as well? Since someone else has obviously been in there trying to seal the stator leak, and since he doesn't want to do the 40A upgrade, would it not be much easier just to pull the swingarm, get a new stator o-ring in there and button it up again?

Just suggesting, as getting that alt shaft and split gear back into there can be a bit of a pain in the arse, as was my experience.
 
Howe thought there was possibly a metal chip somewhere. Pulling the alt shaft assy seemed necessary to rule that out.

Look, the stator has to come off to clean the o-ring area. I've never heard of doing that without removing the swingarm. Let us know if you do it. I'd pull the alt shaft assy to inspect and clean it, but that's me. Turn the engine over by hand to insure the alt isn't causing any binding currently. If not, troubleshoot the starter.

To answer a previous question, the alt shaft assy will have to be pried out as the split gears are engaged with the engine flywheel, and it's a tight fit to the hole in the engine case of course.
 
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Looking at that photo again, it does appear there is a semi-circular piece of metal broken out of the alt shaft housing. Possibly broken off by the last gorilla that was in there trying to bash/pry the stator housing off. I'm thinking that is a potential oil leak point right there, new o-ring or not. That piece of metal could have been lodged in the permanent magnet cluster and then flung out, causing the grinding he heard and then the seizing.

With all that to consider, I now agree that it should ALL come out for a complete inspection and Howe might want to look for a used alt shaft housing to avoid the potential oil leak.
 
Looking at that photo again, it does appear there is a semi-circular piece of metal broken out of the alt shaft housing. Possibly broken off by the last gorilla that was in there trying to bash/pry the stator housing off.
+1 on this...
I'd give the O-ring groove in that area a careful inspection...
If there is so much as the smallest piece of metal missing from the O-ring support, a new ring won't seal (might explain the mess of engine-silicone there...)
 
I love this bike... want it to last. More to the point, I dont want to be somewhere dead in the water. It's best to pull it apart and make sure everything is in order.

My thoughts are that one of the previous owners pried a little too hard and chipped the edge of the housing. I can only assume that chip was retrieved when it was broken. Leaving it in there would be... well.. need I say?

Im going to create a clean work area and pull the swing arm. I know these guys who will make me the special tool for that. I was hoping to not have to go so deep but it is best to do it right. Besides, I can also inspect my drive shaft splines, U-joint, and cush... right? I like knowing how things work and this will be my first breakdown so Im looking forward to it.

Ill chime in as I go forward. Thanks for the thoughts and suggestions.

:attentio: BTW, Luckily I purchased another bike this spring so I can still ride. My new Triumph Trident 900 is fun... being naked it is different. The guys on the Triumph site are great.. knowledgable, friendly, just like here. But the site itself is no where near as good as this one. The organization, speed, layout, everything about this site is top notch!...

:beer3: I raise my mug to those running it and to the members . Cheers!
 
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BTW, Howe, I have a serviceable 28amp alternator shaft assembly you can have. Without the flywheel and split gears, etc. Leftover from my 40amp alt upgrade. You'll have to transfer those parts from your damaged unit, just like when doing the upgrade... are you sure you don't want the peace of mind and extra amps of an upgrade now....?
 
Thank you for the offer on the tools. I joined ST-Riders the other day (thought I had done that back when I joined here) and read your kit requirements. With work and family Im not sure how quickly Ill have this surgery completed and wouldnt want to tie up those tools. I certainly want to take my time. Besides, I like collecting tools.

Hmmm... you know, I really should just do the upgrade. One thing I am confused about the 40A upgrade is this... in reality it's not just a swap... 29A out, 40A in, but rather a "re-use" some parts from the 28A combined with a 40A? I guess I need to read the procedure closer.
 
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