Starter Repair Question. All opinions welcome...no matter how obsurd

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A

Apkah

Active Member
I recently discovered what seems like a simple problem with my starter. After being told by a few professional mechanics that I had a sprag failure I was deighted to discover my sprag was fine... I like to consider the learning of this information a bonding experience between me and my newly purchased broken bike. It turns out, if one of the magnets around the armature has an adhesive failure, it will behave exactly like a bad sprag.

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Now to my question.

Which adhesive do I use?

My first thoughts:

1, JB Weld. It is certainly strong enough and has good tolerances for this application, but will the alternating heat and cold dimensional fluctuations eventually repeat the event? If it expands at the same rate as the magnet and case, it should be ok but i am not sure.

2, Silicone. It is adequate to seal the Boston Aquarium and my crank case so it is probably strong enough and will react well to thermal cycling, but, again, I am unsure.

Any thoughts?
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About ten years ago I had a magnet on the rotor part of the alternator on my outboard come adrift.
as this is all part of the flywheel assembly, replacing the whole thing was going to cost an arm and a leg.I used Araldite super strength epoxy to re-attach it and it is still working to this day.
After a little googling, it appears that your JB weld is the same sort of thing so I would certainly give it a go, after all, if it doesnt work its not a huge deal to pull it of again.
 
Thank you All. It appears we have a clear winner with 2 part epoxy/liquid metal/araldite! I appreciate the input and will keep you posted.:y2:
 
Do you have a starter/alternator rebuild shop around? I would call them and ask if you do.

I have a great one less than two miles away. In my case I'd just give it to them since they'd completely rebuild it with new bearings and everything for about $30.00.

They'd probably also answer a question if I wanted to do it myself.

That said....I'd use the JB Weld for sure on something like this.
 
The Seeker said:
Do you have a starter/alternator rebuild shop around? I would call them and ask if you do.

I have a great one less than two miles away. In my case I'd just give it to them since they'd completely rebuild it with new bearings and everything for about $30.00.

They'd probably also answer a question if I wanted to do it myself.

That said....I'd use the JB Weld for sure on something like this.
Click to expand...

great call. I have been asking around about a rebuild shop. Most have gone under in the past decade near me. I will probably pop it back together and get the bike running. It has been in pieces since it was repo'd back in 2006. It changed hands 5 times on its way to me. I am eager to hear it run. I will probably get it rebuilt over next winter, sooner if it acts up. I plan on checking impedance on the armature to make sure the windings are still ok before I make a final decision. I can only imagine that previous owners in their frustration put a bunch of current through it to try to make it work.
 
Agreed on the JB weld, I held the deck of Sears push mower together for 5 years with JB weld. Neighbor was throwing the mower out.......deck was cracked right where the handle attached to the deck, a good cleaning and JB weld applied to both sides, worked a charm till I sold it for 10.00 when I moved to the Florida Keys.
 
Once you get the magnet fixed back in - give the armature an overhaul as pe:

Once you find new brushes, the alternator comutator needs to be fixed up for best performance.

The comutator (the round coppery thing, for Margo) has axial grooves in it. The grooves "close up" during normal use, reducing the performance of the unit.

Make a purpose built tool from an old hacksaw blade, and scrape a "chamfer" along both sides of each segment - just enough to remove the overhang which forms naturally. DO NOT SCRATCH THE OPERATING Surface!.

Put the shaft in a lathe, if possible, or rig up something with an electric drill so you can rotate the unit at high speed. Using FINE (1200) emery cloth, polish the surface of the comutator to remove any blemishes which may have formed during normal use.
Treat the whole thing until it is a uniform copper colour.

Repeat the chamfer process, but ONLY ENOUGH TO REMOVE THE SHARP EDGE YOU HAVE JUST CREATED.

Blow the unit thoroughly with compressed air to clean.

Fit new brushes.

Off you go.

I give thanks to my apprentice training officer, Mr Roy Candy, for teacing this process to me in 1972.
 
Last edited by a moderator:
Silli said:
Once you get the magnet fixed back in - give the armature an overhaul as pe:

Once you find new brushes, the alternator comutator needs to be fixed up for best performance.

The comutator (the round coppery thing, for Margo) has axial grooves in it. The grooves "close up" during normal use, reducing the performance of the unit.

Make a purpose built tool from an old hacksaw blade, and scrape a "chamfer" along both sides of each segment - just enough to remove the overhang which forms naturally. DO NOT SCRATCH THE OPERATING Surface!.

Put the shaft in a lathe, if possible, or rig up something with an electric drill so you can rotate the unit at high speed. Using FINE (1200) emery cloth, polish the surface of the comutator to remove any blemishes which may have formed during normal use.
Treat the whole thing until it is a uniform copper colour.

Repeat the chamfer process, but ONLY ENOUGH TO REMOVE THE SHARP EDGE YOU HAVE JUST CREATED.

Blow the unit thoroughly with compressed air to clean.

Fit new brushes.

Off you go.

I give thanks to my apprentice training officer, Mr Roy Candy, for teacing this process to me in 1972.
Click to expand...

this little post should be a sticky IMHO. Thanks! It makes a lot of sense to address areas of repetitive use degradation before it fails. I have read I can improve the life expectancy of my sprag by ensuring i have a healthy battery and a healthy starter. I have some dental tools I use for carbs and such. these may do well cleaning the brush dust out from between the cumutor terminal blocks as long as I am careful. I hadn't even considered the issue.
 

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