TOPIC: E-Start sprag blow ups research.

Over the years I have had a few starters come back to me totally blown up from a flipped sprag locking the drive train and causing the starter to rev "to the moon", followed by a destroyed starter.
The final effect is known well enough. The thing I have been researching is what is the failure modes that causes it.
I recently got back a second blow up from the same guy.
Digging a bit harder with him I came up with a few tidbits by examining the associate starter drive parts that I asked him to send up to me.
I will be looking to see if some of the same thing have caused failures in others and what are the contributing factors,
I will be looking into the brands of sprag makers besides the 16 or 18 dog bones/rockers.
These one way clutches are, after all, a standard industrial one way clutch and there are enough sources and price points for these parts to make a worth while survey,
It is curious to note that andover norton is supposidly making modified starter drivetrain components at considerable expense. Their sprag is approaching $180 yet a alibaba chinese one can be had for around $20.Some guys are using the chinese ones successfully so far.

A number of years back I was prepping my commando for an extended trip up to Maine around Mount Desert Island. I didn’t like the position of the clutch engagement so I was adjusting the clutch. I had the bike fully loaded and I took a ride down to the gas station to tank up. Everything was working normal. At the time I had a four brush starter in the bike that had been working for a few years. My 1975 had the original sprag from the factory, as far as I know. The bike had 5000 miles on it when I got it. I adjusted the clutch one more time hit the starter button and I could tell something drastic happened inside the primary, I kind of figured out what it was. I was lucky it happened in my shop and not on the road, needless to say I took another motorcycle on that trip. The sprag
was working normal until it didn’t, there was no sign that anything was wrong before it disintegrated.

Anybody out there?
Who uses OEM stock bronze clutch plates and who uses solid fiber clutch or barnetts?
I can tell you a story....

Fiber

Barnett fiber

PMellin wrote: Barnett fiber

Didn't realize you had a MKIII E-start? The whole point of my research is to find out the reasons and failure modes for the sprag mechanism.Non original clutch material being considered as contamination.