That bushing (and all the gears in the starter drive train) is only used when the bike starts, and for only two or three seconds. It is not lubricated very well, especially since it is only used at start up. It is lubed while the bike is running , and that will be the only oil in it the next time you fire it up. I had the bushing analyzed because I was going to make a new larger one to fit in the stator cover. I was told that the bushing is an iron based P/M product (powdered metallurgy) The powder is sintered together. Besides being iron based it also has a small amount of copper which may be uses to help with lubrication. The P/M make up has a natural porosity which helps it hold lubricants.

 

I understand powder metallurgy bushing... but what do you think caused the wear then if not friction? Or are you saying the bushing possibly fractured from impact... maybe a piece of its in case...

 

I'm 99.9% certain that the damage was caused by the engine trying to basically run backwards a bit. The piston being forced backwards, for whatever reason, ( my guess pre detonation ) and the force being mainly transferred to the small idler gear in the starter gear train. I also think, that the hiccups damaged the idler gear shaft, and it eventually ate through the bearing. At one point I'm sure that the hiccup force was enough to crack the boss on the engine case side. Eventually the bearing and the idler gear were so damaged that the stater gear train slipped and I was stuck out in the woods and had to bump start the bike to get back to the truck.
Pretty sure that's what happened.
I'll post some more pics later
DAn

 

I think the shaft of the gear may have been damaged in the hiccups and subsequently wore through the bushing. The hiccups were violent enough, at times, that I wouldn't be surprised if the bushing had gotten deformed.

 

Pretty sure it didn't fracture. It's possible that small chips may have broken off of it, but for the most part it wore through. I will post a pic of it , and some other stuff later tonight.

 

Fascinating deal, dan. I think it can be traced back to the upside down track experience your bike went through. It's probably been harboring resentment all this time and just waiting to pounce for payback.

 

It has surprised me over, and over, each time i picked it up an rode off. If it were something like one of my crashes that caused the break down I would feel better about it.

I am going to go clean up my workroom. Got my first box in the mail today. A grab bag off of eBay that had the idler gear in it. Got the gear and a pile of stuff for $20 +s/h vs about $60 + s/h for just a new gear.

 

Grab bag off of eBay

got it


"new" idler gear from grab bag.


Stator cover w/worn bearing


bushing removed from stator cover, note that it is still intact at the bottom.


My idler gear, note shaft galling which has worn through bearing.


stator cover without bushing, note worn spot on cover.

engine case on eBay

 

WOW ! Mellow out with the starts, man. Hey Dan, looks like you're getting things lined up.

 

You're a resourceful bugger, dan...and cheap.