AMC Gearbox Mystery Part - Solved

OK, So I'm rebuilding the gearbox on my `63 cafe racer ( I don't trust original layshaft bearings anymore since my Commando fiasco last year ).
Anyway, everything looks really good inside except for a mysterious little piece of metal I found in the sludge in bottom sump of the gearbox.
I've inspected all the gears and shafts looking for a missing chunk of metal to no avail. The mystery piece is steel (magnetic).
It's shaped a bit like a Woodruff key and it has a countersunk hole in one end. It looks like it broke along this hole.
Any ideas? I'm stumped.

Re: Gearbox Mystery part

IF nothing is chipped or missing, perhaps that's a chunk of an old kickstart pawl that was changed out and the piece was accidentily left in the case???

Re: Gearbox Mystery part

Yeah, at this point I'm convinced it's from a previous failure and simply never cleaned-out properly.
It occurs to me that a magnetic drain plug might be a good idea for catching stuff like this.
It's just bugging me not knowing what it is. Looking at the parts diagrams....

Re: Gearbox Mystery part

mschmitz57 said:

Click to expand...

My money's on starter pawl (#20). Hole is probably detent to receive spring-loaded plunger.


http://www.oldbritts.com/1973_g8.html

Nathan

Re: AMC Gearbox Mystery part

You guys are good!
Jaydee

Re: AMC Gearbox Mystery part

Ugh, I hate it when I have too many partial pieces left over or not enough. Almost appears as part of one of the 2 steel KS ratchet stops behind inner cover - except your piece has smaller dia hole than the stake pin hole of my items which also have more metal around hole and my items are black finish not raw steel, so does not compute - unless it was run to chew it down - which does not make sense either as KS would not function if stop bent or fractured off - which is why Trixie AMC is apart now. Can not imagine even a bad attitude mechanic like me missing it leaving inside as would fall out like me reading instructions on boot heel how to pour piss out. Only logical conclusion is shoe eves, pack rat or mean friend dropped it in to injure guts and confuse you and rest of us. Also implies could show up again till solved.

Re: AMC Gearbox Mystery Part

Yeah Hobot, a lot of weird things can happen to these bikes in 50+ years. All manor of bodges and jury-rigging.
We are simply the care-takers...

Re: AMC Gearbox Mystery Part

Ha! I think I figured this out. I think the mystery part is one of the tangs of the clutch actuator lever that broke off and migrated into the gearbox through the opening on the bottom over time. It's not an exact match with the current levers I found online but the old 60's design may have been shaped differently. I found this image here on Access Norton website ( forgive me if I'm using your image). It turns out that I wasn't thinking "outside the box" on this and focusing on components behind the inner cover.
I'll have to verify when I get home but I think I found a match.

Ok good find a cable grabber end fractured off. An old school mod is to grind off the ends a bit to allow easier slip on of cable end like I do mine but that would not weaken it so some ham fisted squeezer succeed to get level in all the way back. Now stick in a 3rd old sleeve bush or two longer bushes, oil groove just short of DS case edge then run any ATF ya like for longer lower gear use with clutch stability. I have put cycle reassembly on lowest priority this year so glad to know others solving mysteries and making useful progress on luxury items.

I can envision someone prying the 2 tangs apart for more clearance and "snap".
Yeah, bearings sleeves and seals on the way from Old Britts. Cripes, servicing these old boxes ain't cheap.