BY FAR the most dangerous lurking famous failure is dumbass axle fracture. Both my Combat broke them, Peel at 90 mph standing on pegs, and yesterday doing parking lot circles on Trixie. My ride buddy Wesley said his Combat broke it axle and also his '71 about 20 yr ago. I hear of this fracture at least twice a year and only about 10% of C'do owners are online regularly if at all, so exprapulating out that implied like a dozen axle breaks a year that we don't hear about expect interviewing at rallies.
Head gaskets blow out mostly at oil drain hole but also to push rod tunnels undiscovered until oil blowing out seams or opening up for the surprise.
Headers fracture near engine then dangle and clang at they blast loud shocker. Wire is about only thing to hold em up to limp back on own power.
Kicer ratchet is common to go away while away from home.
3rd gear cog teeth seem the weakest to break getting on it in lower rpms.
1st gear paper thin bush wears to fractures apart pretty soon, which can jump out of 1st when just barely coasting down w/o power load to hold it in gear, so lost of tire drag can suddenly slip you right down a barely jogging speed on slight little bump in the path, SPLAT. Had that twice now so keep those bushes on hand but not the longer lasting rest of tranny parts.
Rusting leaking bar master cylinder blowing off at speed to go completely away one hard pull down to nothing the very next squeeze of terror.
Worn chain riding up out of sprocket valleys to wipe teeth off to just useless nubbins while out and also causing chain to come off teeth but not off the bike so it just dangles while trying to go up hill but slows down to a stop.
Tail light bulb inside ground strap hanging by an intermittent hair to both cause Boyer missfires or completely dead spark but no fault found until bike bouncing a bit.
Bores wear out in AMC gear box and they also develop crack between the bearing bores, which pretty much trashes the cases for piles of them at various vendors around the world. Atlas shells are the cheap replacement and fit better btw.
Coil brackets tend to break off now and then too.
750 headsteady plate easy to bend and fracture. Can be braced by welding two verttical tabs to support the bend in plate or put in boxed 850 type.
Lower cradle bolt holes are pretty common let go on 850's, double thick plate welded over that is standard fix.
Rear drum clirclip area can pop off.
Nut on RH end of main shaft can back off and prevent clutch adjustment to work.
:!: I bet there is over twenty common original failings,,starting with Combat Rods comming off :!:
