I am working on my daughter's 1972 AT-2, and pulled the primary drive cover with the intent of replacing the crank seal.  I was surprised to see the main case casting bore swedged in three places at the seal bore (see two photos attached).  I am assuming this was done at Yamaha.  Has anyone seen this before?  Does anyone know if Yamaha had a problem with crank seals coming loose or blowing out of position?  That's the only reason I can think of why the bore would be swedged.  I can remove the plus metal condition with a die grinder, but now I am wondering if the replacement seal should be swedged into place too.

Also, there is a conical steel washer that fell out of the primary cover when I pulled it off.  It looks as though it goes on the end of the nylon drive gear.  If that's correct, from the wear on one side of the washer (see attached photo) it looks like the covex side goes agains the primary cover and the concave side against the drive gear.  Can anyone confirm?

Love the forum.  Thanks to all.

Those "dings" are someones attempt to kept the seal in place !!
Yamaha sells a retainer for this. #25 in: www.partzilla.com/catalog/yamaha/motorcy...2/crankcase-cylinder

Wonder if previous mechanic solved reason for pushing the seal out, timing, piston/ring blow by or just a old hardened seal that shrunk ?
Seal is 8mm wide, so unless it's cracked, you should be good.
There is a o-ring on the crank under the collar, may as replace it too while your there.

Shim is in the correct location, it's flat when new.

Man that's disappointing. Yes they did push seals out when many years old or if something happened like a C/case full of fuel then one good kick can push it out. By memory there's room to run two opposing retainters [if you want-if ya realy realy want] as just mount to the crancase/crank pusher tool holes. 8mm holes & 8mm phillips screw with big heads. Just be sure there's room for the screw head behind the clutch basket gear.

 I'm sure that washer should just be flat, so where else could it be from or substituted from. SHIM
248-17837-00-00

Thanks for the input guys. I ordered both keepers - primary side from Partzilla and Magneto NOS from D's Cycle on Ebay. Both case halves have tapped bosses for the keepers. I looked through the Yamaha 125 parts catalogs and see the keepers were added in the 1972 catalog, and continued through ongoing years. I worked for an OEM commercial transmission manufacturer for over 30 years in various engineering jobs, and as soon as I saw the swedges my initial thought was Yamaha may have bored the seal bore plus limits - and swedged the seals to salvage the case... (not that we ever made parts out of spec!). Thanks again.