The seal arrived! Alllmost done getting it in there.
Took quite a bit of time, but got the mystery epoxy removed yesterday! Had to alternate between chipping it off with various tools and wearing it down with sandpaper. Certainly have scratches there now, but I'm not worried about all that; lightly sanded any rough ones. Great news is that I didn't see any significant holes or cracks beneath it!
Today I got the old seal out in a snap! As you can see, there was oil just sitting there behind it.
I was going to use a Dremel or knife to smooth the bore, but I noticed that the opening already had silver showing around the whole, as if someone had already done it. I felt the hole and there was hardly anything that felt sharp. Seeing as the old seal just came out, and while it was worn on outer diameter, I wondered if maybe one of the POs had done the replacement before and gone too far with the sanding/beveling and that's why it flew out. I did some measurements of the hole and compared to seal and didn't seem far off, but it was hard to get solid reading as I couldn't fit caliper in there space fully. Anyway, I didn't want to go too far with the smoothing, especially if someone had already done it, and I didn't feel anything severe so I just hand sanded what "extreme" edges I sensed might be a problem. I did see what felt like something hardened in the hole, kind of looked like the epoxy (see photo below on left hand side of hole).
I got it off as much as I could and also used a safety pin to pick out some stuff that seemed to be in the recesses in the hole. Some seemed almost a part of the recess...
Sanded rod with fine sandpaper and polished with chrome cleaner and oiled before putting it in. Put SylGlide on the seal and bore opening and used a socket and rubber mallet to get the seal in. Everything was going pretty well, but then the top right and bottom weren't going in with the rest of the seal. I went at it for quite some time considering the task, tried other socket sizes, going at it with and without the rod in, tried using a short screwdriver like
@5twins suggested. It's not so uneven now, but it's still not flush to the case...
It got dark and I was starting to mess up the bottom of the seal with my hammering so this is where it was left:
This has me a bit worried that I should've shaved more off of the hole, but perhaps it's just a real pill to get in and I don't have the knack for it yet. I figure once I get it in (and replace chain and retorque chain sprocket nut) and run the bike, if it's leaking worse, then worse case I'll have to just do it again; all the seals I've ordered should be here by then haha. Aaaaand if I don't get it in, then...I don't know, I should be able to. I've learned not to trust what isn't working at the end of the day; so far, it's more because it's dark and the end of the day rather than there being a real problem.
In other news, I'm suspicious of what's behind the sprocket. I know it's also known to leak and I was going to remove and retorque it (and check for any other damage), but then realized I don't have a socket large enough. I have a wrench large enough but from what I know and saw listed in manual for "drive sprocket," it lists it's a 22mm nut that requires 47ft/lb torque, so I need to torque it properly. But that sounded small and I measured the nut and it's about 36mm wide... The torque specs in manual have the parts listed as "thread diameter" though, so it seems the 22mm is literally the inner thread of the 36mm nut.
Is this correct or am I looking at the wrong part/specs/doesn't need specific torque? Looking up 36mm sockets now... Perhaps the 22 and torque is only for rear sprocket...
Oh and I finished my master task list for the repairs/maintenance and modifications!
And if you ever end up getting sick of holding a towel to clean up the mess of oil or tiny sanding specks dropping behind your working hand, just turn one of the fingers on your other hand into a towel.
Updates tomorrow, wish me luck!
Oh and for the generator brushes, I read if they're below 7mm, I need to replace. I'm just measuring from tip of the carbon rectangle to the top of the housing it sits in, yes? (The red line in pic below) They don't look too short/worn at a glance but will measure tomorrow.