Thanks a bunch, Viking. Between you and a buddy who’s a mechanic at a dealer and trial and error, I’m not only getting closer, but am learning, and it’s not nearly as frustrating in December as it would be in June.
On Magura Blood, they used to be the official supplier of BMW, and apparently are no longer after a lawsuit, but my particular, originally spec’d clutch fluid was the red. I later learned they replaced the recommended fluid for all their bikes with newer, blue Magura (but instructed all dealers to bleed out all the red before putting in blue, and not mix), and then after all that, I learned that following the suit, they just told dealers, like you said, as long as you don’t mix, pretty much any hydraulic fluid would work, as long as it’s mineral based, even down to what you buy at CVS. This particular dealer now uses Castrol Vitamol).
Anyhoo, the biggest thing you’ve told me (which makes sense) is that if I had sediment, I had a leak of some sort somewhere. I bought the Barnett clutch pack and put it back together (and double, and triple, checked for assurance of proper re-assembly), but of note, on this bike with roughly 24k miles, when I got it open I saw the plates couldn’t have been in there for more than several thousand miles, and the prior owner had been required to replace them. Kept them, of course. Basket and springs were in awesome condition, though.
Also, I have the Synto Evo levers, and have adjusted them, because I always have to on all my bikes (small hands). The clutch with new levers was working fine before the trans swap.
After trying all the other “remedies,” I’m about 99% that somehow, some way, there’s a leak on the seals at the bottom of the bowl and/or the master cylinder, which goes along with your rebuild idea.
If I pump the daylights out of the lever, and IMMEDIATELY let loose on the bleeder valve, I’ll get at least a decent squirt (3 ft. or so) out of it, but if I pump it up like crazy, and then wait 2-3 seconds, it only dribbles out. If I do the same and watch the bowl, teeny-tiny bubbles come up from the bottom. I’ve bled and re-bled the whole system multiple times/multiple ways, and it’s always the same. I also have double and triple checked tightness of all the screw-in parts of the system which could leak, so it almost has to be a seal somewhere.
Plan now is: try out old slave cylinder, and see if that cures the problem. If not, and it’s not the Oberon, then rebuild the bowl/lever/master cylinder end, or replace the whole assembly with a used one. Is this sound?
Based on what you said about the Oberon, however, I am now wondering if this could be the case? Old system had a leak, but still worked well enough to be effective (over time I did seem to notice a softening of the clutch pull after installing the new levers, but just thought it was the new clutch lever), but won’t work at all with the Oberon, and so even if going back to the stock slave cylinder achieves results, I may still need to rebuild the lever-end of the system.
I greatly appreciate all the help. I’ve never had trouble bleeding anything hydraulic in my life before this, including tractor attachments, and all the “old hats” at it just laughed at me, told me I'd been lucky, and basically at 51 yr. of age, I was way overdue for something like this to happen to me.