Well, you just confirmed what would have been my guess. I can't say definitively that this is Rich's problem but, it would make sense.
I'm going on memory here but, if I remember correctly, that part was cast aluminum, not iron or steel. If that's the case, they really can't do much to harden the wear face.
Knowing that Harleys have the same type of thing on their engines, I did some research this afternoon. The proper name for the assembly is the Compensator. If you google it, you'll find out that this is a weak spot on Harleys and quite the sore spot on the forums. Apparently S&S and maybe some other companies, make aftermarket solutions for their engines.
I post that as a perspective that this is not uniquely an EH problem. It seems that Victorys have them as well, though I didn't read the same kind of problems.
Another non-related thing I stumbled into (again) was the Twin Cam timing chain tensioner problem: basically tear into your Harley and replace the slipper shoe every 15K or have it destroy the engine.
I share this here for perspective: so many people take cheap shots at Excelsior Henderson engines, saying that they had unresolved problems, blah, blah. The truth is, they had a few problems and they were not as bad as some of the brands that live to this day--often without OEM solutions.
Back to the problem of the wearing compensators. If we are in need of replacement compensators, they can be made. The problem will be somebody needing to spend the money to have the broach made to cut the internal splines. There was also a running change made between VIN 510 and 511.
Looking at the parts manual, page 72, we're talking about part 4 and 15. Just guessing from what I see in the illustration and part numbers, they look like similar but different designs. Everything between the starter clutch and the alternator rotor has different part numbers.
Between the two illustrations, I see the following differences: The male splined sleeve (2/13) looks like the splines got longer. The belleville (5/16) springs got a smaller inside diameter. Even the retainer (6/17) changed by getting thinner.
All of these changes suggest that they needed more torsional travel out of the mechanism.
I'm posting all of this because it suggests that the spline shape probably didn't change between them, meaning the parts could be easily manufactured once the splining problem was solved.
Now the question: is this a real problem or do they just spend some portion of their life polishing the two surfaces together (leaving some aluminum in the oil) then not wearing much anymore? Of do they continue to wear, destroying themselves? If it's the latter, the replacement parts could be made of steel (as they appear to be on the Harleys).
The other key question that maybe Dan could answer: who was the OEM broaching company or machine shop that made those parts? That broach is probably still sitting on a shelf somewhere and putting it back into use would be cheaper and easier than reverse engineering it.
I can't definitively say this without looking at the problem more closely but, I believe that changing the material to steel would help matters. A ramp profile change might also help reduce the wear on the rubbing surfaces.
I hate to think that entire bikes are being parted out for a few parts like that.
