Closest I can find is Joe Gibbs multiweight on Amazon.
Given the history there, I'm not even looking that one up. I don't think I'd go there. It could be a perfectly fine "rebox" of something decent
In general though, with anything automotive, if it's got a famous name attached, you don't want it.
The bike is 51 years young. Don't wanna "go there" (engine rebuild) again. It'll be ok..........I'm just obsessive about doing things once.
Yes, I slathered it up with assembly lube and I have a pump inplace to prime the system.
The oil they were talking about back when the manual was written, as close as you'll get to that today is going to be a "circulating oil, ISO 100 or 150 (not a direct cross, somewhere between the two), Stuff has come a LONG way. Yeah, I won't do it either. (Although I do have ISO circulating oil in the air compressors, and thus far positive results over "compressor oil" when it comes to the "blown hose over the weekend", and "the three "car guys" are all changing rocker panels on the same day" abuse.
So I won't do that, I won't put circulating oil in an internal combustion engine (although if you keep up with the old maintenance practices and life expectancy, it'll be fine...), but the engines I've put together (worst one, over 200K value, most 25K to 45K value), straight up put together with the oil they're going to run on, and started within a few days of assembly. Zero issues, zero abnormal oil reports, zero evidence of any kind to indicate that there is any problem with the start up or run-in, and zero "unapproved additives" in a break in lube that is pure murder on the after treatments that modern diesels have.
Where I used to work (refinery) .............we would circulate warm filtered oil sometimes for days before starting up a compressor/turbine.
I bet that had more to do with bringing those massive pieces up to temperature uniformly than it did for lubrication. Once the oil is "there", it is "there". Except for the filter paper It doesn't soak in.
Question- Sorry, I'm not up to speed on old bikes, does that clutch live in engine oil or is that outside of the crankcase lube system?