Must admit I wondered about the amount of slack when i saw the oil pump drive chain for the first time.
But there's not much load on it, and it's not slack enough to jump sprocket teeth, or jump off.
If you shortened it, it would have to be by a whole link or half a link, and I don't think that there's enough slack to do that, so you're stuck with it.
I suppose you could make and fit a little tensioner, but TBH it's just one more thing to go worng/fall off.
Anyway, as the engine only ever runs in one direction it just runs tight on the pull side and slack on the - er- slack side.
I'll definitely put my name down for the coolant offer- once the hi comp's are in I expect a hotter

engine.
Oh, and one update, the cam grinder has promised that they'll be machined on Monday.
Mind you, he's ben making promises since April- good job they're not my only set.......
how does it come, big container or little bottles?
Obviously I'll sort postage and packing costs.
Re the rag method, I'm already a bit concerned abotu how good that ball bearing is behind the clutch, but on the crankshaft they are plain journals- just liuke the big ends- and so the sideways load without the engine running means you are forcing the crank onto the journal.
And that clutch centre nut is tight enough to need a breaker bar, or in my case a socket with a length od scaffold pipe on it. So there is plently of force being applied.
Lastly, just to check, the judder spring sits against a thin metal spacer (the "seat") which fits behind it.
It doesn't run directly in the machined groove in the aluminium clutch housing.
The spacer- "spring seat" according to Honda- is just a plain bit of steel, so should be reversible easily enough.
Did you have a big, thin washer left

over, by any chance?
It's not falling off, it's an upgrade opportunity.