The 850 Workshop Manual says, and I quote - fit and tighten the wheel nuts.
Where did you find those numbers ?
Doing everything by numbers doesn't always work.
How tight do those numbers feel ??
Tighten them up to what feels reasonable, and then use the torque wrench to test what that value actually is ??
Having acquired in the past several bikes which have had stripped axle nuts or axle threads, it is quite possible to overdo it.
I'd also comment that (much) earlier Nortons seemingly had hardened axles, which are probably impossible to strip. ?
P.S. 80 ft/lbs would (probably) be more than the spanner in the toolkit could achieve ??