warm to the touch, but not hot. If however you have done a freeway or motorway ride where you have had a lot of high speed braking, additional heat can be fed into the shaft casing as its dissipated through the brake drum
Back when the original choppercharles forum was active we had a discussion on final drive operating temp. I think it was fall 2008.
I rode my '80 cx500D for an hour or so and then stuck a meat thermometer into the final drive oil thru the fill port. Ambient temp was around 80F if I recall correctly. And the oil temp was around 115F-120F. The results did not alarm those who participated in the descussion.
As above.Warm to the touch so that you can comfortably put your hand on it.I seem to recall I measured one last year on around 20 Deg C day and it was between 30 and 35 Deg C after a ride but will check again some time soon.
Note:I change my drive oil same time I change my engine oil around 3,000/4,000 miles.This is well before the normal service point but engine I use is oil is cheap a sis the Hypoid gear oil so why not treat the bikes nice