Morning Greg et al…
My concern: is this normal?
…No. But as others have correctly pointed out clutch judder is commonly reported on ST1100’s.
Is this the clutch or drive spline bearings?
...Could be. Firstly, you have to correctly identify the source. It would help if you gave out a bit more info about the noise. EG from where…front, rear; can you feel the clutch judder when the noise occurs etc. Also what year is your bike?
EG 1990/91 incorporated x2 judder rings (springs), discontinued after (what I imagine), was Honda utilising a different friction compound on the 2 or more of the friction plates.
For what it’s worth and
if it is originating from within the clutch assembly, until it becomes problematic, I wouldn’t be overly concerned.
That’s a start
Cheers the can :-)