Rob,
I did this job on my 91. Yes, indeed the shaft is pressed onto the lower tripleclamp. The press is pretty tight, not sure what class.
To press it. Press from the bearing side TO the snap ring side, not from the snap-ring side to the bearing side. Reason being is; when they pressed these on, the snap ring was just a convenient stop for them to use, as they pressed it from this side too. Seems counter-intuitive because you think that you are pressing a 10" long piece on, but in reality, it is only a press fit in the one place, where it is supposed to be (for about 1" where the lower triple clamp is). When I pressed mine off, I went the wrong way (aka through the triple toward the bearing).
The part of the shaft that is between the snap-ring groove and the end of the shaft (about 1/4") is a larger diameter than the area where the press fit is. This causes bad things to happen when you push it through, possibly ruining the press fit in the lower clamp. Mine damaged the clamp when I did this. It was also REALLY hard to press out in this direction, because of the lip in the snap ring groove, which is a "sharp" edge, and the larger diameter of that 1/4" of shaft. I was able to recover things and it wasn't so bad in the end, but I learned. Hopefully I am in time to learn you too.
My 2 cents. Hope it helps.
-Parsko
PS- The correct triple bearing are Timkens, I have the P/N at home. They have a seal built into them. Also, if you get the old race out, do yourself a favor. Grind/file/dremel/whatever two grooves into the lip that you press the race onto. Husaberg does not do this, likely cause of cost. It will make the next time you pull the races out WAY easier, cause you will have a lip to pound on with a hammer and punch. Otherwise you will be trying to pound on the race with a lip that is around 1mm thick. I did not change my races for this reason (plus they don't even make a complete revolution). I can tell too, cause it ain't perfectly smooth. Wish I did.