If everything is installed correctly and there are no damaged parts, then that clearance will be there. What I should have also said is that the left hand fork leg should not need to be forced to be flush. The leg should naturally come to rest in the correct position.
For it not to do that would suggest something wrong with the wheel hub installation. The brake disk is bolted to the wheel. But the bearings, collars, spacers, seals are fixed to the axle. So if there is something wrong with the installation then the discs will be out of position relative to the forks when it is installed.
Anecdote.
I have a hobby horse topic that I jump on whenever the opportunity arises (and here I go again). The first time I replaced my own bearings I learned a lot. The bearing was difficult to drive out using the 'I don't have the proper tool, so I'll use a long screwdriver' technique of hammering on the inner race from the opposite side. It was difficult because I couldn't get the edge of the blade onto the inner race. The distance collar was in the way and would not budge. On previous bikes that distance collar was a loose fit and would rattle / clunk when I went over bumps. Nowt to do with me, I never changed the wheel bearings on my previous bikes. Just an observation. But the distance collar on the earlier bikes was not clamped tight, but it was on the STs.
My first ST was the 1100. I had not ridden a motorcycle for 17 years and a solo motorcycle for another 7 years before that. So the twitch that I felt when leaning over on roundabouts I put down to inexperience, tyres, lack of technique, white lines -which in the uk are raised slightly. It turned out to be bearings.
So I set about replacing them. I eventually got the old ones out, and put the first one in. I don't remember whether my Haynes manual required that a particular bearing be driven in first. It may have done. What bothered me was that when I put the spacer in, it was higher than the shoulder in the hub on which I thought that the second bearing should sit.
I remember posting a query and got some very odd answers. Wrong part. Grind it down. Bit of grit at the other end preventing the collar seating properly. First bearing driven in too far. I wish I'd kept my older posts on here as a record, but I had an "I'm getting out of here moment", and deleted about 2,000 posts. No one seemed to know, so I went hunting for other manuals and discovered the Honda manual on line. I downloaded it chapter by chapter. In there it has the requirement that one named bearing, left or right, has got to be driven in first. The second bearing is driven in until it meets the collar. (which side first is stated, but it is different for the front and rear wheels).
I don't know what the gap is between the outer race of the bearing and the shoulder on the side of the second bearing. Enough for me to notice it. My feeling is that it is more than 0.7mm, but I do not know. But whatever it is, if the wrong bearing is put in first, the wheel and brake disks will be displaced by that amount in relation to the hub. So when the axle is flush with the fork leg, the brake disk may then catch on the caliper bracket.
It is a theoretical observation. In practice I think that there is oodles of space between the caliper and the brake disc on both sides.
Oodle is an old Yorkshire term which means greater than 0.7mm ! Or 'more than enough'.
