However, bear in mind a chromed one will go rusty at some point; fwiw, I've fitted polished stainless ones.
my previous experience, of more modern bikes, is that there was a nut/locknut to set the bearings on the steering stem, then the top yolk was attached/clamped independently of the nut. However, according to the drawings I am looking at, the T140e steering stem tube nut/cap provides both bearing set and yolk attachment
on mine, the existing nut looks like it is against the yolk. I wonder why...
Uh-uh, steering stem nut doesn't do yoke attachment. Your bike's steering stem nut is "against the yoke" because the forks parts aren't adjusted correctly:-
. Top yoke should sit on the top steering bearing dust cover. It should be held in place by both yokes' attachments to the stanchions.
. The steering stem nut is through
the top yoke and the top steering bearing dust cover to bear on the top steering bearing itself.
. With the top yoke on the top steering bearing dust cover, even when the steering stem nut is on the top steering bearing, there should be a gap between the top surface of the yoke and the underside of the steering stem nut hex. This gap ensures that, when the steering stem nut is turned, the only friction is the steering bearing adjustment, never
the friction of the nut rubbing on the yoke.
. When the steering stem nut is turned clockwise, because the thread is on the stem but the bottom of the nut is on the top bearing, because the bearing is conical and 'narrow end down', the bottom yoke (attached to the stem) is pulled upwards. The bottom yoke moving upwards pushes the bottom steering bearing upwards; because that bearing's also conical but 'narrow end up', turning the steering stem nut clockwise increases the friction in both bearings (and risking labouring the point, turning the steering stem nut anti-clockwise decreases the friction in both bearings).
. The top yoke pinch bolt around the steering stem nut is just to keep the latter in the position set by bearing adjustment; again risking labouring the point, the steering stem nut has nothing to do with keeping the top yoke in place.
.. Once the top yoke is correctly sat on the top steering bearing dust cover, because turning the steering stem nut moves the bottom yoke
the bottom yoke stanchion clamps
must be loosened before adjusting the steering bearings, and tightened again after adjustment is completed.
.. Especially when turning the steering stem nut clockwise to tighten the steering bearings, ensure the headlamp shrouds (because they're between the yokes) aren't stopping the bottom yoke moving up.
1. As my yolks are already attached and ll clamped up with the bearings correctly set, will I be able to simply unclamp the existing nut, remove it and replace with the new chrome nut, then clamp it back up?
Normally, yes. However, as your bike's top yoke isn't in the correct position (sitting on the top bearing dust cover), when you fit the new steering stem nut, you'd be wise to move the stanchions through the bottom yoke, and thus the top yoke downwards away from the steering stem nut hex. Fwiw, having loosened the bottom yoke stanchion clamps, stanchions will likely still need to be 'persuaded' through the bottom yoke clamps ... I use a piece of wood on to the top yoke and belt the other end with a hammer, alternatively close to each stanchion. Having set the top yoke correctly, fit the new steering stem nut and check the steering bearings adjustment.
2. Shouldn't there be a washer between the bolt and the yolk, rather than the nut acting directly upon the yolk paint?
To amplify Wol's post, no. Because, as I say, there should correctly be a gap
between the yoke and the steering stem nut hex.
3. Is there a way to grease the top and bottom head bearings without removing them?
'Fraid it's as Wol posted ...