For those of you wanting to update the front fork of your CB (in my case a CB350f) with something modern...
A front fork of a KTM Duke 125 / 390 (or RC 125 / 390) is a direct fit.
Just order an extra top stem bearing (30mm ID instead of 26) and you're good to go. You need a 7mm spacer under the bottom stem bearing, but they come supplied in the All Balls kit.
I don't know about clearance towards the tank yet, but technically, it's a direct fit.
Only downside (for some): it's a single brake disc set-up. For my 350, more than enough.