top yoke? For a cb-1 or 400sf? I have a spare cb-1 yoke. You could use it on a 400sf but you'd have to put clip-ons under the top yoke. An interesting idea - twin shocks and low-down clip-ons.
WWW.HONDACB1.CO.NR + NC29 swingarm ('29 wheels soon), Quill T3 Ti, lots of black, blade rear hangers, beet rearsets, brembo brake. Top mods: BT45's, touring screen & rack with 50L box! Stolen recovered, scumbags best not try again.
Try calling around a few breakers. Ask them for a yoke (sounds like egg yolk) not a 'york' (sounds like pork) or it'll confuse them. Alternatively post a wanted in the Parts For Sale or Wanted section of this site.