i,ve got a 500e (british model) with the standard clip on bars, i like the newer  F model,s one piece bars, and would like to change them. has anybody else done this mod, if so what,s involved, i.e. do i have to replace cables, brake hoses for longer one,s. or is it just a case of changing the top yoke and bars  :dunno:

I switched from the one piece bars to the clip ons.
The only thing involved was to replace the top triple tree with the other, and swap the stuff off of the clip ons.

I am not sure about UK bikes but I cant imagine they are much different.
I didnt have to modify anything to make it work.

Proceed with caution.  It's just possible that the Brit clip-ons mean that the clutch cable, brake hose, throttle cable and the like are SHORTER than on the US models with the single bar fitting.  This might mean that you can change from single bar to clip-ons without  too much trouble (your cables will just droop a little more) but that if you go the other way they won't reach.  

Like Dragonfly says, you'll need a new top to the triple tree to mount the handlebar clamps.

find a website to compare clutch cables, choke cables, throttle cables, and front brake hose
compare US to UK.
if they use same parts....swap away
if not....it's a bit more difficult

do the UK clip-ons sit about 3-4 inches above the top tripple?
and you guys also got preload adjusters?