As pointed out to me by Shawn Wright, I think it is sometimes the valve in
the hose that binds not cable/sheath. Drop the spare and look up for it.
Mine works fine when cold but when hot it binds, so check both ways and
blast with oil etc.

  As for fixing the cable you can rebend the 90deg. kink with needle nosed
pliers and refit it into the lever arm.  Then undo the clamp bolt, 8mm? on
the cable sheath and reposition so that you can get full operation. A couple
of minutes fiddle. Lever will only go about 2/3rds way across, but it will
shut off and on fully, so that's good enough for me. If you want to replace
the cables be prepared to pull the dash. The airbox flaps have strong spring
clips that hold the sheath tightly. Need to be pried off with a screwdriver.
Some of the cables are ziptied to parts of the dash/air box etc.  Try the
cheap fix first.  To be fancy you could probably find some kind of small
clevis and solder it to broken cable, then pin through lever..... naw.  bye, tim