While exploring obvious weak areas of the throttle design, engineers concluded that a flawed rotor the throttle cable rode upon caused the throttle to stick
On certain vehicles, a loose or bent inner throttle cable wire may derail off the rotor in the throttle housing on the handlebar. If this occurs, the throttle cable could be pinched between the rotor and the housing, causing the throttle to stick.
Ive always wonder why people when their throttle sticks never think to hit the back brake. You probly couldnt do it in his case but i've heard other stories where people hammer on the kill buttom and try for the choke but why not put slam on the brake.
If you crash enough or replace enough grips, those old throttle assemblies would have been replaced a couple of times by now.
I remember when that recall occurred, the dealer told me I had to bring the bike in to have it replaced. He would not give me the new part. My bike was in many pieces at the time (I think I was also waiting on the motor to be shipped back ) so bringing it in was not appropriate. I offered to bring the throttle assembly in so they can replace the rotor and they said no.
I never did replace it with the new part as the old one worked well and I eventually replaced it with an aftermarket assembly.