What fails with the automatic camchain-tensioner? I cheked mine when I bought it, because of the stories, and checked the camchain aswell. Both were fine, and eventhough the camchain was fairly recent replaced (before I bought the bike) the motor itself have around 93.000km on it. So I guess not all are doomed from the beginning.
I know I love mine.
Ahook93: A high idle when warm is almost certainly a lean condition. Try spraying starter fluid or wd40 around carb, intakeboots ect. If the idlespeed goes up/down, you've found the leakage.