[PerfectStranger]

So I was watching motorcycle crash videos on youtube last night. Call me morbid but I'm looking with a somewhat critical eye. I watched a ton of them and easily 90% were caused by riders doing stupid things. Regardless of the cause, for me it still drives home the reality of crashing.

Question:
When touching the front wheel back down after riding a wheelie, why do so many of the bikes in the videos start the fatal wobble (tank slapping?)? That was a common theme in some of the videos. I don't pop or ride wheelies so don't have any experience with how the handling changes.

Thanks.