Well, you may have a pin of some kind without a "C" clip, otherwise known as a "Jesus" clip,, for the use of language when you remove it and it flies off across the garage.
You SURE it's from your bike?? Either way, they are used to lock a bolt or pin, that is otherwise not wanted loose,, of course.
Thanks!! It was the rear axle C Clip - It seems to have work it way off...actually had to press it tight...it was loose going on.....
It's actually called an E-clip, because the little tab in the middle makes the whole clip look like an E.
I would buy a replacement E-clip, because once the E-clip become loose, it doesn't stay on very well. The dealer should have one for about $2.50. Part number 41139-02 if you a 0.750 rear axle shaft.