The left highway peg on my Fatboy Low (mounted on the new Whisker set up that attaches to the frame) keeps unfolding due to engine vibration. When it's folded up it leans inward. After 5 minutes it has halfway down.

Any advice on how to fix this?

 

Does it have a bolt or pin to hold it on?

 

Yes with a washer in the joint and a washer and retainer ring holding the pin on.