What do I wear to a memorial service being held in a biker bar?
I’m not a biker either, but maybe wear jeans and a tee-shirt or cotton shirt. If it’s in a biker bar, I don’t think most would be wearing suits and ties. Just being there and showing your support is more important than what you wear, so I wouldn’t worry too much about that (what you wear). Your friend might not remember what you wore that day, but will likely remember that you cared enough to be there.