As the widow, what is my legal obligation to items left to others that have not or will not claim their inheritance?

My husband left a hand written will, mailed it to himself, and it remains unopened. He left his son, a motorcycle, which is the most valuable time he had. May be worth $200-$4500. The rest of the items he has are not worth that much. We are not in any probate or have a lawyer. I am concerned that the son (previous marriage,-not related to me) may not take possession of the bike due to the cost of doing so. He lives far away, and there is a collection of past due registration, about $580. I can't find the pink slip, so he will have to obtain one. And he will have to fill out the transfer without probate form (as per the CA franchise tax collections representative's instructions). I rent and not sure what to do if the son doesn't come get this motorcycle. I am preparing an email to him to ask that he take possession by the end of June, as I may need to move. I don't know what I am supposed to do and what I can say to him about it.