Wild_Bill wrote:
I think the parts you're referring to are commonly known throughout much
of the rest of the world, as fenders.

I think you may have better luck finding sources, techniques etc, by
searching for them with terms such as: motorcycle fender fabrication or
forming.. and possibly the word custom.

Americans seem to think they are they rest of the world but fenders
=America, rest of the world= mudguards (English speaking world)