materials

I need some help, I am a scoutmaster, and the older kids want to build something using composite materials, i.e. carbon fiber, etc. There is a merit badge for this , new in 2006. what I am looking for is some links to pages that have good, easy to understand information, and possibly some...

Can anyone enlighten me as to what alloy(s) the crankcases, the head, and the cam cover are cast from. Need to make mods/repairs but want to use the right materials Ta, Roy