Hi christian-used-books-and-more_com,
To post an item to the eBay Motors site, you must first select "eBay Motors" from the "eBay Site" pull down menu on the upper right of the "New Listing" page. This will load the lister form specific to eBay Motors, from which you will be able to select categories from within eBay Motors. I hope this information proves useful
-Mike