Being an HD enthusiast and owner myself and also being close personal friends with my local dealer here is the deal. There is no such thing as HD licensed fabric. If you see this marketed in e-bay, they have cut up sheets. So any you find in ebay is a huge mega rip off!! You can find sheets at lots of sources. I have gotten them at K-mart, and seen them at Walmart and other sources. I just did a quick google search for Harley Davidson Sheet sets and got lots of hits.
Usually they are imprinted with the HD bar and shield logo.
Harley guards their logos and trademarks with a vengence and actively even vehemently go after anyone who they view has infringed on their copyright via their vast resources in an internal legal department. That said there are many "biker" themed fabric choices such as bearpaw quilting and creative matrix. Additionally you can make a harley themed quilt with used T-shirts. Here is a link to one I did recently.
http://www.quiltingboard.com/t-47094-1.htm. Others have posted some as well and they are quite breathtaking and every harley owner that has seen mine has literally drooled over them. Black and orange are traditional Harley colors so you could do sashings, borders and cornerstones in those colors.