Man, if you want a DIY motorcycle, and just pure awesomeness, check this out:
Build your own electric motor - Amazing DIY projects
Video - Amazing DIY projects
It's a homemade 20kW (peak) brushless motor that he put on his electric motor cycle. I don't know what one of those would cost you off the shelf. I am so tempted to buy that book, but the temptation is eased by the fact that I don't have $50. haha