I also had zero motorcycle mechanic experience when I started this project.
A Honda Nighthawk
seems to cover a couple different cycle engine sizes.
I think Nighthawks were what we had in my motorcycle safety class at the Technical College. They were all 250cc engines.
You will want a motorcycle which at least has dual down-pipes, that way, you have something you can built onto to hold the batteries. If there is just a single pipe, it's going to be hard to mount the batts.
SECRETS OF EL NINJA is a good book for a beginner. No, I didn't write it, and no I am not being paid to say that, although I have talked about the book to enough people that I almost should be collecting royalties...
You don't need a sport bike (crotch-rocket) to follow the EL-NINJA plans. I chose to use them because they don't call for chopping and welding the frame. Sport bikes are nice because they have a light, aluminum frame, and typically have a plastic fairing covering the engine, so you can put in batteries and then cover them up when they are all done.
Hope that helps get you started!