I don't have a link, but I know that bikes must have reflectors and a bell to be legal on roads. At least technically anyway. From what I gather this law is very rarely enforced.
I've taken my racing bike with me several times to Japan - good thing that's not enforced. I'm not going to put a bell and reflectors on a racing machine! I ride in Japan just like I do in the US, albeit on the other side of the road.