WD-40 is the stuff of legend, it's true, but not all of the legends themselves are true. A little research for you:
WD-40 does
not contain kerosene, according to the manufacturer's website. It's also safe for painted surfaces.
WD-40 Frequently Asked Questions
WD-40 is mostly solvents and mineral oil, and is safe to use on your motorcycle chain, according to wikipedia.
WD-40 - Wikipedia, the free encyclopedia
As others have indicated, it's perfectly safe to use on most parts of your bike; however, for lubrication, there are specialty lubricants out there that are better tools for the job.
It will also make you stronger, smarter, and much better-looking, but I couldn't confirm those rumors.