Malcom Gladwell did a very good bit of research on this type of topic ("Tipping Point") Here's a short article on that part of the book: http://www.dailymail...m-Gladwell.html
His conclusion was that there is no such thing as a natural born maestro. By his reckoning, anyone considered as such had put in at least 10,000 hours of hard work BEFORE they were regarded as such (Chess, Software, Pianist, Hockey, etc) I suspect he is right and that there is no difference when it comes to motorcycle racing. You need a good bit of natural ability/talent AND the passion and luck to be able to devote a boatload of time to refining it.
-C