What's up? I have what is relatively a simple question, but have gotten several different answers. I live in Northern Kentucky, and own a 1996 zx6r that I've had for about a week and a half. I plan on changing the oil in it soon, so I went to the local dealer to buy a filter and oil. The owner before me said that he ran only synthetic (Castrol Syntec) in the bike. I told the dealer this, and he said that he never would use synthetic oil in any of his bikes. He suggested that I should change over to natural. What do you think?