Hello, I have a 2004 ZX6R, basically the same thing. Great bike, the suspension needs to be softened up quite a bit and they really need a steering dampner. I got a Ohlins for mine. I have about 14,000 mile on mine and usually change at 3000 miles but have been known to go further. I have used Mobil 15w-50 but found I liked the shifting better w/ the Amsoil 10w-40, it also seems to run a little cooler. For the money I've also ran Shell Rotella T 15w-40 and 5w-40, and had good luck w/ both. I think that everyone here will agree there's a lot of good MC oils both synthetic and non-synthetic..