I sent my rear sprocket in to SprocketSpecialists.com and they have found out that the rear sprocket is the same as a 400ex except that the 400ex rear sprocket has a countersunk hole in it. This means that I am sure you can use a 400ex one with a different bolt.
I went and ordered mine from these guys and it ended up being a 72 dollars sprocket and shipping is free. It wasnt even harnened cause I didnt have time to get that, 2-3 day wait, that 12 more.
SO I got it and it will be here friday. It is a link loc sprocket and I hope it lasts. I bought the 34 tooth and when it gets here friday I will let you know my new top speed.
I also found out that the chain rollers are cheap so I went on ebay and bought some new ones. Anyone need some rollers?
The front sprocket is the same as a YFZ450.
Jeff