ive noticed that online, there are front sprockets for the previous-04 and 05-up years, why is this? i know that previous-04 years have 15/38 gearing stock and then 05-up has 14/39. id like to get a 16 tooth front sprocket and put it on my 2007 400ex, what is the difference between the 04 front sprockets and newer ones? are the teeth different? they dont make 16 tooth front sprockets for the 05-up 400ex.

thanks for any help!