i have a 08 rsv and mine is doin the same thing.it starts in 3rd and in 4th it gets louder and 5th its extremely louder and does not go away.the faster u drive the louder it gets.yamaha replaced the cluch basket but didnt help a bit.they told me at the dealership that it was the straight cut gears in the tranny.but my question is why did it start after 30000 miles and all at one time