looking at an 06 sv650s. bike looks great, chain needs to be cleaned/lubed but other than that is like new. less than 7k. engine seems like it has a knock. never had a v twin sport bike, do have a vtwin honda aero but the motor is super quiet. here is a video of what it sounds like - this is not my bike but someone elses.
Also I rode a 01 sv650 today and the engine did not have the "knocking" noise to it.
if you are located close to lansing, mi please let me know if ya could listen to it or let me hear yours!
http://www.youtube.com/watch?v=fu1zKvdU0UI