Hi, just a thought, I always gave my valves on other bikes a quick grind with a fine paste to clean up the faces, but in the the book it says not to grind the LS valves, but replace them. I checked out the price, and a set of valves would cost me £130.for four valves ($187) plus postage. Has anybody successfully ground the LS 650 valves because it is a bit of a slap for me if I have to replace four perfectly good valves that just needs a general clean up,,, :-