I have almost 9k on my 03 636 and Im noticing now that the engine is considerably louder, u can even hear it over my friends bikes when they are idling next to eachother. Im thinking I need some sort of valve adjustment because this noise has gotten louder. Is this something I can do? I think these valves are shim over bucket style so maybe all i need to do is replace the shim? What should I do?