I have a 1993 XR600R, stock everything and recently rebuilt the engine, new just about everthing !!! The bike runs flawlessly, starts easy, etc. I have 15/48 gearing ... When I open it up on the highway, full throttle, I detect maybe some different noise, but barely, cant tell what it is . But againhere is so much wind, chain noise, etc. at this speed I would barely hear a truck horn , let alone knocking. At full throttle, the bike just goes very fast, and power RPM's and power just seem to run out, but its smooth, no missing or anything, but there is a sound thats just a little different as I advance the trottle to the full open position... Im afraid to run it at full throttle for very long, because I dont want to destroy my engine if it is knocking , how can I tell ???