Just drove a new 150cc single cylinder out of the shop- warmed it up first, drove it pretty slow in 1 and 2 gear around a few blocks, cooled down for 15 minutes or so and then took it outta town for 40km, varied gears between 2-4 a lot and gave it some 1/2, 3/4 and almost full throttle for a few seconds with down-shfting. Up to 80kmh max. in 4th gear, maybe 60kmh in 3rd. About half way home I noticed a knocking/clacking sound and thought it might be a bolt or something that didn't get tightened. When I got home, I gave it a close look/listen and it sounds pretty much like its coming from the engine. It happens at idle and every rpm. Seems to run well, but sounds not awesome. This is basically my first bike and I'm not a mechanic. Could this be from riding it too hard at the beginning? Everything I've read points to "no", but I'm still worried that I f-ed it up. It's got a 1 year warranty, but I can see them in the shop givin' me a hell of a time. Any advice, suggestions, what to check, would be greatly appreciated?