Just changed my oil at 10 hrs and after change everything sounded fine. Went on a hour or so ride and mostly kept it around 40mph around 5500rpm with the occasional wide open burst. Next day went to go for another ride and noticed a little valve clatter. I'm using 15w50 Mobil one synthetic it's around 60-80 degrees when I ride. The coldest I'll ride it is around 40 or so. Could it be the oil being to thick or do my valves need adjusted.