The valves make some noise, just like the old bikes it is better for them to be slightly loose than too tight. Neither extreme is good but to the loose side won't hurt anything where as too tight can be very bad! If it doesn't make a little noise get worried.

As said above, ALWAYS make sure there is enough oil. Although I have never had to add any between changes on our bikes.

I learned all I need to know about life by killing smart people and eating their brains.
Eat right ,Exercise ,Stay fit, Die Anyway!