I'd be worried if my bike wasn't noisy, lol. Like Dinqua said if it worries you, check the clearances, it's not that big of a deal. If you intend to do the work yourself invest in a metric feeler gauge set, don't rely on SAE gauges with metric conversions marked on them, they are close but with valve clearances you need more accuracy than they allow IMO.

Outside a dog a book is a mans best friend, inside a dog it's to dark to read.