Something I've noticed on the Hondas that I own - they all have virtually silent stock exhausts.
I take that back - I can't claim that about the Nighthawk since I've never had a stock exhaust. But for the CB550, 750, Sabre - the stock exhaust on them is quieter than anything I've heard on a motorcycle. Quieter than any of the modern bikes I've ridden, certainly quieter than the R1200GS which is a total rattletrap.
I'm not complaining, not by any means - I love silent exhausts, but I really am curious if that's typical of the Honda exhaust systems or just the 4 cylinder bikes in general.
The stock muffler on my CB750 Limited is so quiet I can listen to the engine sounds at idle very clearly.