Just wanted to second this, if you ride a bike regularly, even a quiet one, wear hearing protection. After a year commuting on my 250 I looked outside and saw that it was raining - I hadn't even heard the rain begin. I started wearing earplugs every ride and my hearing's back to normal but it was a wakeup call. These days I don't ride as much but I'll wear ear plugs any time I'll be going over 60km/h.