I have a nealy new 2000 model 426 that I bought from a friend of mine. I noticed today when I started it that it has some engine noise. As soon as I get to 1/8 throttle the noise is gone. I never ride my bike without wearing a helmet. Is this a normal noise that these bikes and my helmet muffles it? I didn't clarify that I bought the bike last October and ride about 2 or 3 times a month. I have never noticed the sound before but hardly ever start it unless I'm going to ride so I usually have on my helmet. I engaged and disengaged the clutch to see if the sound changes through operation of the clutch. It always sounds the same no matter what position the clutch is in. Any comments would be appreciated. Thanks.