i know this is a rookie kinda question but it just bothered me. on my way to school there was a kinda whining noise similar to the noise when the bike is in 1st at higher speeds (15-20). but it was doing this the whole trip all the way up to 6th. but on the way home, about 2 hours of downtime, there was no noise, was smooth as the day i bought it. should i be concerned??? BTW its a '03 9'er with 350miles on it.