Hey was considering buying my first bike today. It is a suzuki bandit i brought a mate to have a look at it for me (cos i know jack) anyway he/we noticed that at around 8-9 rpm no matter what gear it is in the engine (or somewhere around there) a hissing noise will happen for a split second then go away. It didnt really seem to make any difference to the way the motor went, itll just make the hissing noise then keep on going. The noise wouldnt stay hissing no matter how hard i tried to keep the revs constant when it started to hiss. Were at a loss as to what it is. Is this normal for this bike?, if not what would it be? will it cost a lot to fix?