I purchased a brand new C90T April 26, 2006. It back fires when I let off the throttle. I have 540 miles on it. It is completle showroom stock with no after market air breathers or pipes. It is back in the dealers shop at this time for the second time right now for this problem. The dealer keeps telling me that there is nothing they can do about it as the timing is preset and cant be adjusted,and that this is characteristic of the C90T. I cant belive that Suzuki built this bike to back fire but thats what the dealer is telling me. I was just wondering if anyone has had this problem and if you solved it how did you solve it. At this point im very un happy as i spent $12000.oo plus on this bike and it back fires and all im being told is thats just the way it is and I'll just have to live with it.