Hi , My tzr has been regeared with sprockets and dont 50mph when i first got it and now does 60mph , but it cant out drag many rs50´s and my mates XR6 is much faster then it , mine is basicly brand new , will a new exhuast make it go any faster also according to yamaha the tzr should do 50mph ???? . Anything else i can do to my bike . the garage recon that if i put a new carb it will become unreiable and might blow up . HELP PLEASE!