finally i found someone with the same problem i have the x model 17" wheels and mine to will only do 45 flat out it seems as if the throttle is restricted but it isnt, say you were in third doing 25 you would be flat out without the bike really screaming and when you change up it will jump forward. i have had the carb off and the rubber block off the head and there wasnt any restrictors to be seen, i have also had the exhaust off and there was nothing in there i have today however taken the silencer appart ripping the guts out and putting a muffler bar with (muffler stuff) so it becomes straight through took it out for a spin and it was still the same. getting desperate now as i have recently passed my test, cant afford my bandit yet and cant go on the motor way with this bike totally dangerous 45mph not good.
HELP!!!!.plz