Hi returned to my time on the bike after a few years away...kids..mortgage...etc and have bought a FZR 600 genesis it being my old fave from years ago, However, at low speeds sort of 10mph to 45-50 mph it grunts and slightly splutters like there is no power there but when I twist the throttle hard it jumps in to life and runs like a dream .. also runs well for top speeds and for many an hour, however even after a good days ride every time it drops down to 10-50 mph it stumbles and just does not feel right.. any ideas or am i just a paranoid rider?? Oh forgot to say i do not know a jot about engines/mechanics and all that..as you may well be guessing!!