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!!

Sounds like PILOT jet problems. and or carb balancing (or if it did it in very cold weather might even be carb icing)

If your bike has had any modifications (filters, cans dynojet etc) ham fisted carburettor stripping and rebuilding can seriously upset the balance of your setup. as can blocked jets, badly set needle heights or incorrectly set float heights.

What is it like at tickover, (lumpy , coughing, stalling ? smokey?) and what REVS does it start to run ok at ? (as opposed to road speed, which depends on what GEAR you are in)

If you are not a proficient mechanic, getting it right will be next to impossible. Suggest you get it looked at by someone good with carbs, who should be able to get you running smoothly.

You might want to check the HT leads as well, if the caps or connections are loose you could be getting misfires at low revs that cure themselves as you go faster when the sparks generated are a bit fatter (but it is usually the other way round, getting worse as you go faster).

Get the bike in for a full service and you will probably be ok

Hey thanks i was sort of going that way... as take it in to the garage and go to work and do some more overtime!!!! but at least i have a little idea what to do, appreciate your time and effort there will get it in ASAP... i do need it jusr right!!