hi every one , a year ago i bought a crashed fzr600. ive rebuilt and all the way through started every week and kept on an optimate. now its ready for an mot and it wont pull above 6 thousand when being ridden . i have cleaned out all old fuel from carbs and tank i have checked spark on all cylinders and all looks good so at a loss. advice please !

If it runs smooth up to 6k then I would say carb jets or balancing.

Definitely sounds like your main jets are the likely problem as this is where they start working properly. So a strip and clean is in order I would think - you might get away with blasting aerosol carb cleaner up from the float chamber if you don't fancy a full strip-down, certainly worth a try.

thanks for the advice guys. ill give them a ballance.