Hi. I think this is my first post here, but anyway i have a Fzs 600 fazer and as i come up to about 8000-9000 revs it splutters and will go no further up the revs (Before the problem started i could get it to maybe 10000-12000. Ive had cracks in the rubbers of the carbs before and had them fixed and rebalanced but cannot think if they cleaned them or not. Ive also noticed that it also splutters when im starting it. This cannot be the weather as i live in the uk and its currently 25 degrees.

Many thanks for looking

Jack

Have you tried inspecting your spark plugs? It may need some cleaning or replacement. Also it coulb a cause of bad fuel.