Looking at the poll i have the higest milage cbr 600 F out there (65,500 miles) over the last thousand miles i have noticed a fluttering sensation on part throttle in the lower gears, this has developed into all throttle opens, but still more noticable on a feathered throttle.

Any ideas, my mechanic originally suggested worn carb, jets and / or jet surrounds. My bike is a uk spec. cbr600FX manufactured 1999 so i supose this is similar to your F4 model? anyway it was the last of the cbr600 carb model.

 

I have the same thing, when I start my bike and try to put the choke on all the way up, it dies. I have to barely just barely put the choke on for it not to die, like 2 milimeters up. But the hesitation from the throttle goes away after the bike is warm. It could also be the gas your using, if your switching from 91 to 89 or whatever it might be that?

 

thanks for the thoughts, its not the fuel i've tried all sorts. My mech wants to try a new air filter and re setting up the carbs ( again) before we go for the major carb strip down and rebuild. Funny the fluttering seems to be affected by the weather conditions??? hot & dry with high millibars being the worst.
Perhaps i'm just too sensitive and slightly barking mad[]

 

sorted, new CCT , carbs balanced and new drive chain and she's running smooth as new.