hi ive got a bike that wont rev over 8,000 but will rev freely up to 10 not missing until it hits 8000 the bikes had new air fiter plugs carb cleaned and still no joy its lost a lot of power how much not able to tell you as i bought it like this also carb rubbers and vacume pipes are all in good nick also the diaphrams are good please help terry
might be worth asking the guys on the MCNNinjas site
http://www.mcnninjas.co.uk/forum/
they may know of something particular to the zxr?
other then that sounds like a fuel or air starvation issue? but im no mechanic.