My Tornado's been mis-firing intermittently at any rev lately, but mostly at startup. I replaced #3 ignition coil & got rid of most of it. I think maybe another is dodgy as well. Just can't be sure which.
Does it do it as you are blipping down through the gears by any chance? Mine has had this since I got it - seems to be related to the stalling problem which manifests itself occasionally when pulling in the clutch around the 3k mark. My riding style has changed to accomodate it - blipping the throttle on a downshift is not critical anyway due to the slipper clutch but if I do I find keeping the revs higher tends to avoid the misfire.
A while back I did have a very bad misfire which felt almost like a mechanical problem - this was due to a faulty stepper.