Q. My GSX-R has been sat all through winter with the same tank of fuel in it (I know, not the best idea), so now as a result my bike is very sluggish to respond to the throttle movements and hence there is a good delay until the fuel gets through, I am guessing the 'old' petrol has clogged up some filters, injectors etc.
Whatever223, MCN forum
A. Try and get as much petrol out of the tank and try an injector cleaner with new petrol for now. If your bike has a cat in the exhaust you’d need to be careful as the wrong cleaner could ruin it.