Abrupt on/off throttle fueling
The first-generation FZ-09's ride-by-wire fueling is famously snatchy — the bike lurches when you crack the throttle open or shut, a flaw every period review and owner forum documented. It is a mapping problem, not wear, and an ECU reflash (about $300) transforms the bike. Hold a steady small throttle in second gear on the test ride, and ask whether the ECU has already been flashed.
Ask for repair records covering this item. If it hasn't been addressed and the car is in or near the mileage window, price the $250–$350 repair into your offer — or make it the seller's problem.