I just bought a 1999 vn750 with K&N filters and jardine pipes. Bike does not pop or backfire during deceleration and is not difficult to start cold. There is blue discoloration on the header pipes, not sure how old. Anyway to tell if the previous owner had the carbs properly rejetted? Or to see if they are still the stock jets? I am somewhat paranoid and do not want to be running around with a lean problem. Or should I bite the bullit and have it tuned anyway?