Hi...I've had a xt660 for a few months now and yes..there is (was) surging..but a bit of careful practice on a quiet road using the throttle gently and getting used the "open and closed" positions and it cures it 100%..at low speeds it pays to be firm with your right hand..let your guard down and it'll buck and thrust..but open and close methodically and gently and it just goes away..lot of stuff talked about "uncontrollability" of these bikes and it's all rubbish..just ride with skill and care and it need never bother you...buy one!!!..they are truly magic machines..I'm totally hooked and you will be too!!!!..