I have recently noticed a weird noise coming from my K1600GT. In normal riding, I never hear anything or feel anything. It first happened while riding some great paved twisty roads in the South Dakota Black Hills, I am speeding up and down, rowing the gearbox and using the throttle with great gusto (what fun!). It was like I was on a racetrack.

At the point of a hard shift, I hear a loud drivetrain thunking or abbreviated backfire (a backfire that starts but gets only partially out the tailpipe) but I can't tell which. Or perhaps it resembles some large valve or rubber poppet shutting and opening, I cannot pin down where it is specifically coming from. I am not using the brakes when it happens. The bike is accelerating without a hitch and is completely stable without any stumbling, hesitation or instability. I feel absolutely nothing in the drivetrain and engine, it is all auditory. I can reproduce the noise by riding hard.

Is this noise evidence of the traction control in action? I have had automobiles with traction control and they are silent. It is unlike anything I've ever heard. My dealer did not have a ready explanation.