A member just posted pictures over on the BMW K1600 forum of the source of his rattle for the 30,000 miles he's ridden it. The steering damper was never connected on one end and was bouncing around the steering head every time he hit a bump. The only reason he was able to find it was suspension servicing that required removing a lot of the upper plastic. It's not just Triumph folks, it happens on the $25K+ bikes.