Yep, I had that exact thing happen to me last year. Luckily & coincidentally it was when I was already on my way to the HD/Buell shop to pick up some Novus polish and the bolt fell out literally 1/4 mile from there. Just got off at the exit RIGHT at the turn in to the shop. Had to slow to about 10mph but the XB12 pulled itself across the road in 5th thanks to the 87ft/lbs. Just purchased a replacement bolt there and back on my way.
That reminds me, I still need to Locktite that muther.