Was working on a Honda Valkyrie with a mechanic buddy a while back, installing a trailer hitch mount that bolted between the fender rails and the rear trunk mount.
With the bolts out to put the hitch mount in place, the trunk & fender assembly would be subject to collapsing atop the rear wheel.
So, we hooked two tie-down straps to an overhead steel beam and used them to hold up the trunk mount/fender assembly.
Keep in mind that the bike is about 3 feet in the air atop a pneumatic work lift.
Three of the four main bolts went in perfectly. But, one gave us trouble aligning and ultimately had to have it's blind nut retapped.
All that took time.
Enough time that when we were done, we let the lift back down and *forgot* about the two straps holding up the trunk.
So, with it's front wheel firmly clamped in the downward traveling lift, the rear of the bike became suspended in mid air.........fast.
It was a mad scramble to get the air hose reattached to the lift and the lift back up to get the two straps loosened before the somewhat
questionable steel beam gave way and dropped the Honda. Luckily, everything held and the bike was not damaged.
Our hearts were still racing all through lunch as we nervously went over the fiasco with the shop's coowner.
All's well that ends well. When the customer arrived to pick up the bike, he inquired about the strength of the trailer hitch mounting arrangement.
We told him with much confidence, "Yep. It'll hold."
eddie