Here's a cautionary tale about a bike on a lift.
I had my Honda Sabre on the lift (Handy pneumatic type), front wheel in the wheel chock, and 4 ancra straps added for stability. Two on the front forks, and 2 on the rear grab rail. I was removing the bank of 4 carbs which is a PITA on that bike by the way. I went in the house that evening leaving the bike on the lift. Overnight, unknown to me, the front tire was slowly deflating. Apparently this allowed the bike to "sag" to one side enough to get the center of gravity far enough to the side to toppel the lift. When I went back in my shop the next morning, the Honda and lift were laid on their side, the Sabre still secured to the lift! However, on the way down, the tank got crushed by the edge of my workbench..... my spirits were crushed too ! Beware tires with slow leaks left on lifts.