Some Internet sources say you should never rotate the engine backward using the 12mm hex bolt used for setting valves and ignition. The concern is that the bolt will loosen. This warning is hard for a career tech to imagine. It is a fallacy.

You can't accurately time the GL1000 ignition without periodically backing up the engine a little. Don't say otherwise. And static timing is the best method and the one emphasized in the official manual, though both static and dynamic timing are referenced.

If occasionally backing up the crankshaft results in the 12mm hex bolt loosening, while the spark plugs are out, this means it was already loose. This is reality.