Agree. Best is to toss it altogether because it's not long enough to go around the chin piece of a modern full face helmet, and if you want to lock the helmet by its straps, you can just as easily loop the straps themselves through the lock.
The helmet lock on a 2002 DL1000 is just behind your left knee when sitting on the bike, and it opens with the ignition key. Don't know about the DL650, but I know some bikes have hooks for a wire like this under the seat. So by locking the seat you also lock the wire, and thereby the helmet, to the bike.