The Helmet Gaurdian and the original Yamaha lock has the same exterior but slightly different insides.
The below link shows
HOW TO RE-KEY THE LOCK TO FIT YOUR KEY, written by one of my customers.
It should be noted that both Yamaha and HG make the lock that is exactly the same on the exterior BUT has a different style offset (exact opposite). As long as your key will semi go into the lock cylinder, it can be re-keyed to match your key.
I re-keyed HG's locks to fit my old FJR and also re-keyed the second lock I have on the right side of my FZ6 (first pic), pic's 3 &4 are that of a Gen II FJR, the right side ((#4 is hard to see as i have them now color matched to the frame))
The last two pictures show a full face helmet locked to an FJR, soft bottom of the helmet to the bike (no scratching), semi weather proof as it isn't hanging upside down either...
For dislosure purposes, I design and make helmet lock brackets for all year FJR's (using the HG) and have this link on my sales ad for any of my customers.. I do BMW's too with its a completely different lock assembly...
Helmet Guardian locks - FJRForum