My front wears on the left too. If it were because of the crown in the road, then all of my bikes should also wear the front tire on the left side. Not so... only my RS.
Here's my theory:
My bike pulls slightly to the right. I've read where this condition is common among RS's. It doesn't pull a lot, but if I let go of the bars, I have to lean way over to the left to compensate to keep going straight. I've also read where the RS is built with the front and rear tires slightly out of line because of the SS swingarm or something. I haven't confirmed this, but this might be why the bike pulls a little.
Regardless of the reason, to compensate for the pull when riding straight ahead, there must always be a little extra pressure on the grip to countersteer against the pulling. This constant countersteer turns the front tire slightly and constantly scrubs the left side a little more than the right.
I didn't research this much on the forums, so I'm sorry if I re-stated what someone else has already said. This isn't stated as fact. Just my possible theory.