It would be easier to adjust a carb to be leaner, just use a carb with a cable choke that is operated from the bars, slightly open choke is "normal" and completely off is lean. Mark those positions and you don't even have to stop riding to adjust it.
Good luck keeping an expanding and contracting, vibrating bolt set in one position using something that won't require grinding or burning to undo, if nasa hasn't figured it out neither will you (or even me for that matter, maybe.)