| Re the headlight adjusters. Often they don't work no matter how much you twist them, The rack and pinion in there is plastic, I believe. At any rate, it's clearly not man enough for the job. However, if you take the black plastic cover off the bottom of the unit, there is a screw you can find if you poke an allen up vertically into the unit which "overrides" the rack and pinion. It's easier if you take the nose-cone off.
In an ideal world, take the headlight unit right off the bike and open it up "on the bench". | 
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