How do I replace and adjust the headlight?
Start by taking off the fairing. If you have small, nimble hands, you may be able to do this procedure without fairing removal, but removing the fairing makes the whole job much easier, and is recommended at least the first time you try to change a bulb. Also, remember to check your on-bike toolkit to make sure you can do this while you're away from home.
After the fairing, remove the headlight assembly (four bolts).
Locate the wiring harness. The wiring is a 3 point plug into the back of the bulb. Squeeze and pull it back and off. You can do this before you remove the light assembly, or you may find it easier to put a towel on your fender, let the headlight rest on that, and pull the plug from there.
Peel off the rubber boot.
Press in and swing away the metal clip holding the bulb.
Pull bulb out and replace. As always, do not touch the bulb with your hands. Don't.
One member didn't remove the fairing, and he spent one and a half hours doing this little job. That little metal clip can be a big pain to reach. Other members claim they can replace the bulb in five minutes (fairing not removed). Time estimate for doing it the 'right' way is about 30 minutes, most of which is taken up removing and replacing the fairing.
For your entertainment and enjoyment, a moving picture.
Under normal circumstances, you shouldn't have to adjust your headlight when you change the bulb. Everything will bolt back together the same way it was before you started working on it.
If your light is out of adjustment, look at the back of your headlight. You'll see white plastic guides at the upper right and lower left corners. The upper right is for the horizontal adjustment and the lower left is for the vertical adjustment. Grab a phillips screwdriver and put it in the guide, from the bottom.
The blades of the screwdriver engage into teeth lining the inside edge of an adjuster wheel, much like a rack and pinion. Twisting a full turn of the screwdriver results in a small turn of the adjuster wheel due to the gear reduction, allowing for fine adjustment. If the white guide is damaged or missing, the adjusters may also be turned by twisting them directly with the tips of a pair of snap-ring pliers placed into two of the three holes in the face of the adjuster wheel.
If you replaced the bulb, it's possible to have it cocked in such a way that it doesn't sit flush. If this is the case, it will be impossible to adjust the light without first installing the bulb correctly, so it does fit flush.
MOTORCYCLIST Magazine's Headlight Aiming How-to