Pretty soon now, night will begin creeping back into our riding hours. And while you spent the summer using the headlight to alert other drivers and attract insects, now you actually need to see something. Past the obvious--do you have a good-quality bulb, are the lenses clean?--take a moment to be sure your headlights are aimed correctly. (You'd be amazed how many test bikes we get whose headlights are either searching for nightcrawlers or probing the heavens for intelligent life.)
This is an easy thing, but you need to understand what you're adjusting and where to aim the beam. Take a look in the owner's manual and then peer around the headlight area to understand what the manual says. Generally, headlight adjustment hardware falls into one of three categories: A big knob or nifty electric switch that adjusts the beam for you; smallish but exposed knobs; and the devilishly hidden, hard-to-use screw-type adjusters. Bucket headlights normally pivot around the mounting ears, and have a small setting apparatus, usually below the beam (1). This is among the easier-to-use types; turn the screw clockwise to lower the beam.
Then you may discover your bike has exposed adjusters (2) that make quick changes easy. In this case, turning the adjuster clockwise moves the headlight beam upward. There is another adjustment, seen just inside the lower edge of the fairing, that moves the beam left to right.
Finally, some bikes have buried adjusters (3). The idea here is that you're supposed to stick a thin screwdriver up through some piece of bodywork and into the small plastic socket. The teeth of the screwdriver will engage the metal wheel. Turn it one way and the beam moves.
So how are you supposed to aim the beam? A lot of riders simply adjust until the light startles oncoming drivers--and then back off a half turn. Believe it or not, there are official recommendations. Find a flat patch of ground with a white or light-colored wall at one end. (You may have one of these right there at home--it's called a driveway.) Place the bike 25 feet from the wall or garage door (4). Measure from the center of the headlight to the ground with the bike level (5). Now go over to the garage door and mark one line at the same height above ground, and another two inches lower (6). Use a carpenter's level to draw a horizontal reference line (7).
Switch on the headlights and mount the motorcycle. The low beam's upper cutoff point should rest right on the lower line (8). Because most bikes have combined high- and low-beam reflectors, setting the height (and checking to see that the beam is centered along the bike's long axis) is about all there is to it. But if you have separate high beams, make the center of the high beam land on the upper line. That's it. Button everything up--don't leave that screwdriver poking through the fairing--and enjoy autumn knowing you're ready for the dark, short days of winter. Brrrr.