(Or: Why you should change your headlight before it burns out)
Those of us that have been around a while remember what headlights were like before the advent of the halogen bulb. Old lights were yellow. Old lights burned lots of power. Old lights burned out pretty quickly.
Halogen lights are terrific. They produce a bright white light (for this discussion I am ignoring all the "blue" and "rainbow" bulbs) and they put out considerably more candlepower per watt than conventional bulbs.
They will burn for thousands of hours, but therein lies a problem and the purpose for this article. You see, halogen lights wear out. No, they don't slowly grind down till they vanish like my friend James's tires (his wearbars wear completely off and you can actually see what color the air in his tires is before he changes them). What halogen lights actually do, is lose intensity.
Basically, they get dimmer over time. Since our headlight is always on, we put many hours on our headlamps. It is a mistake to take the methods we used with our 70 year old sealed beam technology (replace when they don't work) and apply it to a halogen bulb.
Here is the deal . . . at 15,000 miles a year, change your bulb every other year. They lose about 10% per year at that mileage rate. Note that this estimate is my own, based on my own experience, but is also acknowledged by the bulb makers. If you would like the technical evidence, it's out there, but I'll leave that as an excercise for your internet skills.
I run the standard H-4 bulb (now known as a 9003). This is a 55/60 (watts, low-beam/highbeam) bulb and is pretty much the standard wattage for headlights, though there are different connection configurations for different vehicles. Your standard Valkyrie runs the 9003 or H-4 bulb. They cost about 9 bucks. I am not a fan of the much brighter bulbs (65/100) as I have melted wires and headlight enclosures with those before (although NOT on my Valkyrie, but note, on your standard Valkyrie, that entire expensive and gorgeous headlight socket and lense is plastic).
Here is a comparison from my old bulb to my new one:
I took the first picture, removed the windshield, changed the bulb, and took the second picture. Note the difference in the headlight brightness . . . and take my word for it . . . the picture does not do it justice. These are the same type of bulb (55/60)
If you would really like to test this, change one bulb in your car, then shine the headlights on your garage door at night. You will be surprised.
Also note, the aged, dimming bulbs still draw the same amount of power . . . it is simply converted to heat instead of light as they age. In short, they get hotter and dimmer over time. Remember what I said about that expensive piece of plastic this thing is nestled in . . .
For 9 bucks, change it every couple years or so. It has the added benefit that you will seldom, if ever experience a failure on the road. I carry a spare though, but do not be tempted to carry your old one as a spare (I know, I know . . . it is hard to throw working things away). These bulbs are pressurized and the old ones have been very hot and break easier than their "virgin" counterparts.
Here is the old bulb:
Note the incredibly artistic picture composition . . . the cloudy bulb . . . the literal and figurative clouds . . . the naked woman in the corner . . . HAH! Just checking to see if you were paying attention.