Why are my headlights dim on my Harley? I can't see to ride at night unless I have my high beams on.?

the low beam dimness worssens as time ticks on. The battery is fairly new Low mileage. (on battery) Kickstart only.

9 Answers

Relevance
  • Anonymous
    1 decade ago
    Best answer

    The first 2 items I would check:

    Faulty ground

    Regulator/rectifier output

    And a new bulb would'nt hurt though it's unlikely your problem.

  • 1 decade ago

    You need to do some testing , and lucky for you all it takes is a cheap volt meter from Autozone or the shack .

    Test the volts at the light , rev the engine some , now test the volts at the battery , are they close ? Another way to test the circuit is called the volt drop method . This will tell you the dynamic resistance of a working circuit . With the light on put one lead on the battery post and the other on the light positive , the reading on the meter will be your volt drop . You might see .05 volt on your brand new digital meter . If you see .2 or something of that nature , you have resistance somewhere in the circuit . You can also test the ground side , and this is the one I suspect if both beams are dim . Simply put one lead ( dosen't matter which in either example) on the negative terminal of the battery , and the other on the ground lead , again about the same voltages apply . If you are having some performance issues you may actually have a system that's running too low on voltage , I'd guess it needs to be 13 or better , my beemer lives with that when I have the extra lights turned on .

  • JetDoc
    Lv 7
    1 decade ago

    You didn't say which model and year your Harley is, but if it's kickstart only, I'd guess it's an older one. Many of the older bikes have weak alternators or generators, which won't keep a battery up to full charge with the engine running at low RPMs, or the current draw with all the lights on is too much for the alternator to keep up.

    Check your battery voltage as soon as you notice your lights going dim. A fully charged "12 Volt" battery should actually read around 14 volts on a meter. If yours is down around 10-11 volts, then it's probably your alternator or voltage regulator not putting out enough power to keep the battery fully charged.

  • 1 decade ago

    Are you running a 6 of 12 volt system ? 6 volt lights can be pretty dim. If 12 volts, what is the amp/hr of the battery you are running? Should be at least 5. If you have a dirt bike shop in town (like KTM) you can pick up a great small sealed 12v battery for about 35 bucks. Also check your generator output. At around 2000 rpm you should read around 13 or 14 volts on the battery terminals.

  • What do you think of the answers? You can sign in to give your opinion on the answer.
  • Anonymous
    1 decade ago

    how new is fairly new ,bike batteries usually only last 2-3 years depending on the type of battery. i have a 1952 fl kick start only with a generater and i run a sealed battery and i put in a h-4 bulb kit 55-100 watt , normal bulbs are 50-55 watt. no problems at night and on high beam i don't need the spot lights

  • BP
    Lv 4
    1 decade ago

    I agree with Ride on, it sounds like a faulty ground. Check your contacts in the switch housing for starters. Any moisture seeping in could corrode them. Clean them off and hit them with WD40 or the equivalent there of. If that doesn't do it start testing your wiring. I had a broken ground wire in the harness one time. Ugh! What a job to get that repaired. But it worked beautifully after that.

    Good luck!

    Source(s): experience
  • 1 decade ago

    If it's time to replace the bulb, try a Zenon bulb. A few bucks more but worth it. Much brighter, whiter light. I used Sylvania SilverStars but some prefer G.E. Nighthawks since they're not blue tinted. Walmart or any auto parts store usually has these. There are brands that burn hotter & brighter but they cost more & burn out faster.

  • 1 decade ago

    In addition to the above it could just be time for a new bulb. They tend to diminish in brightness the older they get.

  • Anonymous
    1 decade ago

    mount a hologen light, check and see what charges your battery... generator could be out ...the brightness should increase as you rev it up.

    but I cant see at night too.

Still have questions? Get answers by asking now.