How To Adjust A Motorcycle Headlight

This is our guide on how to adjust a motorcycle headlight. 

If you ride a motorcycle, you want people giving you a thumbs up. But if instead, other motorists are flipping you off, or flashing their brights at you, it’s possible that your motorcycle headlights are not properly calibrated. 

Alternatively, if you find that the headlights on your motorcycle are pointing too low to the ground, off to the side, or any which way except where they should be, they may be in need of an adjustment. 

Another possibility is that you added some aftermarket accessory lights or upgraded the headlight on your motorcycle, in which case they may need to be adjusted for optimal lighting. 

We’ve been testing and working on headlights for over a decade. So if you aren’t sure how to adjust the headlights on your motorcycle, allow us to help. 

Keep reading for more information on how to adjust a motorcycle headlight. 

What You’ll Need To Adjust A Motorcycle Headlight

Adjusting motorcycle headlights is a pretty simple task, and you don’t require that many special tools or expertise. Here’s all the stuff you will need. 

Tape Measure

A standard tape measure will do. This will be used to make all of the necessary measurements, such as the height of the headlight, the distance between the wall and the motorcycle, and the distance between any accessory lights you might have on the bike. 

Painter’s Tape

We chose to use painter’s tape as it’s easy to work with, easily visible against a blank wall, and doesn’t leave any marks on the wall. 

Screwdriver

A lot of motorcycle headlights come with external knobs that let you adjust the headlight on the fly, while others require you to tighten or loosen a screw to make the adjustments. Others might even require you to open the whole headlight assembly, or use a wrench or pliers. 

How To Adjust A Motorcycle Headlight

Alright. Now that you’ve got all the stuff together, it’s time to get cracking. 

Step 1: Measure The Height Of Your Headlight Bulb

The first step is to measure how high off the ground your motorcycle’s headlight is. To do so, position the bike so that it is level. Avoid using the side stand as doing so won’t give you an accurate reading. 

Ideally, you have another person keeping the bike level while you take measurements. 

You might be tempted to use the center stand, if your bike has one. This is also not recommended, since one of the wheels will always be touching the ground while the other is in the air. 

Now, use the tape measure to find the height of your motorcycle’s headlight. This will be the distance from the ground to the center of the headlight. If your motorcycle’s headlight uses two different bulbs for the low and high beams, measure the distance from the ground to the center of the low beam bulb. 

If you do use the center stand, you will need to make sure that both wheels are level by placing something (such as wooden blocks) under them and then subtracting the height of these objects from your final reading. 

If you have any other accessory lights on your motorcycle, also measure their height off the ground, and how far apart they are from center to center. 

Step 2: Mark The Wall With Painter’s Tape

Once you’ve noted all of the measurements, it’s time to mark them on the wall. Pick a large, blank wall, and mark the height of the headlight. Again, this should be the distance from the ground to the center of the headlight. 

For example, the center of the motorcycle headlight we use in this example is 47 in. off the ground. So, we marked the wall with painter’s tape such that the top edge of the tape was 47 in. from the ground and perfectly level. 

Similarly, the accessory lights were 36 in. above floor level, so we marked that as well. And finally, as the centers of the accessory lights were 22 in. apart, we marked those too. A central line for this whole diagram also helps you make the markings more accurately. 

Step 3: Point The Headlight At The Wall

Now that you’ve marked the center points for all of the lights on the wall, it is time to position your motorcycle for the adjustment.  

To do so, you need to position the motorcycle 25 ft away from the wall and keep it level as you point the low beam at the tape diagram you made. As you can see in the picture, the low beam is much lower than the tape, so it needs to be adjusted upwards. 

The same goes for the accessory lights which are not properly centered and need to be adjusted.

Step 4: Adjust The Headlight 

Put simply, low beams should point slightly downwards for normal operation. But the angle differs a bit for headlights at different heights. 

If the height of the low beam headlight bulb is less than 34 in, the upper edge of the low beam should be level with the upper edge of the tape on the wall. 

For headlights that have their centers between 35 and 39 in. (both inclusive) off the ground, you want the upper edge of the low beam to be 2 in. lower than the center. 

Finally, if the height of the headlight on your motorcycle is 40 in. or higher, the upper edge of the low beam should be 3 in. lower than the center. 

The same goes for any accessory lights on the bike as well. 

And, if you’re trying to adjust the high beam of your motorcycle’s headlight, the upper edge of the beam should be level with the upper edge of the tape on the wall. If your motorcycle has a composite headlight, wherein both low and high beams are contained in one bulb, you should adjust based on the low beam and the high beam will be calibrated automatically. 

Here, it is also pertinent to mention that if you don’t have enough space, you can position the bike a bit closer to the wall and adjust your measurements accordingly. 

For example, say you need to adjust a motorcycle headlight, the center of which is 40 in. or higher off the ground. If you can only position the bike halfway from the wall (12 ft, 6 in. instead of 25 ft), you want the upper edge of the low beam to be 1.5 in. below the upper edge of the tape instead of 3 in, and so on. 

To make it easier to gauge how much you need to adjust the headlight, you can also add another layer of painter’s tape, the lower edge of which marks how low the beam should be. 

So in the above example, you would add another layer of painter’s tape such that there is 1.5 in. of space between the top of the first layer and the bottom of the second layer. And then, you would adjust the headlight such that the upper edge of the low beam coincides with the lower edge of the painter’s tape. 

Step 5: Adjust The Accessory Lights

Now that you’ve figured out where the upper edge of the low beam needs to be, it’s time to make the adjustments. 

With the bike in position, point the low beam at the tape diagram and start making adjustments until the upper edge of the beam coincides with the lower edge of the painter’s tape. 

The actual adjustment mechanism will differ from motorcycle to motorcycle. 

Some bikes come with knobs that let you lower or raise the beam with just a couple twists. Others will have a screw that you loosen or tighten, and some might require you to take apart the whole headlight assembly and adjust manually. 

The accessory lights on our motorcycle were the easiest to adjust, as all we needed to do was move them around by hand. 

Step 6: Test The Headlights

Lastly, you need to test the headlights and see if they have been adjusted properly. That means taking your bike out for a spin in the dark and seeing how the low beam performs. 

Have a friend hold the bike level with the low beam on and stand in front of it. The beam should point downward slightly, away from your sightline, and you shouldn’t feel like you’re being blinded by the light. 

On the road, the low beam should illuminate the road a couple feet in front of you, without being a nuisance for oncoming traffic. 

Conclusion

So, to sum up, adjusting your motorcycle headlights is pretty easy and you don’t even need any special tools to get it done. 

Still, if you want to do it correctly, you will need to make some precise measurements and make sure to keep a couple other things in mind.  


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Author

Richard Nickleson is the author and owner behind Headlight Reviews. He first started the site as a hobby to share his insights on car parts and specifically headlight bulbs, but it soon ballooned and now he writes on all topics surrounding headlights bulbs. If you've got a bulb question, contact Richard here.