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Simple rules for adjusting motorcycle headlights

It would seem, what could this be in the headlights? Shine and good! Here are just an incorrect adjustment can cause an accident, if not your own, then someone else’s, when the headlight blinds the drivers of oncoming vehicles. From constant or strong vibration, the mounts are loosened, then the headlight will slowly and almost imperceptibly sink down, depriving you of normal lighting. If you travel a lot on a road that is far from mirror-like smoothness, it is recommended to check the light adjustment more often.

If the owner’s motorcycle is new and it feels like the headlights are bad, it may be a matter of adjustment. The driver’s perception of the illumination of the road depends on various factors, but if the headlight was adjusted by the previous owner for his position, for example, a person was tall, then on the same motorcycle a driver with a short stature may not have enough light in front of the wheel.

Keep in mind that headlight adjustments may be necessary when the bike is heavily overloaded and literally sags beneath you.

“Heavyweights: the top of the heaviest mass-produced modern motorcycles”

To do the adjustment yourself, you should first study the manual. Each model of motorcycles has its own characteristics: somewhere there is open access to the mounts, somewhere you have to look for long screwdrivers. The principle is always the same – the position changes vertically and horizontally.


The headlights are adjusted in the dark or twilight, so it will not be superfluous to have a flashlight at hand in order to illuminate the mounts.

There is no need to release the brakes on the fact that adjusting the headlight is working with an electrical device. There is a potential risk of accidentally damaging the wires with a screwdriver. It’s even trite to catch your clothes on the lever and overturn the bike – it’s easy.

“Basic safety rules for motorcycle repair”

How do I adjust?

The easiest and most tricky way works if you have your own garage. In order not to mess around on your own and not draw pentacles on the walls, you can take the motorcycle to a service where it will be tuned for you. Then, upon arrival at the garage, make notes for yourself for the future. Measure the position of the motorcycle and the line of the headlight beam. In the future, it is easy to compare these indicators by checking the position of the headlight, as in a template. When you don’t have your own premises, and the desire to regulate something too, then the plan to give the bike to the service always works.

If you regulate it yourself, you will have to work a little.

First you need to find a suitable place. The area under the motorcycle must be level so that it does not tilt and thereby distort the measurement. There should be a wall or garage doors in front of the bike. The main thing is that the junction of the site and the wall is perpendicular.

Please note that the low and high beam are adjusted separately from each other, start with the low beam.

For measurements, you will need masking tape and a tape measure. This is a versatile set. Moreover, when glued evenly, a strip of adhesive tape gives a clear straight line, which is not always possible to draw by hand.

Otherwise, it has long been working mathematics, into which you need to substitute the variables from the following formula:

The name of the axes in the picture:
О – О – vertical axis of the motorcycle;
А – А – longitudinal axis of the motorcycle;
B – B – lower boundary of the light spot;
D – D – line of the center of light spots;
L – L and P – P are the vertical axes of the left and right headlights of the motorcycle, respectively.

The plane of the wall is marked depending on the height of the headlights and the distance to the motorcycle according to the following formula:

h = H – (14 * l * H) / 1,000,000 mm.

where h is the height (distance) of the location of the center of the light spot on the wall;
H is the distance from the center of the headlight source to the ground level on which the motorcycle stands;
l is the distance between the wall and the center of the headlight source.

For example, if l = 9500 mm, H = 860 mm, then: h = 860 – (14 * 9500 * 860) / 1000000 = 745 mm

On motorcycles with one headlamp – the center of the light spot must be aligned with the O – O and A – A axes.
In motorcycles with two headlights – the distance between the headlights must be identical to the distance between the L – L and R – P axles.

I repeat that the manuals contain all the necessary information. There are motorcyclists who adjust the headlight position “by eye”, but this is not the best method.

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