Motorcycle Maintenance

Why is My Motorcycle Headlight Dim

Why is My Motorcycle Headlight Dim

The motorcycle headlight is a crucial component as it illuminates the road and augments the presence of the rider, improving visibility and overall safety in dark riding conditions. If your motorcycle headlight is dim or is not working properly, riding can become extremely challenging, especially if you are traveling on highways. Many riders get into fatal accidents because they are unable to see the warning signs, animals, fallen trees, parked vehicles, and pedestrians at night. Moreover, dim headlights make it difficult for other riders and drivers to see you on the road, causing head-on collisions. Dim headlights also make your ability to calculate your speed and the right amount of braking required to safely bring the motorcycle to a halt. Dim motorcycle headlights also make it difficult for you to detect road obstructions because they only illuminate shorter distances as you travel down the road.

Riding a motorcycle with dim or burnt-out bulbs is considered negligence that can result in litigation. Considering all the risks involved in riding with dim motorcycle headlights, you must do everything to ensure your and others’ safety on the road. Properly functioning, bright motorcycle headlights illuminate the roads, allowing you to see any obstructions and other riders to see you. Many riders tend to ignore their motorcycle’s headlights because they travel during the daytime. However, it is still recommended that you prioritize headlight maintenance and check for dim motorcycle headlights. This article brings you all the information you need to understand why your motorcycle headlight becomes dim and how you can fix the underlying issues to ensure optimal visibility and safety on the road.

1. Hazards of Dim Motorcycle Headlights

Old, foggy, or dim headlights pose a serious safety hazard on the road. The most widely acknowledged dangers of dim motorcycle headlights include:

1.1 Impaired Visibility

Dim motorcycle headlights not only make it difficult for the rider to timely detect people, obstructions, and other vehicles, but they also make the rider less visible to other people, increasing the risk of accident manifolds. If the rider manages to maneuver the bike to avoid contact collisions, he may still become the cause of a non-contact collision, which is equally dangerous. In foggy conditions, dim headlights can be dangerous even during daytime.

1.2 Less Reaction Time

Since obstructions and road users only become visible when the rider reaches near them, he has very little time to react and apply the brakes. This increased reaction time often becomes the reason behind damage to others’ person and property.

1.3 Lapse of Judgement

In addition, dim headlights impair a rider’s judgment of distance, and he might not be able to maintain a safe distance between other vehicles. Dim headlights also make it difficult to detect road obstacles that might be approaching fast, leading to accidents.

1.4 Increased Maintenance Costs

Accidents due to dim headlights result in significant damage to the motorcycle, increasing maintenance costs, including expensive replacement and complex repairs. Due to crashes, the overall resale value of the motorcycle also decreases significantly.

1.5 Inability to Read Road Signs

Dim headlights do not illuminate the road signs properly, making it difficult for riders to respond to important information, such as speed limits, slippery road warnings, construction zone signs, and no U-turn ahead warning signs.

2. Types of Motorcycle Headlight Bulbs

Motorcycle headlights come with different types of bulbs, such as LED, incandescent, and halogen. When choosing a new bulb for your motorcycle headlight, it is important to refer to the owner’s manual. However, if you are dissatisfied with the performance and illumination levels of the stock headlight bulb and are looking for a brighter option or an upgrade, it is necessary that you consider the features, pros, and cons of all motorcycle headlight bulb varieties before replacing the existing one.

2.1 Halogen Bulb

Halogen bulbs use a tungsten filament and halogen gas to produce light. Affordable and easy to use and install, halogen bulbs were the first form of automotive lighting technology. From the earliest forms of motorcycles to contemporary low-displacement entry-level bikes, they are being widely used in various types of motorcycles. Many manufacturers offer halogen bulbs in headlights to keep the price point on the lower side, especially for beginner-friendly bikes.

Unfortunately, halogen bulbs only light up shorter stretches of asphalt, that’s why they are only considered safe for urban riding conditions, as street lights and lighting from shops and other buildings augment visibility by lighting the surroundings. However, in foggy conditions, on highways, and pitch black riding conditions, these bulbs are neither practical nor reliable. So if you ride at night on a regular basis, then opt for LED or Xenon bulbs to ensure safety.

Motorcycle Headlight Halogen Bulbs 
Pros Cons
Easy to Replace
Bright Illumination
Not as Bright as LED or HID bulbs
Shorter Lifespan Compared to Other Options

2.2 LED Bulb

LED (light-emitting diode) bulbs are the most preferred type of motorcycle headlight bulbs. An LED bulb is a semiconductor that emits light when current is supplied. LED bulbs are energy-efficient, which also makes them environment-friendly. Though LED headlight bulbs are the most expensive option available, they become cost-effective in the long run because they easily last for over 30,000 hours. LED headlights are among the most popular motorcycle aftermarket parts that riders install for better illumination and a stylish look. Due to their popularity, most modern motorcycles now feature LED lights.

LED Bulb Pros and Cons 
Pros Cons
Longest Life Compared to All Other Options
Easy to Install
Highly Expensive
May Be Restricted in Some States
Overheats Quickly

2.3 Xenon (High-Intensity Discharge) Bulbs

Due to the higher price point, Xenon or high-intensity discharge headlight bulbs are usually present inexpensive and high-end touring motorcycles, cruisers, and sports bikes. In this regard, Xenon bulbs are quite similar to LED bulbs, which are also being preferred for electric bikes by various prominent motorcycle manufacturers, such as Yamaha and Suzuki.

Xenon motorcycle headlight bulbs give out bluish-white light beams that are much stronger and brighter compared to halogen/incandescent bulbs. However, Xenon bulbs need large amounts of electrical energy and this gives rise to the need for quicker replacements. But since these bulbs have an average life of 10,000 hours, they are more popular than halogen bulbs.

High-Intensity Discharge or Xenon Bulb  
Pros Cons
Last Considerably Longer Than Halogen Bulbs
Brighter Than Other Motorcycles Bulbs 
Illuminate Longer Stretches of Road
Complex Installation Method
Frequent Replacements Required Due to Shorter Life 
Consumes High Amounts of Energy Compared to Other Options

2.4 What is the Lifespan of Different Motorcycle Headlight Bulbs

As mentioned above, three types of bulbs are being used in all automobiles, including motorcycles, in the following order of preference: halogen/incandescent, HID (Xenon), and LED bulbs. When it comes to the duration of use, the same order applies.

Motorcycle Headlight Bulbs & Their Duration of Use
Bulb Type Duration of Use in Hours
Halogen  2,000 hrs (approx.)
Xenon - High-Intensity Discharge  10,000 hrs (approx.)
LED  30,000 hrs (approx.)

LED bulbs are highly popular among riders looking for a headlight upgrade due to their long duration of use. Though they are expensive, they can be used for a longer time, ensuring greater value for the money. The LED bulbs also alleviate the hassle of changing the bulbs now and then. The low maintenance and replacement requirements of LED also offer peace of mind to riders. On the other hand, halogen bulbs may be pocket-friendly, but the overall costs of the halogen bulb replacement accrue to the cost of LED bulbs. When it comes to brightness and longevity, Xenon bulbs are a close second but not quite as reliable as LED bulbs. Therefore, if you can afford a modification or upgrade, choose the LED bulbs, provided they are compatible with your two-wheeler’s electrical system.

3. Causes of Dim Motorcycle Headlights

Dim motorcycle headlights are a common issue that many riders face frequently; however, it is quite difficult to identify the reason behind the issue. From faulty bulbs to mismatched wattage, corroded wiring, dirty headlight housing, and faulty electrical systems, many factors can lead to headlight dimming. Being able to detect the underlying cause of dim headlights allows riders to take necessary steps for maintenance to ensure a safe nighttime riding experience.

3.1 Incorrect Headlight Settings

New motorcycles feature various illumination settings, and riders tend to leave the headlight settings unchecked. Unless adjusted, modern motorcycle headlights automatically maintain the brightness level that the riders set initially. There is a high chance that your headlight is functioning properly and you might have just forgotten to change the low beam setting to regular headlight or high beam. Therefore, make sure to check your headlight settings before going out for a ride.

3.2 Oxidized Headlight Lenses

Motorcycle headlight bulbs feature protective lenses that enhance light transmission and also shield the bulbs, wiring, reflectors, and other internal components from harsh weather conditions, debris, dust, and moisture. These motorcycle headlight lenses are crafted from acrylics, polycarbonates, active plastics, or composites. When exposed to direct sunlight, the construction material of headlight lenses reacts with the sun’s UV rays, creating a thick oxidized layer over the lenses and leading to a worn-out, hazy appearance.

The oxidized headlight lenses do not receive an adequate amount of light, reducing the efficiency and brightness of the headlights. If you have replaced the bulbs and your motorcycle headlight still appears dim, then oxidized lenses might be the cause. A mechanic can help you detect and repair oxidized headlight lenses.

3.3 Inherently Dim Bulbs

Similar to the motorcycle’s engine, transmission, suspension, and braking, motorcycle lighting technology has also improved significantly over the years. When out on the road, you might feel that your headlights are dim compared to other motorcycles on the road. This dimming effect is not because of a faulty headlight bulb. Your motorcycle’s headlight might feature an incandescent bulb while other motorcycles may have LED bulbs. Compared to incandescent or halogen bulbs, LED and Xenon bulbs are brighter and offer long-distance illumination. If the headlight bulb is functioning properly but feels dim on the road compared to the headlights of other vehicles, consider upgrading to an LED bulb or a Xenon/HID bulb instead of replacing it with a new incandescent bulb.

3.4 Burnt Out Bulb

Failing or burnt-out bulbs are one of the most common causes of dim headlights. In a burnt-out bulb, the filament fails to produce light, hindering the headlight from transmitting an adequate amount of light. Burnt-out bulbs can lead to dimming or a complete absence of light. When planning to ride at night, it is crucial to inspect the bulbs for any signs of malfunction. It is also important to carry spare bulbs with you even if you only travel in the city. To safely carry spare bulbs, fuses, and essential motorcycle tools, it is recommended that you invest in high-quality motorcycle luggage bags

3.5 Dirty/Cloudy Headlight Cover

Dirt build-up makes the headlight appear yellow and cloudy and also constructs light transmission from the bulb to the exterior. The layer of dirt diffuses the light beam, reducing its brightness, intensity, and range. Regular cleaning is the best practice to avoid dim headlights due to dirt build-up. Cleaning your headlight will surely ensure your safety and also earn your bike compliments for its aesthetic appeal and well-maintained condition. At the time of resale, potential buyers pay attention to these little details; therefore, it is best to add headlight cleaning to your regular motorcycle maintenance routine.

3.6 Incorrect Bulb Type or Wattage

When replacing or upgrading a headlight bulb, one must ensure that the new bulb wattage is in accordance with the motorcycle’s headlight wattage. Headlights of different motorcycles have a specific voltage range and fail to work properly in case of voltage fluctuations. If you install a headlight bulb that requires a higher wattage, it will damage the wiring and may also put strain on the bike’s electrical system, voltage regulatory system, and battery. On the flip side, bulbs with a lower-than-prescribed voltage produce a soft glow that is insufficient for nighttime riding.

3.7 Faulty Stator/Alternator

In automobiles, an alternator or a stator produces the current needed by the electrical components/systems to function properly. If the motorcycle stator is failing, then the headlights dim when the motorcycle runs at idle or at a lower rpm range. In the presence of a failing stator, the motorcycle's electrical system struggles to bear the electrical load, leading to a drastic voltage drop that causes dim headlights.

3.8 Weak Battery

A weak or failing battery is a common wear and tear issue in all automobiles, and the first symptom of a failing battery is dimming headlights. Flickering headlight and other lighting components on your motorcycle indicate that the current generation and flow is inadequate for optimal illumination of bulbs. Dimming headlights due to a weak battery becomes more evident when you accelerate your motorcycle and the headlight begins flickering or becomes dull. This is because the battery experiences additional strain during acceleration, and if the battery is weak, it will not be able to generate the voltage needed to run the bike at a certain speed. But when the rider accelerates the bike, the battery channels all the voltage output to move the bike at a faster pace, and this reduces the voltage supply to the headlights. Consequently, your headlights emit a softer beam as you accelerate down the road.

3.9 Loose or Corroded Headlight Wiring

Motorcycle headlight wiring is susceptible to corrosion. Loose or corroded wiring increases the amount of resistance, significantly reducing the amount of voltage and current flow. The reduced voltage output directly affects the brightness of the headlight. If the wiring is not fixed or replaced, the increased amount of resistance in the wire causes excess heat production, causing more damage to the wiring and dimming the motorcycle headlights.

3.10 Faulty Voltage Regulator

The voltage regulator helps maintain a constant supply of voltage to the bike’s charging system. A faulty voltage regulator fails to prevent voltage fluctuations, causing dim motorcycle headlights.

3.11 Moisture Buildup Inside Headlights

Moisture buildup inside the headlight is a major cause of dim motorcycle headlights. Headlights become foggy due to the temperature difference inside and outside the headlight. If the air outside the headlight is cooler, the moisture in the air trapped inside the headlight will become condensed. You can fix this issue by riding your motorcycle around for an hour or so. The moisture will evaporate as the headlight warms up. When replacing the headlight, it is best to opt for a headlight with small air vents for better ventilation throughout the headlight.

4. How to Replace Motorcycle Headlight Bulb

Replacing the dim motorcycle headlight bulb is an easy task, provided you have some knowledge and the right tools. Initially, you can read the steps provided below and also watch different tutorials on YouTube to become comfortable with the task. As you perform the task multiple times, you will become more confident at it. Changing the bulb yourself will help you learn more about the operations of your motorcycle. Therefore, it is best to learn these simple motorcycle maintenance tasks. Plus, you will save money on labor. However, to avoid any complications, you can initially take your motorcycle to the mechanic, observe how he changes the bulb, and try to perform it yourself the next time.

4.1 Tools & Gear Required

  • Safety Gloves
  • Eye Protection
  • Torque Wrench
  • Center Stand
  • Screwdrivers of Different Tip Shapes and Lengths
  • WD-40 for Lubrication
  • Socket Set
  • Pliers
  • Electric Contact Cleaner
  • Wire Brush

4.2 Steps

The process of changing old and dim headlight bulbs is essentially the same in all motorcycles. However, you will need slightly different bulbs, especially if your motorcycle features a fairing. Sports bikes or motorcycles with fairings usually come with two headlights: the main beam and the full beam that you can choose to switch on and off. It is highly advisable to always consult the owner’s manual when planning to change the headlight bulb.

Choose the Right Bulb for Your Motorcycle

As discussed above, there are various types of motorcycle bulbs available on the market. However, you cannot replace the existing motorcycle headlight bulb with just any bulb. Check the owner’s manual provided with your motorcycle for bulb replacement specifications. You can also consult an authorized motorcycle dealership for part numbers. Your authorized dealer can also help you invest in an OEM headlight bulb. However, if you want to upgrade your bike’s headlight, then check the compatibility of the bulb with your bike’s electric power output. Not all bikes can support your preferred bulb wattage. If you must add a higher-wattage bulb, you might also have to upgrade the wiring.

It is also important to check your state’s headlight laws before opting for a higher-wattage headlight bulb. In many states, there are legal limits on headlight bulb wattage because high-beam headlights increase the chance of accidents by interrupting other drivers’ vision.

Disconnect the Existing Dim Headlight Bulb

Once you get your new motorcycle headlight bulb, remove the existing one by taking off the headlight nacelle.

If your motorcycle has a classic headlight nacelle, remove the external trim ring, holding the headlight in place, to access the bulb inside.

On the other hand, if your motorcycle has an integrated headlight, follow the steps given in the owner’s manual to access and replace the stock bulb.

In case your motorcycle has a fairing, check for removable plastic parts to simplify the process of headlight bulb removal and installation.

Next, remove the headlight power supply plug and the waterproof rubber housing. Release the bulb inside the housing by pushing the spring holding the bulb forward and then downward. As soon as the spring comes out, the bulb will also fall out, so make sure you catch it.

Clean the New Bulb

Before installing the new bulb, clean it gently with rubbing alcohol and a lint-free microfiber cloth. You can also use paper towels for cleaning purposes. Avoid touching the bulb as it may leave marks of your fingerprints, grime, and grease.

Halogen bulbs are designed to handle high temperatures and heat. Touching these bulbs can contaminate the surface of the bulb, causing irregular heat patterns and premature failure.

Next, check any signs of corrosion around the mounting and socket. Clean the corroded areas using an electric contact cleaner and a wire brush. You can also clean the socket by moving the old bulb in and out of the socket multiple times. After a thorough cleaning session, spray one more coat of electric contact cleaner and leave it to dry.

Connect the Bulb to Your Bike

After you have cleaned the headlight mount, apply some WD-40. The old bulb usually comes out with a small black adapter. To remove the old bulb from this adapter, simply pull the two components apart.

Put the new bulb in the black adapter and install it in the housing by just reversing the process of bulb removal. When installing the new bulb, locate its tab and make sure it is pointing upward as you install the bulb. The position of the tab on the bulb ensures a secure and snug fit. Once the bulb is placed in the socket, reinstall the holding spring and the waterproof rubber housing. Plug in the power supply back into the bulb.

Start the Bike and Test the Lights

With the new bulb and power supply securely in place, start the bike, and check whether all the lights are working properly.

Dispose off Faulty Motorcycle Bulbs Properly

Motorcycle headlight bulbs, including incandescent, halogen, and LED bulbs, are free from hazardous elements and can be disposed of with other garbage. However, Xenon bulbs contain mercury, a toxic substance, and must be recycled at a free drop-off recycling site for safe disposal.

5. Motorcycle Headlight Maintenance

Unlike other motorcycle components, the headlight requires the least maintenance. Consequently, many riders neglect motorcycle headlight maintenance altogether. However, regular headlight maintenance, inspection, and adjustment can significantly increase safety in dark riding conditions. To ensure that your motorcycle headlight provides optimal visibility at night, follow the maintenance tips provided below.

Headlight Cleaning

Dust and grime build up inside the headlight nacelle can dim the light. Before you take your motorcycle out for a ride, clean the headlight, tail lights, and indicators. Make this practice a part of your daily motorcycle safety checks. Clean headlights offer better illumination, allowing you to see better. Similarly, clean tail lights, turn signals, and brake lights make you more visible to other riders sharing the road.

Headlight Lens Inspection

When performing regular safety checks, inspect your motorcycle headlight lenses. Headlight lenses that appear foggy, dusty, or yellow tend to diffuse/scatter your light’s beam. The scattered beam fails to illuminate longer distances down the road, impairing the rider’s vision and making it difficult to see obstructions in the dark.

Headlight Beam Adjustment

Always check the brightness of your motorcycle headlight before taking a ride. It is also important to readjust the beam. If your headlight offers soft light, consider replacing the stock bulbs with bright LED bulbs. Make sure that the low beam offers a greater range of visibility, reducing the need to use the high beam. Moreover, if the beam alignment is off or headlight lenses are dirty, get them adjusted and serviced.

6. Last Words

Motorcycle headlight dimming is a major safety concern for riders, especially during nighttime riding. Various factors contribute to dim motorcycle headlights, including burnt-out bulbs, faulty alternators, use of incorrect bulb type, headlight lens oxidation, and many others. It is important not to ignore the first signs of headlight dimming as it may be a symptom of a major malfunction of the motorcycle’s electrical system. To ensure that your motorcycle headlight provides optimal illumination, clean the headlight regularly, replace the bulbs promptly, and upgrade to LED bulbs only after consulting with the owner’s manual or an authorized dealership. Choosing the bulb with the right wattage is also important to ensure proper functioning of the headlight. Though headlights are the most neglected component of a motorcycle in terms of maintenance; however, its regular maintenance is equally important if you want to enhance your riding experience in dark riding conditions.

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