First, a Disclaimer:

I manufacture relay kits, not bulbs, nor motorcycles. Most bikes come with something like a 55/60 watt headlight bulb. The manufacturer specifies a certain bulb rating for each bike. Adding a higher watt bulb is a modification that each owner must be responsible for. So, while I guarantee the quality of my headlight relay kits, I will not be responsible for any heat related problems.

I fully warranty my kits only as far as replacement or refund if faulty. My kits are not faulty if you have a heat related problem. Some bikes, due to their headlight design, do not cool the bulb well, and can have heat problems. Having said that,

MOST BIKES DO NOT HAVE A HEAT PROBLEM FROM HIGH WATT BULBS.

Click here for some photos of different bikes' headlights.

Reasons for Overheated Headlights:

How hot a headlight gets, depends of course on bulb, headlight design, and running conditions. If it's 100 degrees out and your sitting in traffic with your 100 watt bulb burning and your engine smoking hot, your bulb could overheat. Some makes of bulbs tend to overheat more than others. Some bike designs get hotter than others. If you want to run a very high watt bulb, then you must be aware of the extra heat, and take precautions to avoid having a heat problem. On some models, this might mean turning your light off when not moving in a traffic-jam, or providing more ventilation for the bulb. Or using something like a 55/100 watt bulb instead of a 90/100.

Further down, you will find a list of models which DO have a known heat problem with some high watt bulbs, but I can not be responsible for ANY high watt bulb heat problems on ANY bike, whether it's on the list or not. For example, I have a BMW K100RS which so far has never had any heat problem with a high watt bulb. It has a very large well cooled headlight. I've never heard of any bike of this model having a heat problem with its headlight. But if you have this model and you do have a heat problem, I can not be responsible.

Reasons for Relays:

My headlight relay kits provide a safe way 'electrically' to use high watt bulbs. If you want to run higher than stock wattage bulbs, you MUST add relays or you risk burning up your bike's wiring, destroying lighting switches, or blowing fuses. Even with stock wattage bulbs, switches can burn out early due to the high current flowing through them without relays. Adding relays to a bike with a stock headlight bulb is a very good thing. You will get up to 71% more light from a bulb. Your switches will last a very long time with relays. And you will have a fused headlight power circuit.

How to Avoid Headlight Overheating Problems:

Heat can sometimes be a real problem with high watt bulbs, on some bikes. Heat can build up around the back of the bulb area on bikes without much ventilation in the headlight area, especially when the bike is not moving. Check the airflow around the back of your headlights, make sure those rubber boots around bulb sockets aren't getting too hot. If you can re-route wires, vents, or shielding to increase airflow, do so. Be careful not to melt anything. High watt bulbs put out a lot of light, and having relays makes them safe for your bike's wiring. But high watt bulbs create more heat than stock bulbs.

Beware of cheap high wattage bulbs. Often the light thrown is not properly patterned and due to the light scatter, these bulbs will not put more light where you need it.

Avoid having a bulb over 55 watts burning when sitting in traffic. If your bike has an ON/OFF switch, turn your headlight off at times if you don't need it sitting in traffic. Look carefully at your bike's headlight design and decide if the headlight is well cooled. Ask other riders of your model about their experience with headlight heat problems. Check your headlight plug and rubber boot to find out just how hot they're getting. If you see any signs of heat cracking or burning on the rubber boot around the bulb, then you have a heat problem.

EXTRA COOLING TIP: Lift the flap on the back of the H4 Socket. This will help to get some airflow through the socket. This is NOT NECESSARY on most bikes, but may help for those bikes with poor headlight cooling.

List of Bikes with a Known High Watt Bulb Heat Problem:

BMW R1100RS/RT, BMW R1150RS/RT

- Note that on these bikes, I can recommend a maximum of a 55/100 watt bulb. I also recommend not using high beam when the bike is not moving for long periods of time. Many riders report no heat problems with these models, but some owners have had a heat problem with 90/100 bulbs in these models. Remember, with my Relay Kit, your stock bulb will put out lots more light. Before adding a high watt bulb, please try your stock bulb with a Relay Kit.

Better Stock Wattage Bulbs:

Sylvannia/Osram and some other companies make some great bulbs, which put out more light than stock bulbs, but with stock wattage. I suggest using one of these new types of bulbs with a Relay Kit. You won't overheat your headlight and you will be very pleased with the light output.

Be aware that many bulb makers are now labelling bulbs with 55/60 watts that they say output the equivalent of 90/100 or more. Some of these bulbs do in fact put out more light, but many do not, they are just marketing hype. Also, many bulbs now advertise HID type light, or a cooler white colour. Many of these bulbs actually put out less light due to the blue coating on the bulbs filtering out much of the light output. If you want the most light output, stay with a clear glass bulb from a major bulb maker.

Bikes with LO Beam on with HI Beam:

Some bikes, like some BMW K75s, are wired to have both high and low beams on when switched to high beam. I have made a special Heavy Duty H4 Kit for these bikes, if you want to use a higher than stock wattage bulb. However, I highly recommend that you do not run both beams when the bike is not moving, as you risk overheating. You will be fine using both beams under normal conditions of high beam use when the bike is moving, but running both HI and LO beams continuously when the bike is not moving, will cause extreme heat in the headlight, even with a stock bulb.

An option is to convert bikes like this to work normally, with only the high beam on high. Usually there is only a jumper in the bike's wiring that needs to be unplugged. See here.

But, if you like having both beams on in the high beam position, I recommend that you stay with stock wattage bulbs of 55/60, or get the Heavy Duty H4 Kit.

There is a reason why most bikes don't keep the LO beam on with the HI beam. Too much foreground light close to the bike at night, keeps your eyes from seeing further down the road where your HI beam is pointed. Depending on the type of riding you do, having both beams on can be a good or a bad thing.

Dual H4 Headlights:

If your bike has dual H4 headlights, you should not install higher than 55/100 watt bulbs maximum. In fact you should get plenty of light from dual 55/60 watt bulbs. Remember that two high watt bulbs draws a lot of electricity and your bike might not be able to keep your battery charged. Particularly if you are using other accessories like heated clothing. Around town riding would definitely run your battery down with two high watt bulbs.

Note that I now make a heavy duty H4 Dual Headlight Relay Kit with heavier wiring and heavy duty relays. If you want to run dual high watt bulbs then this is what you need.

Auxiliary Driving Lights for More Light:

More lighting is often better handled by auxiliary driving lights. Plus the triangulation of headlights and auxiliary lights makes your bike more noticeable to oncoming cars.

Summary:

Remember, when you're running more than stock wattage, you need to keep the headlight cool. This means the bike must be moving. If you need and want high watt lighting, you must be aware of the potential for a heat related problem on some models, in some conditions. I highly recommend a 55/100 bulb. 100/130 bulbs put out extreme heat!

If you have any problems with, or related to my kits, please do not hesitate to contact me about it. If you need a kit modified or rebuilt, that can be arranged too.