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« on: December 01, 2007, 08:02:13 PM »
The following information is a quick guide to the ‘dark arts’ of vehicular lighting. Current (no pun intended) UK legislation regarding headlights on motor vehicles dictates that the maximum wattage for dipped beam is 55-watts and main beam is 60-watts. The beam should not dazzle other road users but to my mind, a 100-watt beam correctly adjusted will not dazzle any more than a 60-watt beam would.
Suffice to say, if you were to upgrade your halogen headlight it would not be legal. However, the chances of this upgrade ever coming to light (pun intended) is slim. However, this upgrade is purely ‘for show use only’ as they say.
The problem you have with just a straightforward swap of bulbs from standard 60/55 to say a 100/80 is that the new bulb draws more current. There are other choices of bulb – 100/55, 80/55 etc. Back in the 80’s a friend of mine changed bulbs in his Alfa Romeo. Everything seemed fine until his steering column burst into flames! Suddenly it was a lot lighter and hotter in the car than outside.
Modern cars have wiring capable of handling this increased power but motorcycles still do not.
With modern cars (1990 onwards in most cases), the solution is to increase the fuse rating from say the standard 8 amp fuse to a 16 amp fuse. This means both dipped beam fuses and both main beam fuses. If you go 100/55 you only need change the high beam fuses.
Motorcycles and older cars use much thinner wiring to save weight and money, so changing the fuses is not an option as you may have an ‘Alfa’ moment.
The solution is to fit relays to the wiring circuit. The relay is really just a secondary switch, once fitted. If you flick your headlight switch to high beam, the power that would have gone to the bulb now goes to the relay. This effectively powers a switch inside the relay, which flicks over to provide full on power to the light. Your original switch is only coping with a minor draw of power whereas the relay is doing all the work.
Relays, wiring, fuses and connectors are available at many accessory shops but they are not too expensive. You need one relay per circuit, one for dipped and one for main, so most bikes need two per headlamp. The diagram is hopefully self-explanatory but to clarify:
Site your relays where they can stay reasonable cool. Mount inside the fairing, under the tank or in the seat hump. Buy the ones supplied with a mounting bracket and site them so that the terminals point downwards. This is to reduce the likelihood of water ingress.
The wiring you need is for a max load of 17.5 amps. You’ll need some black, red and two colours that will be high and low beam circuits, the choice is yours or match the original colours.
You need to fit 16 amp fuses to each of the power leads from the battery to the relays.
You will probably have to upgrade the terminal plug to the bulb, as the original plug will have the original weedy wiring.
The crimp-on terminal connectors you need for the diameter of the wiring used are blue, however, soldered connectors are obviously better. Don’t forget insulators.
Wiring diagram in attachement (hopefully).
I have modified both my ZZR1100 and Yam XTZ660. The ZZR is a slightly tidier installation as I learnt from doing the XTZ. I got relays, fuse connectors, wiring and crimp connectors sufficient for both bikes for about £25. They both have 100/80 bulbs as have both of my cars. The bulbs last forever for some reason, which is a good thing as they are a bit more than standard.
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