A Little More Light

What can I do to stop my headlight from dimming too much when the revs are low. I was riding home later than usual and had a real problem seeing.... I needed to keep the revs up so I could power the light enough to see clearly. Is there a solution to get good light at low revs without too much electrical work ? Do I need a battery ?

I have a single position headlight and rear light/brakelight and thats the way I want to keep it - simple.



If you do use a battery, you should use a voltage regulator to prevent overcharging. The lead acid batteries will merely boil, but the newer solid state batters will rupture/explode if overcharged.

Another thought might be to fabricate a nighttime throttle stop(fast idle). It could be something quick like a hot start button you could quickly and mechanically enable or disable only when you needed it. A little quicker than adjusting the idle screw.

You could see if a led equivalent bulb is available (most likely there is)and use it in place of your filament bulb. They use much less power. Use a red LED for a red tailight. The led bulb end must point rearward toward the red lens, it cannot lay sideways in the tailight. You will not get enough brilliance if it does. This will make more power available to the headlight.

If the bike has a light it already has a voltage regulator. The wr is mounted near the stearing stem in front of the gas tank. The newer wr's have a 120 watt lighting coil. The older ones had a 80 watt coil. baja designs has a 100watt bulb that replaces the stocker. It will give ya more light but it will dim more at idle.

I have a reworked 130 watt stator w/ a acerbis blitz light on my yz400. I have 2 50watt bulbs in it and it seams to work fine. Not too much dimming at idle. Im even runing 35watt hand warmers and a tailight. Although I think I need to reduce the wattage of the bulbs while I am using the warmers in the winter. They arn't gettin to warm. maybe with the reduced wattage bulbs it will be better.

if you put in a smaller wattage bulb it will not dim at idle. But it wont put out as much light either. Its always a tradeoff. Dual sport bikes are better equiped to handle this problem. But trail bikes seem to be more suseptible to it. If your looking for a cheep solution I dont know if there is one.

You want more light? Check out Baja Designs HID ligthing system. You will need to Run DC current and the HID will not dim on idle. Kind of pricey though. It uses the equivalent of 35 Watts and produces way more light than the 55 W halogen. Anybody with this sytem like to comment?


I rode with that dual HID system in a race lately, and I was very impressed with the visibility that they provided. The flood side illuminated what a normal low-beam would provide, and the pencil beam went out there for miles!

Even with both lights on, they did not dim at idle.

I REALLY wish I could afford a set of those for my ride....


Sounds like the easiest thing to try may be replacing your stator w/ a new (higher output) one and retaining the stock lighting for now. Then if you choose to go briter you'll have the juice to run it.

Another more technical thought, would be to setup a high/low beam unit where the low beam would be slightly less wattage, but if your traveling at low rpms (slow speeds) you wouldn't miss it. As you increase your rpms (traveling speeds) you flip on the high beam. All you would need to do is replace the stock switch with one that is an On-OFF-On, and then replace the head lamp w/ an automotive style (Halogen) bulb. While this is still just theroy I believe it'll work, just check the wattages of the bulbs your trying. I believe stock WR's come with a halogen 55/60 watt bulb wired onto the 60 watt high beam. So you may not even have to change plug ends. If I get a chance to try it I'll post my steps.

BrandonW, I thought that HID light was the "cyclops" one with a small MR2 halogen in the cyclops eye and an HID in the main lense? Or is there a version with HID in both spots? HID seems to be catching on automotively, but I'd be a bit nervous in the rain or water crossings with that gizmo occasionally putting out spark-plug-like voltages. Still, I'd like to run one some day. I have big (185 W) lighting, but get substantial low rev dimming. Up at rev my system works great for mid speeds, but not well for 90 mph where you basicly want pencil beams pointing down what has to effectively be a "road" in order to allow you to go that fast in the first place. I'm also curious about the durability of HID, electronically and bulb wise. If G-outs and shocks can sag the filament out of an 1157, it'll probbly beat up the HID system too vs automotive or street bike use. The HID $$$ is unreal at the moment for anything I've found. Geoff, PM me if possible.

Yes, you need a battery.

Thanks for the options guys. I'm going to try the LED trick and the hi lo hi trick as well.

If I were to replace the stator (lighting coil??) this would provide more juice right, so it would dim less...right ? So how do i upgrade my stator ? Is there anything I should watch out for ?

Rich, on the battery thing, what would I need to install and how would I go about installing it & wiring it up ?


Hey techman the Bajadesigns light that you are talking about has a halogen light at the top and the HID at the bottom.

THe hid buld is actually more durable than the standard filiment type bulb. The hid has no filiment. Instead the electricity arcs acrost 2 polls creating an arc of light. That arc is seald in a glass bulb so nothing (water) can get at it.

Yeah, what YZMAN400 said.


You and I both have a '99. I upgraded the stator to the higher output stator from a newer model year (120 or 130 watts, depending on where I read about it). Without a battery, the headlight dims just as much with the new stator as the stock stator did. Basically, the light dims so much as to be useless at idle.

To wire in a battery, you need to rectify the current to DC first. I've got a Baja Designs regulator/rectifier, but you can just put a rectifier inline after the regulator and achieve the same results. Then you take the rectified positive wire and plug that into the positive battery terminal and connect the battery ground to bike's ground. (Floating the lighting coil's ground is preferable because you don't get any AC "interference" from the ignition coil's ground. If you do float the ground, remember to attach a ground wire to the voltage regulator or it won't get any juice.) Then take all the lighting power right off the battery.

I and several friends use a 1.2 ah sealed lead-acid battery. It behaves just like a regular automotive battery and has plenty of capacity. They are small enough to fit nicely in the airbox. Or you could put it behind the headlight. I had a Ni-Cad battery from Baja Designs but it died on me after just a few months. This battery has lasted me a couple of years, so far. I also power my GPS off of it.

Regarding LEDs, I replaced the stock 1157 bulb (tail/brake light) with an LED 1157. It's very bright, especially at braking, and I think it's a lot less drain on the electrical system. I also use LEDs for the high beam indicator and license plate light. So the only incandescent bulb I'm using is the headlight.

Rich, thanks for the battery help.

I looked on the Baja Designs site and they only have regulator/rectifiers - is that OK ? They have a choise of two, one wired & fused the other not. I presume the wired & fused.

As for the battery I presume its a 12V 1200 millamp. Can I use a regular airplane remote control type battery or do I need to get something special.

As you may be able to tell i'm not much of an electrics geek so I may have a couple more questions.... like this one... what is a 'floating ground'?

thanks for the help


As for batteries, I highly recommend Powersonic Gell Cells. These are sealed units that can be mounted in any position without concern for any leakage. I am using a 0.8 Amp to power just the signals, horn, and relay. In terms of size, they pack more power than regular lead acid as well. Check it out for yourself at Power-Sonic

On another matter, has anyone mounted an LED lights in their

conventional signal lights? I am not sure of the bulb size but one would need to match the bayonette. I am not sure if this size is yet commercially available? Another problem would be the relay. One would need a relay that could be triggered by the extremely low current required by these LEDS. Rich? Techman? Anyone?


The ground as it comes stock is the frame. The lighting coil on the stator (naturally) has a positive and negative connection. The positive power leaves (well, actually the electrons flow back through) the stator by a couple of wires. The negative, or ground wire is soldered to the body of the stator which is bolted to the motor, which is connected to the frame, so the frame is the ground for the lighting (and ignition) circuits. The power is AC for both. In order to use the Baja Designs regulator/rectifier, which replaces the stock voltage regulator, you have to sever the ground wire where it connects to the body of the stator, connect it to a wire of equal length to the two positive wires, and epoxy the base of it to one of the coils so it doesn't come in contact with the flywheel. The BD kit comes with instructions on how to do this, a flywheel puller and a torx wrench for removing the stator.

If you just install a rectifier, you can float the ground after the stator by connecting a wire to the frame and using that as the ground coming into the rectifier. Then the ground wire exiting the rectifier will be the ground for all of the lighting circuits. This effectively isolates the DC lighting ground from the AC ignition ground and elimintes any weird AC interference.


I have been experimenting with using LED lights for turn signals recently and have come to a kind of roadblock. As you correctly surmised, the extremely low current draw of an LED (or cluster of LEDs) is not enough to trigger a standard turn signal flasher. I've searched the internet to see if I could make an electronic turn signal flasher using a 555 timer, but my knowledge of electronics is extremely limited and I wouldn't know a timing circuit if I saw one. A local electronics store had a kit that used a 555 IC and some resistors and capacitors on a small circuit board that I thought would work. But just as I was about to pay for it, I saw that the minimum pause duration was 2 seconds. (Pause duration was adjustable between 2 and 60 seconds and "on" duration was similarly adjustable.) I realized that 2 seconds was just too slow of a flash rate and was back to square one. I figure this sort of timer has to be simple for somone who knows much about electronics.

So, to all you electronics wizards out there: could you help a brother out and tell us how it's done?


I'm a little confused from the conceptual point of view. Maybe cos I dont understand electrical systems. Just tell me to shut up if I'm being a idjit.

So here is my theory...If I need to convert the output from the electrical system to DC then without the rectifier the elcetrical system is AC, right ? So if I convert that to DC so the battery charges and isn't screwed up by the AC, how will the lights now run with a DC current when before they were running with a AC current ? Dont the lights ONLY work with DC anyway ? Hmmm... I think I'm missing something.....

I was wondering perhaps if you were running a YZ that was converted to run with a light system. Electrics would be AC from the stock set-up (no lights) and to install lights you would have to convert to a DC setup. But you say you have a WR. Did it come without lights ?

I know I'm wrong somewheres but ....... help?!!!...?

Missile, Let's go through your questions one at a time:

If I need to convert the output from the electrical system to DC then without the rectifier the elcetrical system is AC, right ?


So if I convert that to DC so the battery charges and isn't screwed up by the AC, how will the lights now run with a DC current when before they were running with a AC current ? Dont the lights ONLY work with DC anyway ?

Wrong...the lights work with either AC or DC; they don't care. The only reason to rectify the current in your application is to be able to charge the battery. If you wanted an electric horn or turn signals, those devices only work with DC. Floating the ground prevents AC-DC interference and allows you to wire the rectifier properly.

I was wondering perhaps if you were running a YZ that was converted to run with a light system. Electrics would be AC from the stock set-up (no lights) and to install lights you would have to convert to a DC setup. But you say you have a WR. Did it come without lights?

I've got a '99 WR400. Stock, it comes with lights powered by an AC lighting coil. The lighting power on my bike has been rectified with a Baja Designs regulator/rectifier, which replaces the stock voltage regulator and also rectifies the current. It allows the battery to charge and the horn and turn signals to operate.

Also, I was working on my bike this weekend and turned the lights on while the motor was off. The lights were very bright. Just thought I'd rub it in. :) BTW, a YZ doesn't have a lighting coil at all.


What brand of hand warmers are you using on your bike? Do they require a rectifier to be installed; the same as you would have for a horn and turn signals?

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