XR600 electrical/lighting question

Hello, I just discovered your forum. I'm new to dirt bikes. I want to fix my lighting system. I'm hoping someone can offer me some help.

I recently purchased a well worn '97 XR600 that a previous owner has apparently equipped with a lighting kit. It's got an Acerbis plastic fairing contraption (complete with a sliding plastic cover like a roll top desk to protect the headlight) up front with an H4 bulb, a left handlebar switch with a switch for high, low and horn, a toggle switch on the fairing that (when fed 12V with a battery and no motor running) kills the tail light, and kills the motor with the engine running, and a tail/brake light with no apparent way to activate the brake light. There was some sort of sealed battery (a little bigger than a pack of cigarettes, fully discharged, and not connected) duct taped inside the air box.

None of the lights worked when I got it. A friend loaned me a factory workshop manual for XR600 models earlier than mine. Very few of the wire colors on my bike match the colors in the factory manual, and there are clearly many more wires on my bike than the factory wiring diagram shows. Many of the wires were broken and/or unplugged. Today, using a 12 volt garden tractor battery to help me figure things out, I patched up the wiring. I installed a new tail/brake light. I got the headlight working on high beam and low beam (high beam has a little red LED indicator mounted by the toggle switch on the side of the fairing). I resoldered a little diode into one of the connections - I have no idea what this is for, and I'm not sure I have it installed correctly. The diode wire was broken from it's connector and was clearly arcing and badly burned inside it's rubber insulator. I didn't even notice there was a diode there and almost tossed it in the trash with the rest of the burned wire, insulation, and electrical tape. The diode still works.

I was pleased when the bike started after my electrical rooting around, and particularly pleased that the headlight and tail light came to life as soon as the engine started. Trouble is - the headlight goes out as soon as the motor revs off of idle. The tail light stays on, but gets brighter when the headlight goes out. At idle, both headlight and tail light are on. As soon as I rev the engine a bit, the headlight goes out, when the engine drops back to idle speed the headlight comes back on. What did I hook up wrong? Is the diode suspect in this? Could I have installed it backward? Or is the diode related to the charging system? Any clues from you are most welcome. I'd really like to have a functioning headlight.

Thank you for your time.


Check your voltage out of the stator, if it's ok check your voltage out of the voltage regulator/rectifier. At idle and at RPMs above where the headlight cut out.

Welcome to Thumpertalk, nice first post! Sounds like you inherited a bit of an electrical mess. Is your new bike street legal and if so, do you need all of the street legal accessories to work? I ask because it's a lot easier to get just a basic headlight & taillight working than a whole street legal kit.

Based on your symptom, I can't help but wonder if you have a rewound dual-output stator. If your headlight & taillight were operating on the same hotlead it seems like they'd both dim proportionally with engine RPM assuming it's a voltage drop issue (it also could be that RPM vibration is breaking the headlight contact which would certainly be worth checking.)

How many wires are coming from your stator? What color are they? Is there a regulator (metal box) mounted on your frame to the left of the upper shock mount? Is there one on the airbox?

Thanks for the suggestions. The bike is street legal, but the only thing I need other than head and tail lights is a brake light. I figure I can rig a brake light switch in later. My next clueless move was going to be to check if vibration was breaking a contact, I'll check the ground and feed today, would be nice if it was that simple. I'll also count the wires from the stator, note their color, and look for the regulator. There is an electrical gizmo mounted inside the air box that I don't think is oem. From memory it's got 2 yellow wires, a red wire, a black wire, maybe a white? It's aluminum with a transparent green cover. Didn't look like anything in the factory diagram. What's the purpose of a dual output stator? What about that diode?


The gizmo on the airbox you mentioned sounds like a rectifier/regulator from the dual sport kit. I believe that same rectifier/regulator was used by most of the dual sport kit manufacturers out there.

Sometimes XR600 stators are rewound for high output with two lighting coils instead of just one. A stock stator has one single output. If the stator has two separate outputs the lighting system requires two regulators to use them both.

The diode is a mystery to me. Perhapse some sort of half wave rectification for the LED indicator? A voltage limiter for the headlight or something else? I don't know but I can tell you that a basic electrical system (on road or offroad) shouldn't require it.

had the same kit on mine but not so much as the trouble it was a baja design had a toogle switch with indicator light and a tether kill switch like on a jet ski all the same pieces like the battery and box with clear in it to see the internals check with them they can probly help you with the wiring :)

Thanks for all the help. Headlight is working all the time now. I cleaned up and tightened up several wire connections, fired it up and it works. I think it's only got one regulator/rectifier, I guess the one with the clear green panel inside the air box. Only the CDI and a relay near the shock mount. Have no idea what the diode is about, I guess it doesn't matter at this point. Seems strange that the toggle switch kills the engine rather than turning off the headlight - is that the way it's supposed to be? As it is, I don't see a way to turn off the headlight, seems like the plastic headlight cover would melt if left in the down position with the headlight on.

The baja kit you describe had no way of turning off the headlight. I put a toggle in mine to cut power to the taillight and headlight so I could control it. In the directions for that kit they even tell you to unplug the headlight for a faster battery charge. You probably have or had a switch that is mechanically pulled down by the brake pedal which would fire up the second element in the tail light. The newer kits have a hydraulic switch and a position on the handlebar switch that just runs the tail light and a small bulb in the headlight housing. I will bet your toggle switch is there so the owner could have a little security when he ran into the store so some yahoo did not just jump on kick it and go.

Ah, security feature, makes sense, but I would have tucked it out of sight. No mechanical switch to be found, no wires running down there either. But now that I think of it, there are a couple wires with real small female spade connectors in a gray colored wire sleeve that are coiled and tucked under teh seat. Maybe those are the brake light switch wires? I'll check that today. I'm thinking I'll install a hydraulic switch.

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