Headlight problem

[ddralston]

I have a People S200. The headlights work fine at idle but get bright and then go out when the throttle is advanced. They come back on when the throttle is reduced to idle. All the other lights remain on. Does anyone have any ideas?

[zombie]

Could be the regulator. The lights will ALWAYS brighten up a little w/ rpm's, but it sounds like your reg. is going Try putting a volt meter on any accessible 12v wiring. you should see a low reading around 12v, and a high of 13.5. on the center stand you can rev, and check. If your voltages check out go to the haedlight wiring off the switch. could be a bad contact in there. Check the voltage into, and out of the switch to verify.

[Shaka]

I would definitely check the voltage regulator. 

[abobotek]

The headlight controller is likely at fault.  It senses engine RPM from the ignition controller, dims the lights at low RPM, and is supposed to give them full brightness at high RPM.  It's under the front cover near the fork stem.

New ones are around $55, depending on the dealer.

Let us know what you found was at fault.

[zombie]

What you are the "headlight controler" I believe is the same part as the voltage regulator/ rectifier. (same location/ function)

[racewalker]

It is called the headlight relay. It is different from the regulator. On the 125 the regulator is on the left as you face the front of the bike and re relay is close to the center as I recall.

[zombie]

If there is a problem w/ the relay, I would suggest a quick re-wire of the terminal ends, and replacing w/ a BOSCH 30amp relay. Most auto parts will have one for around $13.00 us

[OldGuy]

Since you didn't state a mileage the brushes could be the problem.

[abobotek]

On the People S 200, S 125 and a few other models, there is this part:
  SKU: 3860A-LCD3-E02 CONTROL ASSY UNIT LIGHTING. 

You can see it at http://www.stadiumyamaha.com/pages/parts/viewbybrand/default.aspx by selecting 2007 People S 200, and selecting the Wire Harness page.

This headlight controller has 3 inputs:  hi-beam select (from the switch by the left handgrip), low-beam select (same switch), and ignition pulse.  Its function is to control the power to the high and low beam headlight filaments.  It senses engine speed based on the frequency of ignition pulses, and has three power states:  off, dim, and full.  When the engine is at idle, the headlights are in the dim state.  Above idle, the lights go to the full state.  In addition, this assembly switches between low-beam and high-beam as you flick the switch.  I think the dim-at-idle behavior is designed to minimize the electrical load when the bike is at idle, when the alternator produces little electricity. 

This unit is not a simple relay, although one of its functions is to act as a solid-state relay, energizing the selected beam (low/high). 

[zombie]

Thank you for the Info. this cleared up e few different things. Complex little setup!