headlight issue

[reporon]

good day men, I have a question. the headlight on my df seems ok at idle but when I bring up the rpm's the headlight dims. when going down the road at night it is about as bright as a flashlight. not sure what to do to fix the problem. I checked most of the wires. I will take the headlight switch apart on the throttle side today. this switch doesent seem to work. any ideas would be great. thanks...

[Reveeen]

Check the voltages @ the battery, idling/revving, sounds like an over active voltage regulator.

[Barnone]

reporon,
Let me check my DF bobber before you tear into the switches. I never have ridden it at night but will try it tonight and get back to you.

[reporon]

thanks much Barnone

[Weldangrind]

I agree with Mr. Reveeen's diagnosis. A replacement regulator would be relatively cheap and easy to replace.

[Reveeen]

or an absolutely minimal ground at the front end/frame.

[Barnone]

reporen.
Right now my DF has the small bulb (parking light?) and the headlight always on. Your headlight is coming on right?

I hadn't ridden my DF at night lately so I didn't want to comment on the headlight I until refreshed my memory which I did just now. The low and high beam seem fine to me, probably only a 35w light. I do need to adjust it up a little.

The switch on the right side has three positions which don't do anything since we have a USA model that requires the headlight to be on all the time. I might investigate changing the wiring so the switch works with headlight off, small bulb on(parking light?), headlight on.

[reporon]

I did hook up a ground to the headlight with no better results. tested the battery before starting motor 13volts. started motor 13volts, raised the rpm's & volts went to 15. checked volts at headlight at idle 13volts raised the rpm's & volts dropped to 10. I am guessing a bad rectifier ( is the rectifier the voltage regulator?) thanks.

[Barnone]

You have 15 volts at the battery when the engine rpm is raised but only 10 volts at the headlight? Sounds like to me that the charging system is working properly.

You should have the same voltage reading at the battery and the headlight.

That is strange and needs some more though before parts are swapped out.

The owner's manual has a wiring diagram that needs to be studied.

What is causing the voltage drop of 5 volts?

[Weldangrind]

Perhaps I'm interpreting reporon's results differently.

If I understand correctly (irrespective of where voltage was read), voltage was steady at 13 volts, and then voltage jumped to 15 upon revving the engine. Upon revving the engine again, voltage dropped to 10.

reporon found 13 volts at the battery before starting, 13 volts at the battery while running and 13 volts at the headlight while running. It was upon revving the engine that voltage increased or decreased.

reporon, since you saw voltage decrease, I would be inclined to replace the regulator. We often refer to it as R/R, because it can serve as a regulator or rectifier, depending upon the AC or DC status of the CDI.

[reporon]

good day men, I ordered a new voltage regulator. will keep you updated. thanks

[BillR]

I did hook up a ground to the headlight with no better results. tested the battery before starting motor 13volts. started motor 13volts, raised the rpm's & volts went to 15. checked volts at headlight at idle 13volts raised the rpm's & volts dropped to 10. I am guessing a bad rectifier ( is the rectifier the voltage regulator?) thanks.
Welcome to my world... :wink:
Good advice from all the guys.
I had a Lifan GY-5 that did the same thing. Never did get it worked out. Changed the regulator, checked the stator, all voltages were just like you describe.
Finally put a switched relay on it and ran the lights straight off the battery.
There's a big thread on the dual-sport section.
Good luck with it, I hope you can get it working.
Bill R

[makenzie71]

Some of these china bikes are tricky...have wierd R/R's. My quad has two outputs on the hot side of the R/R...not shared voltage, though. One is charging side for the battery and the other is lighting. I can see one side failing while the other stays okay.

What I've done with both of my quads is I have wired the R/R to charge the battery only, then all my lighting is on a separate circuit off the battery. This has reduced strain on the bike all around.