Trying to diagnose a flickering headlight

francisjohn

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Just for clarification, the headlight is not connected to the magneto, it is ran on a completely different electrical "system" and is in no way connected to the engine.

-It is not the connectors.
-It is not the headlight itself.
-It is not the power source.

I apologize in advance for the essay.


Powered my 7" headlight and everything was great until 40 minutes into my ride, the light started flickering. The next day, I first power on the light and it stayed on. As soon as I bump start, the light begins to flicker/on/off etc. I replaced the connectors I used, I then powered the light and it stayed on. I did a half-ass bump start and it was flickering. I shut off the bike and the light stayed. At this point, I knew there was some sort of electrical interference, but from where?

I wanted to see if vibrations from the engine loosened something etc. I took apart the light, and inspected the entire "electrical system" for the light which turned up nothing. I ditched the connectors and soldered all the wires involved, I turned the light on and kept it on for ten minutes. I go to kick start it with a super light kick (not enough to try and fire it up) When I went to kick start it, it began to turn on/off and flickering.

This evening I saw the malfunctioning in real time, it was very strange. I held the battery pack in my hand to see what it does when it's flicking. The battery pack has 25%-100% light indicators which will stay on when the battery pack is in use. The lights on the battery were solid (indicating the current battery life) and as soon as I bump started it, the lights on the battery pack itself began to flicker. I shut the engine off, and the battery pack went back to solid and the light was staying strong.

I believe there is some sort of interference occurring when the engine is running (doesn't matter if it's idling, half-throttle or attempting a bump start or kick start) I do have the wires from the power source to the light itself insulated.

A) Where would be a good place to start when diagnosing an electrical malfunction like this?
a1) If there is a "process of elimination" to start from, what should I begin cancelling out in order to isolate the problem?

B) If the spark is jumping (from the wire) would I insulate the spark plug wire? If so, what would you insulate it with?
 
Only vibration can cause your issue. Bulb filament is loose. Connection somewhere is intermittent, if there's a circuit board involved a solder connection. OP stated only happens when running and the light system is separated from the motor.
 
Just for clarification, the headlight is not connected to the magneto, it is ran on a completely different electrical "system" and is in no way connected to the engine.

-It is not the connectors.
-It is not the headlight itself.
-It is not the power source.

I apologize in advance for the essay.


Powered my 7" headlight and everything was great until 40 minutes into my ride, the light started flickering. The next day, I first power on the light and it stayed on. As soon as I bump start, the light begins to flicker/on/off etc. I replaced the connectors I used, I then powered the light and it stayed on. I did a half-ass bump start and it was flickering. I shut off the bike and the light stayed. At this point, I knew there was some sort of electrical interference, but from where?

I wanted to see if vibrations from the engine loosened something etc. I took apart the light, and inspected the entire "electrical system" for the light which turned up nothing. I ditched the connectors and soldered all the wires involved, I turned the light on and kept it on for ten minutes. I go to kick start it with a super light kick (not enough to try and fire it up) When I went to kick start it, it began to turn on/off and flickering.

This evening I saw the malfunctioning in real time, it was very strange. I held the battery pack in my hand to see what it does when it's flicking. The battery pack has 25%-100% light indicators which will stay on when the battery pack is in use. The lights on the battery were solid (indicating the current battery life) and as soon as I bump started it, the lights on the battery pack itself began to flicker. I shut the engine off, and the battery pack went back to solid and the light was staying strong.

I believe there is some sort of interference occurring when the engine is running (doesn't matter if it's idling, half-throttle or attempting a bump start or kick start) I do have the wires from the power source to the light itself insulated.

A) Where would be a good place to start when diagnosing an electrical malfunction like this?
a1) If there is a "process of elimination" to start from, what should I begin cancelling out in order to isolate the problem?

B) If the spark is jumping (from the wire) would I insulate the spark plug wire? If so, what would you insulate it with?
Pictures and more specific information on the battery and the light. I assume the light is LED? If the battery is a LiPo, then there could be an issue with the BMS (Battery management system) circuitry built into the battery pack
 
Only vibration can cause your issue. Bulb filament is loose. Connection somewhere is intermittent, if there's a circuit board involved a solder connection. OP stated only happens when running and the light system is separated from the motor.
I agree with the above statement.. Change the bulb. While you're at it...if it's not an LED bulb then this would be a good time to convert to LED.

The headlight bulb on my bike was an incandescent bulb when I bought the fixture. My lipo battery would last about 45 minutes or so on this bulb. I switched to an LED bulb and now the lipo battery lasts for 4+ hours. It's super bright too.
I did have to change the bulb socket to make the switch but it's an easy project to do.
 
A) Where would be a good place to start when diagnosing an electrical malfunction like this?
I will almost bet it is the spark plug...These bike kits come with non resistor crappy "Chinesium" Chinese made spark plugs...I usually urge everyone to just chuck em out since they screw up bike computers from giving true speeds and other stats so I wouldn't be too surprised that they might interfer with light sets as well.

Just to eliminate the plug as the culprit, and assuming that your bike is a normal China Girl 2 stroker, replace the plug with an NGK-BR6HS resistor spark plug and see if that elliminates this as a cause of the problem...The R in the alpha-numeric code stands for resistor.

I have seen the prices jump up and down by a few dollars per plug in the last few days, from 4 to 5 bucks a few days ago, to $8.19 cents today.

If you buy it online, you can buy just one, but for the price, I get the 4 pack myself...lol.

Single plug at at $8.19 at the moment.

Or a 4 pack for $14.25 at the moment.
 
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Be careful of clone plugs on Amazon and Ebay, lots of fakes. That might be the problem, I've never heard of an ignition system interfering with light circuits. Doesn't mean it won't.
 
Only vibration can cause your issue. Bulb filament is loose. Connection somewhere is intermittent, if there's a circuit board involved a solder connection. OP stated only happens when running and the light system is separated from the motor.
It isn't a vibration issue as I mentioned. The light remains to be mounted in the same place it always is. Once I change the location of the battery pack either on my cell phone holder or on the handlebars the issue goes away. As I mentioned, the lights on the battery go in and out and the issue is electrical interference to the battery pack.
 
I will almost bet it is the spark plug...These bike kits come with non resistor crappy "Chinesium" Chinese made spark plugs...I usually urge everyone to just chuck em out since they screw up bike computers from giving true speeds and other stats so I wouldn't be too surprised that they might interfer with light sets as well.

Just to eliminate the plug as the culprit, and assuming that your bike is a normal China Girl 2 stroker, replace the plug with an NGK-BR6HS resistor spark plug and see if that elliminates this as a cause of the problem...The R in the alpha-numeric code stands for resistor.

I have seen the prices jump up and down by a few dollars per plug in the last few days, from 4 to 5 bucks a few days ago, to $8.19 cents today.

If you buy it online, you can buy just one, but for the price, I get the 4 pack myself...lol.

Single plug at at $8.19 at the moment.

Or a 4 pack for $14.25 at the moment.
I don't run the stock plugs. I was running the BR6HS and went to a B7HS for the summer time. This actually came to my mind yesterday if I ought to go back to a resistor plug to see if it will work. I'm actually going to go outside and swap out the B7HS for the BR6HS I have, and then if it works, go to a BR7HS.

Almost ten bucks for a plug online? Jeez. I buy the BR6HS for $3 at AAP in my area.
 
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