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Why does light bar flicker/flash?

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So my stock bulb was pretty similar at idle and even at high rpm.it was pretty useless. I decided to hook up a cheap LED light bar and it is much brighter. The only issue is that when the bike is idling at low rpm the LED flickers but as soon as a little bit of throttle is applied it smooths out.

Why it is flickering and how do I fix it?

Is it because the stator isn't high enough wattage or it doesn't have many coil or could it be a bad regulator and capacitor?

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What sort of bike is it? Are you sure it has a regulator and capacitor?

If it's like mine, a kickstart only model with no battery then you'll find there is no regulator/rectifier. The power is AC and the voltage is highly variable, which means the lights dim when the revs are low because there is no storage in the system to even things out.

LED lights only emit light with current in one direction. When they are fed an alternating current they still work, but only 50% of the time. Most of the time this flickering is quick enough that the human eye cannot pick it up (while your cat is thinking "I'm going to have a seizure").  When the revs drop the flickering becomes visible to you, the volts have dropped and the lights dim. The bad news is that if you are running LEDs on an AC system it will eventually kill them. 

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Not limited to kick start only bikes,

most bikes that do have a battery / E-start run the headlight in AC current and

the rest of the accessories (starter, taillight, turn signals, horn etc.) in DC current.

Edited by mlatour

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46 minutes ago, mlatour said:

Not limited to kick start only bikes,

most bikes that do have a battery / E-start run the headlight in AC current and

the rest of the accessories (starter, taillight, turn signals, horn etc.) in DC current.

 

59 minutes ago, DirtShow said:

What sort of bike is it? Are you sure it has a regulator and capacitor?

If it's like mine, a kickstart only model with no battery then you'll find there is no regulator/rectifier. The power is AC and the voltage is highly variable, which means the lights dim when the revs are low because there is no storage in the system to even things out.

LED lights only emit light with current in one direction. When they are fed an alternating current they still work, but only 50% of the time. Most of the time this flickering is quick enough that the human eye cannot pick it up (while your cat is thinking "I'm going to have a seizure").  When the revs drop the flickering becomes visible to you, the volts have dropped and the lights dim. The bad news is that if you are running LEDs on an AC system it will eventually kill them. 

I believe it is DC as there is a black capacitor hooked up to a unit which I believe is a regulator/rectifier combo although I am not certain. What is the best way to test if the current is AC or DC?

The bike is a 1990 xr250r but hardly anything is stock as there have been many previous owners. It is also quite possible that the wiring harness is from an xr250l.

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The wiring harness microfiche for the 1990 XR250R shows an AC regulator but no 'rectifier'.

Same as my CRF250X, the headlight bulb is listed as a common 12V / 55W unit but it runs on AC current.

Edited by mlatour
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17 minutes ago, eaglesomme said:

 

I believe it is DC as there is a black capacitor hooked up to a unit which I believe is a regulator/rectifier combo although I am not certain. What is the best way to test if the current is AC or DC?

The bike is a 1990 xr250r but hardly anything is stock as there have been many previous owners. It is also quite possible that the wiring harness is from an xr250l.

A frankenbike with unknowns! That makes things a bit more complicated. 

Maybe this also will be useful to you: 1991-1996 XR205L wiring diagram.  

https://4strokes.com/download/file.php?id=1458&mode=view

https://4strokes.com/download/file.php?id=1459&mode=view

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6 minutes ago, mlatour said:

The wiring harness microfiche for the 1990 XR250R shows an AC regulator but no 'rectifier'.

Same as my CRF250X, the headlight bulb is listed as a common 12V / 55W unit but it runs on AC current.

I.found another wiring diagram and it listed the regulator as a rectifier. Also a while back someone said that there is a difference between the European and American import xr250 wiring.

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I think you could put a multimeter on the headlight wires in Volts, AC, and set range to auto, there should be something believable if it's AC. If it's DC you'll probably just get 0. Then test again in DC mode and if you get something believable then it's DC. 

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