# wr250f lights

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I've heard that the lights on a wr have to stay on or it will burn up the stator I need to know because I put number plates on my wr and I don't want to burn the stator up. Thanks

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Yes, but it's the regulator which will blow eventually; it's in the same unit as the rectifier.  I smashed my light off on a tree a while ago and just used an aftermarket light with no bulb in.  When I eventually tried to wire the lights it just kept blowing the bulb so needed a new regulator/rectifier.  The headlight bulb runs on 12v AC current straight off the stator, through the regulator.  The rear light runs on the 12v DC circuit and this is ok to disconnect.

Edited by Ooshka

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Yes, all the WR's that have the headlight on permantly (which run directly of the stator on 12AC) are hard on the stator if there is no bulb. The stator has to dump the power generated if it is not used by the bulb, as heat

Best solution is to wire in a resistor in place of the bulb, to take the load and covert the power to heat instead of the stator having to do it

You need approx 4 ohm 35watt (but greater is better as it won't get so hot, so 50W plus would be better) cement resistors and mount it on something metal to dissipate the heat

Watts = Volts X Amps, so 36W / 12V = 3amps, therefore 3amps needs to go through that resistor @ 12V to replicate the 36W of the bulb... so how do you figure out the resistance?

You use the equation electronics revolves around, Ohm's Law.

V = IR,               I = Current (Amps), R = resistance (ohms)

so...

12V = 3A x Resistance

R = 4 (ohms)

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so...what if the light switch is turned off

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1 hour ago, yamahawryz250f said:

so...what if the light switch is turned off

Yes, Yamaha put switches on these bikes for a number of years.

I believe the disappearance of the switch was more of a cost cutting measure than anything else.

I have plenty of 2003 model WRs that run with the light off unless it is dark and the stator and regulator are just fine.

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7 hours ago, GuyGraham said:

Yes, all the WR's that have the headlight on permantly (which run directly of the stator on 12AC) are hard on the stator if there is no bulb. The stator has to dump the power generated if it is not used by the bulb, as heat

Best solution is to wire in a resistor in place of the bulb, to take the load and covert the power to heat instead of the stator having to do it

You need approx 4 ohm 35watt (but greater is better as it won't get so hot, so 50W plus would be better) cement resistors and mount it on something metal to dissipate the heat

Watts = Volts X Amps, so 36W / 12V = 3amps, therefore 3amps needs to go through that resistor @ 12V to replicate the 36W of the bulb... so how do you figure out the resistance?

You use the equation electronics revolves around, Ohm's Law.

V = IR,               I = Current (Amps), R = resistance (ohms)

so...

12V = 3A x Resistance

R = 4 (ohms)

Sorry, but this is not correct.     I think you must mean the regulator not the stator...

Because even in your scenario of the resistor the stator is still going to be putting out a large amount of current.

With no bulb the stator is not working hard but the regulator is as it tries to dump the excess current and keep the

voltage in range.

Resistor would simulate a load, but is a bit of a hack.   Why not just put a bulb back in it...

Also, you don't need to simulate a full load...   that just keeps all of the components working hard at their limit.

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13 hours ago, Ooshka said:

The rear light runs on the 12v DC circuit and this is ok to disconnect.

Depends on the year of the bike...    For the newer ones with the LED tail light this is correct.

However on the older bikes (steel frame) the tail light is an ordinary 1157 bulb and runs off the same 12VAC

We don't know the year of the OP's bike...

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2 hours ago, DeepPurplishBlue said:

Sorry, but this is not correct.     I think you must mean the regulator not the stator...

Because even in your scenario of the resistor the stator is still going to be putting out a large amount of current.

With no bulb the stator is not working hard but the regulator is as it tries to dump the excess current and keep the

voltage in range.

Resistor would simulate a load, but is a bit of a hack.   Why not just put a bulb back in it...

Also, you don't need to simulate a full load...   that just keeps all of the components working hard at their limit.

No problem if thats what you believe. Good luck.

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2 minutes ago, GuyGraham said:

No problem if thats what you believe. Good luck.

It isn't just "what I believe" it is fact.

What do you think is producing the power your resistor is dissipating?     Your argument is it relieves the stator of stress when in fact it keeps it under stress.

What tends to fail is the regulator and it may or may not be because of no light bulb.

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my bike is a 2003. And I cannot find a replacement.im thinking about putting an it250 light on

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14 minutes ago, yamahawryz250f said:

my bike is a 2003. And I cannot find a replacement.im thinking about putting an it250 light on

2003 WR250F came from Yamaha with a headlight switch...     so apparently they thought it was OK to leave the light turned off

Does the bike still have the tail light?

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No I removed the tail light too do you have any thoughts on what others headlights will go on from different Yamaha models