Headlight bulb keeps blowing please help me its expensive :(

[dudejb46]

hi guys i have now bought a yamaha dtr 125 1998

https://sphotos.ak.fbcdn.net/hphotos-ak-snc3/hs358.snc3/29524_1486489407391_1388581737_1279488_7666709_n.jpg

now to my anger it keeps blowing bulbs i am using this bulb

https://www.hq-auto-lighting.co.uk/images/H4--HQ-Xenon-Bulbs.jpg

and everytime i ride the bike from idle as the revs get higher it dims more and more and then at around 10 000 rpm it goes pop litterly cracks sometimes other times just the filament goes.

i did have the origianl bulbs in but it went and im unsure weather this was wear and tear as it came with the bike or if it was the same problem.

now i have no clue what it is weather its in the loom or battery is wrong :S

another thing to bear in mind when diagnosing it not sure if its related but when the headlight is on and working if i apply brake or indicators it dims for the brake and flashes with the idicators.

if anyone can solve this you will be saving me so much money ill be so so happy please please help
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2002 zip 2002 bandit project 2004 fzs1000 2009 883r

[Paxovasa]

A wiring fault, possible earth problem.
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Suzuki GSF600 K3 (in the fastest colour, black).

[dudejb46]

[doggone]

Probably some wires rubbing through insulation and brushing against the frame.
Under the seat, and round the headstock likely problem areas.

[dudejb46]

[Vincent]

As above or your reg/rec has gone. You'll need to measure the voltage at the battery when revving the bike. If the regulator has gone it might reach 9-12Volts, (I take it the bike is 6 Volt?). Check that the headlamp is still rubber mounted, vibration can murder bulbs too.

[dudejb46]

[Kickstart]

Hi

Another vote for a bad earth. Don't forget the obvious and check the connection to the battery.

All the best

Keith
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Traxpics, track day and racing photographs - Bimota Forum - Bike performance / thrust graphs for choosing gearing

[dudejb46]

[Vincent]

[27cows]

[Raffles]

[Pete.]

[Robby]

Is the black wire earth on Yamahas? On my bike the earth is green, and the black is positive. Mine has a spare black wire in the headlight shell that doesn't attach to anything, and isn't meant to going by the wiring diagram.

[Raffles]

A H4 bulb requires 3 wires to function correctly. If yours has only 2 connected to it then you will encounter problems. The missing wire is almost certainly the earth ground wire.
The symptoms that you describe are typical of an appliance trying to find an alternative path back to earth.
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A good loser will always be a loser.

[dudejb46]

this is helping me alot im getting ready to go out and get another bulb for another attempt.

so the reoccouring idea is this earth and one the should be sorted, how and were should i attach it to earth it properly?

thank you
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2002 zip 2002 bandit project 2004 fzs1000 2009 883r

[Raffles]

Something has just occured to me. Is the headlight unit OE or aftermarket?
If the original lighting was non-dippable then there will be only 2 wires entering the unit but just 1 of the beams will function. The other beam will not work at all. This may explain the redundant dangling wire and will negate most of what I posted earlier.
____________________
A good loser will always be a loser.

[dudejb46]

[27cows]

DO NOT use the lights until the dangling black wire is connected. There should be a connector nearby for it to plug into. Or at least a black wire missing its connector etc. It's possible you may have to bodge that black wire into the system. But without it connected, the h/l bulbs will blow every time the revs rise.
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The RXS100: vehicle of choice for Chuck Norris

[Pete.]

I still don't understand. With the bulb earth disconnected, using main beam nothing should happen except the main beam warning light would show as there's no return-path after that, and using dip would put +12v(ish) across the dip, main and main beam warning light filaments in series so they would all show dimly.

Why does it dim as revs rise, and why would it blow the bulb with the earth off? There's something else going on IMO.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[dudejb46]

[finpos]

I'd tend to agree with what Pete says, all is not as it seems. You really need to trace the two wires that are connected to the headlight socket all the way back to wherever they are coming from.

f.

[27cows]

[Pete.]

There are only three things that I can think of that will cause a bulb to blow prematurely:

1. Vibration
2. Over-volting
3. Intermittant connection.

Vibration is common on small bike headlights - the vibrations cause the filaments to shake until they fail.

Over-volting is almost always caused by a failed reg/rectifier. Most all other failiures of the charging system cause low-voltage. On small bikes a duff battery can cause it too.

An intermittant connection causing the filament to heat up & cool many times will shorten it's lifespan.
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a.k.a 'Geri'

132.9mph off and walked away. Gear is good, gear is good, gear is very very good

[delvey91]

One thing to note is that the Headlight on a DT 125 runs straight off the stator
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