Why doesn't this work?

[Caravan Monster]

Can anyone tell me why this wiring loom swap doesn't work ?

My '06 EC300 came with a badly damaged wiring loom. I seperated the ignition wiring and put on a seperate kill switch. The ignition wiring works fine.

I have a virtually unused lighting kit from a MX conversion that was fitted to my TM 125. It is a simple kit for hi/lo headlight, tail/brake light, horn and output from a rectifier that can power a trailtech speedo. I fitted this kit to my EC300, but the headlight output is low, the trailtech backlight works intermitently and flickers and the brake light is on all the time, only going off when the brake switch is operated.

The power for the lighting kit came from the yellow and black wires (from the coils at 3 and 6 o'clock in the picture) and it worked fine

I assumed it would work plugging the loom into the yellow and white wires (coils at 12 and 2 o'clock) on the Gas Gas (picture below), with the resulting malfunctions described above. Is there a difference between how the lighting coils work that could cause this problem ?

 

[wence]

There is a huge thread on lighting and related issues but I do remember people hooking up lighting looms to the white and yellow and not getting good results. Something about the phases or something.
Try the floating ground mod on the stator and then run off of the yellow wire.
If you run the yellow wire into a rec/reg and then to the horn, brakelights etc you may have better results.
The brake light problem sounds like either it is wired wrongly or the switch is wrong.
Good luck,
Mark

 

[GMP]

White wire IS NOT ground on a 2K-3 stator, thats your problem. White is another winding output out of phase with Yellow. Is there a black wire? The rectifier you mention is a half wave device with a common gnd, correct? This should work but is not neccessary for lighting, horn yes.

 

[Caravan Monster]

Thanks for the input. I'll try grounding to the chassis the wire that I had previously connected to the white wire.

@GMP the rectifier I mentioned is the same as the standard GG item that fixes to the headlight surround and only powers the horn. I was incorrect in asserting that it also powers the trailtech speedo - the wire for that comes off the input, not DC output for the rectifier.

On the TM stator (upper picture), would the black wire at 6 o'clock behave as a ground ?

 

[Caravan Monster]

I grounded the lighting loom wire to the chassis and fired the bike up. The horn works great. The standard headlight (12v 35W hi / 35W lo) gave really strong light for a few seconds and then blew ( hi, then switched to lo which also blew).

Do I need a voltage regulator to stop the bulbs blowing ? There doesn't appear to be one on the standard lighting loom.

I'll re- read some of the threads on this subject and hopefully improve my understanding.

 

[Neil E.]

Bulbs blowing is an indication of over voltage. The rectifier for the horn only changes your AC to DC (and likely only halfwave at that).

If you look at a standard rectifier/regulator the case will usually have some finning on it. That finning sheds the heat produced when the regulator clamps peak voltage.

It's like the zener diode on old british bikes. They were mounted in a big finned heatsink that is out in the airflow. You've probably seen them under the fork crown on a BSA. The excess electrical energy is converted to heat which has to be disspated.

You definitely need to add voltage regulation. A TrailTech unit would work well, but any combination reg/rect (single phase) should do.

 

[Caravan Monster]

You definitely need to add voltage regulation.

Absolutely correct. Happily I found the OEM voltage regulator amongst the box of broken cr@p I took off the bike when I first purchased it (didn't understand what it was for at the time). Everything works great now, even the trailtech speedo