DT 125/175 Electrical Problems

[JacobHendry]

Hi guys, I'm still working on sorting out this tail light dimming problem when the indicators are on. Had an inspirational thought and bought a LED bulb for the tail light thinking that it would take so little power that sould solve the problem. It didn't ! Now, being aware that electrics are not a strong point of mine, I've been thinking about the regulator. I know, but it's better than counting sheep to go to sleep! Could the regulator be the problem? If it's not working properly and when the lights and indicators are on it's not sending the correct amount of power back to the battery because it's fluctuating, then there wont be enough battery power to have both items on at once. Does that seem plausible? Have I explained my thoughts properly? Any comments much appreciated as this really does my head in.

Thanks

Paul

[Airhead]

The regulator is only for the headlamp bulb so forget that one

I suggest

1: will the battery operate the horn without the motor running...ie is it a good battery?

2: without engine running, turn key to operate tail light, take a measurement across the battery terminals and note the reading

3: take a measurement of the voltage at the blue wire bullet connector that feeds the tail lamp to battery negative (whilst still plugged in and light on)

report back with readings

[Cynic]

Hi guys, I'm still working on sorting out this tail light dimming problem when the indicators are on. Had an inspirational thought and bought a LED bulb for the tail light thinking that it would take so little power that sould solve the problem. It didn't ! Now, being aware that electrics are not a strong point of mine, I've been thinking about the regulator. I know, but it's better than counting sheep to go to sleep! Could the regulator be the problem? If it's not working properly and when the lights and indicators are on it's not sending the correct amount of power back to the battery because it's fluctuating, then there wont be enough battery power to have both items on at once. Does that seem plausible? Have I explained my thoughts properly? Any comments much appreciated as this really does my head in.

Thanks

Paul

Personally, it think your chasing gosts. The tail/brake light will always dim when the indicators are on as the indicators take such a lot of power relative to the rest of the electrics.

I have had 3 different bikes with 6 volt electrics and indicators and in all cases at low rpm or high load like brake lights/lights on etc they were shite.

The best reccomendation i could make is track down a 6v electronic signal relay as the heating element in the std signal unit is a massive drain on the system, far more than the actuall lamps.

[Airhead]

The best reccomendation i could make is track down a 6v electronic signal relay as the heating element in the std signal unit is a massive drain on the system, far more than the actuall lamps.

Thats a good idea, you mean a more modern solid state device for a 6v indicator?

[Cynic]

Thats a good idea, you mean a more modern solid state device for a 6v indicator?

Yep, surely something like the led indicator relays with an electronic timer inside will take a tiny amount of power over the stock thermal unit.

[Airhead]

Yep, surely something like the led indicator relays with an electronic timer inside will take a tiny amount of power over the stock thermal unit.

I was heading down the road of trying to sort this from what is standard, ie it could be that there is a fault and that the degree of flashing of the tail light is unacceptable even taking into account the drain a standard relay introduces. I still think this is a sensible investigation at this stage.

However I do like the suggestion of introducing a flasher relay with much less draw from the battery, an electronic one rather than a bi-metal strip with heat coil. I have found this, purpose built and not an led version...what do you think?

http://www.autoelectricsupplies.co.uk/product/710

[Cynic]

I was heading down the road of trying to sort this from what is standard, ie it could be that there is a fault and that the degree of flashing of the tail light is unacceptable even taking into account the drain a standard relay introduces. I still think this is a sensible investigation at this stage.

However I do like the suggestion of introducing a flasher relay with much less draw from the battery, an electronic one rather than a bi-metal strip with heat coil. I have found this, purpose built and not an led version...what do you think?

http://www.autoelectricsupplies.co.uk/product/710

Thats the kind of thing i was thinking of, whats in there, a 555 timer and a little 40w relay.

Just as a curiosity OG, is it worth a current check on a stock relay to see what it draws.

[Airhead]

Thats the kind of thing i was thinking of, whats in there, a 555 timer and a little 40w relay.

Just as a curiosity OG, is it worth a current check on a stock relay to see what it draws.

I could do a current check if I can find my flashers and a relay...as you know mine havent been titted for a long long time, but i DO still have the mounts on the frame

I think i'll buy one of those relays and re-fit mine now, then do the test with each

[Cynic]

i DO still have the mounts on the frame

Cheeky,

[JacobHendry]

The regulator is only for the headlamp bulb so forget that one

I suggest

1: will the battery operate the horn without the motor running...ie is it a good battery?

2: without engine running, turn key to operate tail light, take a measurement across the battery terminals and note the reading

3: take a measurement of the voltage at the blue wire bullet connector that feeds the tail lamp to battery negative (whilst still plugged in and light on)

report back with readings

Battery is relatively new, back in April/May and I did charge it last week.

Took readings

1/Horn not very happy sounding without the engine running

2/ With ignition key in lights position I get 5.28 Volts across the battery

3/ Across the blue wire and battery negative I get 4.48 Volts

I did have a look last week at an electronic relay wondering if it would make a big enough difference to stop this dimming. I've had other bikes in the past and yes the lights have always been pretty shit but I've never had anything like this where it's such an obvious dimming, the tail light disappears to almost nothing then lights back up during the other part of the indicator cycle.

Thanks for all your help guys, I'm sure there is a solution out there!

[Cynic]

Thanks for all your help guys, I'm sure there is a solution out there!

I think mine is the neatest.

Remove the whole sorry shebang and bin it.

In my case, the frame brackets too. I was either smashing em up in the dirt or kicking them to death when i got on the bike.

[Airhead]

Battery is relatively new, back in April/May and I did charge it last week.

Took readings

1/Horn not very happy sounding without the engine running

2/ With ignition key in lights position I get 5.28 Volts across the battery

3/ Across the blue wire and battery negative I get 4.48 Volts

I did have a look last week at an electronic relay wondering if it would make a big enough difference to stop this dimming. I've had other bikes in the past and yes the lights have always been pretty shit but I've never had anything like this where it's such an obvious dimming, the tail light disappears to almost nothing then lights back up during the other part of the indicator cycle.

Thanks for all your help guys, I'm sure there is a solution out there!

I'm sure we can improve greatly on this too, in a perfect world the two readings should be the same so you are losing a hefty 0.8 volts through loose or dirty connections.

[Airhead]

do all tests in the same way, ie engine stopped...lights on...test across battery and note voltage then negative on battery to test points.

now start to compare readings further back up the loom like the blue/red out of the ignition switch by the way that blue changes to blu/red in the main loom, you will see that at the 3 way connector (under the seat?)

You may find the culprit is the ignition switch itself due to a dirty contact, especially if it is an old or original one.

[Airhead]

If you do suspect the ig switch try unplugging the connector from it that houses the blue/red wire. Then on the loom side of the connector short out red - brown - blu/red

this will effectively bypass the ig switch as if it is in position 2

[JacobHendry]

Hi again guys, back with more questions! Decided that I would strip back the loom a few days ago to see if I could shed any more light on the problem I’ve been having. Not a pretty sight. Been repaired and changed a lot! One thing that has been changed is that there are now two separate earth circuits within this loom. One starting from the regulator and the other starting from the battery, and at no point do they meet within the loom, therefore first thing is to rectify that then check out the Blue/Red which has been altered, chopped and joined somewhat.

Having studied the wiring diagram and photos of a new loom on eBay would I be right in saying that the black from the loom attaches to the regulator and then a cable from the regulator goes to the battery negative. Does that sound right to other DT owners?

Thanks

Paul

[Cynic]

Hi again guys, back with more questions! Decided that I would strip back the loom a few days ago to see if I could shed any more light on the problem I’ve been having. Not a pretty sight. Been repaired and changed a lot! One thing that has been changed is that there are now two separate earth circuits within this loom. One starting from the regulator and the other starting from the battery, and at no point do they meet within the loom, therefore first thing is to rectify that then check out the Blue/Red which has been altered, chopped and joined somewhat.

Having studied the wiring diagram and photos of a new loom on eBay would I be right in saying that the black from the loom attaches to the regulator and then a cable from the regulator goes to the battery negative. Does that sound right to other DT owners?

Thanks

Paul

All the neg from the battery needs to do is connect to the frame, with maybe a flylead onto the motor to ensure good ig etc. The regulator, by this i'm thinking you mean the silver matchbox sized ally block above the rear brake light switch earth's to the frame.

If on the other hand you are talking about earths from the flywheel generator then they are separate as some of them are to do with the ig system.

[Airhead]

All the neg from the battery needs to do is connect to the frame, with maybe a flylead onto the motor to ensure good ig etc. The regulator, by this i'm thinking you mean the silver matchbox sized ally block above the rear brake light switch earth's to the frame.If on the other hand you are talking about earths from the flywheel generator then they are separate as some of them are to do with the ig system.

Dont forget there are two versions Jason, the early bike has the regulator on a bracket attached to the plastic airbox assy, therefore it has a black lead behind a mounting screw and then into a loom socket.

Paul...make sure you are looking at the correct wiring diagram if yours is a later bike with square swing arm, one of the haynes manuals doesnt have a diagram for these later models

[Cynic]

Dont forget there are two versions Jason, the early bike has the regulator on a bracket attached to the plastic airbox assy, therefore it has a black lead behind a mounting screw and then into a loom socket.Paul...make sure you are looking at the correct wiring diagram if yours is a later bike with square swing arm, one of the haynes manuals doesnt have a diagram for these later models

Hmmm, that how yours is set up Paul? TBH i thought yours was on the frame too.

[Airhead]

Hmmm, that how yours is set up Paul? ......

Yes mate, thats how mine is and all the early bikes.

[Cynic]

Yes mate, thats how mine is and all the early bikes.

Obviously caused problems then if it only lated 12 months or so.