Dt Mx Wiring Help

[Airhead]

Me again... , Just given it another test with the Multi Meter and tbh with you I am not entirely sure what settings it should be on, here are my results.

Wire Going In -> Ignition Coil Ground = 0.12 On 200 ohm Scale (It sometimes moves much higher at the start but seems to settle on this number and this is the only setting I can get a reasonable / registering number on)

Ht Coil Wire -> Ignition Coil Ground = 6.20 ish on 20k ohm Scale

What would this suggest?

(I am in the Uk)

0.12 Ohms...that sound like a dead short to ground. I bet you get that reading by holding both meter leads together.

New coil £13 including delivery

Yambits coil for DT175

[GreatWill]

You have persuaded me to carry on with this! I believe my engine is a 2A8 Model and http://www.transmic.net/fichiers/modelcodes_yam.htm would then suggest it is a from '78?

The ebay auction say its fits DT125 1974-1977, Would this still be ok for my model?

[Airhead]

You have persuaded me to carry on with this! I believe my engine is a 2A8 Model and http://www.transmic.net/fichiers/modelcodes_yam.htm would then suggest it is a from '78?

The ebay auction say its fits DT125 1974-1977, Would this still be ok for my model?

Just read it more closely, no it's not for CDI models

This is though and is even cheaper

http://cgi.ebay.co.uk/Yamaha-DT125-DT175-DT250-DT400-New-Ignition-Coil-QC125-/310191454436?cmd=ViewItem&pt=UK_Motorcycle_Parts&hash=item4838d9f8e4

Dont beat me up though if it still dont work, I can only do so so much on a qwerty keyboard,

[GreatWill]

Ok here is a little update: I received the Ignition Coil, but still no spark. I have been out testing the Volts I am getting from each wire and think it might have discovered a problem?

The Black Mag wire (Connected to the black CDI wire) is the only one from the Magneto not producing any voltage.

I hooked up one of the Lighting / Charge wires in its place and its the only time I am getting any volts to or from the Ignition coil. I am getting anything from 0.20 volts to 4 volts coming out the HT Lead. (set on 20)

Does this mean anything at all?

Thanks

[Airhead]

The Black Mag wire (Connected to the black CDI wire) is the only one from the Magneto not producing any voltage.

I hooked up one of the Lighting / Charge wires in its place and its the only time I am getting any volts to or from the Ignition coil. I am getting anything from 0.20 volts to 4 volts coming out the HT Lead. (set on 20)

Does this mean anything at all?

Thanks

You wont see any voltage on the black wire, this is because the black wire is connected to the backplate and so is grounded. Remember I marked it on your picture in post #6

You must understand that there is no way of checking the CDI function and so what you have to do is check everything else and when happy...replace the CDI.

We havent checked everything yet though.

you need to connect the black back up to the CDI

did you ground the ignition coil mounting to the common ground?

Wired like this?

[GreatWill]

Every thing minus the Switch is identical to your drawing. Still no spark.

[Airhead]

Every thing minus the Switch is identical to your drawing. Still no spark.

Check the resistance of the magneto stator coils

Pulser white/red to black = 12.4 Ohm +- 10%

Source coil, Brown to black = 420 Ohm +- 10%

[GreatWill]

The plot thickens (Or gets clearer ) I don't seem to be getting any resistance between both of the two you told me to check.

Let me just check I was doing it right: The end of the Black wire coming out of the Mag and the end of the Brown wire coming out of the Mag with the Multimeter ends on each. And the same with the White / Red and Black? That seems a bit confusing to explain, but I think I am checking correctly.

[Airhead]

The plot thickens (Or gets clearer ) I don't seem to be getting any resistance between both of the two you told me to check.

Let me just check I was doing it right: The end of the Black wire coming out of the Mag and the end of the Brown wire coming out of the Mag with the Multimeter ends on each. And the same with the White / Red and Black? That seems a bit confusing to explain, but I think I am checking correctly.

Yes you are checking correctly. The black wire is connected to the baseplate so double check now from the two coloured wires to a clean part of an engine screw, and from the black wire to an engine screw (this should be a dead short obviously)

[GreatWill]

Brown & Red / White to an engine screw are still resulting in nothing.

Black to an engine screw is resulting in a settled result around 0.2 ohms, but moving it around on the engine screw constantly creates a bigger changing resistance.

[Airhead]

Right you need to clarify something you said.

"The plot thickens (Or gets clearer ) I don't seem to be getting any resistance between both of the two you told me to check."

Does this mean you are seeing a dead short just like holding the two test probes together.......or.....does it mean you are not seeing any value of resistance, just like holding the probes in thin air??

That comment of yours can be taken either way..try to be clearer, like open circuit or short circuit

[GreatWill]

Sorry I am not very good at electrics (No surprise there)

It is like holding the two probes in the air, so that would be no values of resistance from the two coloured.

The black is a dead short, like holding the two probes together.

[Airhead]

Sorry I am not very good at electrics (No surprise there)

It is like holding the two probes in the air, so that would be no values of resistance from the two coloured.

The black is a dead short, like holding the two probes together.

right now make sure that you are not on the 200 Ohm range when you do the brown wire, you are expecting 430 Ohms here so you need to be on the 2K Ohm range. 200 Ohm range is fine for the red/white one though. At least we know the black is properly grounded.

check again

[GreatWill]

Checked them again on the settings you said am I am getting the same results, both are still showing no values of resistance.

[Airhead]

Checked them again on the settings you said am I am getting the same results, both are still showing no values of resistance.

ok you get to remove the rotor and stator again, you need to make sure that the coils are grounded at one side properly and connected securely to their respective coloured wire.

[GreatWill]

I have looked at all the coils and unscrewed them to check, they appear to all be grounded onto the metal ok. Its hard to see clearly if all the wires are securely connected due to the covers on them and how they join but I can't see any problems.

There is a small hole in the tape that covers the Source Coil and I can see some of the wire, I assume that wouldn't cause any real problems?

[Airhead]

Dont assume anything!

If the coil has been bashed with something sharp it will cut the insulation cover and possibly the winding too.

My main concern is the pulse coil as thay are expensive and very hard to come by. The other one is available as a non yamaha replacement at a good price.

I want you to be very careful, examine each coil you will see how one side is grounded under a mounting screw. if needs must you will have to remove the coils to check this tab is attached to a ciol winding. The trouble is if someone wasnt careful and omitted the washer that sits under the screw...then this tab could twist as the screw was tightened and snap free of the winding.

[GreatWill]

I would be surprised if they had got damaged over the years of storage, as they would have been protected by the flywheel.

I have carefully unscrewed the screws, the washers are present and the windings are attached. Thought I would take a picture as well just to demonstrate the general condition:

[Airhead]

I would be surprised if they had got damaged over the years of storage, as they would have been protected by the flywheel.

I have carefully unscrewed the screws, the washers are present and the windings are attached. Thought I would take a picture as well just to demonstrate the general condition:

Now thats a good picture, far better than the earlier ones.

Tell me...that wire on the pulse coil...it looks like it's under the screw??

[Airhead]

Come to think of it, Is that a bloody huge hole in the pulse coil (bottom in the picture)?