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DT175 mx CDI


taffny
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Hi all,

I wonder if anyone can help with the problem of which CDI I need for my bike. Unfortunately the bike is a non runner and came without one, and as I gather there are more than one type, I thought I had better check before I splash out.

My engine is 1979 but the magneto has only 5 wires coming from it, and only one source coil (contrary to what the parts book says I should have) which makes wonder if I have a magneto from a different year, I don't know if this will be a problem or whether I just need to match the CDI to it.

Does anyone know anything about this.

Any help is appreciated.

Regards,

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5 wires doesn't sound enough, from what I've read there should be either 5 or 6, read this Here

You've pulled it out of the bag again oldgitonabike!!!!!! The single source coil that I have needs a 6 wire CDI. I had read that post a little while ago, but had forgotten about it.

My next problem will be where my missing wire from the magneto has gone. I will get hold of a manual with a wiring diagram in it, which should help.(i bought the wrong one by mistake).

Anyway thanks again for you input as it has clarified another issue.

Kind regards,

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You've pulled it out of the bag again oldgitonabike!!!!!! The single source coil that I have needs a 6 wire CDI. I had read that post a little while ago, but had forgotten about it.

My next problem will be where my missing wire from the magneto has gone. I will get hold of a manual with a wiring diagram in it, which should help.(i bought the wrong one by mistake).

Anyway thanks again for you input as it has clarified another issue.

Kind regards,

Here is the 6 wire CDI and Magneto

DT1751980CDI.jpg

And here is the 7 wire CDI

DT175MX1979CDI.jpg

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  • 3 months later...

Hi all,

I wonder if anyone can help with the problem of which CDI I need for my bike. Unfortunately the bike is a non runner and came without one, and as I gather there are more than one type, I thought I had better check before I splash out.

My engine is 1979 but the magneto has only 5 wires coming from it, and only one source coil (contrary to what the parts book says I should have) which makes wonder if I have a magneto from a different year, I don't know if this will be a problem or whether I just need to match the CDI to it.

Does anyone know anything about this.

Any help is appreciated.

Regards,

I have had a similar problem, finally figured it out with help from Haynes 100,125, & 175 trail bikes manual. The dt manual doesnt mention it but the DT 125 and 175 G, H us models have a 5 wire magneto (or stator) that goes to a 6 wire cdi unit. I had the 5 wire magneto and a 7 wire cdi, WTF that was confusing me for more than a year. Of course I had given up and left it alone for months at a time.

Does anyone know where I can get a 6 wire cdi????

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....My engine is 1979 but the magneto has only 5 wires coming from it, and only one source coil (contrary to what the parts book says I should have) which makes wonder if I have a magneto from a different year, I don't know if this will be a problem or whether I just need to match the CDI to it.

Does anyone know anything about this.

Any help is appreciated.

Regards,

The one I brought today has a 5 wire also

wire1.jpg

I have just posted in another thread to see if someone can help me out with the wiring.

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The one I brought today has a 5 wire also

wire1.jpg

I have just posted in another thread to see if someone can help me out with the wiring.

Yes 5 out of the mag and 6 go into the cdi, with the 7 wire version you have an extra red out of the mag going direct to the cdi.

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Yes 5 out of the mag and 6 go into the cdi, with the 7 wire version you have an extra red out of the mag going direct to the cdi.

I do have the 6 wires from the CDI bunched into 2 sets of 3. All I need now is to work out what I need to connect as the wiring is butchered.

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I do have the 6 wires from the CDI bunched into 2 sets of 3. All I need now is to work out what I need to connect as the wiring is butchered.

You need to expand on 'butcherd' but here is a quick discription:

there are 2 systems,

the 2K4(78-79) and 2X2(79only) Dt 175mx had the following:

Brown, red, white/red,black They come direct from the mag.

orange, black/white, black, come out of the loom.

The 4J4 (80-85) Dt175mx and the Dt125mx (4J3) of the same period had the following:

Brown, white/red, black. They are direct from the mag.

Orange, black/white, black, coming from the loom.

All of these bikes have the orange feeding the coil, the black and white kills the engine via the handlebar stop switch and the black is the battery return/negative.

On both bikes there is also green/white, light blue and yellow.

The yellow being the lighting feed to the ig switch, the light blue the neutral light earth and the green and white which turns to white in the loom?? charges the battery via the rectifier.

Some of the 125s had points.

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You need to expand on 'butcherd' but here is a quick discription:

there are 2 systems,

the 2K4(78-79) and 2X2(79only) Dt 175mx had the following:

Brown, red, white/red,black They come direct from the mag.

orange, black/white, black, come out of the loom.

The 4J4 (80-85) Dt175mx and the Dt125mx (4J3) of the same period had the following:

Brown, white/red, black. They are direct from the mag.

Orange, black/white, black, coming from the loom.

All of these bikes have the orange feeding the coil, the black and white kills the engine via the handlebar stop switch and the black is the battery return/negative.

On both bikes there is also green/white, light blue and yellow.

The yellow being the lighting feed to the ig switch, the light blue the neutral light earth and the green and white which turns to white in the loom?? charges the battery via the rectifier.

Some of the 125s had points.

By butchered I mean that the bike has been used off road and no battery no, presumibly a total loss system?

There is no headlight and a lot of the wiring is connected by connector blocks. The frame starts 2k4 (The frame and engine numbers are matching)

As per the picture I have Green, Yellow, Brown, Red/White and Black coming from the Mag. The orange appears to run to the CDI which has 2 sets of 3 wires.

Brown, Black and White/Red

and

Orange, Black/White and Black.

The Orange wire appears to go to the coil which has 1 LV wire.

If I put a 6v tester to the mag and earth and kick over there is power from the mag from the Brown wire. The rest appear not to be producing power but this may be down to a bad connection.

I cant really test for a spark as I need to shhot out to get a spark plug spanner as I don't have one but should I be getting any juice from anything but the brown?

Thanks

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By butchered I mean that the bike has been used off road and no battery no, presumibly a total loss system?

There is no headlight and a lot of the wiring is connected by connector blocks. The frame starts 2k4 (The frame and engine numbers are matching)

As per the picture I have Green, Yellow, Brown, Red/White and Black coming from the Mag. The orange appears to run to the CDI which has 2 sets of 3 wires.

Brown, Black and White/Red

and

Orange, Black/White and Black.

The Orange wire appears to go to the coil which has 1 LV wire.

If I put a 6v tester to the mag and earth and kick over there is power from the mag from the Brown wire. The rest appear not to be producing power but this may be down to a bad connection.

I cant really test for a spark as I need to shhot out to get a spark plug spanner as I don't have one but should I be getting any juice from anything but the brown?

Thanks

In the mag

Ignition pulser coil Wht/Red - Blk = 12.4 Ohms +-10%

Charge coil Brn - Blk = 420 Ohms +-10%

. Red - Blk 13.6 Ohms +- 10%

Orange from CDI to coil LT

You say the bike has been used off road, what means of stopping the engine has been used, maybe theres a switch in the off position, this is done by switching the B/W CDI wiring to chassis.

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In the mag

Ignition pulser coil W/R - B = 12.4 Ohms +-10%

Charge coil Br - B = 420 Ohms +-10%

. R - B 13.6 Ohms +- 10%

Orange from CDI to coil LT

You say the bike has been used off road, what means of stopping the engine has been used, maybe theres a switch in the off position, this is done by switching the B/W CDI wiring to chassis.

Thanks for this.

The kill switch was connected but I have disconnected that. I have cleaned up all of the connections to the CDI (the CDI was not connected when I got it) and earths that I need and with a new plug and it sounds like I have a spark. There is no 2 stroke oil in it or fuel pipe so I will need to get these. I may have to wait until it gets dark and then kick it over with the plug out but earthed to see if I am right about the spark. Thanks for the information so far.

I sent my other half and her kids off to the pictures so I can get some time with the bike. I only brought it yesterday and love it. Non starter and rough as old boots or not.

Cheers but I am sure that I will be asking more questions in the future.

Bad wiring pictures below

wire4.jpg

wire5.jpg

wire6.jpg

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. There is no 2 stroke oil in it or fuel pipe so I will need to get these.

If the two stroke oil tank is completely empty, you will need to bleed the air from the pump after filling it, its also wise to purge the line too to get the oil to the carb, also serves as a means of checking the pump is working correctly

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If the two stroke oil tank is completely empty, you will need to bleed the air from the pump after filling it, its also wise to purge the line too to get the oil to the carb, also serves as a means of checking the pump is working correctly

Oh yes!!

I am keen to start it but need to check everything on the bike first.

Thanks

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Oh yes!!

I am keen to start it but need to check everything on the bike first.

Thanks

One option you have on a PURE dirt bike is to get hold of the flywheel and stator plate from a (78-79) 125mx they use a bigger field coil and points so you would only need ONE wire. From the mag to the coil. Well via a kill switch too i suppose.

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One option you have on a PURE dirt bike is to get hold of the flywheel and stator plate from a (78-79) 125mx they use a bigger field coil and points so you would only need ONE wire. From the mag to the coil. Well via a kill switch too i suppose.

Hi Cynic,

My aim is to put it back on the road as a street legal bike. I have the logbook which shows the reg number. There is no ignition or front lights and no silencer. The tyres are "not for highway use" and no horn, chain guard/tensioner nor clocks. The frame has been drilled about 2 inches back from the hole which holds the front of the shock in the frame. I guess that this was to raise the bike but the original hole is there so that is an easy job. and this is what I know so far looking at it for the first time..

The frame and engine numbers match and there seems to be a good compression.

A nice labour of love but first things first so I will check the spark tonight, get the 2 stroke oil bled through tomorrow and get the tank connected to the carb and see if it runs. Gulp

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, get the 2 stroke oil bled through tomorrow and get the tank connected to the carb and see if it runs. Gulp

If you do get her going, after you have bled the air from the pump by removing the little screw from the top of the pump, then start the bike and while its idling use your hand to turn the pump pulley to maximum, this will pump the oil at full stroke so it will get to the carb quickly... ;)

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Cheers.

I have taken the cover off and there was some 2 stroke oil in the bottom of the case. I have cleaned it all out and made sure that I could undo the bled screw, which was fine. So I will do what you suggested and open the cable manually. I can also check for 2 stroke leaks at the same time. I will kick the bike over a few times with the spark plug out and the throttle fully open to get the 2 stroke as close to the carb as possible. There is no fuel in it so this will also prime the carb for petrol. I can use an old plug in case it floods as I brought a new one today.

That you for the advice.

I have just been out and kicked the bike over. Now that I have cleaned the terminals and earths I got a nice fat spark at the plug. Well happy :lol:

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if your getting spark then put some petrol in 'er and get it going! :D, can't imagine your neighbours will be pleased though considering it has no silencer...

best of luck :)

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if your getting spark then put some petrol in 'er and get it going! :D, can't imagine your neighbours will be pleased though considering it has no silencer...

best of luck :)

That is the plan for later today. The front pipe I have was not connected to the cylinder so not only no silencer, no exhaust at all. I have good neighbours (at least at the moment). Just a quick start.

Thanks

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