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source coil for 1980 dt175


Bub
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Has any one found a place to buy the sator coil for 1980 dt 175cc bike how many years had this type coil ive been trying to get this bike ready to ride for 4 years and the cycle shop said they couldnt get the parts ive had it back home for one day and already found cdi box im going to replace it first and see if it will fire and if it doesnt ill try and find the sator coil. Thanks

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Two questions

Have you measured it with a multimeter?

How many wires does the CDI have?

I made a step by step test for these

DT175MX Ignition checks

There were two versions of ignition systems on DT175MX bikes. The mk1 version from the earlier bike had a 7 wire CDI the early bikes had a round section swing arm.

The mk2 version had a 6 wire CDI, the red wire is absent on these. These bikes have a square section swing arm.

The HT cap (AKA spark plug cap)

unscrew it off the HT lead, it is supposed to be a resistor cap so should be around 5K Ohms

The ignition coil primary...Orange wire to battery neg should be 1 Ohm +- 10%

The ignition coil secondary...HT lead to battery neg should be 5900 Ohms +- 20%

If the readings are much higher, check the ignition coil has a clean ground connection.

Yes and the ignition coil mounting is a wiring harness ground point too, so check its clean and bright there.

Disconnect all the wires from the CDI.

Then using your multimeter on the loom side of the connectors.

Black probe on a clean part of HT coil ground point

Red probe on......

Orange, Meter to 200 Ohms, expect 1 Ohm (HT coil primary)

Brown, Meter to 2k Ohms, expect 420 Ohms for mk1 and 300 Ohms for mk2 (Magneto charge coil)

White/Red, Meter to 200 Ohms, expect 12.4 Ohms for mk1 and 10 Ohms for mk2 (Magneto pulser coil)

Red, Meter to 200 Ohms, expect 13.6 Ohms for mk1 only. (Source coil 2 or high speed coil)

Black female connector, Meter to 200 Ohms, expect dead short

repeat for black male connector

Any difference in the results for the two black wires may possibly be rectified by cleaning the front engine mounting bolt and a little of the frame behind the bolt head, then tighten to torque spec.

Black/White, Meter to 20K Ohms, with ignition off expect dead short, with key on expect open circuit, with kill operated expect dead short (Engine kill operation)

If all these tests are good you would be well advised to try another CDI.

If they are not good...reading higher...disconnect and clean any plugs/sockets you find along the way, if the magneto coils are reading lower, new ones needed if more than 10%...or so the book says

Now...how about an intro in the noobs section, where are you...UK?...Paul

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we can test the cdi unit. We have a full test rig to run the unit off bike. The source coil is easily tested with a multimeter.

Rex's Speed Shop have new built cdi units for most DT/YX/IT/MX 250-465 from the 70's. We'll be looking to include the smaller bikes as well.

Testing is 15.00 and new cdis start at £77.00. Having seen 30 year old DT 400 units on ebay selling for £150 we think you'll agree a new item at £77 with a years warranty is good value!

www.rexs-speedshop.com

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