Trac to Tomos Wiring help

I need some help with some wiring that is driving me crazy. I have a 84 Trac Hawk that has an A35 2-wire CDI motor/stator on it. I cant seem to figure out how to wire this thing up.

Here is the Trac wiring

https://myronsmopeds.com/wp-content/uploads/2008/08/Trac-Clipper-Eagle-Hawk-1982-1984.jpg

and Tomos

https://myronsmopeds.com/wp-content/uploads/2008/04/Tomos-Wiring-1993-97-Sprint-100dpi.jpg

Currently I have the black running from the stator to the cdi and also black connector on trac wiring harness. Yellow to yellow, and grounded the black/blue wire to the cdi ground and grounded it all to the frame. I cant seem to get any spark and I have tried a few other combos of hooking up wires because why not.

I did fully take apart the stator and cleaned it because it was pretty rusty/corroded when I got it so not ruling a bad stator. The yellow does get about 7 VAC on the kick start but black and spark cable has nothing. CDI box is new.

Re: Trac to Tomos Wiring help

I think you've grounded the ignition. The ignition side is pretty simple, the lighting side will require a little more work.

Re: Trac to Tomos Wiring help

Don't just wire stuff up randomly. Buzz it out with a multimeter and connect it correctly.

Re: Trac to Tomos Wiring help

Make sure the other side of the ignition coil is grounded, that ensures you get power to the black wire.

Re: Trac to Tomos Wiring help

John Sharvin /

Tried out that wiring scheme with no luck, took the stator apart again and started there. First cleaned all the connections with electrical cleaner and 1000 grit sandpaper. Checked solder connections. Tested Ohms of ignition coil on stator (87ohms). Not sure how to test the connections with a multimeter, should the black have continuity? or resistance? All the wiring diagrams dont really have ohm readings on there nor what should read what so I am kinda at a loss of how to test the connections, plus I know DC power a lot better than AC.

PXL_20210511_172605822.jpg

Re: Trac to Tomos Wiring help

John Sharvin /

Ignition/CDI box is grounded (brown), red to the blacks, yellow to yellow (also really not too concerned about the lights right now, I can work on those later). I feel like im missing something super obvious but really just cant figure it out.

Edit:

I should also state that before I started this build the original bike would turn over and "run" (at like 5 mph) (edited)

Re: Trac to Tomos Wiring help

That looks correct as long as the kill switch isn't shorted, you could disconnect that lead that goes to the harness so the magneto is just connected directly to the coil.

Re: Trac to Tomos Wiring help

Wires should show continuity. Continuity is really just low resistance; if you measure it you'll find something like <1Ω.

Which CDI / ignition box is that? It doesn't match either diagram. Obviously the HT coil from the original Trac wiring won't work with a CDI stator.

My recommendation is to unplug everything except for the ignition circuit to start. As others have said, one end of the ignition coil goes to the frame "ground", one goes to the CDI box. Verify that the "grounded" side of the ignition coil has a low resistance path to the CDI box "ground." Aside from the spark plug wire that's all you need, electrically.

Re: Trac to Tomos Wiring help

John Sharvin /

its the after market CDI from Dos Cycles for this stator. I am not getting continuity from internal ignition coil to the ground side of the CDI. So I am guessing I need a new internal ignition coil?

Heres a picture of what I tested to make sure I tested the correct thing. (also I know that the coils are "upside down" I was trying it both ways just for shits because nothing has been working). I also tested continuity between the two wires of the CDI and go no continuity so not sure if I got sent a dud or if that is correct?

PXL_20210512_011731643_2.jpg

Re: Trac to Tomos Wiring help

♣Slew Foot♣ /

The result can't be definite if Theres a Hall effect sensor.

The box was paired to the stator?

Easiest way is to bare bones wire it and ground strap frame disconnect kill.

If you need to mechanically set the base timing use an audio signal it will waiver when it is firing.

Re: Trac to Tomos Wiring help

John Sharvin /

I got the CDI from Dos Cycles and everything I read seemed to me that the box would work for this stator, but no its not paired with it.

Re: Trac to Tomos Wiring help

> ♣Slew Foot♣ Wrote:

> -------------------------------------------------------

> The result can't be definite if Theres a Hall effect sensor.

Two coil Tomos CDIs do not use a hall effect sensor or trigger coil.

A55 CDIs use a trigger coil, but this is not one of those.

Re: Trac to Tomos Wiring help

> John Sharvin Wrote:

> -------------------------------------------------------

> its the after market CDI from Dos Cycles for this stator. I am not

> getting continuity from internal ignition coil to the ground side of the

> CDI. So I am guessing I need a new internal ignition coil?

>

> Heres a picture of what I tested to make sure I tested the correct

> thing. (also I know that the coils are "upside down" I was trying it

> both ways just for shits because nothing has been working).

I think you're saying that your stator plate is not grounded? The plate itself does not have continuity to the CDI box brown wire, which is connected to the frame? That would absolutely be a problem.

> I also

> tested continuity between the two wires of the CDI and go no continuity

> so not sure if I got sent a dud or if that is correct?

No. That's fine.

Re: Trac to Tomos Wiring help

John Sharvin /

> I think you're saying that your stator plate is not grounded? The plate

> itself does not have continuity to the CDI box brown wire, which is

> connected to the frame? That would absolutely be a problem.

The stator plate to CDI brown wire does NOT have continuity. I dont think my stator plate is grounded (or should it be?). also not sure how to test that, try continuity between the stator plate and case?

Thanks for helping out trouble shooting this! Its been plaugeing my mind the past few weeks and just cant figure it out. Right now I have it wired very bare bones, no kill switch, just red to black, yellow off right now, and cdi brown grounded. If everything was correct I should see spark at the plug when I kick start right?

Re: Trac to Tomos Wiring help

As already stated not having continuity between those two spots on ignition coil is an issue.

Re: Trac to Tomos Wiring help

John Sharvin /

Ok resolved the stator plate being grounded, its all good now, but still no spark. Checked the boot, cable, coil and everything checks out. Really stumped everyone ive talked to so far.

Re: Trac to Tomos Wiring help

If there's no continuity on the white coil in the pic above , that's the problem .

There should be some resistance through that coil .

Re: Trac to Tomos Wiring help

John Sharvin /

There is 74 ohms between those two points, red and green, I just cant find a chart anywhere that has resistance readings on them for the stator.

Re: Trac to Tomos Wiring help

> John Sharvin Wrote:

> -------------------------------------------------------

>

> The stator plate to CDI brown wire does NOT have continuity. I dont

> think my stator plate is grounded (or should it be?). also not sure how

> to test that, try continuity between the stator plate and case?

Yes. For the CDI box to "see" the voltage from the coil it will need the same reference point. In this setup that reference point is the frame.

Voltage is always relative. Another way to think about this is that the current flowing from the coil must have a return path back to the coil. Current always flows in a loop back to its source.

Re: Trac to Tomos Wiring help

John Sharvin /

I got the stator plate to cdi ground to have continuity, just had to grind the engine mounting bracket a little and strip the fresh paint off.

Re: Trac to Tomos Wiring help

John Sharvin /

Update to this!! I finally got the new internal ignition install and it fired right up, big rich blue spark!! Im super stoked! Also lighting and everything works, just need a regulator for the voltage, wiring was correct the whole time!

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