Tomos Electric Woes

Last i rode my bike, as I'm a block away from my house, and the whole bike cuts out, no spark to be found, tried a new spark plug, no dice.

I start to check for grounding problems in the stock wiring harness, can find anything. Caxe and I decide to just overhaul the wiring, as it has become a rats nest of obsolete accessories and previous repairs. Stripped everything non vital out, so I'm only running head/tail lights and a kill switch. Wired everything up as correctly as i assume it can be, going off of various wiring diagrams, as i could not find one that matches the set up of my bike.

still, no spark?

current theory is that the CDI box is bad, or more likely, I have wired something wrong and am going to feel dumb. who can say?


This is the center mass of wiring


These are the kill switch wires, black goes to the cdi box, blue grounds at bare metal on the handlebar bracket

I'll post more pictures of the rest of the wiring.

Re: Tomos Electric Woes


here's deets on the CDI box, I cant really find any other information on it, its got four wires tho?


Headlight wiring, and the grounding for it and the kill switch and the handlebars

yes, I've tried for spark without the killswitch wire grounded

Re: Tomos Electric Woes

last one, of the brake light


grounded to bare frame there

hopefully this is more information than it takes to diagnose whats wrong but any info, advice, or direction would be great

thanks dooders

Re: Tomos Electric Woes

I think that's the treats ZA50 ignition pack if you want to search for a wiring diagram.

Re: Tomos Electric Woes

make sure your powering up your cdi.

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Shawn Skibicki /

Those treats CDIs are known for the coil failing out of nowhere. just a heads up.(edited)

Re: Tomos Electric Woes

Alright, did some research and some testing, Stator puts out enough juice, lights are wired correctly, spark plug and boot are new.


it sure seems like my CDI box went bad, so i stuck another questionable CDI on there that ALSO did not work

are there other Compatible CDI boxes with this stator?

should i just overhaul the whole ignition system for something more reliable?

Re: Tomos Electric Woes

Are there suppose to be two sources from the magneto feeding the HT coil ?

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In that second photo you have a HT coil, but no CDI. The stock unit is a CDI bundled inside the HT coil. You'll need a compatible coil.

Re: Tomos Electric Woes

your coil cracked, yes to wiring correctly cuz' you'll burn up cdis in a sec wiring wrong. unless u rich.

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You have both the trigger and coil going to the ht coil and no cdi box. This is not fine

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Yeah, the HPI coil is confirmed wrong part and also already dead, we stuck it on in almost joking desperation.

I’m gonna grab the tomos stock ignition and parmakit box and just get it over with

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Or you can just get a new box and replace the pick up for 1/3rd the cost.

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♣Slew Foot♣ /

That cdi box bad two poles a pos a and negative the Box that is the regulator is missing the ground wire the other is the trigger the ground wire go straight to the frame closer to the engine you join all your grounds and mount them near the engine rear not on the back of the frame near the Tail it makes the dry ground travel too far and works like a kilchers switch ground the regulator and run the negative Port of the high-tension coil or CDI box grounded right at the engine on the frame that is if it's an a359 a55 that had the other triggered CDI which would have four wires and it wouldn't be duplicate power and Lighting some kinetics had that that is a kinetic box the old ones like an A35 will work with that whereas the a55 need the trigger or be modified with an A35 stator and flywheel if you have an electric start it's an it's in a five five

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