Atc70 coil?

[ivan-083]

Hey guys I’ve just brought a atc70 with a 79 frame and a 74 motor! It’s missing the coil. Can I use any atc70 coil or do I need to be specific! The ones on eBay here in Australia only sell 79 to 85 coils! Will these fit? Thanks for the help


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[coolpool]

My first thought is that since they are all points machines it should be no issue; but there are some electrical gurus on here who can verify. Calling PS2Fixer!

[ivan-083]

Someone told be it needed to be the same as the engine year? Hopefully someone can clarify it for me?


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[stoshu]

They are slightly different. A 6 volt coil should work on any 6 volt trike. I do have a 74 coil I could ship you. It won't be cheap from Canada though.

[shortline10]

Mounting brackets are different but the newer style coil should work just fine .
Your using a newer style frame so yes just buy a 79-85 coil .

[ps2fixer]

I'd agree with the rest, the coils should work electrically for points engine to points engine. FYI, the ignition coil circuit and the lighting circuit are not the same or the same voltage. Here's the wire diagram to illistrate. The only common thing is the ground and sometimes the green wire.

https://i.gyazo.com/1656a479f29350149289a5f0e904c836.png



Anyway, the main thing to determine if a coil can interchange to another machine is the working voltage of the exciter coil in the stator and the physical mounting/wiring. Since you're looking at at 79+ coil, I'll grab up the 79 atc70 stator part page.

https://www.partzilla.com/product/honda/31141-098-731?ref=f6f75a8b2f01cd366a32aeeb35c134392855f78f

In the listed fitment it has ATC70 (K0) and ATC70K1 so that covers all years before 79. Also the stator fits the CT70 so the coil from one of them would work too. I don't know the years vs K models too well, just haven't worked around the ATC70's that much.

Also there's a few different part numbers for the coils

83-85
https://www.partzilla.com/product/honda/30500-957-013?ref=91dde1ee3624a57c298374674ae5092de8c02bc4

78-82
https://www.partzilla.com/product/honda/30500-957-003?ref=901b3c341b10faf281f60d3481bb6ea86e5d8db5

K0-K1
https://www.partzilla.com/product/honda/30500-937-000?ref=a0f1c4411c21068665bd43904a3cfb37e6997e2e

For the fun of it, I grabbed the newer stator part number too

81-85
https://www.partzilla.com/product/honda/31141-957-005?ref=92e20c740feb5f76860f2cfa57f12f9441f3882d

So since there's overlap on all the ignition coils and stators, it should mean electrically they function the same and can be interchanged.

You'll want to check what wiring exists for your coil and see if it will match up to the 78-82 coil to match your frame's mounting. I've been poking at the ATC70's a tiny bit lately on wiring, if you're missing any of the sub harness parts, let me know or post pics of what you have for the black wire (exciter coil, ignition coil, and kill switch). There isn't really a "main harness" for the atc70 since it's effectively just that one wire.

Hopefully this was useful for you, good luck on sourcing the ignition coil.

FYI, all of the part numbers are based on USA models, generally there's no major differences for machines made for other countries though.

[shortline10]

83-85 coil had a removable plug wire were the 78-82 plug wire was fixed to the coil , that’s the only difference I know of and the reason for different part numbers .

[ivan-083]

These are the two styles I can buy here on eBay in Australia!
https://uploads.tapatalk-cdn.com/20190830/b4f7de3d97c66c7c7230d93a32072ff3.jpg
And this one below!
https://uploads.tapatalk-cdn.com/20190830/f98319cc7a43ace2d16e885abcb6a3b6.jpg



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[ps2fixer]

Interesting coils, looks like made in china stuff. Like the wire on the second one has heat shrink on the connection area of the terminal. Kind of doubt the OEM ones had bare copper exposed, I suspect that will corrode quickly on the first one. Don't have any experence directly with Chinese ignition coils, but I've seen people test coils on youtube with a spark gap tester and the OEM china ignition coils were stronger than the aftermarket "race" ignition coils.

Anyway, based on the part diagrams on partzilla, the top one is the K0-K1 style, and the bottom one is the 78-85 style.


Looks like the same coil is being sold in the usa ebay pages and it has shotty reviews, basically no spark or weak spark, and mounting bolt pattern isn't right.

https://www.ebay.com/itm/IGNITION-COIL-FOR-HONDA-ATC70-ATC-70-1978-1985/153049826350?fits=Model%3AATC70&epid=2288063920&hash=item23a27b042e:g:GQcAAAzy1-NSkDFZ#rwid

There's also a NOS one for sale, pretty pricey though, I'm sure they'd ship to AU if you was willing to pay though.

https://www.ebay.com/itm/NEW-OEM-HONDA-IGNITION-COIL-ATC70-1978-1985-KT-30500-957-013/382653848889?epid=2219548782&hash=item5917f25d39:g:45sAAOSwDPNb2zGx#shpCntId


If I was in your situation, I'd probably look around for a good OEM (says made in japan) used ignition coil since they fairly rarely go bad.

[ps2fixer]

@ivan-083

FYI your Pm inbox is full.

Anyway, for a reply for your last pm, the stock stator uses 3.5mm bullet terminals, the 4 pin connector (3 spots used) is a Sumitomo 0.250 4 Pin Male connector, good luck with the rewire project.