Wire Harness Identification for Honda ATC's

[ps2fixer]

Work in progress as I collect enough harnesses. Basically a thread to showcase year to year changes for harnesses per model. Bit of a reference for myself, but is useful to ID what year/range your harness is. I'll make image quick references as I can on this post, detailed/wordy I'll link to the post as well.

ATC90/US90 (All years interchangeable from my understanding)
ATC110
ATC125M (WIP)
ATC185/ATC185S/ATC200/ATC200S
ATC200E/ES (WIP)
ATC200M (WIP)
ATC200X
ATC250ES (WIP)
ATC250SX (WIP)
ATC250R (WIP)
ATC350x (All years are the same)

WIP = Work in progress, aka waiing on harnesses to arrive, missing years, or I haven't completed the image yet.


If there's any mistakes, let me know, or if you can cover years I don't have on hand.

[ps2fixer]

1984-1986 ATC200S

(I don't have all years on hand to check length differences).

While researching 84+, found the wire diagram in the service manual is incorrect for what connectors the taillight uses. The diagram says it's the 80-82 style, but all photos I can find of an 84 harness, and tail light part number interchange says it's the same as 83+.

CDI connectors changed in 84 to the round 6pin style, in 86 it changed to the common 4+2 CDI connector. Besides the connection differences, the CDI's should all function the same electrically (also same timing specs)

The tail light connectors changed in 86 as well, instead of a single double female terminal, they changed it to two single female connectors, end result is the same though, just a different way to go about it.

84 and older all used the same Coil connections (Green ring terminal + Black/Yellow Flag Spade terminal), in 85 it appears to have changed to both wires with the Flag Spade terminal.


Details that shouldn't effect anything except maybe aftermarket options.

Yellow power wire went from a single bullet female to a double bullet female terminal in 85. There's only one wire though for 85+ so shouldn't effect anything. Anyone know of anything that uses that connection (like a speedometer back lighting etc)?

Since 85-86 ignition coil is different, the harness changed it's frame ground location to near the tail light wire (according to the wire diagram).


If any info is incorrect, let me know. I might need some proof to have me change it, but it will give me something to research more to be sure.

[ps2fixer]

1980 - 1983 ATC185/ATC185S/ATC200

Note, this was first post, moved it down here to make the thread more generalized.



Focused on 80-83, but each year does have a unique difference. All connectors are in the context of the main harness side. Also note, machines of the same year (ex: 81 185s & 81 200) used the same harness exactly, matching part numbers.

First thing first, the engine plugs (alternator/exciter coil), 80-81 used a 3 pin connector for all 3 wires, 82+ used the same connector, but the black/red wire got moved to a bullet terminal

Tail light connectors were green as a bullet male, and brown as a 3x bullet female 80-82, in 83 it changed so both wires were 2x bullet female terminals

Everything else including lengths etc are a perfect match 80-83.

In other words, the handle bar light controls from an 82-83 will work on 80-81. I suspect there's a few things like that with these machines.

Ironically, this research helped me ID the 83 200 harness I bought was intact a 82. Glad I didn't Try selling them for the wrong application. I have 3x 82 harnesses now (one was unknown year) lol.




I'm looking to build a template harness for these machines, ideally I can make a single harness that fits 80-83 machines, but I think I'll have to split it based on the engine connector (can't have a hot wire being a bullet male terminal floating around).



If there's any interest, I can make an adapter harness to go between the two engine hook ups as well.

Update, got an 86 harness on hand now. The 84 was a little longer at a couple spots vs the 80-83 harness, and 86 is longer than the 84.

[ps2fixer]

1979-1985 ATC110

Wire lengths for 81, 82 match up, the 85 is a little longer for the tail light and where the handle bar controls (kill switch/lights etc) hook up by 2-3in.
79-80 are the same part number, but different from 81+ (points vs CDI)



CDI plugs
79-80 points engine
81-83 square 6 pin
84-85 - round 6 pin

Tail light plugs
79-80 - brown bullet female
81-82 - green single bullet female, brown bullet double female
83-85 - green bullet double female, brown bullet double female

Alternator/engine plugs
81 - 2 pin male connector + 2 pin female connector
82-85 - 2x bullet male + 2 pin female connector

Coil Connectors
81-84 - Green ring + Black/Yellow Flag terminal (81-82 near tail light, 84 near CDI)
85 - both flag terminals (located near CDI)

Handle bar switch connectors
Functionally, seems to match across all years (81+ atleast)
81-82 - green wire double bullet female
83 - green wire double female + normal bullet female, yellow wire is double bullet female
84-85 - green wire has 2x single bullet female

[ps2fixer]

ATC200X

Just received the 83 & 84-85 ATC200X harnesses and also have an 86 on hand too. I have confirmed that 83 and 84-85 are exactly the same connectors/length except for the actual CDI connector. The 86 harness is nothing even close to the older years.

Still need an 87 harness, I have a guy that knows a guy that might lend me one, but never hurts to have a second option for backup too. I have to make the fancy photo for the ATC200X machines when I get some spare time.

[Three Cubed]

Hello! I see posts regarding CDI units and wire harnesses you've made. I know it's been fiver years ago, but I have a question for you if you're still active here...I have an 84 200X with the round style CDI plug. My service manual only lists the pin layout and test parameters for a 2 plug rectangular style. Do you happen to know / have the data for the 200X round plug CDI? Is it the same as a 200S or other ATC model you have listed on your other post? Thanks in advance. - Rob

[ps2fixer]

The pinout is really similar for ATC200X and the 84-85 ATC200S, but the 200x has a sensor ground (green/white wire) that the 200S grounds to the main system ground (green wire). The CDI might short those two pins together, but you'd have to test it on a 200S CDI to validate. Worst case could splice both of those wires to the single wire for the 200S CDI and it should work. Ignition timing for the 200S CDI might not be as aggressive as the 200x one, however I suspect most of that is done in the pulse generator mechanically with the springs and weights that advances the signal for when to spark.

Honda's published timing specs are similar but not exactly the same, but it's hard to know where the difference is exactly with out specialized equipment.

84-85 ATC200X
Base Timing: 5 BTDC @ 1300 rpm
Full advanced: 30 BTDC @ 3150 rpm

84-85 ATC200S
Base Timing 10 BTDC @ 1400 rpm
Full advanced: 30 BTDC @ 3350 rpm

[Three Cubed]

Thanks for the reply / info. Yeah, I assumed that the timing would be different; that's why I was reluctant to just do a straight swap. I followed the troubleshooting info in the service manual but didn't get any reading at all except green pin and green pin showed continuity - duh. I think I've narrowed my no spark problem to either the CDI or ignition coil (also readings not consistent with service manual). Ordered a replaced CDI from DRATV. Current ignition coil is just cheap-o from Amazon. Worked great. But 6 hours on rebuilt engine / resto ATC and bike just died. Like I hit the "off" switch - but I didn't. So, could be the cheap-o ignition coil. I'm deciding on what to do for one of those. Any suggestions on where to get / who has a quality ignition coil?

[ps2fixer]

First suggestion is only stick with used OEM or bare min Brand name parts. If it's a no name china part on ebay/amazon there's no telling if the company that made it had an ounce of integrity.

Ignition coil primary windings are a low ohm reading to take, have to have a fairly good meter to get an accurate measurement, real cheap ones (mainly from China) don't do well in those situations. I've used $6 meters before and it's night and day when using an actual name brand. For the el cheapo ones, I've found the chrome plating they use is really terrible for conducting electricity and gives very wild results. I've sanded down the ones I got like that so the ends as well as the connection into the meter is just plain brass, not as anti corrosive, but readings are a lot more stable. Then next thing is short the two probes together and see what it reads in ohms, it *should* be 0.0 or very close. My china meters would read around 20-50 ohms unmodified, and "fixed" were closer to 4-6 ohms. If you subtract that value from the readings you get a rough idea of the true reading. Aka shorted together gives 5 ohm reading, and you read an ignition coil primary at 6.6 ohms, then the "real" reading should be around 1.6 ohms. Of course if you have a good meter and it passes the short test for 0.0 ohms, then you should be good.

All of the ohm tests in the service manual can be done directly at the CDI connector as well, this could be a reasonable way to test if the wiring is good and has connection. The actual wire does add a tiny bit more resistance so have to allow the tolerances to be a little higher than what the book says but normally it should only be around 1-2 ohms higher at tops (that's why testing components is done directly at them).

For the ignition coil readings, only the OEM one will be the right readings, but aftermarket should be similar. Basically you're looking for if it's super low ohms (failed shorted) or higher than expected ohms (burnt sometimes), or no connection at all (wire broke internally). The ignition coil has 2 coils in it, so don't forget to test the spark plug side too. Most of the older tests were done with the spark plug cap removed, general rule of thumb is add 5000 ohms to the spec and you should be able to test with it on.

CDI testing isn't consistent really with the service manual, it's basically swap in a known good one for testing them. They list an exact part number for a multi meter, that basically has to be used or one designed in the same way to get accurate readings.

It's not the perfect option, but can try to use a new "newer" model ignition coils on your machine. I'd personally think that's a whole lot better than random China replacements. It might require some wiring modification and/or mounting rework to make it function, but it's an option.

https://www.partzilla.com/product/honda/30510-HN6-A31

That's the 200x/350x etc sport model style more or less.

https://www.partzilla.com/product/honda/30540-MJP-G51

That one is the bolt on style more like the ATC200S used, not sure if the bolt holes are similar/same sized, if you went with this one, you'd have to bolt it to the frame and make sure that connection is good, generally the main harness also grounds to the coil/frame at the same spot.

I have an oscilloscope now, but I'm not big in the ATV market any more, so I can't really buy a bunch of ignition coils and test their performance to validate which one is the most OEM like. Generally the ATV market eats up the China stuff so for the most part I've hopped over to making demo derby harnesses. I'd like to get back into the atv side of things down the road, but it's more of a side project idea than the main business's income, basically just want to do it to help people like what I orig was going for back in 2013 when I started making harnesses and parts.

Anyway, it's worth a mention, the ignition coil, CDI, exciter coil (part of stator/alternator) are all a matching set on those machines so that's why there's very little overlap for interchanges. Most other ones will work, just doesn't perform as well as they could. Like if the coil draws more power than the CDI can store/send out, then the overall voltage is lower which makes a weaker spark. If the CDI can hold more of a charge, it has a larger capacitor (battery effectively) which the exciter coil needs to charge up. If the CDI draws more than what the exciter can provide, then again voltages are lower than normal and weaker spark can happen. Similar effect is true for the opposite case, like a smaller capacitor in the CDI would make it charge up no problem, but then it might not have enough stored energy to efficiently saturate the ignition coil if it draws too much.

To be completely honest, I don't understand why atv's haven't followed the concept of automotive ignition systems. Like a coil over plug works on basically all engines, it's all self contained. Basically it gets a 5v pulse (digital but similar to a pulse generator, but it's from the engine computer) for when it needs to fire, the "igniter" inside is what powers the coil, which it runs off 12v which isn't as easy to solve for no battery models. Once the 5v pulse stops, coil turns off and that's when the spark happens. Some igniters are special and they calculate the time it's on for (dwell time) automatically. I think it would be neat to convert the old ignition system into that style, but it would require a computer to have proper spark advancement which is another 12v device. Technically the lighting coil could be used as the power source, capacitor or small battery for the steady 12v power, so it's very doable, not just the norm at least for that era of machine.

I'm sure I'm starting to talk gibberish so I better stop before I start talking another language lol. I do have some idea's and concepts I'd like to pull off to "modernize" the old atv ignition systems, but like I said before, it's more of a side project more than the main focus of the business. It actually is somewhat similar to a project I hope to pull off on the demo derby side of things, so ideally if/when I solve everything on that side, most of it should translate to the atv side of things, just 1 cylinder instead of 4-8.