How to Convert an ATV to Ford Ignition

Jun27-141There was no way I was going to spend $280 on a cdi box for my Yamaha Moto-4 ATV. I knew how to wire up a Ford ignition since I had to figure it out earlier for my Jeep. It isn’t very hard, and it is a lot more reliable than the cheaply made cdi boxes. I got the idea from an old website that no longer exists. It had a wiring diagram of how to wire a Ford Duraspark ignition module into an older Ford car or truck. There was nothing to it really; all that is needed is a regular Ford coil, a ballast resistor, and the Duraspark ignition module. You can probably get the whole mess including the wiring connectors from a junkyard for almost nothing. Wire the bike’s regular stator wiring to the input wires of the Duraspark module, and wire the coil up as shown in the diagram. The ignition switch is going to have to be messed with to make it work again. I guess that is something that is different on a lot of bikes, so you will have to figure that part out on your own if you even bother with it. I took off the original key switch and disconnected the start button; then I wired the ignition and starter into a universal automotive key switch. The hardest thing I had to figure out was where to put the coil. I finally zip-tied it to the frame near the carb.

Jun27-201If the thing barely runs above idle after it is wired up, reverse the wires on the stator. If they are backwards, it retards the timing a lot. Also the ignition pulls more power than stock, so be careful running lights or other accessories. The best thing about that ignition on an ATV is that you almost can’t flood the thing or make the plug foul up. I put an Accel Super Coil on mine for a little extra kick. It is still a lot cheaper than any Yamaha coil. I opened the gap on the plug to .050, and it doesn’t miss a bit.

One thing I noticed after using this ignition for awhile is that the battery runs down after a long period of low engine speed. I hooked an ammeter to it and found out that the charging circuit only puts out a small amount of power, something like 5 amps running the engine wide open. The ignition pulls about 2 amps, so you have to have the engine running about 1800 RPM before the thing charges the battery. So if you idle around a lot like I do, that is kind of a problem. One thing that worked on this engine that I figure is the same on most of them is that the original cdi box had a separate coil in the engine to power it. I checked the voltage and current coming from it, and it was a pretty high voltage but not much current. I took the coil out of the engine and found that it was wound with a lot of turns of small gauge wire. I rewound it with a slightly larger gauge than the charging coil was wound with and put as many turns on it as I could without causing it to rub. I put an old diode out of a Chevy alternator on it and connected it to the battery. Now at idle the 2 charging coils put out enough power so that running the original headlight, the ignition, and a pair of 35w halogen lights on it puts about .03A into the battery at idle. Anything above idle puts a good charge into the battery. Now I should be able to run about anything else I want and have the power to keep the battery charged.atv-wiring

 

Jun27-13I have had that ignition on it now for a while, and the only problems I have had were from my wiring job. I originally wired the whole thing using one color of wire; needless to say, I had a mess when a wire messed up. I gave up and rewired it using a lot of different colors. After that, it never has had any trouble from the ignition. I noticed that it knocked a little under heavy load, so I hooked a timing light to it and found the timing was too far advanced. I dug some resistors out of some old junk electronics and put them on the stator wiring (purple and orange). I started the thing up and kept trying different resistors until I got the timing back to where it was supposed to be. I liked the extra power the advanced timing had, so I wired a toggle switch to the resistors. This way I could turn the advance back up when I wanted a little extra power for going up a hill. As for the resistors, I settled on a 1k ohm resistor between the wires and a small capacitor from each wire to ground to get rid of any electrical noise from the wires. Depending on the bike, you might need to hook a small resistor (about 33 ohms) in series on one or both wires. Also the white wire can be eliminated. It retards the ignition when starting, so it is only needed if the ignition bumps the starter hard enough to keep the engine from turning over easily.

I hope that some other people get this working because I hate to see people waste so much money on a thing like an easy-to-break cdi box when there are things that are so much cheaper and better. The new coil and ignition box can be put in for less than $50, and I know that it is a lot stronger. I did this mod in 1998 for anyone that is curious and I ran the 4 wheeler up through about 2009. It finally gave up from just being wore out and not being worth fixing. The duraspark was still running strong.

20 Responses to “How to Convert an ATV to Ford Ignition”

  1. Hey man cool wiring info….We have a 87 Polaris Cyclone ..coil went bad , and maybe something else too….but I want to wire this on the same way…I would like to get a phone number from ya if possible…so I can get a better under standing…as a matter of fact here is my number (xxx)xxx-xxxx…..cell…..(xxx)xxx-xxxx…..Please call….thanx Lacey..or …Wally…

  2. contact info is on the link on the left side 🙂

  3. I noticed you had a battery on your Yahama!?!? Would this rewire job work the same on an old Kawasaki KLT 110A with no battery?

    Thanks,
    Don

  4. It is possible it can work without a battery but it would be harder to get it running stable I figure. The battery keeps the ignition running stable so running without one might make it backfire and miss a lot more.

  5. Hey man you are way cool, thanks for the info. I just bought a 93 yz250 and got it built from the bottom up, all needle bearings and then when it was time to fire it up, I noticed the damn cdi is missing. My friend has a bunch of them, but they’re old like from the 70’s, do you know if an older one will work with a newer high rpm motor like mine, can it do the rpms? and what about spark curve? Any info you can offer about how the pickups work on my bike and which wires go where would be appreciated, hell I’ll put a battery on it if I have to, but sure would be nice if I could run a light also. thanx in advance, and screw the cdi companies trying to charge an arm and a leg for a few damn chips and a capacitor!

  6. I have chinese ATV 250ccm, for stroke, double cylinder, with CDI ignition and a lot of problems vith ignition, and ignition box.
    What you think, could i make this on my ATV.
    I live in Sarajevo Bosnia so I can’t easy find orginal parts.

  7. This is a very cool ideal. I have a 70 hp 1976 johnson outboard and the cdi has went out on it motor.Im considering using your setup for an R&D project.I only have noticed one critical flaw with my project as compared with jap cdi’s is that my outboard has an mechnical advance on its timing base.
    Do you think the duraspark module can support this mechnical adjusment?

  8. The duraspark will work fine with mechanical advance, it actually doesn’t have a built in advance since it is made for a car with built in mechanical and vacuum advance.

  9. Great information, and thanks for sharing. One gem there, you just just add=
    ed in, was how to adjust timing on an cdi machine, as well… a little resi=
    stence works wonders.
    =A0
    Thanks a bunch

  10. Net wiring trick.I just got it hooked up on a chiese 250 and it work great.I did notice that the ballast resister gets kinda hot when running.Any idea on that?Oh ya .Without the battery hooked up the motor wants to skip a little and hasn`t got all the power so best to have a battery in the 4 wheeler. Thanks again.

  11. Hi Rick, Great information here. I was wondering if this set up will work on applications that do not have a mechanical advance. I think the Yamaha Moto-4 ATV does not have a mechanical advance, but I wanted to make sure. I plan on doing this conversion on a 82 Kawasaki 250 KLT three wheeler. I tried using a GM ignition module but I don’t think the signal from the magnetic pick-up is compatable. Hopefully, the Duraspark module is :).
    Oh, one more question, When I go to the junk yard, what model years and models of Ford should I be looking for to grab parts from? Thanks.

  12. Super Super write up and info. I will be doing this to a Suzuki quadrunner. Thank you for saving me money and time as this is more durable than that silicone filled cdi box.

  13. i put a duraspark on my kawasaki 300 lakota sport, and im not getting any spark. due too no pulse coming out of the box. i wiried it up exactly how the picture said aswell

  14. nevermind, relized i fried the box wiring it wrong, bought a new one (BTW a duraspark box for an 83 ranger 2.0L is only 31 bucks. so if you cant find one in the local salvage yard, you can always buy it new for cheap) my quad runs again!!! now to find those resistors to get the timing right lol

  15. I put a Ford Motorcraft Duraspark II box on my Suzuki LT 4WD Quadrunner 250 CC ATV… Wow!!!… it’s wonderful!!… my quad is more powerful than the original CDI 🙂
    One thing about the timing:
    With my Suzuki quad, I need to add a 5 ohms resistor between the pick-up coil wires (stator) orange and purple!
    The voltage level from the pick-up coil to the orange et purple wires is the best at 0,5 volt AC, the 5 ohms resistor help to keep the voltage level to 0,5 volts AC, not more!
    My Suzuki ATV run very very good with the Duraspark II box! 🙂

  16. do you hook the puler coil or the trigger coil to the ignition box

  17. Do the resistors go inline between the stator and duraspark or do they bridge the two stator wires. I can’t get rid of knock under load on a yamaha Kodiak

  18. Hi Rick. I tried the ford ignition on my 300 bayou and it got it running again. However my atv does not have a mechanical spark advance so I tried a thick film ignition module from a late model ford and it brought it to life. If you or anyone else wants to try this I am more than willing to help just email me. and thanks for getting me started in thr rite direction. yarddog1015@yahoo.com

  19. hey man thanksfor the info,i just got my 85 suzuki lt 250 wired up to a ford duraspark box and it runs great.and was a lot cheaper than the 400.00 dollar cdi box.

  20. DID THIS ON A 250 UNISON..WHICH I CAN’T FIND PARTS FOR………..WORKS AWESOME THANKS FROM ONTARIO, CANADA