CDI differences

[Mudflap]

How do you determine which 6 pin AC CDI unit will work with a particular Honda CG clone engine? There are 2 plug designs, one with rounded off plugs and one with squarish plugs, but there are also internal differences. Not all square plug CDIs will work with square plug engines and the same is true for rounded plugs.

I bought a square plug CDI as a spare for my Taotao ATA250D with CG250 clone engine that was advertised to work with that quad. Turns out the ignition timing at idle is too advanced which causes it to kick back when starting and prevents it from idling. I now have one ordered from a different seller who also advertises that it will work with the the CG250 but it looks the same.

Is there a way to tell by looks if a particular CDI will work with a particular engine?

[Weldangrind]

I've read that you can tell AC vs. DC by the size of the box, but I'm not sure which is which.

With a standard black box CDI, there shouldn't be any significant ignition advance differences, but the fancy aluminum-boxed CDI's are reported to have a more aggressive curve.

Did your CDI look exactly like your original unit?

[Mudflap]

The replacement CDI is slightly larger than the Taotao OEM unit (marked Xianfeng) by about 2mm per side but is the same size as the AC CDIs on the Lifan and Zongshen. Same plugs as the Zong also. It's not one of the aluminum encased "performance" CDIs and is not advertised as such, just a standard unmarked black box type. DC CDIs are larger according to what I've read.

I did manage to keep it running at idle speed with the replacement CDI long enough to check timing with a strobe. The timing was so advanced that the mark was not even visible through the timing hole. The OEM timing is right on the mark.

I now have one on order from a different seller who also advertises it as working with the Taotao 250 ATV. Should arrive early next week.

[humanbeing]

Taiwanese elite (CH125 / street term "大沙") clone also use that squarish plug
The curve had some difference
CG http://www.sanxin.com.cn/Exhibit/exhview.asp?pid=5
CH http://www.sanxin.com.cn/Exhibit/exhview.asp?pid=12
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Noone can ensure unmarked black box is the right type.
Model & brand name are factors to consider when buying new CDI.
===
U won't belive the REAL cost from factory direct sale:
http://item.taobao.com/item.htm?id=9274629428
¥2.80 AC-CDI | ¥7.00 uiversal DC-CDI

[Mudflap]

Thanks. That is an unbelievable price. I now see how they can sell them on ebay for $5 with free shipping.

I'll see if this next one I have on order works and if not I'll either order from Taobao or Taotao.

[Mudflap]

Got the next one from a different seller and it too doesn't work. Ordered one right from Taotao this time for $16. That one should work, I hope.

[Rule308]

I'm interested in what you find that will work best. I want to have a CDI spare (the original) and upgrade, if it's possible. Please post the link and part number when you find one that gives you gains.

Seems like everything is a crap shoot and the manufacturers don't know what they are making, which they probably don't.

[Mudflap]

The one from Eagle ATV parts https://www.eagleatvparts.com/ part number 12882-A161-2
CDI works just like the original. $16 + shipping. I have no idea which one if any would give you a performance gain.

[Rule308]

I found this info on Amazon from the vendor. Here is the link

http://www.amazon.com/Wings-Ignition...l+ATV+vertical

This Listing Is A Brand New Racing Ignition Coil For CG 125cc 150cc 20cc 250cc Vertical Air-cooled and Liquid-cooled Engine which is common used on Chinese made ATV dirbike Motorcycles.
Please Note: The 6-pin CDI in the kit is a AV fire version
How to tell AC fired or DC fired CDI :
1. In the CG 6-plug set-up, you have AC if you have 3-wires going into the 4-plug side and you have 2-wires going into the 2-plug side. On the other hand, you have DC if you have the larger CDI box, 3 or 4 wires going into the 4-plug side and only 1 wire going into the 2-plug side.
2. In general, the DC CDI's tend to be larger in size than the AC ones.For example ,the common AC fired CDI box is length 65 x width 36 x height 22 mm or length 58 x width 33 x height 22 mm ,but common DC fired CDI box is larger than AC fired cdi box in size ,suze as length 75 x width 42 x height 24 mm or length 96 x width 55 x height 24 mm .Certainly this size is only for your common original CDI Box reference,don't include the racing cdi box size ,please note.
3. Another test is if the headlights turn on without the engine running, (with just the key on), it is a DC system. In the AC system the headlight requires the engine to be running. Another indication is, if the engine will only run with a battery it is DC. If it will run without a battery, it is a AC system.
Kindly Remander please DO check wheather you need the AC fired CDI or a DC firedone for your scooter before order,thank you.
Specification: 90 degree performance amber elbow.
Fitment: CG 125 150cc 20cc 250cc ATV DIRTBIKE QUADS Motorcycle MAKES OF Roketa Taotao Coolster Sunl Kinroad and so on.
Please compare with picture to confirm the compatability before orders. If you could not confirm please send us message for assisant.
Package includes£º 1 X Ignition Coil 1 X 6 PIN AC CDI 1 X NGK D8EA SPARK PLUG

Looks like its some good to know info.

[Weldangrind]

Yes, that is very good info. Thanks.

[Patrick4653]

.
Quality Parts Designed to Improve Your Ride!
Available From a Dealer Near You. Click Here to find
your Dealer.
IS YOUR UNIT AC or DC CURRENT?
IN THIS ARTICLE:
In this article we are going to explain a little about CDI boxes and how to determine if your unit is
an AC or DC system.
About: Capacitor Discharge Ignition (CDI)
A CDI is a type of electronic ignition system which is widely used in outboard motors,
motorcycles, lawn mowers, chainsaws, small engines, turbine-powered aircraft, and some cars. It
was originally developed to overcome the long charging times associated with high inductance
coils used in inductive discharge ignition (IDI) systems, making the ignition system more suitable
for high engine speeds (for small engines, racing engines and rotary engines). The capacitivedischarge
ignition uses capacitor discharge current output to fire the spark plugs.
Many times if you do not have spark it is due to a faulty CDI module. CDI Modules come in AC
(Alternating Current) and DC (Direct Current).
TESTING YOUR UNIT: AC or DC?
Most engines generate alternating current to power lights, accessories, and to provide the
necessary spark for the engine to run. If your engine was built prior to 2008 the odds are good it
requires an AC CDI. A DC CDI is wired to the scooter's battery and uses the 12 V +/- drawn from
the battery to supply the voltage for spark.
In order to get the proper replacement CDI you need to determine if you have an AC CDI or a DC
CDI. A standard direct replacement AC CDI will be smaller in size than a DC CDI, measurement
specs are listed for each of our part numbers. DC CDI's are larger because they contain a DC to
AC transformer.
Another way to figure out the type of CDI your scooter needs is to check for voltage at the CDI.
Turn the scooter key to the "On" position and, using a test meter or test light, check if there is
current at the CDI. If there is 12 V at the CDI it is a DC CDI, if there is no voltage at the CDI it is
an AC CDI. This is assuming the battery is charged, of course.
Find quality parts at www.OutsideDistributing.Com

[Adjuster]

I just purchased one the supposedly high performance cdi's. I will let you guys know if I can observe a difference. If interested here is the one I purchased. Got my 'shipped' notice yesterday so should be here in about 20 days from China.

http://www.ebay.com/itm/271804757394


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[Mudflap]

I have a "high performance" CDI for my Lifan 200, supposedly a name brand. Made the engine kick back on starting, would not idle below 2500 RPM, pinging even on premium fuel. Only a performance loss, no positive attributes. Went into the junk drawer the day I first tried it.

[Adjuster]

Have you guys seen the ones that are adjustable? They have a usb port and you can use a computer to change all the internal parameters. I'm not smart enough so no thanks. Plug and play is what I'm all about.


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[Mudflap]

I doubt any "high performance" CDI is going to make a noticeable difference on a 8000 RPM CG clone engine. More likely it'll decrease performance and cause engine damage from pre-ignition. A fuel line magnet would probably work just as well.