250cc High Performance CDI

High performance DC-powered CDI for your CFmoto and CN250 vehicle. This CDI has an RPM ceiling of at least 9000 RPMs. See below for more information.

This CDI is adjustable!

The stock spark timing on most CN250 and CF250 vehicles is ~12° before TDC. This CDI advances the base timing to 15° before TDC and allows you to adjust the timing between 15° and 20° before TDC. Simply turn the dial on the face of the CDI to make the adjustments.

The dial on this CDI will turn from around the 5 o'clock position to approximately the 7 o'clock position. At 5 o'clock it's set at 15° and at 7 o'clock it's advanced to 20°. (Note: the timing adjustments made only begin to kick in once the vehicle is above 3,000 RPMs (in motion). You should not notice any engine noise changes at idle!)

Generally, we recommend setting it around the 12 o'clock position, but you can also try multiple settings and timed runs of a measured distance to determine the best setting for you.

Part Info:

• Type: CDI
• DC-Powered
• Has Adjustable timing
• Automated timing adjust from stock 12° before TDC to 15° before TDC at lowest setting.
• Can be changed from 15° to 20° before TDC with the adjusting knob
• All timing adjusts will happen gradually, beginning at 3,000 RPM, and reaching the full set adjusted point by 7,000 RPM.
  • This takes place automatically, based on the setpoint of the dial on the CDI.
• Compatible with all CN250 and CF250 engines used in buggies. Will not work with scooters using these engines that have AC-powered systems (mostly from the 1980s and 1990s models)
• Price is per item

This product is a performance replacement for the original part numbers listed below (and will work with many other vehicles as well)

Baja Reaction 250 (2-seats) Part # BR250-171
Baja Dune 250 Part # DN250-331
Joyner Sand Viper 250cc Part # D250.10.917, D250.07.917
Joyner Dirt Devil 250cc Part # D250.10.917, SZ15400000
Hammerhead 250 Part # 6.000.255
Kinroad 250 Part # KB004080000
Roketa GK-06 Part # GK-06-250-2-30
Roketa GK-13 Part # GK-13-250-02-04
Roketa GK-19 Part # GK-19-250-02-21
SunL SLGK-250-2A Part # 250-2A-1802000

More info about CDIs:

CDI's are programmed with a "map" that tells the coil to spark at a certain time in the each revolution. The CDI receives the information from the pick-up sensor down near the stator that tells it at what point in each revolution the motor currently is at.

So, for any given RPM level, the CDI knows "when" to fire the coil based on the plotting of this programmed "map".

Stock CDI's generally are only programmed with a map that goes to 5500-7000 RPMs or so (depends on model and the CDI the factory used). When you rev the engine up past this point (by modifying it in such a way as to increase the top end RPMs - like with lighter roller/slider weights), the stock CDI does not know what to do and slightly retards the timing to slow you back down until you're back on the "map".

A "No-limit" CDI is a bit of a misnomer - of course it has an upper limit programmed into it. The thing is, you're unlikely to have a transmission setup that would allow you to reach those high 10,000+ RPMs (and if you did, your engine is taking a heck of a beating on a regular basis!).

A vehicle with a CVT transmission will not continue revving up indefinitely until the motor blows up simply because you have a higher RPM limit CDI. It will increase in RPMs until the weights in the variator are fully extended and the belt is out as far as it will go (reached the max gear/pulley ratio). This is a physical ceiling to your RPMs as higher RPMs will not push the belt or weights out farther.

Lighter variator weights and heavier main torque springs will alter how high of RPMs that are required to hit this RPM ceiling, but generally speaking you have to go out of your way to reach 9-10,000 RPMs - most people will never come close to hitting that even with 10g GY6 weights or 13-15g weights in a 250cc.

That being said, the aftermarket transmission mods often easily raise your top end RPMs beyond the 5500 or so RPMs the stock CDI is mapped for. The aftermarket CDIs will allow you to rev the motor well past that point giving you the benefits of more top speed (relative to the stock CDI) and better low end power (due to the lighter weights in your tuned transmission).

Some aftermarket CDIs also come with the benefit of some timing advance. This is often built into the CDI and advances the timing curve usually around 3,000 RPMs and again later on around 7,500 or 8,000 RPMs. Many "adjustable" CDIs have this kind of auto timing advance built into them already and don't need to be manually adjusted. We generally recommend leaving these adjustable ones at the default "12:00" position unless you have a specific need for further adjustment, as the CDI has a built in advance that will accomplish timing advance without any outside interaction.