Stock DC CDI for GY6
This stock DC powered CDI is an exact replacement for most DC-powered CDIs found in GY6 150cc engines and more.
This CDI plugs into your existing wire harness and is a perfect fit in your buggy's electrical box where the stock one was mounted. Truly plug and play! Comes with new rubber mounting sleeve.
Note: This CDI is not compaitible with systems that use AC-powered CDIs. Please see below for how to tell the difference.
(Actual CDI received may vary in appearance from photo)
Measurements of this CDI:
Longest side: ~75mm / ~3"
Short side: ~42mm / 1-5/8"
Height (including plugs): ~43mm / ~1-11/16
How to tell if you have a DC CDI:
Your CDI has two plugs, a 4-pin and a 2-pin. The 4-pin side may have 3 or 4 wires connected to it (both AC and DC versions). If the 2-pin connector has only 1 wire going to it, it's a DC CDI. If there are 2 wires attached to the 2-pin connector, then it's an AC CDI. Note: A very few DC-powered CDI systems will have two wires on the two-pin connector. For these systems, please check to see if your headlights will work while the engine is not running, and if your stock CDI has "DC" printed anywhere on it. In these cases, you need a DC CDI.
Please do not attempt to install this AC-powered CDI on the Hammerhead 150GT or ASW Carbide 150cc buggies or you will destroy the CDI and blow your fuses. Returns will not be accepted for CDIs installed on these vehicles.
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.