what does a cdi box do

What Does A CDI Box Do: What Are The Things You Need To Know?

Learning the functions of CDI box could be a lot easier. In fact, you are not required to be a professional one just to know about its functions. There are just important things you need to know about.

What Is CDI Box?

A CDI or capacitor discharge ignition that is found on most bikes is linked to the ignition where it mainly stores the electrical charge. It is responsible for increasing the spark’s power in the spark plug. CDI box can be found only on vehicles that are based on the gasoline engine. It was originally developed in order to overcome the long charging times, which are associated with the high inductance coils mainly utilized in IDI system or inductive discharge ignition, thus making the ignition even more suitable especially for the high engine speeds.

What Does A CDI Box Do?

Bestseller No. 1
GoMyself 5 Pin AC CDI Box Replacement for 50cc 70cc 90cc 110cc 125cc 140cc 150cc 160cc Chinese ATV Quad Go Kart Pit Dirt Bike Motorcycle - 2 Pcs
  • ●AC CDI/ Connector: 5 Pins male plug/ CDI Dimension: 70mm x 36mm x 29mm (L x W x H).
  • ●5 Pin CDI Box for GY6 engine 50cc 70cc 90cc 110cc 125cc 140cc 150cc 160cc Chinese ATV Dirt Bike Moped and Go Kart
  • ●Package include: 2 x CDI 5 pin,cdi box 125cc
  • ●Aftermarket Product with Premium Quality.
  • ●We provides one-year warranty for all products sold from us! Carefree return! Money back if dissatisfied!
Bestseller No. 2
Glixal ATMT1-147 GY6 High Performance Racing Blue CDI Box 50cc 125cc 150cc 139QMB 152QMI 157QMJ Chinese Scooter Moped Go Kart ATV Quads No Rev Limit
  • AC-fired and NO REV LIMIT
  • Material of body: Alloy
  • Connector: 2+4 Pin
  • Reset the ignition advance curve for better acceleration.
  • Please confirm your original CDI is AC or DC before ordering.
Bestseller No. 3
HIAORS 6 Pin AC CDI BOX for GY6 50cc 125cc 150cc ATV Taotao Roketa Sunl Lance Scooter Moped Go Kart 4 Wheeler Quad Bikes Parts
  • Fit for GY6 49cc 50cc 125cc 150cc 157QMJ Engine Chinese Tao Tao ATM50A-1 Powemax Thunder Wolf RX50 Jonway Peace Sports Roketa Kymco Vitacci Viper Bentelli Baodino Motofino Daelim Besbi Scooter Moped Hammerhead Twister Yerf Dog Kandi Zircon Baja Reaction Go Kart Cart 90cc 110cc Arctic Cat Youth Arctic Cat DVX 50 Polaris Sportsman 90 kayo Fox ATV Quad 4 Wheeler Parts
  • 6 Pin Round Connector
  • AC Fired CDI
  • 6 Pin AC CDI BOX for GY6 50cc 125cc 150cc ATV Taotao Roketa Sunl Lance Scooter Moped Go Kart 4 Wheeler Quad Bikes
  • Please check the description to confirm the compatibility before purchase.
Bestseller No. 4
GOOFIT 6-pin AC CDI Box for CG 125cc 150cc 200cc 250cc Vertical Engine ATV Dirt Bike Go Kart
  • AC unit,6 Pin male plug CDI
  • Fit for CG 125cc 150cc 200cc 250cc ATV dirt bike go kart,
  • Attention:does not for GY6 or horizontal engine
  • Unlimited CDI adopt high quality plastic and metal,Professional manufacturing facilitating installation,Owning long service life
  • Warranty:We are always available to help our customers.If you are not satisfied with the order,please leave us a message.Wish you have a happy shopping experience,we are committed to providing the best service
Bestseller No. 5
6 Pin DC CDI Box for 150cc 200 cc 250 cc Roketa Taotao Jonway Mopeds Scooters Go Karts Dune Buggy Parts
  • For Gy6 49cc 50cc 90cc 125cc 150cc 200cc 250cc Tao Tao Kymco Jonway Vitacci Lance Cabo Scooter Moped Manco Hammerhead Trailmaster Rocket Carter Talon American Sportsworks Go Kart Cart Dune Buggy Polaris Arctic Cat Can Am DS Baja Hond* Kawasak* ATV 4 Wheeler Quad Parts
  • Compatible with: /Kymco agility 125/Kymco agility 50/Jonway Yy250t/Lance Cabo 50/ /American sportsworks 6150/Rocket GK-13B/Can Am DS 90/Kawasaki kfx 90/Polaris Outlaw 50/Carter GTR 250/ E-TON Viper 150R/
  • Length: 75mm/2.95"; Width: 42mm/1.65"
  • Its working principle is that the high-voltage electricity from the generator coil passes through the electronic igniter, then through the high-voltage package, and then through the spark plug to complete the ignition process
  • Please carefully check the model and size of the product before purchase
Bestseller No. 6
Trkimal High Performance Racing AC Cdi Box 6pin + Ignition Coil + 3 Electrode Spark Plug for GY6 50cc 80cc 125cc 150cc Moped Scooter ATV Go Kart
  • 【Specification】High performance racing cdi & ignition coil, racing 3 electrode spark plug, red color, cdi is AC fired, 6 pin
  • 【Fitment】 139QMB 152QMI 157QMJ engine, GY6 50cc 80cc 125cc 150cc Moped Scooter ATV Go Kart
  • 【Quality Guarantee】1 years quality warranty promised after you purchased
Bestseller No. 7
CDI Box- Ignitor Module Unit 5YT-85540-00-00 5NF-85540-00-00 for Yamaha YFM350X Warrior 350 2002-2004/YFM 350 Warrior California 2002-2003/YFM350 Raptor 350 2004-2013/YFM 350 Raptor SE 2005-2007
  • Package Including: 1 PC; OEM Repl.# 5YT-85540-00-00 5NF-85540-00-00
  • Compatibility: please refer to the Product Description
  • Features: Standard products ,best quality, perfectly fit.Our company has links with many brands of motorcycles to make products that fit perfectly. Our company introduces German manufacturing equipment , and many technologies and processes are in the leading position in the same industry
  • Warranty:150,0000 kilometers service life
  • Gurrantee:If not fit, Provide us with the model of your vehicle with a picture of what you have received , you get your money back instantly; Any quality problems within a year, provide us with a picture and you get your money back instantly.
Bestseller No. 8
PRO BAT 5 Pin AC CDI Box CDI with 5 Wires Cable Wire Harness Plug for 50cc 70cc 90cc 110cc 125cc 150cc Dirt Bike Kids ATV Quad Go Kart Buggy
  • ★5 Pin AC CDI Box for Chinese 50c - 160cc Horizontal Engine Tao Tao Coolster Kymco mini pocket bike ATV pit dirt bike motorbike go kart, XR50 CRF50 XR70 CRF70 90 110 125cc quad ATV, Coolster 125cc 3125B 3125R 3125XR8 ATV, X15 X18 Mini Pocket Bike.
  • ★CDI Dimension: 60mm x 35mm x 23mm (L x W x H). Connector Dimension: 18mm x 14mm (L x W).
  • ★5 Pins Male Plug 1.Timing Trigger 2.Ignition Coil 3.Ground 4.Kill Switch 5.AC Ignition Power ( AS THE SECOND PICTURE SHOWN).
  • ★Package Included: 1pc x 5 Pin AC CDI Box CDI, 1pc x 5 Wires Cable Wire Harness Plug, 2pcs x Ties.
  • ★Please check pictures and specifications for compatibility. Quality assurance, unconditional lifetime guarantee, so you can purchase now with confidence.
Bestseller No. 9
GY6 Ignition Coil CDI Box for 50cc 125cc 150cc 200cc 250cc Motorcycle Chinese ATV Mopeds and Scooters,Pit Dirt Bike Performance Parts and Four Wheeler Accessories
  • Universal Lgnition Coil: High performance racing ignition coil for GY6 50cc 150cc 125cc 4-stroke engines scooters, ATVs, mopeds, quad, pit Bikes, dirt Bikes.
  • Compatible Connector: 2+4 Pin, this CDI is 6pins, it works with the GY6 type plug on it. If your CDI has the same plug, this will work for you.
  • Enhance Lgnition Intensity: Ignition coil CDI box can Increase the ignition energy intensity for easy start and smooth driving.
  • Eliminate Speed Limit: This AC ignition CDI eliminates the speed limit, keeps the bicycle in a restricted state, and resets the ignition advance curve to achieve better acceleration, makes your bicycle 5-10 miles faster, and eliminates the speed limit.
  • Easy to Install: Ignition coil CDI box easy to install, just plug in. Can directly replace the old or damaged.
Bestseller No. 10
Racing Ignition Coil 5 Pins AC CDI Box for GY6 4-Stroke 50cc 70cc 90cc 110cc 125cc 150cc Scooter ATV Go Kart Moped Quad Pit Dirt Bike With 3 Electrode Spark Plug
  • Compatible with GY6 50cc 70cc 90cc, 110cc, 125cc, 150cc 4-stroke engines. For most motorcycle, atv, quad, scooter, go kart, moped, pit bike, dirt bike, racing bike and other bikes.
  • Fit most Chinese Made Pit / Dirt bikes, almost all of the bike brands from China, such as Compatible with TaoTao, Buyang, Coolsport, Jonway, Znen, NST, BMX, Kazuma, Sunl, Roketa, AIM-EX etc.
  • Racing Ignition coil surface finish: plastic;Color: Orange;Overall length:19", comes triple electrode head Spark plug.and 5 Pins AC CdI Match original equipment exactly for a perfect fit, easy to install.
  • Package including 1 AC 5 Pins CDI box + 1 ignition coil + 1 spark plug
  • The product is not sponsored or endorsed by ,or affiliated with the brands it fit ,including TaoTao, Buyang, Coolsport, Jonway, Znen, NST, BMX, Kazuma, Sunl, Roketa, AIM-EX .For any reason you're not completely satisfied, you can ask for a replacement or full refund, no quest
Bestseller No. 11
6 Pin DC CDI Box for CG150cc 200cc 250cc Vertical Engine ATV Quad Go Karts
  • Not Fit GY 250cc Engine,only Fit CG150cc 200cc 250cc Vertical Engine
  • pls carefully make sure the connectors with your orignal one
SaleBestseller No. 12
30410-HC4-770 CDI Box Fits Honda ATV 300 TRX300 Fourtrax TRX300FW 1988 1989 1990 1991 1992 1993 Replace 30410 HC4 770
  • Package included: 1*Voltage Regulator
  • Fit: Honda TRX 300 Fourtrax -- 1988-1993 Honda TRX 300 FW Fourtrax -- 1988, 1990-1993
  • Replace:OEM Number 30410-HC4-770 30410-HC4-003; 30410-HC5-970; 30410-HC5-971; 9900-5127 10027
  • Performance: Help the car eliminate clutter interference, stabilize the output voltage, improve the instantaneous discharge capacity of the power system, increase the torque output.
  • Tips: Please check with us if not sure about your replace number, If you have any questions we will be pleased to assist you.
Bestseller No. 13
5 Pin AC CDI Box Compatible with COOLSTER 125cc 3125B 3125R 3125XR8 SSR Dirt Bike Chinese 50c 70c 90cc 110cc 125cc ATV Quad Go Kart Pit Dirt Bike
  • 5 Pins Male Plug/ Type: AC Fired CDI/CDI Dimension: 64mm x37mm x 21mm (L x W x H)
  • This AC CDI Fit COOLSTER 125cc 3125B 3125R 3125XR8 SSR Dirt Bike Chinese 50c 70c 90cc 110cc 125cc Tao Tao ATV Pit X15 X18 Mini Pocket Bike Horizontal Engine
  • The 5 Pins CDI NOT have a rev limiter, Easy to install, small enough to strap where its supposed to go
  • This is AC CDI, Which is smaller than the DC CDI While the appearance is just same only size different
Bestseller No. 14
5 Pin AC CDI Box Compatible with SSR Chinese 50c 70c 90cc 110cc 125cc 3125B 3125R 3125XR8 ATV Quad Go Kart Pit Dirt Bike
  • Wide Compatibility - This universal 5 pin CDI fit for SSR Chinese 50c 70c 90cc 110cc 125cc 3125B 3125R 3125XR8 ATV Quad Go Kart Pit Dirt Bike
  • Enjoy Optimal Performance - The 12V AC CDI works well in areas where there is extreme cold temperatures and other harsh environments and is very precise during ignition. A small body contains big functions that will surprise you
  • Sturdy Construction, Utilitarian Design - This cdi box is of guaranteed quality, sturdy, resistant to aging and abrasion, ensuring maximum strength and durability. Can be placed at will without any problems of getting stuck or unable to be placed
  • Intimate reminder - we have prepared a detailed wiring diagram for you, if you are not a professional, you need professional help
  • Superb Value - 1x 5 Pin AC CDI Box, 1 x Wiring Diagram
Bestseller No. 15
JINGKE 6 Pin DC CDI Box for GY6 4 Stroke 50cc 125cc 150cc Scooter Moped Taotao ATV Quad Go Kart Bike (DC-GY6)
  • Compatibility:Chinese 50cc, 150cc, 200cc, 250cc, 300cc ATV, Go-Karts, Mopeds Chinese brand, like Tao Tao, Buyang, SUNL, Roketa, Lifan, JCL, Kazuma, Coolsports and so on
  • Characteristic:High Quality.Special design and unique Style,100% Brand New High class quality and very durable, Easy to Setup
  • Products include:1 x 6-Pin DC CDI,1 x A7TC spark plug,2 x Connect
  • DC (not AC),Please note that this is DC, not AC
  • Professional after-sales:We sell professional parts ,and provide free technical support. If you have any problems or dissatisfaction after receiving the products, please contact us directly to get New Replacement or Return.
Bestseller No. 16
Fan Alarm Control Unit CDI BOX For HONDA Fourtrax 300 TRX300 TRX300FW 1988-1997 TRX200D 1991-1997 38710-HC4-003
  • Compatible Models: For Honda FourTrax 200 TRX200 1991-1997 FourTrax 300 TRX300 1988-1997.
  • Manufacturer Part: 38710-HC4-003
  • Package: 1x Alarm Control Unit BOX
  • Tips before Purchase: Please carefully check whether your model is applicable to our products before buying. You can refer to the applicable models, pictures and OEM numbers on our page to help you determine your choice.
  • After-Sales Service: If you have any questions about our products during the use or purchase process, you can contact us by Email at any time. Every product purchased from us comes with 24-hour friendly customer service and 1 year product service
Bestseller No. 17
CDI Box fit for Polaris Sportsman 500 1996-2002,for Polaris Big Boss Magnum Worker Ranger 500 ATV with Ignition Coil&Starter Solenoid Relay Spark Plug
  • CDI box for Polaris Sportsman 500 1996-2001
  • CDI box for Polaris Sportsman 500 6X6 2000-2002
  • CDI box for Polaris Big Boss 500 6X6 1998-2000
  • Replace Parts Number: 3085639 3084691 3086982 3085564 3085382
  • Package Include: 1 x Ignition Coil, 1 x CDI Box, 1 x Spark Plug, 1x Starter Solenoid Relay
Bestseller No. 18
CDI Box Ignition Coil 5 Pin Regulator Rectifier Relay Spark Plug for Kazuma Meerkat 50cc Falcon 70cc 90cc 110cc Taotao Roketa Coolster 110CC ATV 3050B by Lucky Seven
  • Fits almost all years Chinese made electric start upright engine 49cc 50cc 70cc 80cc 90cc 100cc 110cc 125cc engines. For ATV, Coolster, Quad Bike, Dirt Bike, Pit Bike, Go Kart, Kawasaki KLX, 4 Wheelers, Scooter, Buggy, Motowork, Dune, Taotao.
  • 12 Volt Coil+5 PIN CDI BOX+4 PIN Regulator+Solenoid Relay+Spark plug.Fits ATV / Quad / Kawasaki KLX / Coolster / Scooter / 4 wheelers / Buggy / Dirt Bike / Go Kart /Pit Bike/ Motowork more.
  • This kit include 2-pin Male Plug Relay,Ignition Coil 135 Degree Elbow,12v 4-pin Voltage Regulator,5-pin CDI. (Does Not fit for GY6 engine).
  • The kit Compatible with many brands,such as: Atomik, Pitpro, Hummer, Orion, Xmoto, Lei, DMX, SWD, TDR, DDR, Tommahawk, Monsoon, Grudge, Kazuma, Bull, Trooper, Hunter, Motox, Trojan, Blitz, Crusade, Link, Bigfoot, Kuda, Motoworks, Nitrous, Reign, Fury, Prox, Raider, Zongshen, Loncin, Ducar, Lifan, Thumpster, Thumbstar, Chongqing.
  • The items are the same as the pictures.5 Pins CDI module + 2Wire Ignition Coil + Starter Relay Solenoid + 4 PIN Voltage Regulator Rectifier + Spark Plug. Fits for: 50cc 70cc 90cc 110cc 125cc 140cc horizontal engine,Bikes & Quads,ATV, Buggy's.
Bestseller No. 19
CDI Box & Ignition Coil Spark plug For Yamaha Warrior 350 1997 1998 1999 2000 2001 348cc 3GD-85540-40-00
  • Compatible Models: For Yamaha Warrior 350 YFM350X 1997-2001.
  • Manufacturer Part Number: 3GD-85540-40-00
  • Replacement Part:3Gd-82310-10-00, 3Ns-82370-00-00
  • Package: 1 x CDI(5 PIN), 1 x Ignition Coil, 1 x Spark Plug
  • Tips before Purchase: Please carefully check whether your model is applicable to our products before buying. You can refer to the applicable models, pictures and OEM numbers on our page to help you determine your choice.
Bestseller No. 20
CDI Box For Honda FourTrax 300 TRX300 2x4 TRX300FW 4x4 1994-1997 30410-HM5-505
  • Applicable vehicles: For Honda FourTrax 300 TRX300 2x4 1994-1997 FourTrax 300 TRX300FW 4x4 1994 -1997
  • OEM Part Number: 30410-HM5-505
  • Package Contents: CDI Box*1
  • Accessory Description:This accessory can be used as a direct replacement for damaged old accessories. If you have any questions during use, please contact us to solve it for you.
  • Tips Before Buying: Please confirm whether it is applicable to your model according to the product information before placing an order. If you are unsure, you can always contact us to advise you.

Many parts are there that primarily comprise the ignition system and all these parts are very imperative most especially when learning the way how it works with the ignition system and most of all, to answer the common question ‘what does a CDI box do?’. The major parts include the charging coil, the stator, the flywheel, the timing mark as well as the hall sensor.


This plate has the ability to hold the electrical wire coils, which in first place work to power the lights and battery charging circuits as well as ignition.


Charging coil, on the other hand, is a coil found on the stator. It mainly creates power for the spark plug, condensers, and flywheel.


This is responsible for measuring the point where the magnet of the flywheel changes from north to the south pole. It will then send a pulse to the CDI box. The pulse will then trigger it to move the energy that it has right from the capacitor into the high voltage transformer.


This pertains to the alignment point shared by the engine case and stator plate. This is very useful mainly because the stator plate can be rotated right to the left according to the mark. It will then change the CDI’s trigger point.

We cannot deny that not all people are aware of what a CDI box do. To give you the basic understanding and knowledge of it, here is how the CDI ignition actually works. Read this to know how to bypass a CDI box.

The CDI ignition mainly starts thru generating the charge while storing it up right before sending it out to the next system’s component. When the electrical level successfully reaches the right value, it is where the current signals and then charges a spark plug, thus allowing off the excess electricity in pulses, which in the first place power the engine.


The power passes all through the capacitor. After that, it is transferred to the ignition coil, which helps in boosting the power through acting as the transformer while allowing the energy to pass through it instead of catching it. Therefore, the CDI ignition lets the engine to keep running as long as the power source has a charge.

Take note that the CDI ignition systems have a fast charging time. It powers themselves even more compared to the inductive ignition system. These power sources’ types are perfect for much smaller machines including outboard motors, chainsaws, and motorcycles. In spite of the usability that it has, a certain limit is still there to the amount of charge a capacitor mainly holds right before it burns out.

This is the main reason why it is not an ideal resource most especially on the larger vehicles and machines. Keep in mind that the faster the CDI system spins, the lesser power it exudes. This is why it cannot power either a truck or car.

How To Troubleshoot A CDI System

For those who already know the answer to the question ‘what does a CDI box do?’ they are perhaps wondering how to troubleshoot a CDI ignition system. Well, that is not a problem anymore, since there are many ways to solve the problem.

The ignition problems mainly originate within either the charging system or battery. To generate the current needed and create a spark, there is a need to make sure, that the battery should have what it takes to supply the CDI box with the full twelve-volt current. On the other hand, the battery should at the same time power the lights of the motorcycle.


If the engine of the motorcycle turns over, yet it does not start, just completely charge its battery with the use of automatic battery charger right before you check anything else. However, if the motorcycle refuses to start, there is a need to conduct various tests with a multimeter.

This is done in order to know if the CDI box has incurred any damage. The good thing is that, the factory service manuals offer testing procedures along with CDI box specifications needed by the motorcycles. Click here to know more about CDI testing and troubleshooting.

How Do You Check A CDI Box?


Start by checking the owner’s manual for CDI box in order to find the electrical resistance specs of the device. If the CDI box works properly, the ohm meter’s readings should match with the specs.

Starting from the input wire, just plug the ohm meter in. After that, simply turn over the engine where the CDI box is attached. Take note of the readings, and if they are right within the range that is listed in the manual, all you have to do is proceed in order to check the output wire. Watch this to learn how to test motorcycle box, ignition coil.

Knowing the right answer to the common question ‘what does a CDI box do’ is very important. Not only you will become aware of how it works, but you will also know other important things that are related to it. We hope that the above-written article has given you an insight about CDI box.

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