Moped ignition system

The most common thing that most young or inexperienced moped mechanics struggle with is the machines electrical and ignition system. Most systems are actually very simple and crude by todays technology standards. The lighting coils are not well vented and also produce more heat.

Heat is the number one cause of coil break-down. Often times these terms can best be visualized by thinking how water moves through a pipe or garden hose.

You live in a house that has a garden out back. You water that garden with a tank of pressurized water that is up on a stand next to the garden. You use an air compressor to keep the tank pressurized. Okay, you want to water the garden so you open the faucet all the way on the pressurized tank volts and water electrons starts flowing out the hose wire once you squeeze the spray nozzle trigger switch.

Makes a little more sense now, huh? Okay, here is another one. The spinach on the other end of the garden looks awful because you keep trying to water it with high-pressure water but the pressure and amount of water combined watts is too much for the plant. All that force is destroying it. You need to water it with a bucket. You reduced the tank pressure volts back to its normal pressure and open the valve ohms all the way. The more you squeeze the trigger, the more water that squirts into the bucket.

The water rate amps coming out of the hose is being regulated by the spray nozzle because the restriction ohms in the nozzle is adjustable. Your water nozzle is a variable resistor. A watt is a unit of measure that is used to explain total electric power generated or in this case, total power that is generated from the flowing water. You get that measure from multiplying the volts x amps.

In the middle of the garden, you have a windmill thing that when it spins, makes the little character on top of it look like he is cutting wood or something. When you are out watering the carrots, you like to spray the windmill to make the figure move. The force of the water hitting the wheel determines the total power or watts. To make the wheel turn faster or harder, you can increase the water pressure volts or increase the amount of water amps hitting the wheel.

If you spray that windmill with too much force and too much water, it will break and the little guy will no longer be able to cut wood. Now that you understand the three basic components that determine how strong and how much electricity something generates, you will soon be able to use the following calculation wheel to help find answers to your electrical issues.

If you know what your voltage is and how much amp draw something has, you can use the wheel to figure out what your capacity for additional bulbs are. These are just a couple of examples but once you master the theory, you will be able to diagnose or design or build many different electrical applications. In most applications the voltage is constant at the supply.

If you want to adjust the amount of energy that flows through a circuit, you normally do that with resistance or some kind of transformer component. The reason is that most old mopeds used a magneto system. A magneto creates A. We will get into the difference between A. The current is generated from the magneto by a magnetic field passing over a coil of special wire called magnet wire or resistor wire. The rotation takes place because the flywheel is attached to the crankshaft.

As the engine spins, so does the flywheel. As the magnets pass over the coils of wire and stopdeveloping electrons are pushed through the coil. The electrons moving through the wire is electricity. The faster the magneto spins, the greater pressure Volts of moving electrons. The thicker the wire, the more current Amps capacity it has because the resistance O hms is less.The ignition coil or module for a two-stroke engine regulates the ignition power, and converts it to charging electricity for the battery system.

When the module and coil begin to fail, it's typically because the units have been burned out. The result will be an engine that performs badly, if it starts at all. Testing such units involves using a few electrical tools to gauge if the part still works, since most modules and coils are sealed with no serviceable parts. Disconnect the spark plug cap from the spark plug. Carefully remove the plug wire to the ignition coil from its hooks that keep it in place on the engine.

Pull the plug wire out of the coil where it inserts: It's typically just pushed-in onto a spike in the coil. Use a screwdriver to disconnect the coil unit from its harness, or bracket on the engine.

Put the securing screws aside. Carefully pull the coil off the bracket, and then carefully disconnect the engine and vehicle wires from the coil itself. Attach the ends of a multimeter to the coil connections for input and to ground, testing electrical resistance in the unit. Replace the coil unit with a new one, if the reading shows as infinity or zero.

This means that there is no resistance the unit is burned out. Take the good unit, or a new coil and reconnect it to the engine bracket. Insert a new length of spark plug wire, after connecting the spark plug cap to one end.

Insert the other end into the coil receptacle for the wire. Reconnect the spark plug cap to the spark plug. This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.

To submit your questions or ideas, or to simply learn more about It Still Works, contact us. Step 1 Disconnect the spark plug cap from the spark plug.

Step 2 Use a screwdriver to disconnect the coil unit from its harness, or bracket on the engine. Step 3 Attach the ends of a multimeter to the coil connections for input and to ground, testing electrical resistance in the unit.

Tip If a replacement coil for your two stroke engine is fairly inexpensive, you're better off just replacing it with a new unit, rather than trying to make an old one work again. Warning Do not just yank electrical wires off the coil connections. Many times, two stroke engine wires are old and will break or snap from sudden pulls. Pull on the wire end connector instead, when separating from the coil. Items you will need Screwdriver Multimeter. About the Author This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.Most motorcycles built after use a Capacitor Discharge Ignition System to power their engines, replacing the older points-type mechanical contact breaker ignition.

CDI ignitions provide the engine with powerful, reliable power and require very little maintenance. Understanding what the CDI is and how it works can help you weed out problems within your motorcycle's ignition system. A basic Capacitor Discharge Ignition system is composed of four separate components: the CDI box, pickup coil, source coil and an ignition coil. The CDI box is the heart of a motorcycle's ignition system, containing a series of diodes and semiconductors that amplify the volt current supplied by the motorcycle's battery between a to volt range.

The amplified current transfers to a capacitor, a device used to store an electrical current for short periods, housed within the CDI box. The pickup and source coils, a pair of hall-effect sensors responsible for charging and discharging the capacitor, mount near the magnetic flywheel attached to the end of the engine crankshaft.

At the output side of the ignition system is the ignition coil, which amplifies the current further before releasing it into a spark plug.

As the motorcycle's engine runs, a notch cut into the side of the magnetic engine flywheel passes between the source and pickup coils. The sudden drop in the magnetic field triggers the source coil, allowing a volt current to flow into the CDI box.

How Do You Bypass a CDI Box?

The current amplifies to a higher voltage, usually between and volts, and is stored within the capacitor. A drop in the magnetic field triggers the pickup coil and the capacitor discharges its stored current into the ignition coil. The current passes through a tightly wound wire within the ignition coil, called a primary coil, where it is amplified further to an excess of 10, volts. The final output current feeds through the ignition coil spark plug cable and into the spark plug, where it discharges within the engine's combustion chamber.

This cycle repeats itself at every revolution of the engine. Under normal circumstances, a CDI-type ignition system requires very little attention aside from regular spark plug changes.

Some motorcycles allow for some adjustment in the ignition timing, which changes the points at which the source and pickup coils are triggered, by using a movable coil plate. Ideally, the pickup coil should trigger the ignition coil just before the engine's piston reaches the top of its stroke.

Moving the plate against the flywheel's rotational direction advances the timing and creates a spark sooner. Alternatively, moving the plate in the same direction of the flywheel retards the timing, generating the spark later. A mark along the edge of the coil plate will indicate the timing position relative to the position of the piston.

Adjustments to the ignition timing are not usually required unless the motorcycle is being used for competition. Such adjustments can affect the machine's reliability unless performed carefully. Most CDI ignition problems experienced in a street-ridden motorcycle originate within the charging system or battery.

In order to generate the current needed to produce a spark, the battery must supply the CDI box with a full volt current. Unfortunately, the battery must also power the motorcycle's lights as well. If your motorcycle's engine turn over, but doesn't start, completely charge the battery with an automatic battery charger before checking anything else. If the motorcycle still refuses to start, perform tests with a multimeter to determine if the CDI box incurred damage.

Factory service manuals provide the testing procedures and CDI box specifications needed by your motorcycle. This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.

To submit your questions or ideas, or to simply learn more about It Still Works, contact us. About the Author This article was written by the It Still Works team, copy edited and fact checked through a multi-point auditing system, in efforts to ensure our readers only receive the best information.The cc GY6 ignition system is fairly easy to troubleshoot in the case of malfunction.

Ignition system testing, Magneto coils, Points and CDI

There are 4 major components that work together to produce spark, if any of these are defective spark will be lost. What we will be doing here is troubleshooting these ignition parts starting at the source, and working towards the spark plug. To diagnose your ignition system, you will need to do each of the steps in this article, in sequence.

Before getting started, take a look at this diagram. Although there are many differences in wiring between models, most GY6 ignition systems work the same as shown in this illustration.

A very common cause of no spark is a defective ignition or kill switch. Before beginning to troubleshoot ignition problems, it is best to bypass the switches. Note the wrapped ignition winding, and trigger module. Ignition Winding: Depending on your stator type, you have either 6, 8, or 11 windings.

Of these windings, one is dedicated to supplying the CDI with ignition power. This winding is usually wrapped in white cloth material and sealed over with clear epoxy.

moped ignition system

Trigger pickup: A simple type of crankshaft position sensor. Sends a signal to the CDI to let it know when to send fire to the plug. This current is stored in a capacitor within the CDI unit. When a signal is received by the trigger pickup passing over the flywheel magnet, the CDI will discharge the stored energy into the wires leading to the ignition coil.

The minimum we have seen working is around 18vAC. Black is neutral, green is input from the CDI. The function of the ignition coil is to multiply the voltage of the power supplied from the CDI, and to send the multiplied power to the spark plug.

Troubleshooting the Ignition Coil: Check for 0. The best way to tell if the coil is bad is to perform steps the steps above. If there is still no spark, the coil is likely bad. The plug is very rarely the cause of no spark on the GY6. If the plug is fouled or cracked it may not spark. Ensure that the spark plug is gapped properly. Recommended spark plug gap: 0. Please consider supporting this article and our efforts to provide the best technical support to the GY6 community.

We have all of these parts.Ducati style CDI box plus ignition coil with spark plug wire. Convenient all in one package for late model Vespa CDI mopeds. Includes roughly 13" spark wire. Original points ignition coil for Vespa Piaggio and Kinetic mopeds. Piaggio Universal points ignition coil. Can be used on 6 or 12 Volt systems, points or CDI set ups.

How to Test a Two-Stroke Engine's Ignition Module and Coil

Puch Maxi Points ignitions as well. Mounting hole eye Original Kinetic TFR internal ignition aka feeder coil with lead and male end clip.

Please compare before purchasing. Original Kinetic TFR internal light coil. Includes the grounding earth wire. Mounting hole distance is Best used with terminal nut style plugs. The mounting hole distance is about 32mm so be sure to measure yours first.

The mounting hole distance is about 48mm so be sure to measure yours first. Novi number Tomos 2 wire CDI ignition coil with spark plug lead. As well as other Ducati ignitions. Tomos Will work with Puch Maxi Points ignitions as well. Mounting hole distance is 52mm center to center. Also works on early NC50 and NA50 models with similar setup.The electrical system on a moped is the most mysterious and crucial set of components on a bike.

They control the primarily the lights, horn, and ignition since mopeds tend to not have other electrical subsystems. But it is because of the bare bones nature that they exhibit some of the illogical problems. Loss of spark due to a brake light failure and that sort of tom-foolery. The majority of mopeds fall into the category of fixed-magnet, ac generator with simple points and condenser ignition and a balanced load for lighting with a common ground through the frame.

Bikes with blinkers installed in the system have blinker relays and voltage regulators primarily and may or may not have voltage rectifiers installed and a battery lighting system.

Tomos early models only have regulators and relays for signals while Vespa Grandes have battery system for instance Some newer and much less moped-y bikes have electric starts and all the works that come along with that.

All electricity on a moped comes from an electrical generator called a magneto which is powered by the engine itself. The magneto consists of a flywheel with permanent magnets inside mounted to the crankshaft. The crank rotates the magnets around coils which in turn produce the electricity. This is different from the alternator on a car which has electromagnets to produce the electromotive force EMF and a regulator that can change the strength of the fields to suite the load on the system to account for turning lights on and such.

Inside of the flywheel or outside if it's a Jawa there will be 2 or more coils.

moped ignition system

One coil is dedicated to powering the ignition system and the rest are for the lights and horn. These coils may be called the generator, low-tension or exciter coils although all the terms are a bit confusing when the word coil usually refers to the large thing that goes to the spark plug.

So care will be taken to use specific terms when referring to coils here. Generator coils are grounded to the bike through themselves and a wire comes off that goes to whatever it is they power. Some generator coils have more than one winding and will have two wires coming off of them but both go to something and are not ground.

Puchs are a good example of that style of generator coil. What is important to observe is that generators produce AC current, not DC. And that ground on a moped is not positive or negative it's just ground.

moped ignition system

And a DC voltmeter will not work on a moped. The generator coil that powers the ignition system will then travel to either a set of points and THEN to the high tension coil series or will run to the points and ALSO the high tension coil parallel called a "energy transfer ignition". If you disconnect the wire going from the generator to the HT coil and ground it through a continuity tester when you roll the motor over it will show an open circuit when the points open if its in series and will not change if its a parallel meaning its a pain in the ass to set point timing.

Always in parallel with the points is a condenserwhich is just a fancy word for capacitor. The condenser's role is to hold off the back emf that comes from the high tension coil to the points until the gap is wide enough that they don't arc. Arcing across the point faces wear down the material quickly either leaving poor ignition firing, changing the timing, or it simply welds the points closed keeping the bike from running at all.

The points are an electrical switch that is operated by the crankshaft and sets the timing of the spark. A wire leads from the points to the HT coil and will also branch off here to the kill switch. When the switch is set to run the switch is an open circuit to ground does not conduct and when the switch is set to kill it's closed current can flow. While the switch is in kill mode the coil is still physically connected to the points the same way they were but what happens is the resistance between the points and ground through the kill switch is much lower than the resistance between the points and HT coil.

Meaning all the current is diverted to ground instead of through the HT coil. It is effectively a short circuit in the ignition system that you control unlike the ones you don't control that leave you stranded somewhere.


The spark itself is created by the high tension coil which converts low voltage to high voltage when the current through it is changed say when the points open and the current drops from whatever it is to zero instantly. The high voltage travels down the big wire to the plug cap then into the spark plugacross the spark gap, and back to ground through the head. It does this every time the cylinder fires, which is every revolution on a 2-stroke and every other on a 4-stroke.

Which means that if you are going 9, RPMs then its sparking 9, times a minute, or every 6. Which is a lot considering that it must do it at the same point in every revolution with enough strength to spark strong enough to ignite the fuel.

The generator coils that go to the lights and horn make up the rest of the electrical system. The wires go to the switches and then to the lights and then back to ground. Sometimes there are turn signals and sometimes there are high and low beams for the headlight.This should work for most U. This is for a three wire points system without blinkers. The Vespa ignition system should only have two internal coils. If it has three coils, then its a system set up for blinkers and a battery.

Check out our Mopeds for sale in Houston for Vespa moped models. To begin we will be wiring up the external ignition coil for spark, front, and backlights. The Vespa moped engine should have two wires coming from the engine and one connector on the engine case.

From the engine, there should be violet or black wire. It may look pink as well. The violet or black wire connects to the external ignition coil. This would be a good time to hook up a kill switch. To do that, you need a basic two position switch. Connect a wire from one post or connection on the switch to the violet wire on the external ignition coil.

The other connection on the switch will need to be ground out. Some switches will ground to the handlebars they mount to, others may have a wire that can be connected a ground post on the engine or to bare metal on the frame. Next, we will connect the brake light. Connect the blue wire from the engine to the brake light post on the rear light.

The tail light should have three posts.

GY6 150cc Ignition Troubleshooting Guide: No Spark?

One post is for the running light. A second post is for the brake light. The brake light shines brighter than the running light. The last post is for the ground to complete the circuit. Then branch off from the blue wire another blue wire to one of the posts on the right brake lever switch.

Then connect a wire from the second post on the right brake lever switch to one of the post on the left brake lever switch. Finally, connect a ground wire from the second post on the left brake lever switch to complete the circuit. It is also a safety feature for some U. If the brake light bulb burns out, the circuit will not complete and the ignition coil will not get any power from the violet wire causing the system to not provide the spark.

Finally, we will finish up with wiring the headlight, taillight, and horn. A switch for the lights is optional, but if wiring a horn, a button will be needed. The button will need to also ground to the handlebars or connect to the ground circuit. There should be a male connection post on the side of the engine near the area where the blue and black or violet wire.

This is the power lead for the headlight, running taillight and the horn. Connect a red wire from the engine post to one post on the horn.


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