The moped has lost spark, what should I do?

Very often the reason that the engine does not start is the lack of a spark at the spark plug. This is diagnosed very simply:

you need to unscrew the spark plug from the engine (or take a spare one),
put a candle cap on it,
turn on the ignition,
press the spark plug to ground
crank the engine with the starter, or better yet, with the kickstarter.

If a spark does not jump between the electrodes of the spark plug, the engine will not start.

But fortunately, the ignition system on Alpha mopeds is quite simple and you can find the fault on your own.

I always try to follow the principle “from simple to complex” when troubleshooting. That is, before disassembling half of the moped, you need to try to check everything that is easy and cheap to check.

First, remember what preceded the malfunction: some work may have been carried out or there may have been mechanical damage (for example, the moped fell). If something like this happened, start troubleshooting from there. There is a high probability that upon inspection you will find a broken wire, damaged insulation, a damaged connector, or something else.

Be sure to try cranking the engine with a kickstarter; it happens that the starter turns too slowly and there is no spark.

Spark plug, high-voltage wire, tip

Next on the list is the spark plug. It happens that an apparently serviceable spark plug does not work, so it is better to immediately replace the spark plug with a known serviceable one. Even if the spark plug was in good working order, it’s okay, spark plugs are “consumables”.

Be sure to take a spark plug recommended by the moped manufacturer, or its complete analogue, selected from the catalog. Do not listen to “experts” who recommend non-standard spark plugs, for example, with an increased gap or three electrodes.

If the spark plug is working but there is no spark, check the tip of the spark plug and the high-voltage wire. There should be no mechanical damage or cracks on them.

Mopeds of the Brize Delta Dingo series.
A little about repair and operation. >> If there is no spark Carpets 2008

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Turn the ignition key to the operating position; if the number corresponding to the engaged gear (speed) does not light up on the dashboard, then check the serviceability of the fuse located under the battery cover. Or there is a problem with the battery. If the new fuse is blown, you will have to look for a short circuit in the headlight, between the gas tank and the steering wheel, under the side covers, under the rear panel. Very often, after a trip in the rain, the ignition switch burns out. Checking it is very simple - open the headlight and disconnect the connectors from the harness from the ignition switch, try to start the engine.

If the engine starts working normally, then you will have to change the lock or repair the old one.

Remove the lock from the instrument panel, disconnect the power wires, then carefully release the latches and remove the contact part.

Ignition

Between the contacts you will see burnt textolite, which will have to be removed with a sharp object. Assemble the lock and connect the power wires. Start the engine. If it does not work, it means that the burnt-out conductive textolite was not completely removed. Repeat the procedure. (As a rule, such a breakdown only occurs once, so do not bother with the idea of buying a new lock).

Switch

Well, in the worst case, your generator coil has simply burned out and there are only two options: 1. Rewind the coil. 2. Buy a new one. It is extremely rare to find specialized workshops for rewinding such products, after which the restored reel will last a long time (and your moped will not break somewhere in the forest). ignition switch

Babina

Electronic ignition of these types of engines is a rather complex mechanism, where the generator induction coil produces current, the sensor removes the voltage at the right moment, and the switch determines the spark advance at various engine speeds.

The power ignition coil or coil, as it is popularly called, serves to convert low current into the high voltage necessary to produce a sufficiently powerful spark at the spark plug.

Starter relay

Provided that the battery is in perfect order, the fuse is working:

1. Briefly tighten the two 10mm nuts on the starter relay.

The starter revs, which means it is working. Using the method of elimination, we will find out that the reason is not in it, but either in the starter relay or in the start button on the steering wheel (on some models).

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Ignition coil

If everything looks intact, check the ignition coil. To do this, disconnect it (remembering how the wires are connected) and use a multimeter to check the resistance of the windings.

The primary winding is made of thicker copper wire. Its terminals are connected to two terminal connectors at the end of the coil. It has a small number of turns and therefore its resistance is low, approximately 0.5-5 Ohms. One wire of the coil is connected to ground - you need to check it, attach one multimeter probe to the nearest metal part of the moped, and the second to the coil connector. The resistance should be close to zero.

The high-voltage coil consists of several thousand turns of very thin copper wire, so its resistance should be on the order of 2-5 kOhms. The resistance must be measured between the coil contact connected to ground and the core of the high-voltage wire.

In this way, we will check the coil for a break, but without special equipment we cannot check for other coil faults, for example, an interturn short circuit, so we will leave the coil alone for now, also because a coil without visible mechanical damage is most likely working.

Why is there no spark on the moped?

So, your moped has lost spark. Now I will tell you what needs to be done in this situation. 1. First of all, you need to check the serviceability of the candle; it should not have excess dirt and be of a natural color. 2. It happens that the spark disappears due to a faulty ignition coil. To check this, you need to use a low-power light bulb to make sure that the current is supplied. 3. You should also check the distributor and the wires leading to it, because the distributor is often to blame for the loss of spark. 4. It is possible that the reason for the loss of spark on the moped is insufficient battery charge. For a 12-volt battery, the level is at least 9 volts.

5. Another problem may be a malfunction of the generator. First you need to check that the adjacent contacts are in working order and check that the capacitors are working correctly. Or it could be a defective generator winding.

But still, it is best to visit qualified motorcycle mechanics. And this is regardless of whether a problem is detected or not, because the problem of spark supply can be serious. Why is there no spark on the moped? Link to main publication

moped-info.ru

Switch

To check the switch, we need a test lamp - this is a regular 12-volt light bulb with wires routed out for easy connection. A test light and connect one end to the ground wire, the other to the ignition coil wire. We turn the engine with the starter.

If the light comes on, the switch and its wiring are working properly. If the light does not light, then the switch or switch wiring is faulty. In order to be 100% sure that the problem is not with the switch, I recommend replacing it with a known good one. A switch for Chinese mopeds is inexpensive, if it suddenly turns out that the old switch is working, let it remain in “stock” until the next check.

What else could be wrong?

By the way, a weak spark on a Chinese motorcycle is no more rare than on domestic two-wheelers. At the same time, some motorcycle owners are sure that it is easier to find and eliminate the cause of a weak spark on a domestic motorcycle than on an imported one.

If inspecting and replacing the coil did not help, if you are convinced of the integrity and normal connection of all contacts, and even if replacing the spark plugs with new ones did not help, further search for the cause of a weak spark on the motorcycle will have to be carried out inside the pulse sensor or in the engine control unit.

It will not be possible to carry out this diagnosis using simple improvised means in an “open field”. To measure sensor pulses, you need an oscilloscope and a technician who understands its readings, the shape of the curve and the amplitude that the device produces. If the pulse sensor fails, you can replace it with either an expensive kit with generator coils. Or a non-original analogue - having searched for a suitable replacement in the markets and disassembly shops. The main thing is to leave the original generator windings.

Generator and ignition sensor

You can check the generator and sensor without removing them from the engine.

We switch the tester to the AC measurement mode for the 2V range or, if your tester has such an option, for 200mV. With one probe we touch any metal part of the scooter or engine, with the other probe we touch the sensor wire (in the picture above it is labeled as a Hall sensor, but in fact it is an inductive ignition sensor). We turn the engine with the starter and look at the multimeter display. If the numbers are flashing on the display, it means the sensor is generating a signal and everything is fine with it. Otherwise, the sensor is faulty or the wire is broken.

If you know easier ways to check or something is not described in sufficient detail, write in the comments. I will be glad to improve the article based on your feedback.

What could cause

The reasons why mopeds no longer start may be the following:

fuel system
ignition system
compression
engine oil.

Each of these categories includes many details, which we will learn about below.

Fuel system

Nothing to burn, or lack of fuel in the combustion chamber, is the main reason why the moped will not start. Below are a number of common breakdowns and ways to fix them.

Low quality fuel. Diluted gasoline or old fuel will not allow the engine to start. A particularly pressing problem is when the delta or alpha does not start after winter. The fuel in the tank has lost its combustible properties and may not even ignite.
Faulty fuel valve. If fuel from the tank does not flow into the carburetor, the fault lies in the fuel tap. If you have a scooter, then immediately change the tap, first checking the presence of the supplied vacuum. You can try to clean the faucet on a moped.
A dirty fuel filter can prevent gasoline from entering the carburetor. The filter must be clean.
Carburetor. If the moped starts and stalls, there is an 80% chance that the cause is in the carburetor. To clean it, you can use a carburetor cleaner, but the safest thing to do is disassemble it and wash it yourself. The shut-off needle must be free of defects and the fuel jets must not be clogged!
A clogged air filter is another reason why the moped has difficulty starting. After all, for an engine to operate, it requires not only gasoline, but also air. Remove the air filter and try to see if the moped starts. If it starts, then the problem was in the air filter - clean it.

Motorcycle won't start when cold

Trying to start the engine in cold weather? You'll have to work hard to "wake up" him. The fuel mixture in the combustion chamber ignites only at a certain temperature, and engine oil becomes very thick in cold weather. We check the condition of the oil and depress the clutch during the starting process.
Was the equipment stored in a poorly heated garage during the winter? In spring, rust appears on its components due to high humidity. Before you go on your first spring trip, the rust from the ignition parts must be removed.
Difficulties with cold starting also occur in the warm season. If the motorcycle does not catch (does not start) after a long period of inactivity, you need to check the condition of the carburetor or increase the fuel level in the float chamber.

Checking the ignition timing

If there is a spark, fuel is supplied, compression is fine, but the moped still does not start - the ignition timing may be off.

On 139fmb engines, which are installed on alpha, the ignition timing is not adjustable. It is rigidly determined by the position of the flywheel on the crankshaft. The engine crankshaft on the generator side has a conical surface on which the flywheel (also known as the generator rotor) is tightly seated. The correct position of the flywheel is set using a key that is inserted into the crankshaft keyway.

You can check this visually (remove the generator cover, unscrew the nut securing the flywheel and see if the grooves match). But the groove on the crankshaft cannot always be seen (depending on the specific instance), so there is a more reliable way: buy or borrow a strobe light from someone (many car repair shops have one), unscrew the plug on the generator cover and check that flashes occur at the same time the label || appears in the window.

The service life of a moped depends on maintenance. Care comes down to following the rules recommended by the manufacturer.

The main ones include:

Testing a new scooter. The first concerns the running-in of a new scooter. The scooter must not be overloaded for the first 1000 km. When driving for a long time, you must stop every 30 minutes to prevent the engine from overheating.
Correct use in winter. You need to drain the fuel before storing the scooter in the garage for the winter. Remaining fuel can destroy the tank and flood the carburetor. If you plan to use the scooter in winter, you need to change the fuel, check the battery charge, oil level, condition of the filters and tire pressure (it should be about 1.5 atmospheres).
Correct use in summer. In hot weather, it is important to prevent the scooter from overheating. When driving for a long time at 30 degrees, the cylinders will be constantly overheated. This could cause the belt to break or the engine to break down. You should also not squeeze the throttle for too long, and when stopping, immediately turn off the engine.
Use quality fuel. Gasoline must be at least 92. On a new moped, you need to change the oil for the first time after a run of 500 km. Subsequent replacement will be required every 1000 km. The first time to change the oil in the rear gearbox is after 200 km, then every 5000 km.
Replacing the variator belt. This part is considered a consumable item, as it wears out quickly due to the high power load. If the moped stops squeezing out high speed, then the part and its components need to be replaced.
Carburetor maintenance. The procedure includes a visual inspection for leaks and gasoline consumption levels, checking the condition of the connecting elements and the serviceability of the unit elements.
Filtration quality control. The filter must be replaced promptly and impregnated with a special product after installation. This is necessary for high-quality air purification. Dirty air reduces the life of the motor.