Possible reasons
First of all, you need to look for a breakdown in the scooter’s structure, but you also shouldn’t forget about other reasons, for example, external influences. The main breakdowns will be discussed below.
Belt variator
A variator is a device for increasing the speed of a scooter by using rollers of different diameters. The main element of this mechanism is a belt that transmits torque. It must be of a certain length, width and, most importantly, thickness. A slight wear of the belt by just 1 mm can change the overall radius of the belt loop, which leads to a drop in the maximum speed. It is clear that you cannot measure the thickness of the belt by eye; for this you will need a caliper. If the measurement shows a deviation from the norm by 1 or 1.5 mm, the belt should be replaced
There are several types of scooter breakdowns
CVT rollers
These elements of the gear shifting mechanism wear out over time. They become thinner or lose their correct geometry, for example, only one side of the roller wears off and it stops performing its functions. The repair is simple - replacing the worn out roller. There are two options for rollers - expensive high-quality and cheap. Knowledgeable people recommend buying cheap ones, since both of them are erased after about 3-5 thousand kilometers. Therefore, there is no point in overpaying.
Air filter
A visual inspection of the spark plug helps to understand that the reason is in this particular unit - it is covered with black deposits. It is also worth paying attention to increased fuel consumption, this also indicates a problem with the air filter. That is, the combustible mixture becomes enriched due to lack of air, hence the deposit on the spark plug and increased gasoline consumption.
Piston
Several parts in this unit may become unusable - sealing rings on the cylinder, cylinder walls, for example, due to scratches, chips on the piston. Piston problems are easily diagnosed by measuring compression. If it is less than 7 atmospheres, then you need to disassemble the engine. Repair depends on the degree of destruction of the piston, but in any case, it is necessary to replace all gaskets in the block, even if the repair consisted of replacing the O-ring.
The variator belt must be of a certain length
Muffler
If it is clogged, then the engine power is sharply reduced. Repair consists of replacing the muffler or burning it. It is possible, in principle, to remove it completely, but then the roar of the engine will disturb the peace of the townspeople.
Dirty carburetor
This device is designed to prepare a combustible mixture consisting of gasoline and air, which are mixed in certain proportions. A carburetor is a rather complex device, having a lot of nozzles and jets. This is precisely how they can become clogged during operation with dust or small fractions floating in gasoline. The holes are so small that to clean it you will have to completely disassemble the carburetor and blow them out with a compressor, and the device itself must be thoroughly wiped with gasoline, both inside and out. If you don’t have a compressor at hand, you can try to clean the inside of the carburetor with a special compound, sold in auto stores in the form of aerosol cans.
The carburetor needs to be cleaned regularly, approximately once every 3-5 thousand kilometers.
Poor quality gasoline and oil
You need to understand that a scooter is not a jeep or a truck. Its carburetor, cylinder and piston group are very small in size. Even the smallest particle that gets into the fuel or oil can damage them. That is why gasoline and oil for a scooter must be of high quality, clean, and free of impurities. Gasoline must be exactly the octane number specified by the scooter manufacturer. Under other conditions, the engine will perform poorly and, accordingly, the maximum speed will decrease.
Engine power is sharply reduced if the muffler is clogged
Worn bearings
The crankshaft of the scooter engine has bearings installed for better rotation. When they wear out, the crankshaft rotates more slowly and the engine runs weaker, which reduces speed. The way out of this situation is to replace the bearings. Such repairs cannot be done “on the knee”, so you will have to change them in a service workshop or in a garage, completely disassembling the engine.
Heavy weight
Why doesn't the scooter gain momentum and speed if the driver weighs more than 90 kg? This answer was partially answered above: the scooter is very small, and it is simply not able to pull more than the designers intended it to. Not every motorcycle can support a heavy person, so it’s not surprising that a scooter fails.
Riding against the wind
Oddly enough, driving against a strong headwind also leads to a decrease in speed. This is not surprising, because this phenomenon occurs in any transport. Even an airplane flies much slower in a headwind than in a calm or tailwind.
Faulty spark plug
The spark plug produces a spark that ignites the combustible mixture in the cylinder. A spark is formed between the contacts under the influence of electric current. And, if the contacts are dirty or faulty, or there is too much distance between them, then the mixture will ignite slowly, which will affect the speed of the scooter. Spark plugs need to be changed regularly, without waiting until they burn out. This is usually done every 2-4 thousand km, depending on the quality of the spark plug and the operating mode.
Spark plugs need to be changed regularly
Faulty starting enrichment
This unit is serviced together with the carburetor. If you clean it regularly, then there will be no problems with the starting enrichment.
Transmission malfunction
The scooter does not develop power due to problems with the gearbox. This is easily determined - the top gear does not engage. This happens due to the breakdown of one of the gears in the box, and the repair will consist of replacing it. This procedure should only be carried out in a garage or service center.
Piston wear
During operation, the sealing rings on the piston are changed. But over time, the piston itself wears out, and compression in the engine decreases. The way out of this situation is to replace the piston, as well as the sealing rings, gaskets and oil in the engine.
Alpha moped does not gain momentum
Many owners of Alpha brand mopeds are faced with a lot of troubles, because depending on the year of manufacture, a 4-stroke engine can operate at different rates. The technology, as you know, is Chinese, and therefore the engine will sooner or later make itself felt, quite standard breakdowns and unstable engine operation will begin. Repairing such mopeds is quite simple and inexpensive, so if you have minimal knowledge, we recommend carrying out repairs yourself. One of the most common breakdowns is when the moped does not pick up speed and the owner of the motorcycle does not know what to do, traffic stops.
The first step is to find the cause of the breakdown, because it is possible that the moped will break down again in the future. When Alpha does not gain momentum, other unpleasant symptoms will result:
- significant loss of power;
- difficult engine starting;
- increased fuel consumption;
- The engine runs unstably, with fluctuations.
Spark plug
The repair procedure is quite simple, the first thing you need to do is get into the engine and find the unit that has failed. Experts point out that a frequent case of breakdown is a faulty or damaged spark plug, so the first thing we do is remove it. Carefully examine the spark plug for defects and other damage; a working spark plug should produce a spark and do so correctly. To check, just insert the spark plug into the “cradle” and lean it against a metal surface. Then turn on the ignition and pull the kickstarter, a spark should form on the spark plug. The absence of a gap and the presence of a huge amount of soot can also be considered a defect in the spark plug. If the reason is the spark plug, change it and try to drive again. If the alpha moped does not gain momentum even after changing the spark plug, move on to the next probable cause.
Carburetor
Carburetor cleaning occurs regularly, so most Alpha mopeds have already disassembled the carburetor, thereby changing its original settings. As you know, any manufacturer provides its own data regarding the settings of the carburetor of a certain model, so it is important to make this adjustment. Cleaning the carburetor is a fairly simple but important procedure; our website has a detailed description of this process. The carburetor should be blown out, washed and completely cleaned of foreign debris.
Moped does not gain speed under load
In the case of a high load, a malfunction may occur, as a result of which the moped does not gain momentum. The moped owner will immediately have to look at the gas distribution mechanism, that is, the valves. Parts such as valves are located in the cylinder area, so if you often notice an extraneous and unpleasant sound from the cylinder, there is most likely a problem in the gas distribution system.
The cause of such a serious breakdown could be an insufficient air supply, and often the air filter has a hole through which air passes. In the absence of special skills, the best solution would be to contact a specialist; repairing the gas distribution system is almost impossible. In this case, experts advise buying a new air filter or a complete gas distribution unit. The replacement process occurs as follows: the old head is removed, a new part is put in its place, and the valves and clearances are adjusted.
Conclusion
Now we know why the moped does not gain momentum; the reasons, as you can see, are simple, but require certain skills. If your Alpha moped does not gain speed, the reasons for this will be a broken spark plug, a malfunctioning carburetor or a faulty gas distribution unit.
Inspection procedure and repair methods
If the scooter does not travel more than 40 km. h., then there is a certain procedure for checking and searching for causes. Accordingly, for each reason there is its own algorithm for repair work.
There is a specific algorithm for repair work for each breakdown.
First of all, the spark plug is checked. To do this, you need to unscrew it and inspect it. If the contacts are clean, then everything is in order. If they are covered with black soot or, on the contrary, they are clean but have a red tint, then there is a problem with the mixture. Repair in this case consists of cleaning and servicing the carburetor.
Next, you can check the quality of the spark on the spark plug and, if it is weak, you need to check the contacts on the high-voltage coil, on the inductive ignition sensor and on the ignition switch. The presence of a short circuit in the specified components and breakdowns to the housing are also checked.
The next step is checking the engine. To start with its temperature. If it overheats, it could mean the mixture is too lean or the fuel is bad. This can be eliminated by cleaning the carburetor.
You can measure the compression at the nearest service station, and if it is low, you will have to disassemble the engine and look for a problem in the piston group.
Scooter engine runs at high speeds
Even after tuning, the scooter engine runs at high speeds . First, you need to make sure that your scooter's throttle is completely closed to prevent throttling. If the throttle is not completely closed, you need to check the adjustment of the throttle control cable (throttle) and adjust the cable properly.
However, if the damper is closed, and the speed is still high and cannot be adjusted, you need to check the idle jet in the carburetor to ensure it corresponds to the required markings, namely, the required diameter for a specific scooter model.
