DIY scooter (moped) repair
The popularity of scooters is growing every year.
And this is not surprising. Low cost, ease of maintenance, good performance characteristics make the moped an indispensable thing in the lives of many. In many countries around the world, the number of scooters on the streets exceeds the number of cars. They have high maneuverability, which allows residents of big cities not to think about traffic jams. However, sometimes situations arise when the moped breaks down and does not want to start.
You can repair the scooter yourself or take it to a workshop. This is everyone's personal decision. Having decided to repair it yourself, you need to prepare the space for this. Most often, repairs are performed in the garage.
The most common problems associated with changing oil and filters . Incorrectly selected oil may cause the engine to not start.
First you need to drain the old oil through the drain hole. Then the carburetor is completely disassembled.
The installation and repair of Chinese mopeds should not cause big problems for a person who understands this at least a little.
From a four-stroke internal combustion engine to a car
The team of engineers who worked on the creation of the unit included one talented guy - Gottlieb Daimler.
He was then passionate about the idea of creating a real car based on this engine. But Otto did not want to modernize an already successful engine. Daimler was forced to leave the project, but the desire to build a car did not go away.
As a result, together with his friend and like-minded person in 1889, Daimler assembled a car based on a four-stroke gasoline engine operating according to the Otto algorithm.
How to detect a breakdown
In order to identify a scooter malfunction, it is necessary to check all elements in turn. The performance of any scooter depends on the proper functioning of components such as compression, fuel and spark. If one of the elements does not work, the scooter will not move.
Fuel may cause the moped to not start if gasoline has been added for a long time. As studies show, the octane number of gasoline decreases when it stays in the tank for a long time, that is, its quality noticeably deteriorates. There is only one result: a spark does not ignite such gasoline. If you know that you have been filling up with fuel for a long time, it is best to drain the old gasoline and fill in new gasoline in its place .
The second reason that the scooter does not start may be a dirty filter - fuel or air. A fuel filter is necessary to clean gasoline from various impurities and rust. The engine must receive clean gasoline, since this affects the wear of many parts of the moped.
The air filter is designed to clean the air that enters the carburetor. It needs to be changed quite often, since dust, dirt, etc. constantly settles on it.
The third reason that the engine will not start may be the lack of a spark. Checking whether the candles are to blame for this is as easy as shelling pears. It is enough to replace with new ones. If it is not possible to start, and the gasoline is fresh, you need to look deeper for the reasons.
Kill cord
If the kill cord itself is connected correctly, you should check the “Stop” button. There is a spring inside it, which over time can rust and become unusable and stop working as it should. This often happens if the kill cord is left connected for a long time. If the button does not fire back, you need to replace either the entire button with all its giblets, or just the spring. A poorly functioning button may prevent the engine from starting at all.
Kill cord and stop button on a 4-stroke outboard motor
Do-it-yourself repair of individual parts
Having determined that neither spark plugs nor gasoline are the cause of the malfunction, we move on.
As noted earlier, engine problems can vary. Very often these problems are associated with spark plugs or the carburetor. The spark may not jump due to carbon deposits on the spark plug, which occurs due to the use of a rich mixture.
There may be a small gap, which also does not contribute to the appearance of a normal spark. In a two-stroke engine this gap is 0.6-0.7 mm. With a smaller gap, there is a high probability that the electrodes will melt. Increasing the gap causes current consumption to increase and more voltage is required to produce a spark.
There are situations when the moped stalls while moving, and then continues to move on. This occurs due to the detachment of carbon deposits from the electrode. For some time the spark is lost and the engine stops working. After self-cleaning, performance is restored.
Interruptions in engine operation may be due to moisture getting on electrical appliances and wiring. This results in a loss of voltage. After drying these parts , engine operation should be restored.
A fairly common cause in our climate is water getting into the fuel and then into the carburetor .
The reasons considered are easily eliminated by the driver themselves. However, if these steps do not bring the desired solution and the engine does not work, the scooter engine should be repaired.
Carburetor repair
As for the carburetor, the causes of malfunctions may be caused by improper mixture quality. If the mixture is lean or rich, the performance of the moped will be at risk. The quality of the mixture can be checked by the condition of the candle. A black color will indicate that the mixture is rich, that is, there is excessive oil consumption. White color will indicate a lean mixture and a decrease in engine power for this reason.
Repairing a scooter carburetor is performed on a warm engine. Before this, if there is a possibility of clogging, it should be cleaned and washed. The carburetor adjustment itself consists of the following actions:
- Step 1 – you need to adjust the idle speed.
This action is performed using the idle screw. In order to increase the speed, the screw is tightened, and to decrease it, it is unscrewed. After warming up the scooter, with the help of simple manipulations, you can set up stable idle operation of the engine.
Step 2 - check and adjust the quality of the mixture for the carburetor using a special screw.
The combustible mixture that enters the carburetor must clearly have the proportions set by the scooter manufacturer. If the mixture is too lean, the scooter loses power and overheats. With a rich mixture, fuel is used uneconomically. This problem can be solved by turning the screw. Turning the screw clockwise enriches the mixture, counterclockwise turns it leaner. The quality of the mixture will be indicated by the color of the candle. The candle is black and has carbon deposits, which means the mixture is rich. If, on the contrary, it is white, the mixture must be enriched.
Step 3 – set the quality of the mixture by moving the needle.
The following manipulations are performed with the needle: when raising the needle, the mixture is enriched, and when lowered, it is leaner.
- Action 4 – adjusting the fuel level in the float chamber.
Checking the fuel level is done with a transparent tube located at the bottom of the carburetor. The procedure is as follows: unscrew the oil screw, lift the tube up and check the fuel level. The fuel level is monitored while the engine is running. The tube should be kept above the carburetor. The fuel level should be slightly below the curb of the carburetor cover.
Features of repair of Chinese mopeds
Repairing Chinese engines does not cause any particular difficulties for most scooter owners. It should be remembered that the main fastenings of the “Chinese” are more delicate than in domestic mopeds, so there is no need to pull anything with all your might.
For example, sudden movements when repairing the carburetor of a Chinese scooter can damage the pipe . Then the muffler is removed. Many Chinese scooter manufacturers use plastic soldering. This must be taken into account when disassembling the moped.
Manufacturers have foreseen that many scooter owners will want to carry out repairs themselves, so there is simply nothing complicated in the design of such scooters. The repair manual for Chinese scooters will allow you to perform all the steps yourself. Anyone can figure out the main problems and repair the engine of a Chinese scooter.
Adjusting the idle speed on a scooter
After the engine is warmed up, you can adjust the idle speed, this is done using a special screw located on any carburetor. The idle speed is adjusted to ensure that the scooter operates correctly and smoothly when not in use. The location of the screw may vary depending on the scooter model. For example, the screw is located in the center, and the mixture quality screw is installed on the left side.
The adjustment process is quite simple, as soon as the scooter starts, rotate the screw, where when tightened the speed will increase, opening the jet reduces the speed. Again, adjustments are made only on a well-warmed engine.
Scooter repair - general principle of troubleshooting
In order for an internal combustion engine to work, it needs three components: fuel, spark, compression. The main slogan of a motorcycle mechanic is “there are no miracles.” You must always remember that if, when troubleshooting and repairing a scooter, it turns out that there is a spark, there is compression, fuel is flowing, but the engine does not start, this, as a rule, only means that one of these components is actually missing .
DIY scooter repair
Too lazy to send the scooter in for repairs and pay money for it. Common situation. Then it's time to take on the repairs yourself.
The basic principle of troubleshooting and repairing a scooter is to step by step eliminate the elements of the system, trying to identify the cause of the malfunction in any of them. Search and repair must be carried out strictly sequentially, from the very beginning of the chain to the very end. That is, for example, if there is no spark, you should not immediately change the switch. First we need to make sure that our generator is “alive”, then test the wiring. Etc.
Important note: if you have a device in front of you that, according to the owner, “used to work like a clock,” it makes sense to ask whether old gasoline was poured into the tank. A couple of months of storage is enough for gasoline to lose its octane number to such an extent that it loses the ability to ignite.
It is important to remember that before making a final diagnosis and starting repairs on the scooter, you need to make sure that a known working spark plug is installed on it, and that the carburetor is functioning normally.
In addition, you need to know that the correct operation of the engine (even at idle speed) is closely related to the correct operation of the variator, clutch, as well as the camshaft and valve group. In other words, with normally functioning power supply, ignition and CPG systems, the problem may be, for example, in the transmission, since the crankshaft torque is directly transmitted to the variator.
When carrying out diagnostics and repairs, you must remember that in some circumstances that lead to the need to repair a scooter , it is necessary to check not a separate element, but the entire system. For example, if the carburetor is clogged, provided that the air filter is intact and saturated, you need to check whether there is dirt in the gas tank and fuel filter. If the scooter has been driven for a long time without an air filter, or with an unimpregnated filter, then everything needs to be checked: the CPG, the crankshaft and the main bearings.
Below are some problems that may occur, as well as basic steps to resolve them. The links indicate places where you can find information on this item.
DIY Chinese scooter repair
DIY Chinese scooter repair
The rhythm of life in a metropolis leaves few options when choosing a means of transportation. You have to ride the subway, in close contact with similar sufferers, or spend a significant part of the day inside a car that is moving slowly in a traffic jam. There is another option. Buy a scooter at an affordable price and now you don’t have to be alone in a car showroom, or join the cramped society of a subway car.
What can this vehicle offer the owner in return for lost capabilities? Buying a scooter will give you the opportunity to significantly reduce the time spent traveling to your place of work and on the way back. There will be time to communicate with family and friends, and there will be additional opportunities to do household chores. You no longer have to put everything off for the weekend and then face the new week without having time to rest.
Do-it-yourself repairs
A maneuverable and lightweight vehicle can significantly improve the quality of life, save money, time and nerve cells. And the fact that repairing a Chinese scooter with your own hands can be done simply and inexpensively will add advantages to the scooter in the vehicle market. And the spare parts offer is impressive.
Imagine for a moment: you are a city dweller, your friends bought mopeds a long time ago and ride for their own pleasure, and now you have decided to get an iron friend yourself. When purchasing, the driver is unlikely to be given a manual on how to repair a Chinese scooter with his own hands; moreover, sometimes they may recommend the wrong oil. For example, they gave you oil for a two-stroke moped, but you ride a four-stroke. As a result, you will have to carry out chassis repairs, because the scooter
won't start. You'll have to do a complete disassembly.
Be careful when repairing your scooter
But without special equipment, you won’t be able to repair a Chinese scooter yourself; you need to have at least a screwdriver on hand. First, you need to drain the inappropriate oil that has stained the internal mechanisms. Next, complete disassembly begins. A job like removing a carburetor looks very simple at first glance. But if the part is removed abruptly, the special pipe may be damaged. Then you need to loosen the muffler, or remove it completely. Most Chinese products are made using plastic soldering.
Oil
Four-stroke outboard motors have an oil pan for lubrication. It should tell you how much oil you need. You need to add oil slowly, constantly checking the sight glass, but if you overfill the oil, drain the excess into the container through the drain screw located under the sight glass.
Oil level inspection window in 4-stroke PLM
DIY scooter repair
Do-it-yourself scooter repair involves troubleshooting by sequentially eliminating specific elements of the operating system. The basis of the operation of a scooter is three components: compression, fuel, spark. If any of these components are missing, then starting the scooter is impossible. Therefore, the entire algorithm for repairing a scooter with your own hands comes down to troubleshooting, and sometimes this is the most difficult thing in the work being performed. Remember: even if you checked all these three components, the scooter
still won't start, then you checked poorly!
For those who have worked with computer repair, I will give an example. Let's say your monitor doesn't show anything (black screen and that's it). Therefore, you first check the functionality of the operating system itself, then the monitor. If the tested components are functional, then the problem is different. You check the video card and find a problem. This is the principle of mutual exclusion, which is the basis for repairing everything, including scooters.
Repair
scooter repair always begins with the fact that it turns out that you are too lazy or sorry for the money to go to a professional workshop.
First of all, check the gasoline. Gasoline in the tank quickly loses octane number, which leads to the mixture not igniting. A couple of months of gasoline in the tank is enough for this. So we change the gasoline and try again.
Do-it-yourself wheel studding.
Good day everyone! This article is from the category “It was evening, there was nothing to do.” This is not an instruction manual, it is just a description of my studding process. I haven’t discovered America, but maybe someone will find it useful. I’ll try to explain everything in an accessible way.
Lyrical digression
Recently my wife and I moved to my mother-in-law, and now I live in a remote village. The nearest city, where there are glimpses of civilization, is about 20 kilometers away. Of these, 5 kilometers are off-road, where the wheels of snow removal equipment have never driven, the remaining 15 are just snow rolled by cars. For personal transport, I have a mountain bike and a scooter. No, a bicycle is, of course, good, but it’s slow, and the load capacity of a scooter is better.
As always, winter suddenly came, and the question became acute: how to get to the city? After the first attempt to ride in snowy weather on ice, thoughts about preparing the scooter for winter appeared in my head. It was decided to install studded tires. Because Factory tires are expensive, so I started googling how to make studs with my own hands. Unfortunately, this issue is poorly covered on the Internet. On one forum I came across instructions from Evgeny Matveev. TYTS
In principle, from what I read, almost everything becomes clear, the only thing that is not clear is what the length of the screws and the diameter of the washers should be. And it’s not clear how much there should be, and how much all this fun will cost. I have experimentally determined that the optimal length of screws for me is 16 millimeters (5x16), although it’s probably possible to take it shorter. And the washers needed are 5x15. I didn’t have spare tires, so I went to a scooter workshop, where they kindly gave me two dead tires. They gave us different tires, one a little larger. But, as they say, “Don’t look under the tail of a gift horse.” Having marked the tenon markings with a pencil, I counted 100-150 screws per wheel. I decided to take with a reserve (in case my imagination runs wild), and took only 350 pieces. All this cost 95 UAH (about $11.5).
The tenon took 225 screws. 75 for the front, and 150 for the rear wheel. One tire was softer, so I had to put washers on the inside to prevent the screw heads from falling through. I have cameras in my wheels. To prevent them from rubbing against the heads of the screws, I made gaskets from old inner tubes around the entire circumference of the wheel. Perhaps it will also hold air on tubeless cameras, because... everything is held together very tightly. I note that the most convenient way is to tighten all the nuts and tighten everything with a screwdriver with the appropriate attachment. The spikes protrude by 10-11mm. There are 6-8 studs per contact patch.
Studded tires side view
I immediately carried out a test run, the result exceeded all expectations! The scooter handles very confidently on snow and sometimes drifts a little on ice. It also drives fine on asphalt. You can drive on a flat surface at speed without fear of falling. The wheels do not slip, the spikes cling tightly. The brakes work very well. Since I put wide tires on the front, the spikes caught the beak a little when driving, so I had to shorten them a little. If you drive on asphalt, the spikes may wear off quickly.
PS.PS: On video
test drive immediately after studding. I drove slowly, because... I’m not used to it yet, and the thorns caught the beak. Now I drive faster and more confidently.
Scooter repair: what you need to know
For more than a decade, two-wheeled scooters (colloquially referred to as scooters) have become a common, cheap, affordable, inexpensive and, accordingly, widespread means of transportation in both cities and rural areas.
Their owners, like any other two-wheeled vehicle, regularly face such an unpleasant need as scooter repair. The reasons why you may need to repair your vehicle can be very diverse, ranging from factory defects or poor quality of components and assemblies to breakdowns caused by accidents or natural wear and tear of parts during operation, since nothing lasts forever in nature.
How Otto developed the engine
The unit, invented by a scientist named Alphonse Beau de Rocha, and then built by the German engineer Nikolaus Otto in 1867, was considered in those years to be the maximum of manufacturability and almost perfection. There were simply no analogues for it. The motor was very inexpensive to operate, had a compact size, and also did not require frequent maintenance.
The operation of the four-stroke engine was built according to a clear algorithm. Today it is called the "Otto cycle". In 1875, Nikolaus Otto in his company produced more than 600 engines per year.
Major breakdowns
If you intend to repair the scooter yourself, and not use the services of special workshops, then you need to understand that all faults can be divided into several large categories, namely:
Each category also includes several subcategories. The most common faults are those related to electrical equipment and the engine power supply system. Therefore, we will consider them in more detail, since repairing a scooter often consists of eliminating them.
New technologies according to the old principle
Ever since the four-stroke engine was invented, it has been constantly improved.
There were many new products in the timing mechanism. For example, now the number of valves per cylinder can reach up to 5. Modern manufacturers also use special systems for changing the phases of gas distribution.
There have also been changes in the food system. Modern engines no longer use a carburetor - injectors and electronics are everywhere.
To improve the filling of combustion chambers with air, pressurization systems are used. This allows you to increase power with a small volume, as well as reduce fuel consumption.
But with all this, the principle of operation of the internal combustion engine remains the same as it was.
Troubleshooting
The first and main sign that the equipment needs repair is the inability to start the engine. Scooter repair begins with identifying the fault and then eliminating it. In this case, the breakdown must be looked for starting from the place where the thermal energy of the burnt fuel is converted into mechanical energy of the rotating crankshaft of the engine. So let's get started:
— determine whether fuel enters the combustion chamber,
— is there a spark between the spark plug contacts?
If all of the above factors are present, then the following malfunctions are possible:
1. There was a breakdown of the spark plug insulator. To do this, simply replace the spark plug.
What vagaries does a single-cylinder diesel engine have?
Since a single-cylinder diesel engine creates high temperatures during operation, its rubbing parts that create steam need cooling and good lubrication. And the gaps between them must be periodically washed in order to remove unnecessary products of mechanical wear. In addition, oil also ensures heat removal from loaded surfaces. It follows that it is necessary to maintain a good level of high-quality oil in such a car.
In order to prevent overheating of the worker and to cool the elements of the engine heads and cylinder liners in a timely manner, an additional cooling system is used; it can be either air or liquid. These systems are equipped with thermostats to ensure stable operating temperatures. When all these components work smoothly, your machine performs as efficiently as possible and is a pleasure to use. But from here we can also talk about significant discomfort in the event of any breakdowns; this becomes noticeably noticeable.
Troubleshooting
Malfunctions of electrical equipment and fuel systems are the most regular of all problems that arise among scooter owners.
It often happens that a breakdown suddenly occurs to the scooter. Repairing the carburetor, as a rule, allows you to resume the functioning of your “faithful horse”.
Usually, to do this, it is enough to remove the carburetor, clean the dust from the outside and the tarry deposits of gasoline and other debris inside. Clean and blow out the air and fuel channels and jets, check the condition of the fuel needle and throttle valve, and then reassemble and adjust it.
Fixing more complex breakdowns at home is not always possible, since specific tools are often required that are not widely available.
Thus, for a technically literate person, repairing a scooter with your own hands will not be very difficult if you have minimal knowledge and skills in handling equipment, as well as the necessary tools.
Four strokes: disadvantages and advantages
The main and “bold” advantage of such units is their efficiency. Plus they are not too noisy.
The use of catalysts together with them makes it possible to reduce the toxicity of exhaust gas emissions.
Another advantage is, of course, high reliability. The resource can reach up to a million kilometers, and this is far from the limit. Four-stroke engine repairs do not need to be done very often.
Disadvantages include complex design, expensive production, and demanding operation. These units definitely need high-quality fuel and oil. It is almost impossible to carry out repairs on your own.
To ensure that there are never any problems with these engines, “feed” them only with high-quality gasoline. And then they will work for a long time, reliably and properly. A design that has not changed for so many years is an indicator of reliability and efficiency.
Engine Features
The engine of the Chinese Alpha moped has characteristic features, thanks to which fans of motorcycle technology prefer this particular model.
Engine for Alpha moped
Engine capacity - 72 cc. With the right approach, it can be upgraded to 110 cc. Also, if desired, you can increase the speed by 10 kilometers.
The weak point of the engine is the gearbox, which requires close attention and a delicate approach . When repairing the “heart” of a moped, you need to know how to correctly disassemble and reassemble this part of the motorcycle “organism”.
Alpha is equipped with a powerful engine, the circuit of which is complex. If you can’t figure it out on your own, it is recommended to contact an experienced specialist. The price of repairs is quite affordable.
Four-stroke motorcycles
Yes, these engines are very popular among manufacturers of good, serious motorcycles. The main difference is the design. If in cars the engine is hidden under the hood and its design has not been particularly developed, then in the world of motorcycles the appearance of the power unit is of serious importance.
For more than 15 years, the two-cylinder four-stroke motorcycle engine has been in fashion, today represented by many models with a wide variety of displacements. Such engines can be distinguished by their characteristic sound.
However, in-line four-cylinder units are especially popular among motorcyclists. These engines are only slightly ahead of automobile internal combustion engines. For example, the four-valve design has only recently gained acceptance in automobile construction. And it has been used on motorcycles since the 70s.
For a motorcycle, a four-stroke is more relevant. So, these internal combustion engines are more economical, efficient, and environmentally friendly than two-stroke units. These are the advantages of these engines on motorcycles. Also, motorcycle engines are made to run at high speeds. Maximum power is produced at speeds up to 14-16 thousand on modern models.
Causes of malfunction
The Chinese Alpha moped, whose price is affordable, does not cause owners many problems. Interruptions in a moped engine have several causes, and once you understand them, you can quickly fix the breakdown.
Disassembling the moped engine
So, if the engine starts with great difficulty, the muffler “shoots”, and smoke comes out of the chimney, it means that the moped is “capricious” due to problems with the carburetor. In order to solve this problem with the Alpha moped, you need to:
If the Alpha slowly picks up speed, and its engine is not able to develop the declared power, then the reason is the incorrect operation of the moped valves. It can also “get sick” due to gaps and incorrect timing. In order to make the Alpha moped function normally, it is necessary to replace the used valves with new ones.
If the Alpha moped is not able to reach the required speed, despite the roar of the engine and solid revolutions, it is impossible to stop the spinning wheel, and gear shifting occurs intermittently, then the cause of the malfunction is clutch wear.
Moped clutch parts
To eliminate the breakdown, you must perform the following manipulations:
- remove the engine;
- remove the plastic cover;
- unscrew the tightening screw;
- Unscrew the adjustment mechanism and tighten the screw tightly;
- start a moped;
- turn on first gear and drive a few meters.
Another cause of moped engine malfunction may be wear on the drive sprockets. If they are very worn, they must be replaced with new ones.
You may encounter the problem of engine overheating. The situation can be corrected after adding oil. If oil leaks, you must urgently contact a professional service .
Alpha moped engine overheating
Engine disassembly
Disassembling the Alpha engine is quite simple. To do this you need:
- “arm yourself” with a key;
- Unscrew the bolts on the intake manifold (by 10);
- unscrew the cylinder covers and the bolts located there (4 pieces);
- remove the cylinder head.
After performing the necessary manipulations, you need to properly assemble the engine, installing all the parts in place.
A diagram can help you understand the nuances. Also, a lot of useful tips regarding repairing the most important “organ” of the Alpha moped are contained in the training video.
Removing the piston
We clean and blow off the cylinder connectors, cylinder heads and valve covers. Unscrew the bolts on the valve cover and remove it from the head
Unscrew the nuts and bolts on the cylinder head
Remove the camshaft bed. The camshaft bed is practically not subject to wear. After removing it, just wash it and check for cracks.
We remove the chain from the camshaft and take it out of bed. The camshaft has two problematic points that are worth paying attention to: wear of the support bearings and the working surfaces of the cams
The cylinder, head and camshaft bed are centered relative to each other using guide bushings. These bushings tend to fall out of their sockets and then try to find it. To avoid this, immediately remove the bushings and put them somewhere away. Here and below, the bushings will be indicated by arrows.
Remove the cylinder head. The cylinder head is the most vulnerable part of the engine and the operating parameters of the engine directly depend on its condition. To avoid problems later: the head must be completely disassembled, inspected for cracks, the valve seats cut, new valves installed, the valves ground into the seats, new oil seals installed and the plane ground in on a plate or milled
Remove the cylinder. Immediately after removal, check the cylinder for liner wear and
We remove the retaining ring from the piston boss, push it out of the pin, and remove the piston. We check the piston for cracks and wear, paying special attention to the condition of the ring grooves and the rings themselves
Gearbox disassembly
It is necessary to disassemble the gearbox in order to replace used parts. This is done after the following parts have been dismantled:
Gearbox disassembly
Repair of this part of the engine is carried out as follows:
- Using a screwdriver or blade, remove the retaining ring and the drive gear;
- Carefully unscrew the gear fixing bolt and remove the gear shift mechanism;
- remove the gear shift fork and shaft;
- remove the crankshaft and drum (including the core);
- After replacing the worn part with a new one, reassemble (in reverse order).
