what compression should be in a gasoline two-stroke engine

Is it possible to increase engine power

Increasing engine power is called boosting; it is not easy to do, but it is possible. Today there are two options to increase engine power:

• Remove the limiter and change the valve clearance, only suitable for small engines.
• For larger units: replace some spare parts and motor components.

You need to approach such work responsibly, because it is not only difficult, but also expensive. Each type of engine has its own techniques:

1. Strengthening a two-stroke engine can be achieved by making some improvements in the reed valves and, better yet, with the help of knowledgeable people.
2. Four-stroke: bore the carburetor, this way you can increase the diameter of the diffuser.

Domestic production

During the summer holiday season, many people dream of riding on the water with the breeze, while having an inexpensive but reliable engine. But they don’t have great speed, which means they can hardly please you. But any mechanism, if desired, can be modified to increase power.

• First you need to increase fuel combustion in the chamber. And also increase the diameters of the channels for its supply. In this case, you need to buy a new carburetor. External fastenings only need to fit.
• Next we change the piston system. It is necessary for the fuel combustion chamber to be larger and able to cope with large volumes of fuel. And it is necessary to increase the screw blades.

Make it a rule, on every fishing trip, the first thing you do is start.

Foreign production

They almost always make engines with too much power, but they put a limiter on it. This is a common marketing technique; they present only one engine, but in different transformations and different powers.

This means that by purchasing an inexpensive and low-power motor, you remove the limiter and get a more powerful motor for the same money. And besides, it is possible to apply a technique to speed up the engine.

Source

FAQ: Why does the cold one move, but the hot one stalls?

Everyone wants their equipment to ride well and do it in any conditions, but many people paid attention to the fact that when it’s cold, the moped rides much better than when it warms up. I, just like many now, was puzzled over this question and understanding of its essence did not come immediately...

Physics.8th grade

Everyone studied in the eighth grade, at least those who were interested in the pressing issue. All bodies and gases expand when heated, and the lower their initial temperature, the greater their expansion coefficient will be when heated to a certain temperature relative to the initial one.

Intercooler or nitrous oxide injection

Almost everyone knows about nitrous oxide, everyone has watched super-sophisticated children's films like “The Fast and the Furious” (by the way, the real name of the movie is “Fast and Fierce”, but marketers don’t give a damn about the correctness of the translation. Author’s note), fewer people know about the intercooler, but about the principle of operation Few people even know both systems. So what am I talking about?

Almost the essence

Everyone thinks that nitrous oxide is something really fucking flammable and when it burns it releases an equally crazy amount of heat and energy. Anyone who thinks that way, go back to school, only this time to chemistry class. Bullshit! Nitrous oxide creates an environment for combustion, or rather, it just cools the fuel-air mixture to fairly low temperatures and, in addition, by disintegrating at high temperatures, it releases an additional portion of oxygen.

An intercooler does almost the same thing: it’s a kind of refrigerator that simply greatly cools the atmospheric air before it enters the combustion chamber. That’s all.

Have you noticed that in cold weather the moped really stalls, but in the heat it drives rather mediocre?

The essence

So, what exactly is the whole point? It is that while the engine is cold, firstly, an additional portion of gasoline is supplied to it for a cold start, and secondly, IT IS COLD, and the air does not heat up against a cold engine.

Ask: well, why doesn’t a hot engine drive so well? It doesn’t drive because even before the fuel-air mixture ignites, it manages to heat up in the engine itself and pre-expand to some extent, which is completely unnecessary and out of place, well and plus to everything, the enrichment channel has already closed, which no longer provides additional. portion of gasoline and air.

I had one fuckmobile for repairs: Suzuki Address V, and so it didn’t want to start at all, and after various attempts to correct the situation, I took it and simply unscrewed it and threw out the jet on the enrichment channel. I never thought that the moped, however It’s more of a crappy Suzuka, maybe it can drive like that. It’s true that she ate accordingly...

pitstopsaki.com

Motorcycles Ural and Dnepr

Which one does the Urals have with 76 gasoline and which one does it have 92? measure the same as for a car? Thank you

I measured the compression: I start the Ural on one cylinder, a spark plug is unscrewed from the second one in advance, you insert a compression gauge and measure. And regarding compression for 76 it should be at least 7 atm, with a difference in the cylinders of no more than 1 atm.

It's just very cool to measure compression with the engine running

You need two people, one with a compression meter, the other vigorously working with a kick. Be sure to open the gas fully. Compression should be

6 but not less than 4.5.

Measure with a normal compression gauge and don’t hold him by the head. If the compression is small, fill it with a syringe of engine oil, if it increases, then the rings...... and also be sure to fit into the valves, rub them in.

The air vent cannot have compression like a car.

sam quote: Compression should be

6 but not less than 4.5.

4.5, well, that’s a really bad piston, I have 8.5 in the Urals. And a friend on the Dnieper has 9.5

In general, as a rule, the compression should be equal to the compression ratio + 2, but this is on average, and this is not suitable for all types of combustion chambers. I'm not confusing anything this morning. :-))))))

stop . .correct me if I’m wrong ;-)) I was always sure that compression is an indicator of the condition of the piston group, etc... and the degree of compression... with what actane number should a motorcycle be poured into the tank...

for Alogizm: in general, yes. Although there are exceptions with the compression ratio and gasoline - it depends on the shape of the combustion chamber. It is especially incorrect to compare the compression ratio of a turbocharged engine - there it can be 7 and gasoline 95. In the field I am going to measure the compression - in order, as you correctly said, to assess health.

And I generally have 11 atm compression

And I hammer a piece of newspaper into the candle hole like a cork and pull it with a kick. If it shoots into the eye, then the compression is good and it is there

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I decided to look/check the condition of the piston in my engine (JPX). The engine flew for a total of 80-90 hours, the piston and rings were not changed.

Removed the cylinder head and cylinder. Removed the piston from the connecting rod. At first glance, everything is good and correct. The cylinder liner is clean and free of burrs. The piston also has no signs of sticking, but here’s what bothered me: carbon deposits below the 2nd ring. The soot was not very strong, it was washed off after a minute with a rag soaked in gasoline.

The trick is that my engine does not have a decompression “device”. No hole. There is also no decompressor, like on the 25th Jeepix.

I have a 19, an antique one.

(decompression holes that close only in operating mode, that is, when the engine is running) - quote.

Compression ratio and compression

Compression ratio = total cylinder volume/combustion chamber volume.

For classic engines it is 8.5. It is changed by changing the volume of the combustion chamber (for example, by a gasket). Increasing the compression ratio in a carburetor engine is limited by the fuel's resistance to detonation.

Compression refers to the pressure at the end of the compression stroke. This value is measured by a pressure gauge (compression meter).

What is the relationship between compression ratio and compression?

A little theory. Compression is usually greater than the compression ratio (12 for a new run-in 2103 engine), since compression occurs almost adiabatically, and, accordingly, is accompanied by a change (increase) in the temperature of the mixture. This value would be equal to the degree of compression if compression occurred isothermally in a hermetically sealed volume. In the case of adiabatic compression, the maximum possible pressure at the end of the compression stroke ("compression") is estimated according to Poisson's equation

Compression is measured as follows. On a warm engine, all the spark plugs are unscrewed, usually one of the spark plugs is installed with the central electrode on ground, the gas is pressed to the floor and the engine is cranked with the starter until the value on the compression meter installed in the spark plug hole stabilizes.

It should be noted that compression meters, especially those with a rubber tip, can have a significant error, and if low values ​​are obtained, it is advisable to check the measurement results with another compression meter. In addition, the starter must provide sufficient crankshaft rotation speed, for which the engine must be warm and the battery properly charged.

Often, even experienced specialists confuse concepts such as compression and compression ratio, while the difference between them is significant (about the same as between grandparents). Let's be clear.

In the technical characteristics of the engine, the compression ratio is most often indicated, which reflects the perfection of the design, the degree of boost, and the ability to operate on modern, high-octane fuels. Compression ratio and compression are related. From general considerations it is clear that the higher the compression ratio, the greater the pressure created as a result of this compression should be. Everything would be so simple if there were no such factors as heating the mixture and its

How to check compression on a scooter engine?

Sometimes, in order to more accurately diagnose the condition of the engine, it is necessary to measure compression, that is, by and large, measure the pressure in the combustion chamber of the engine. Compression can only be measured using a special device: a “compression meter”. You can measure pressure both on a “cold” engine and on a “hot” one; if at different engine temperatures the readings differ significantly, then based on the specific engine, we “dig” in the appropriate direction.

So, we unscrew the spark plug, remove the carburetor, insert a compression gauge into the spark plug hole, press it firmly and use the starter or kickstarter to crank the engine for a few seconds.

An example of measuring compression on a 1E41QMB engine

We insert the compression gauge into the spark plug hole and press the tube well against the hole.

We crank the engine, I cranked it with the starter. If you crank the engine using a kickstarter, try to press the foot very vigorously, otherwise the readings will be inaccurate.

This pressure is considered quite “tolerable” for this engine model (1E41QMB). Ideally, the pressure on this engine should be in the range of 8 - 9 kg/cm.

An example of measuring compression on a 139QMB engine.

For engines 139QMB, 157QMJ, a compression of 9-10 kg/cm is considered normal, but here, as you can see, the pressure in the combustion chamber is clearly below normal. I had to remove the cylinder head and see what was what, how to remove the cylinder head is described in detail in the article: How to remove a piston from a scooter engine. As it turned out, a piece of carbon got under the valve, which did not allow the valve to “sit” tightly on the seat. Because of this, all the pressure “leaved” through a leaky valve.

Here is this valve with a piece of carbon stuck to the chamfer; this malfunction is easily “cured” by cleaning and grinding the valve to the seat, as this is done in detail in the article: How to grind a scooter valve

On “soviet cycles” we perform the same actions.

For many “ants” such compression is the “ultimate dream”.

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When diagnosing an engine, and when troubleshooting a problem in the engine of a scooter or other motorcycle, an important indicator is the amount of compression in the cylinder. Cylinder compression is, by and large, the amount of pressure that is created in the cylinder at the moment when the piston is at top dead center. Compression is measured using a special device - a compression meter, the design of which is very similar to that of a pressure gauge. No other methods of determining compression, for example, indirect, by feeling the force applied to the kickstarter lever, can give an accurate result.

Compression measurements can be carried out both on a “hot” engine, that is, an engine warmed up to operating temperature, and on a “cold” one. For more accurate diagnostics and fault detection, measurements are carried out in both ways. But it should be said that when indicating the compression value in a cylinder, as a rule, we mean the compression value measured on a hot engine. The difference in compression on a hot and cold engine can reveal some malfunctions. We can say that it is not enough to just measure the compression and get some numbers, you also need to be able to correctly interpret the resulting measurement result, and this is the prerogative of a specialist. However, given the value of compression in the cylinder, many faults can be diagnosed without much experience.

To measure compression, you need to unscrew the spark plug, in addition, it is advisable to completely remove the carburetor, or remove the air filter and open the throttle completely. We insert the tip of the compression gauge tightly into the spark plug hole and turn the crankshaft using an electric starter or kickstarter until the compression gauge needle shows the maximum result. The crankshaft must rotate quite vigorously, otherwise the measurement results will not be accurate.

Examples of power increases

All reconstructions are also cheap, almost free, but sometimes this may require a significant amount of money, let's look at some models:

It's a four-stroke engine, and adding another horsepower to it is very easy. You just need to buy a carburetor for a boat with a Tohatsu 6 engine and change it, you get a Tohatsu 6. It will cost about $170, and the difference between these two engines is $450. A little, of course, but you can save money.

The Yamaha 5 two-stroke engine also has slightly underestimated technical characteristics and, therefore, simply replacing the carburetor will not work:

• The throttle valve delimiter must be located and removed.
• In a petal valve, you need to press out the petal, but it is advisable to first consult with knowledgeable people.

The limiter is installed due to increased environmental requirements. They are banning them in many countries and protecting nature from excessive carcinogenic emissions into the atmosphere.

More detailed diagnostics

To avoid problems with the moped and be completely confident in the serviceability of the scooter, you need to conduct a more complete check. One of the main characteristics of a working scooter motor is normal compression. More on this indicator of the condition of the piston group later.

Scooter compression check

• Unscrew the spark plug (at the same time assess its condition)
• Screw the compression gauge tightly into the spark plug hole
• We press the kickstarter lever several times, thereby creating pressure in the piston

Attention! During diagnostics, you should not try to start the scooter engine using an electric starter. .

We look at the compression meter readings

• Ideally, the compression value should be 10 units
• The normal indicator for a used scooter is 7 ... 9
• The numbers below are unacceptable - the engine must be immediately put in for service: replacement of piston rings, piston or CPG. If this is not done, then there is a high probability of failure of the power unit, and its replacement is quite expensive and can reach half the cost of the scooter

It is worth noting that any other methods of checking the compression of a scooter engine do not pretend to be the slightest objectivity and are often used by dishonest vehicle sellers in order to mislead the gullible buyer.

Of course, in this publication we did not reveal all the methods for diagnosing the condition of the motor when choosing and buying a used scooter, but knowing the basics will help you avoid a completely unsuccessful purchase. If in any doubt, contact a moped repair specialist. Enjoy the shopping!

How to check compression in a scooter engine

If the engine of your vehicle has decreased power, it starts poorly and runs unstably with a properly adjusted carburetor, then it’s time to pay attention to the compression in the scooter cylinder. Compression is the existing pressure in the cylinder cavity at the very end of the compression stroke of the mixture

Compression is measured in atmospheres, bars, pascals, and also in kgf/cm². If the engine of a scooter or motorcycle is fixed, then its normal compression will be within 9-11 atmospheres. It turns out that the higher the compression, the better the engine will work, because less gases penetrate back into the crankcase. Naturally, a larger amount of gases significantly improves performance and ensures normal engine efficiency.

Compression is the existing pressure in the cylinder cavity at the very end of the compression stroke of the mixture. Compression is measured in atmospheres, bars, pascals, and also in kgf/cm². If the engine of a scooter or motorcycle is fixed, then its normal compression will be within 9-11 atmospheres. It turns out that the higher the compression, the better the engine will work, because less gases penetrate back into the crankcase. Naturally, a larger amount of gases significantly improves performance and ensures normal engine efficiency.

Why and how to check compression in a scooter engine?

Checking compression is one of the methods to assess the condition of the cylinder-piston group without disassembling the engine. If the compression is low, this indicates that the rings are worn out and must be replaced. As for four-stroke engines, there is a possibility of valves not being sealed in their seats.

To correctly measure the compression in a cylinder, you will need a device called a compression meter. Simply put, it works like the well-known pressure gauge, only with a check valve. It can be purchased at any motorcycle store. The choice of compression gauges is actually quite large, but everyone has the right to choose the one that suits their pocket.

Compression gauge of your choice

There are compression gauges with a flexible hose, which are very convenient to screw in if the bike frame is placed low above the cylinder and interferes with taking measurements, but they are much more expensive. And the most inexpensive ones come with a pressure attachment, which also sometimes helps a lot.

We unscrew the spark plug, if anyone is interested in how to do this, you can read about this in another article. Pre-warm up the engine, since compression in a motorcycle or scooter occurs on a hot engine, at the moment when the thermal gaps of the rings are able to assume a working condition.

We install a compression gauge in place of the unscrewed spark plug. If you have a pressure compressor, you need to hold it with your hand. When the compression gauge is set to the working position, you need to pull the kick starter leg of the motorcycle or scooter several times. We make the necessary measurements. The compression gauge begins to show the pressure in the cylinder as the mixture is compressed. We look at the compression readings.

How to understand compression numbers?

You can start from the fact that normal pressure is above 8 atmospheres. If your cylinder is capable of producing a compression of less than 6 atmospheres, then it needs to be repaired, at a minimum, the worn rings should be replaced.

Another indicator of low compression may indicate worn cylinder gaskets, as well as uneven or insufficient tightening of bolt connections at the cylinder head mounting points. If the mixture is etched, this can be seen on the cylinder; it manifests itself as oil stains.

x7.by

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What should be the compression on a scooter?

Guys, who knows how to measure compression in a scooter? Cold or hot? What should be the indicators for a serviceable and faulty piston? In general, share practical advice. I've looked all over the Internet and everyone has conflicting information. Everyone measures and makes diagnostics in their own way, but no one has yet come to a common opinion. Here's what you can check out from this article:

In the article you provided, everything is described correctly! So measure it! The engine is warm, the throttle is turned all the way, turn the starter on a charged battery. But don’t forget that compression gauges are still the same! You need to take a proven one, not just any random one. and this is difficult. You can check the CPG using the “old-fashioned” method. You measure the compression as described above, then pour 1-2 cc into the cylinder. engine oil (with a syringe) and measure again, if the difference is large, there is a problem with the CPG.

They say that if the compression measurements are good, you can disassemble the piston and measure wear in the ring gaps. And the result can be impressive. Is it true?

Sergej_K

, what's so funny about that? You never know what happens.

The funny thing is that it’s stupid to take apart a working thing to see if everything is in order.

You can also check the compression meter this way - you take the compression meter and measure it on a fresh, normal car, where the compression is exactly close to ideal, you look and compare the readings of the device and what is written in the “Murzilka” for the car. and you conclude that the compression meter is approximately correct or whatever.

Sergej_K

, in principle, also an option.
I somehow didn’t think about it. I have a new car, but now I need to come to an agreement with the driver, but I don’t think he will let me measure the compression on his Renault
. He's only had it for 3 months.

it all depends on your ability to persuade! There are two ways - 1 to interest, 2 to force

I'm not on my own. I read it here somewhere and was impressed. It was written here that given the compression standards, people for some reason disassembled the piston and measured the degree of wear of the piston rings by the gap at the joint of the ring. the result is from 0.5 to 1.5 mm. That doesn't fit into any gates. Am I still confused? It happens? Then what to believe.

Well, why are you Russians all fists? You can rustle with a Moscow! for example, tell him that somehow the engine in his car is not working properly! and offer to measure the compression for free with a compression meter that you have already prepared! A Russian person will most likely agree with the magical word “free”! you need to take it and try it!

Compression is measured on a cold engine because this is real compression without adjustments for temperature. The figure should be no lower than 8 kg, although it will work at 6 kg, but this is already the beginning of problems with starting and fuel consumption. The throttle valve must be open; if the throttle valve drive is vacuum, it is advisable to disconnect the carb. Pouring oil into the cylinder helps check the condition of the piston rings; if the rings are normal, the pressure will rise by 1 or 1.5 kg; if more, check the rings

It doesn’t matter what you turn, something else is important - you need to turn it until the arrow of the device stops

pochemuchka

, Thank you. This is already something on the topic. Can anyone else give practical advice?

pochemuchka - take a tanometer and go and measure the blood pressure of your neighbor’s grandmother. If the pressure is in the range of 140 to 60-160 to 80, then the piston on the scooter is normal! For those who did not understand my allegory, I’ll explain - you need to measure compression with a HOT engine! Because

We drive hot engines and it is the pressure at operating temperature that is important! We are interested in pressure in a cold engine, just like the weather in Afghanistan

What the hell are the amendments and what the hell is the temperature? Atmospheric air enters the cylinder, with atmospheric temperature, and the fact that the engine is warmed up is its operating mode, then in what conditions it operates!

Sergej_K

, have you read why I need to measure compression?

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

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

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.

Principle of operation

One revolution of the crankshaft is one cycle of the operating process of an internal combustion engine.

Fuel (gasoline + oil) with air is supplied to the working combustion chamber of the cylinder, after which, due to the formation of a spark from the spark plug, an explosion of the combustible mixture occurs, the energy of which sharply pushes the piston down.

The fuel mixture enters the engine crankcase through a window that opens due to vacuum as the piston moves upward from bottom dead center (BDC) to top dead center (TDC). This movement also opens a window for the release of gases from the burnt mixture. After milliseconds, the purge window opens. A new portion of fuel is supplied through the purge window.

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.

Advice

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.

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

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.

Tools for taking measurements

To obtain accurate information regarding engine compression, compression gauges with rubber seals or threaded connections can be used. Each of them has features and scope.

Pressure compression gauges

The first type of device is most often cheaper and is used to take measurements in gasoline internal combustion engines. The permissible pressure indicator of such a compression meter is 16 atmospheres.

Such a device is inconvenient to use alone, since it is necessary to hold the device tightly in the spark plug hole, but, nevertheless, its use makes it possible to obtain information regarding compression in the cylinder.

Thread compression gauges

Thread compression meters are often used to diagnose diesel engines.

The maximum permissible pressure value for such devices is 40 atmospheres. The threaded connection makes it possible to securely install the device and ensure accurate data regarding compression, despite high pressure.

Description:

The model has become one of the most popular in its class, thanks to its efficiency and stylish design. Wide 12-inch wheels ensure the stability of the model and allow you to move freely along the city streets and beyond. The maximum speed that the device develops is 70 km/h. A convenient electronic instrument panel allows you to monitor indicators without distraction. The front suspension is equipped with a telescopic fork, the rear suspension is reinforced with an oil shock absorber. Minimum fuel consumption is 2.5 l/100 km. Scooter warranty!

What compression should be on a scooter?

In most cases of engine malfunction, the cylinder-piston group is to blame, which is why it is important to monitor the performance and condition of the engine. What compression should be on the scooter. Most often, the scooter has trouble starting or its power drops significantly

Even after properly cleaning the carburetor and fully adjusting it, the malfunction does not disappear; look at the compression of the scooter; perhaps it is too bad or absent altogether. Do not rush to disassemble the piston; checking the compression should come first.

Compression is a certain pressure that forms inside the cylinder and begins to form during the end of compression of the fuel mixture. To maintain an optimal indicator, there are devices that allow you to measure compression, which is also calculated in a certain value. The indicator can be measured with a compression meter. In appearance and in its properties, the part strongly resembles a conventional pressure gauge; the main feature is the presence of a check valve in the design. Depending on the purpose, there are also different models of compression gauges with different designs. Measuring the compression indicator is quite simple; just screw the device into the hole where the spark plug is located. Please note that you can measure the indicator without removing the engine and piston.

Some scooter riders do not know what compression should be in a scooter engine. If you measure compression in atmospheres, which most devices do, the optimal value should range from 9 to 10 atmospheres. A reduced indicator indicates significant wear of the piston group, in particular the piston rings. In the case of a deviation from the norm on 4t scooters, another reason for low compression may be incorrectly configured valves.

Before checking the compression, be sure to warm up the engine, just wait 10-15 minutes. The fact is that while the engine is running, the rings will shrink and take the correct position. Then unscrew the spark plug and insert the compression gauge; some models are difficult to put on, they simply rest against the frame or other parts of the scooter. The kit should include a rubber nozzle, which simplifies the task. After you have inserted the device, pull the kickstarter several times, the device should show a minimum of 8 atm. Mandatory repairs must be carried out when the reading is below 6 atmospheres. In some cases, the cause is determined to be simply worn out cylinder gaskets, allowing air to pass between the cylinders. It is enough to replace the gaskets and recheck the compression.

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What do we have to do?

First of all, we install the car downhill, in principle, it doesn’t matter what the angle is, ten to fifteen degrees is enough. The most important thing is that the car rolls easily, but there is no need to choose a very steep descent; the test results may be incorrect.

How is it checked?

We stopped the car on a descent, engaged second gear, released the clutch and handbrake. Let's note the time. After some time, the compression tightens, the compression is released from the cylinders, but the car, of course, does not start.

We are waiting, after some time there will be such a failure - OP, that’s it, the car started, OP, until the next cylinder, it stopped. We measure the time interval between these dips

. After a while the compression tightened and the car started moving again. And so you need to measure the time four times - unless, of course, you have a four-cylinder engine.

If this distance is equal, plus or minus 10 seconds is allowed, then everything is normal. If some interval turns out to be shorter, then get out of the car, open the hood, open the distributor (if the car is carburetor) and look at where the slider is, on which cylinder the compression is taking place (in the injector you need to look at the timing marks).

Now get into the car and do the same thing, only in ignition order, for example - first and third, fourth and second. As a result, you will know exactly which cylinder has weak compression.

Is it possible to increase the engine power?

When buying an imported engine, you need to remember that foreign manufacturers often produce most models with a power reserve and fixed limiters, but in a rather different price range. All this is done to ensure that their products do not violate environmental laws.

Therefore, a reasonable solution in such a situation would be:

• purchase of an inexpensive imported engine;
• removing restrictions from it;
• obtaining more engine power without additional costs.

And in order to achieve an increase in boat power without significant transformations in the engine, you need to:

1. Get rid of unnecessary things and unnecessary ballast.
2. Monitor the condition of the propeller and promptly clean it from dirt.
3. When filling a watercraft with fuel and oil, you should not skimp on its quality and quantity.
4. It is necessary to clearly monitor the pitch of the propeller. Depending on the situation, it needs to be increased or decreased.
5. Before starting work, the engine must be adjusted and run-in.

Another interesting way to increase the horsepower of an engine is to manually convert a cheap engine with a small volume into a more powerful one.

It is important to consider the following nuances:

How to catch more fish?

I have been active fishing for quite some time and have found many ways to improve the bite. And here are the most effective:

1. Bite activator. Attracts fish in cold and warm water with the help of pheromones included in the composition and stimulates its appetite. It’s a pity that Rosprirodnadzor wants to impose a ban on its sale.
2. More sensitive gear. Reviews and instructions for other types of gear can be found on the pages of my website.
3. Lures using pheromones.

You can get the rest of the secrets of successful fishing for free by reading our other articles on the site.

after a visual inspection of the motor, you need to immediately determine which components need to be replaced and the components strengthened; determine whether there is a travel limiter; change the distance between the valves by removing the limiter; replace carburetor jets, commutator, manifold and reed valves; Next, it is important to increase the diameter of the diffuser by boring the carburetor, unscrew the adjusting screws and the jet tube; insert a suitable screw with a locknut into the resulting hole.

If at any stage of the remodeling you do not have confidence in your abilities, then it is better to contact the service center specialists.

Two stroke motor

A two-stroke engine is an internal combustion engine in which the entire process of work in each of the cylinders is completed in one revolution of the crankshaft. If you are using a motor of this type, then to increase its power you must adhere to the following sequence:

1. The throttle limiter needs to be removed. If it is present, you can find it by looking through the carburetor window.
2. Next, you should conduct a thorough inspection of the reed valve. It is often located in the cylinder block. If one of its parts is clamped by a metal plate, it must be released.
3. Thanks to this maneuver, the amount of fuel entering the combustion chamber increases. Thereby increasing the engine power.
4. The carburetor also requires special attention. You should drill out the jet by about 0.1 mm and do not forget to adjust the fuel level and ignition angle after that.

Four stroke engine

A four-stroke engine is a piston internal combustion engine in which the entire process is completed in two revolutions of the crankshaft, in other words, in four strokes. Peculiarities:

• gas exchange is almost completely ensured by the movement of the working piston in the cylinder;
• a separate gas distribution mechanical process is used to switch the cylinder cavity between intake and exhaust;
• During a separate half-turn, each phase of gas exchange of the crankshaft is performed;
• The gas distribution drive of the ignition and fuel injection systems must rotate at a frequency half as fast as the engine crankshaft rotation.

To increase the power of this type of engine, the method with a two-stroke engine is also suitable. It is also worth trying to increase the distance between the valves of the gas distribution mechanism and the ignition angle. On expensive engine models, reconfiguration of the electronic control unit is necessary.

Operating rules

Any manufacturer includes an instruction manual for their product. It describes when and how the scooter is serviced, how its correct operation is checked (ignition, gear shifting, engine compression and exhaust systems). If the scooter does not pick up speed, then this is primarily due to violation of these instructions. That is, you need to regularly change spark plugs, belts, oil, air filter, and monitor the quality of gasoline and oil. It is necessary to clean the contacts of the electrical system and change the battery on time. Maintenance is not only wiping the scooter from dust, but an in-depth diagnosis of all its components and mechanisms.

Compression on a scooter

What is compression, what is it for and where does it come from and why does it fall? Let's figure it out.

What is compression on a scooter?

When the mixture burns in the cylinder, a micro-explosion is formed, which with a certain force presses on the piston, which in turn moves the crankshaft

It is very important that this gas, which pushes it, is used with maximum efficiency, without leaks. For this purpose, compression rings are used, which are made of high-strength steel and cannot be compared in strength to an aluminum piston.

Over time, they wear out, the gap in the lock increases, and efficiency decreases. It's like a worn cuff in a pump, you seem to be pumping, but there is little effect, you feel that sometimes even the pump is pumping at idle, the air is being squeezed out. This pressure that is created inside the pump, scooter cylinder and other units is called compression.

The higher quality the components, the less they are subject to wear, and the longer your scooter will delight you with pleasant dynamics and speed. But most of the spare parts are Chinese. which we see on store shelves still do not reach the quality of the original. However, the prices are pleasantly pleasing, and at the moment we can buy a Chinese or Taiwanese piston almost 3-4 times cheaper than the original from Japan. Not every owner of a $400-600 device can afford a $200 piston one.

How do you measure compression on a scooter?

To measure compression, special devices are used - compression meters. They calculate the pressure created in the cylinder and display it on a scale.

What compression should be

Usually on a scooter it should be about 10 ideally, but 7-8 is not bad either, you can still ride. But indicators below these values ​​should already alarm you; inevitable repairs are coming.

Why does compression drop?

This happens when the equipment is used excessively intensively, to the limit of what is possible, due to incorrect selection of components, incorrect boring of the cylinder, etc. If a turner, boring a cylinder for repair rings, does his job incorrectly, you should not expect long-term performance from such a piston. The rings should have a thermal gap in the lock, should not jam in the piston grooves, and should move easily in the cylinder, naturally after lubrication.

You can also read other articles on the topic:

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Motorcyclist

The most common reason is a worn clutch, then a worn variator belt, worn variator rollers, a worn clutch spring, and the variator itself can also be worn out. The most dangerous thing is examining and replacing the variator. On most scooters, the nut that secures the CVT is unscrewed clockwise; Do not unscrew it with a bolt gun under any circumstances, because you can break the crankshaft thread (then you get a lot of money: crankshaft from 3000 rubles + work to replace it with engine overhaul)

There are, but less frequently, other causes of breakdowns. In the event of such a breakdown, getting into the engine is the last thing; at least first measure the pressure in the cylinder with a compression gauge (at the same time check the spark plug). It happens that the carburetor is clogged, as well as the exhaust pipe (in the latter case, a scooter that accelerates to 60 km/h has difficulty accelerating to a maximum of 20 km/h). As for a clogged exhaust pipe, either the pipe is replaced, or the removed pipe is placed in a fire, heated, and then the soot is shaken out of it. Another method is possible (if you know a welder): a thick part of the pipe is sawed with a grinder (lengthwise), the soot is shaken out, then the pipe is welded.

Operation of a two-stroke engine

In addition to the well-known four-stroke engines that are used in cars, there are also two-stroke engines that are installed on technical units: chainsaws, motorcycles, lawn mowers, ATVs, scooters, motor boats, etc. The main difference between a two-stroke and a four-stroke engine is the operating principle of the internal combustion engine. In addition, 2-stroke engines are smaller in size, capable of developing less power and, therefore, have lower efficiency.

1. The structure of a two-stroke engine.
2. The operating principle of a 2-stroke internal combustion engine.
3. How to increase engine power with your own hands?
4. How to increase traction?
5. Problem with purging after increasing power.
6. Video.

Checking the spark plug

The condition of the spark plug provides a lot of information for understanding the causes of the malfunction and, accordingly, for choosing repair actions.

Acceptable view

The appearance is light, slight precipitation or electrocorrosion is possible.

To understand the causes of a malfunction, the condition of the spark plug provides a lot of information.

Carbon deposits on the candle

Recommended actions:

• adjustment of the working mixture;
• adjust the cold start system of the scooter engine;
• replace the air filter;
• Cleaning the spark plug or replacing it with a new one. In this case, it is important to select the correct heat number.

Overheat

Recommended actions:

• change the torque of the scooter's spark plug;
• debug the scooter engine cooling system;
• understand the ignition system;
• understand the glow number of the spark plug (a value characterizing the spark plug, proportional to the average pressure at which glow ignition begins to appear during testing of the spark plug on a motor calibration unit).

Carbon deposits on the spark plug may cause the scooter to malfunction.