Honda dio carburetor design

The design of a scooter carburetor and its operating principle

The design of a scooter carburetor is quite simple; Once you understand it, you will be able to understand how to properly configure the carburetor so that the vehicle does not let you down in bad weather, how you can tune it and improve the performance of the engine. You will be able to control the quality of the mixture and many other processes that affect the operation and operation of the device.

Tips and tricks

Setting up the carburetor on a 4t 50cc scooter is an important and responsible procedure for servicing motorcycle equipment.

When performing adjustment operations, it is important to follow a number of rules:

perform adjustments only after the engine reaches operating temperature;
rotate the adjusting elements smoothly, observing the operation of the engine;
Make sure there is no debris inside the fuel chamber and the jets are clean.

Before starting work on setting up the carburetor, you must study the operating instructions and clearly determine the location of the quality and idle screws. If you have a 150cc scooter, the carburetor adjustment is done in a similar way. After all, the process of regulating the fuel system is the same for engines of different powers.

The principle of operation of a scooter carburetor

The carburetor design of a 4t scooter is not very complicated. The basic principle of its operation is as follows: a certain amount of fuel and oxygen enters the float chamber of the device, where they are mixed in the required proportions and supplied to the combustion chamber of the engine.

The design of a 4-stroke scooter carburetor may vary slightly depending on the model, but in general it is the same for all types of carburetors. The float version of products is most often used. It is distinguished by the presence of a float chamber in which fuel is mixed with air, after which the finished mixture is fed into the cylinder. In order for air to enter the fuel in the required proportion, the carburetor includes the following elements:

Jets.
A needle that meters the supply of oxygen.
Spool.
Throttle valve.

Sometimes the design of a 4t carburetor on a 50cc scooter includes an element such as an accelerator pump. It works in tandem with a starting mixture enricher. These devices help the scooter engine to work correctly and start in damp and wet weather. The correct operation of the motor depends on the coherence of the devices, so it is important to pay attention to their settings.

Scooter starter booster

Most often, scooters are equipped with an electric starting enrichment; on older models you can find a manual one. The task of this device is to create the right mixture in order to start the engine after a long period of inactivity.

The carburetor has an additional channel for connecting the enricher. If the device is automatic, the channel opens itself when you try to start the scooter and closes as the engine warms up. If the enrichment is manual, you need to close its valve yourself. The operating principle of the device is as follows:

Inside the housing there is an element heated by electricity, which pushes out a needle that blocks the fuel channel.
After the engine is stopped, the needle will be retracted.

Float chamber device

Mixing of fuel with air in the carburetor occurs with the participation of the float chamber; Thus, the finished fuel, saturated with the required amount of oxygen, enters the combustion chamber, where it explodes and sets the scooter in motion.

From the gas tank, fuel enters the carburetor through special pipes. But mixing cannot occur in them, so first the fuel ends up in the float chamber, and only then it is enriched with oxygen and further moved. To ensure that gasoline does not flow continuously, but in the right quantity, the carburetor is equipped with a special system with a float and valve. When the chamber is full, the float rises and the valve blocks fuel from entering the carburetor; when the float is lowered, the flow of fuel resumes.

Fuel dosing system design

The mixture is supplied to the cylinder in finished form, so it is necessary to control its quality. For this purpose, the carburetor has a special needle with grooves and a locking ring. The position of the needle depends on the position of the ring: the higher it is, the richer the mixture, and vice versa. Modern carburetor models allow you to tune them without disassembling them.

For proper operation of the device, the diameter of the main jet is important. It is selected based on motor power and diffuser size. When tuning, the nozzle hole can be enlarged.

Idling - principle of operation

If you need to start the scooter after a long period of inactivity or when it is cold, adjust the carburetor idle jet. This is necessary in order to enrich the mixture with oxygen at startup. As a result of correct adjustment, the engine will idle smoothly and stop stalling.

The system has a special valve that, at the right time, blocks the possibility of mixing fuel and air. In order for the engine to stop stalling, we make adjustments with the quality screw, adjusting the idle speed to the desired value. The adjustment screw is located on the side and is accessible while the engine is running. There is no need to disassemble anything, just carefully turn it with a screwdriver to the left or right. As a result, the speed will rise or fall.

If the quality of the mixture is insufficient, we achieve maximum idle speed. When the engine warms up, it will be enough to reduce the speed again to normal.

How to adjust engine idle speed

Work on setting up the power system is carried out after the engine has warmed up to operating temperature. All types of carburetors installed on scooters are equipped with a screw designed to regulate idle speed. Changing the position of the adjusting element allows you to ensure that the engine operates at stable speeds during idling.

Depending on the vehicle model, the adjusting elements are located in different places, so you need to carefully study the instructions and determine where the idle speed adjustment screw is located on the scooter.

Rotating the screw in a clockwise direction allows you to increase the crankshaft speed. Turning in the opposite direction, accordingly, ensures a decrease in speed. To perform adjustment operations, it is necessary to warm up the power unit of the scooter for a quarter of an hour.

Setting the engine idle

Then the screw is screwed in or unscrewed until a stable and precise speed of rotation of the vehicle engine is achieved. The adjustment is made in small increments by smooth rotation. After each manipulation, the engine should be run for several minutes to stabilize the speed.

Why adjust the carburetor?

Carburetor adjustment may be required in the following cases:

The spark plugs are serviceable, but do not work very well; their color has changed to black or yellowish.
The engine does not provide the required power
Scooter won't start
Fuel consumption has increased excessively.

All these problems in most cases are caused by an insufficiently enriched or, conversely, overly enriched mixture with oxygen, and they can be corrected by correctly adjusting the carburetor.

The settings, regardless of whether you have a 2t or 4t scooter, have three phases and are made as follows:

Idle speed adjustment
Setting the fuel level
Adjusting the quality of the mixture.

On some carburetor models there is no screw that adjusts the fuel quality, so you have to disassemble the carburetor to change the position of the needle.

The idle speed adjustment is carried out after the engine has warmed up: this takes no more than 15 minutes. For this purpose, the design provides an idle screw. It allows you to make the engine stable by selecting the desired idle speed. When the screw is tightened, the speed will increase, and when it is rotated counterclockwise, it will decrease.

It is important to adjust the quality of the mixture. If it is too lean, the scooter will ride with difficulty, and the engine will noticeably lack power. If the mixture is too rich, the spark plugs will turn black and quickly fail. Fuel quality adjustment is usually carried out using a screw located on the carburetor body. To enrich it you need to turn it clockwise, to lean it counterclockwise. If there is no screw, the carburetor is opened, the locking ring on the needle moves up for a richer mixture, down for a leaner one.

Adjustments are made as follows:

Start the engine and warm it up for 10 minutes, after which you need to turn it off
The screw must be tightened clockwise until it stops, but without force.
After this, it is unscrewed counterclockwise 1.5 turns
The engine needs to be started and the screw turned an additional 1/3 turn in the same direction. Wait 2 minutes
As the speed increases, you need to unscrew the screw an additional 1/4 turn and observe the reaction for about 2 minutes. If the speed does not drop, repeat the steps
If the speed begins to decrease, the screw must be turned clockwise 1/4 turn.

Ideally, the engine will operate exactly at 1.5-2 propeller revolutions, but its position depends on the quality of the fuel. In the case of a needle, the quality of the mixture will vary depending on the position of the needle locking ring. The disadvantage of such a carburetor is the small number of needle positions and the need to disassemble it each time to make adjustments.

You can adjust the fuel level in the chamber as follows:

Unscrew the drain screw
The phone is lifted up
You need to check the fuel level while the engine is running. The melting level is slightly below the skirt located on the float chamber cover
Most often, the level rises above normal and the carburetor overflows, so you need to adjust the float so that it fires earlier. To do this, the needle holder is usually bent. A lot of force is not required, only a few mm are needed.

Cleaning the carburetor of the Honda Dio AF18 moped

In fact, cleaning the carburetor on mopeds is not much different, so this article will apply to many models.

1. In order to get to the carburetor, you need to remove the side plastic, remove the seat with the glove compartment and remove the air vent.

2. To remove the air filter housing, you need to unscrew the 2 bolts under the housing and unscrew the clamp on the carburetor diffuser.

3. move the fuel hose clamp and the oil line clamp.

4. Unscrew the throttle valve. To do this you will need pliers.

5. Unscrew the carburetor from the inlet pipe.

6. Remove the casing from the cold start needle (unscrew 2 screws), remove the bracket and pull out the enrichment needle.

7. Using gasoline, remove dirt from the carburetor (you can use any container and a brush. A grimy carb)))

8. After we have removed all the dirt from the outside of the carburetor, unscrew the drain bolt of the float chamber and pour out all the contents. Then unscrew the float chamber.

9. Remove the float and needle valve.

10. Unscrew the idle jet and the main fuel jet with the emulsion tube. We put the unscrewed jets into the float chamber, into which we first screw in the drain bolt and fill the float chamber with any liquid for cleaning the carburetor.

11. Unscrew the idle speed adjustment bolt, unscrew the mixture quality adjustment bolt, and pay attention here! remember the order and completeness of what will be here, and the following will be here: an adjusting screw, a spring, a washer and at the end a rubber seal. Accordingly, we then assemble everything in reverse order.

12. Wash the adjusting screws with gasoline.

13. Spray all holes in the carburetor with cleaner.

16. Wash all carburetor components with an ether-based cleaner.

17. We pay special attention to the fuel jet of the cold start needle.

18. Putting everything back together)

19. After we have tightened the adjusting screws, unscrew the idle speed screw by 2.5 turns and the mixture quality screw by 1.5-2 turns.

A clean carburetor means dirty hands.

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Design and connection of a Yamaha scooter carburetor

The Yamaha Jog scooter is one of the most popular on the Russian market: this is explained by the simplicity and reliability of the model, and its affordable price. The carburetor design of this scooter is standard, so you can figure it out using the description given above. However, when installing it, inexperienced owners may encounter some difficulties, which we will help you sort out.

The device is worth considering in more detail. This will help you understand not only how to adjust the carburetor and use it correctly, but also how to connect it correctly.

A starter enricher is attached to the carburetor body: it is small in size and housed in a plastic case. It has two bolts with rubber seals. The enricher is powered via a 12 V battery. This device is used to start the engine when cold, as it allows you to automatically enrich the mixture with oxygen.
The fitting is connected to the fuel supply hose coming from the gas tank tap.
If the enrichment unit needs to be removed, you will need to not only unscrew the bolts, but also disconnect the electric valve, to which there are only two wires.
The mixing chamber has a special cover to which a bolt is attached. If you unscrew it, you can get to the throttle valve. This allows you to check whether the throttle cable is connected, and also to get to the needle that regulates the level of fuel and air supply. If the carburetor needs cleaning, you will definitely need to remove the throttle.
The enrichment connector has two wire outputs, the yellow one is connected to the generator, the green one goes to ground. In principle, if you reverse the polarity, nothing will happen and the device will still work.
For the enricher to operate, voltage must come from the battery. When the element inside the device heats up, the needle will extend.
A special fitting is connected to the air filter, and there is a rubber elbow between them.
There are several screws on the carburetor body with which you can adjust the idle speed and mixture quality.
The float chamber is screwed from below and has 4 mounting bolts.
There is an additional fitting for oil supply: it is the smallest.
The second fitting is needed for communication with the atmosphere; you do not need to put anything on it.
The third one is connected to a gas hose. It goes to the gas tank vacuum valve.

Tuesday, March 24, 2015

Setting up a scooter carburetor, using the example of a Honda Dio.

54 comments:

Question: Tell me what could be. Gasoline rushes from the carburetor into the air filter and flows out at the carburetor-air filter connection. This happened after cleaning and blowing the carburetor. Answer: Your scooter carburetor is overflowing. That is, the fuel level is higher than possible, obviously the needle or float is not working correctly. The carburetor may not be assembled correctly.

Thank you. I took it apart and it turned out that the float was prevented from working normally by silicone sealant, which I smeared under the gasket in the carburetor. When twisting the carburetor, it went beyond the possible limits and the float simply got stuck.

Look at the gasoline connection, you mixed up the air connection with the gasoline connection.

Tell me what size needle carburetor Honda Dio scooter 34/35.

My Honda Dio scooter won’t start and gasoline is gushing out of the orange hose when I start the scooter. Please help me.

Nikita. First, tighten the screw in front of the hose, this screw is for draining gasoline from the carburetor. And start the scooter, it will not start immediately when the carburetor chamber is filled, unless there are other reasons and breakdowns, unless of course we are talking about the hose that I thought of.

Tell me I have a Honda Tact. starts and works only when the screw is fully tightened to enrich the mixture. If you let it go, the moped stalls and the idle screw does not help. what could it be?

In short, the cause may be a clogged carburetor, poor idle speed, or a malfunctioning or incorrectly working enrichment system. Accordingly, the cause must be eliminated. I would start by cleaning the carburetor and look at the color and condition of the spark plug. Do not forget to make carburetor adjustments on a warm engine, and a temporary mixture enricher is responsible for a good start.

Carburetor design (video)

For clarity, we suggest watching a video instruction about the design of carburetors and the principle of their operation:

Knowing the structure of the carburetor and understanding what needs to be connected where, you can easily disassemble, reassemble, clean and adjust it yourself, regardless of what brand and model of scooter you have, with some skill. All these procedures will not take much time and will help you save money on car services. The ability to carry them out will help you out when the engine does not want to start.

How to adjust carburetor float height

The carburetor is the most misunderstood part of a motorcycle and many small cars. All engines require a proper mixture of air and fuel to burn; carburetor controls the ratio of fuel/air mixture entering the engine. It sounds simple enough, but there are many carburetor parts that, if not adjusted, at best the bike won't ride properly or at worst, you won't be able to start it. The correct fuel to air ratio is critical to engine performance.

Adjusting the carburetor on a 2t scooter: setting it up together

We continue to discuss DIY motorcycle repairs.

The carburetor has been cleaned, the next step is to adjust the carburetor of the 2t scooter. Over the summer, you have to adjust and adjust the operation of the engine several times.

Anyone who is at least a little familiar with the structure of the carburetor will be able to set it up on their equipment themselves. On 2-stroke engines, carburetors are adjusted according to the same principle. Therefore, the topic will be of interest to owners of any brand of 2t 50cc scooters. Whether you have a Honda Dio 27, 34, 35, stroke, Yamaha Jog, BVS or other 2-stroke mopeds.

Scooter rider

The fuel supply system is necessary for engine operation. Even if there are craftsmen who can ride without a battery, then without a carburetor the scooter will not even start. However, a more modern analogue is becoming increasingly common - an injector. It is common in Europe and Japan, but in our country the owner of an iron horse, as a rule, has to deal with a traditional device. It is important to correctly configure the carburetor on a scooter, otherwise excessive fuel consumption and breakdowns cannot be avoided.

HOW TO ADJUST A CARBURETOR ON A SCOOTER?

Diagnostics

Before installing the air filter, turn on the ignition and jerk the kickstarter foot several times until the engine starts.

If it does not start, then the most common reason is that the cold start system is malfunctioning.

We check this way: cover the carburetor hole with your fingers to maximally enrich the mixture with gasoline, and continue to push the kickstarter.

If the engine starts and the speed does not drop during operation, then look for the reason in the cold start system.

If the cold start system is working properly, then after starting the engine the speed will rise and gradually, within 10 minutes, begin to fall. On a warm engine, gradually unscrew the large screw (amount of mixture) until the speed drops to medium, confident idle.

At the same time, drops of gasoline should not splash or pour out of the carburetor.

If gasoline splashes out of the air supply hole, this indicates a malfunction of the reed valve in the engine. Then the valve needs to be removed and cleaned or replaced with a new one.

And if gasoline leaks out, this indicates a high level of gasoline. Adjust the float level and ensure the needle valve is sealed.

Setting the gasoline level and the correct position of the float in the chamber

A correctly adjusted fuel level in the float chamber does not allow the spark plugs to get wet and the engine to stall. In the chamber where the floats and jets are located, there is a valve that provides fuel supply. The correct position of the floats determines the closing or opening phase of the valve and prevents fuel overflow in the carburetor. The position of the floats is changed by slightly bending the fastening bar.

The closing or opening phase of the valve is determined by the correct position of the floats

Gasoline level is monitored with the engine running using a tube made of transparent material attached to the drain point and raised up. The gasoline level should be a few millimeters below the flange mounting of the cover. If the level is insufficient, remove the cover and adjust the needle firing phase by slightly bending the metal antennae.

Intermediate setup

Adjusting the carburetor of a 2t scooter is carried out after installing the air filter in its place.

Start the engine and let it run for about five minutes to warm up.

Adjust the idle speed (ISR) with the quantity screw: by tightening it, the throttle rises and the idle speed increases; and when unscrewing, the throttle is lowered and the CO is reduced.

Set the speed so that the scooter operates at a lower speed.

Medium and high speed tuning

Using the quality adjustment screw, the fuel proportions at idle speed are ensured. For medium and high rotation speeds, the engine operating mode is adjusted using a different method. After turning the gas handle, the fuel nozzle starts working, supplying gasoline to the diffuser. An incorrectly selected jet cross-section causes a deviation in the fuel composition, and the engine may stall when gaining power.

To ensure uninterrupted operation of the motor at a higher frequency, it is necessary to perform a number of operations:

remove debris from internal cavities;
set the gasoline level in the carburetor;
adjust the operation of the fuel valve;
check the cross-section of the jet.

The correct operation of the engine is indicated by its quick response when turning the throttle.

A quick response when turning the throttle indicates proper engine operation.

Lifehacks for the last time

— Before adjusting, you need to check that the air filter is clean and soaked in engine oil. How to clean the air filter, read the article: Scooter maintenance.
— If the rubber cuff on the quality screw is torn, then it can be replaced with a cuff from the quality screw of the classic Lada carburetor.
— On Suzuki Sepia models, lets 2,

In the latest models of Honda Dio 34 everything is simpler. The carburetor has only one large screw, which is used to regulate the XO. The small one on dio 34 is located under the plug.

The first time the setup will take 15 - 20 minutes, and then everything will be automatic. Feel free to get down to business and share your experience in the comments.

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Repair and maintenance of Honda, Yamaha, Vento 250 and BMW motorcycles: types of breakdowns

Engine

You can count up to 50 reasons why the internal combustion engine does not work. Most often, problems with repairing a motorcycle engine are solved by cleaning, adjusting or replacing parts, which does not take much time. If you bring your “horse” to the workshop in the morning, then it is likely that you will cover the evening journey home on your own bike.

Electronics

Clutch, brakes, front fork - all this will not function normally if there are problems with wiring and microcircuits. Inexperienced technicians suggest changing the entire system, but this is very expensive and is not required. We carry out initial diagnostics and find out the localization of the problem, only after that the client is informed of the price of the work and deadlines.

Motorcycle engine repairs should come with a warranty as it is the main part of the bike. Replacing an internal combustion engine is the most unpleasant thing that can happen. In some cases, it is indeed easier to buy a new vehicle, but if the engine has a chance of “survival,” then our auto experts will be able to save it.

Scooter carburetor. Correct adjustment

The carburetor is a unit whose importance cannot be overestimated. Since it is in the carburetor that gasoline is mixed with air and, thus, a fuel mixture is formed before it is directly supplied to the scooter cylinder. The quality and correct composition of the fuel mixture determines fuel consumption, wear of the cylinder-piston group and spark plugs, maximum speed and dynamics of the scooter, and much more. This is why it is so important to take a responsible and comprehensive approach to setting up the carburetor. A properly adjusted carburetor will ensure stable, reliable and productive engine operation, as well as make driving comfortable and safe.

Unfortunately, scooter riders often, due to ignorance or lack of experience, underestimate the importance of comprehensive carburetor tuning. For example, there is an extremely widespread misconception that adjusting the degree of richness of the mixture only means adjusting the quality screw on the carburetor. In fact, this setting allows you to achieve the correct mixture only at idle and low speeds. At the same time, at medium and high speeds the proportions of the fuel mixture can be completely disrupted. Let's figure out how to properly configure the carburetor.

Signs that adjustment is needed

Based on certain signs that appear in abnormal engine operation, we can conclude that the carburetor needs adjustment.

The list of deviations is quite wide:

the power plant does not develop the required power under load;
when the scooter accelerates sharply, failures in engine operation are felt;
a cold engine is difficult to start with the starter after a long period of parking;
the scooter's power unit consumes fuel in increased quantities;
there is no quick response of the engine to a sharp turn of the accelerator handle;
The engine may suddenly stop due to insufficient fuel mixture.

The carburetor should be adjusted if there are signs of the need for adjustment.
If one or more of these signs is present, the carburetor should be adjusted, and then its condition should be diagnosed and the engine should be checked.

Scooter carburetor - design and principle of operation - Scooters Maintenance and repair

Before you start making adjustments, you need to warm up the engine, and if there is contamination, the carburetor should be cleaned.

Carburetor settings

It's like another miniature carburetor in the main carburetor.

Honda Dio 27 does not hold xx installed a new carburetor, when it is started it is necessary to constantly The device and ...

Scooters of the Tact family are designed for novice drivers.

Float chamber It is important that the fuel in the float chamber is always within certain limits and does not drop below the permissible norm.

We tried to start it, but the result was the same.. Still, I think that I’ll go buy the enricher tomorrow, because when disassembling this unit I also discovered that the needle itself does not hold in the latches inside, one of the 3 latches is broken, and the wiring is broken, it cannot be repaired. There is only a big plus from RACING around equipment - broken and torn bolts are changed in parallel, brake pads are replaced and so on. If they had started the scooter right away, then they definitely wouldn’t have gotten around to it until the fall Reply Reply with a quote Quote Report to moderator 0 Alexey82ua After capitalization on a Honda tact fullmark, gasoline flows from the carb from the lower tube, and not from the tube where the drain screw.

It completely refuses to start, and if it does start, you have to squeeze the gas all the way down, as if it was missing something.

The principle of idle operation is very similar to the main one. This is a kind of miniature carburetor within a carburetor. It is needed for idle speed, which prevents the scooter engine from stopping during a temporary stop when you do not turn off the engine.

Recommendations for carburetor tuning

Idle speed adjustment

When idling, the engine runs normally but does not use fuel to keep the wheels spinning. When you press the throttle, a choke in the carburetor rises, preventing the fuel mixture from flowing. The higher the damper, the more fuel will have time to enter the combustion chamber. Accordingly, at idle speed, the fuel mixture entering the chamber is only enough to prevent the scooter from stalling. If the adjustment does not work correctly, then at idle speed the engine will consume more gasoline than necessary. But gasoline still costs money. In addition, this causes the engine to overheat.

There is an idle air adjustment screw on every carburetor; all you have to do is find it and select the appropriate screwdriver. The exact location of the screw for your model can always be found on the Internet. For example, adjusting the carburetor on a Honda Dio scooter takes place without any problems. In its original carburetor, the idle speed adjustment screw is in the center, and the mixture quality screw is on the left. But on a Chinese moped, most likely, there is a carburetor with a single screw, which is responsible for adjusting the idle speed. The sequence of actions will not cause difficulties:

Turn on the engine and let it warm up. Don't turn it off.
To increase speed, turn the screw clockwise.
To lower, respectively, counterclockwise.
After each turn, run the engine for two minutes.
If it runs smoothly, then the idle speed is adjusted.

Sources:

https://priormoto.ru/vse-statyi/regulirovka-karbyuratora-2t-skutera.html https://xn74-4lcplk8d.xnp1ai/Honda/regulirovka-karbyuratora-Honda-dio-27.html

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You should monitor the tread height of your tires and replace them as necessary. Riding a scooter with worn tire tread is extremely unsafe.

The turn should be done “pull”, controlling the gas or releasing it in advance. Always turn on low beam headlights when riding a scooter.

Float chamber It is important that the fuel in the float chamber is always within certain limits and does not drop below the permissible norm. It is also important that gasoline does not rise above the permissible standards - this will help to avoid overfilling.

Actually, the float, which on the opposite side has a shut-off needle at its disposal, is responsible for the optimal level of fuel in the float chamber. Gasoline filling the chamber raises the float as it enters, which is constantly afloat.

cleaning the carburetor Honda Dio 27

When it reaches its maximum fulcrum, it closes the channel through which gasoline is directed from the gas tank to the carburetor. This is how the stable presence of a small amount of gasoline in the float chamber is regulated.

These are probably all the main systems of the Honda Dio 27 carburetor, so once you understand the operation of this device, it will not be difficult for you to put your scooter in order using the instructions in the manual.

Auto parts for foreign cars, auto repair

The scooter should accelerate smoothly, without a Honda Dio af 34 carburetor, and there should be no jerking while driving. If you are unable to achieve acceptable operation of the scooter, remove the throttle from the carburetor and raise or lower the needle.

To do this, remove it from the damper and move the retaining ring along the grooves. You can find out the quality of your mixture, and thus in which direction to adjust, by looking at the spark plug, or more precisely, by the color and deposits on its electrodes.

Adjusting the level of carburetor hoses on a Honda Dio me Honda Dio If it is black, with a predominance of a large amount of carbon deposits, the mixture is rich.

If the spark plug is almost white, the electrodes of the Honda Dio af 34 carburetor melt - the mixture is lean. Adjusting the fuel level in the float chamber. You can check the fuel level in the float chamber using a transparent tube located at the very bottom of the carburetor.

What is a starting enrichment

A starting enricher (electrovalve) is a device designed to supply an additional amount of air-fuel mixture into the combustion chamber during a cold start of the scooter engine. The fact is that when starting the scooter when cold, the engine requires an enriched mixture. The supply of such a mixture is ensured by the carburetor solenoid valve . If the starting enrichment is in good working order and there are no breakdowns in other engine elements, the scooter engine starts easily even at temperatures around zero degrees.

Scooter starting enrichment device

There are two types of starting concentrators - manual and automatic.

The manual (mechanical) starting enrichment requires adjustment - it must be opened at startup and closed after the engine warms up using a cable on the steering wheel. But manually opening and closing the additional channel for supplying the mixture is inconvenient. An automatic starting enricher (thermoelectric valve) is installed on most modern 2t and 4t scooters. We will learn about the device of the automatic starting enrichment further.

Solenoid valve body
Ceramic heater
Drive (powder)
Stock
Pusher
Damper
Fuel chamber
Float chamber
Starting fuel jet
Spring

The scooter carburetor has a small additional fuel chamber 7, which is connected to the main float chamber 8 through the start nozzle 9. The tube from chamber 7 leads to the mixing chamber into which air is supplied and from which the air-gasoline mixture goes into the engine. A valve 6 can move in the mixing chamber, similar to a carburetor throttle valve, only much smaller in size. Just like the throttle valve, the starting valve contains a spring-loaded needle that closes the fuel channel when the valve is lowered. Valve body 1 is wrapped in thermal insulation (polyethylene foam) and covered with a rubber boot. This enricher design is used on almost all modern scooters.

Older models may use a design without an electric heater, heat is transferred to the drive through a copper heat-conducting cylinder directly from the scooter's engine cylinder, and a membrane . One cavity of the flask, where it is located, is connected through a thermal valve to the intake manifold, which is mounted on the cylinder head.

The principle of operation of the scooter carburetor solenoid valve

When the engine is cold, the valve with the spool needle 6 is raised as high as possible (open). The needle opens the fuel supply channel, and the flap opens the air supply hole. At the first engine revolutions, a vacuum is created in the emulsion channel and gasoline located in chamber 7 is sucked into the engine through channel A, causing a strong enrichment of the mixture and facilitating the first flashes in the engine. After the engine has started, but has not yet warmed up, it still needs a rich mixture. The enricher works like a parallel carburetor - gasoline enters it through jet 9, mixes with air and enters the engine.

When the engine is running, alternating current from its generator is always supplied to the contacts of the ceramic heater 2 of the thermoelectric valve of the starting system. Heater 2 warms up drive 3. As the engine and drive warm up, the rod gradually extends by 3 ... 4 mm and drives the damper through pusher 5. Thus, the engine warms up along with the thermoelectric valve, the spool with the needle drops and closes the air and fuel channels, and the mixture gradually becomes leaner. After 3...5 minutes, the damper closes completely and the degree of enrichment of the mixture on a hot engine is regulated only by the carburetor idle system .

When the engine stops heating of the valve stops , the damper drive cools down (the powder is compressed) and under the action of spring 10, pusher 5, rod 4 and damper 6 return to their original position, opening the channels for subsequent start-up. Cooling down and returning to its original position also occurs within a few minutes.

The disadvantage of this type of enrichment is that it operates separately from the engine. For example, very often, especially in warm weather, while the engine is still hot and there is no need to enrich the mixture, the thermoelement is already cooling down. We start the engine and it gets a rich mixture.

Operating principle of the second type of starting enrichment (with a membrane)

When cold, the valve is open . After starting the engine, a vacuum occurs in the manifold and is supplied to the membrane through a thermal valve. As a result of low pressure, the membrane rises and opens a channel for additional air supply. As the cylinder head warms up, the valve closes and the valve with the needle is lowered under the action of a spring, cutting off the additional fuel supply.

With this design principle, the connection with the actual engine temperature is maintained, and fuel dosage is carried out more correctly.

How to change the quality of the fuel mixture

For all scooter engines, it is important to receive fuel with an adjusted ratio of gasoline to air. A lean mixture leads to improper operation of the engine, a drop in power and overheating of the engine, while a rich mixture leads to an increase in consumption and the formation of soot.

Adjustment operations are performed by changing the position of the quality screw and moving the throttle needle.

Turning the screw to the right causes the mixture to become richer, and unscrewing in the opposite direction causes it to become leaner. The same happens with the needle: when the needle is raised, the mixture becomes richer, and when lowered, it becomes poorer. The integrated use of both methods allows you to achieve optimal results during setup. However, not all carburetors have this feature, so, as a rule, one of two options is used.