How to synchronize carburetors on a Ural motorcycle

Preparing to adjust carburetors

Before you start adjusting carburetors, make sure that the valve clearances are set correctly and that the ignition is not disrupted and is working correctly.

It is recommended to read the information on setting up valves in the Urals. And in this article you can find out how to set up the Ural ignition.

The carburetors should not be worn out or different, otherwise nothing will work out for you, and tuning will be impossible. The carburetors themselves must be clean both outside and inside without plaque, traces of rust and other deposits, each jet must be blown with compressed air, the shut-off needle is in working order, and the floats are sealed . Check the condition of the rubber pipes; cracks are unacceptable. Is the air filter clean?

It is important to know: one of the big problems is the leaky installation of carburetors and the connection of rubber pipes with the air filter. If there is an air leak somewhere, this can lead to engine overheating and dust getting into the cylinders.

Preparing for adjustment

Adjusting the K-37A carburetor of the Ural motorcycle has three stages of adjustment: 1. idle; 2. at medium speeds; 3. uniform operation of both carburetors.

Before starting the setup, it is advisable to remove the carburetors and disassemble them to check for serviceability. To do this, check the fuel level, if necessary, change it and bring it to normal. Clean all jets and fuel and air passages. Check the control drive of each device

When installing, pay attention to the tightness of all connections.

Before starting, pay attention to the condition of the piston and measure the compression ratio in the cylinder. The cylinder-cylinder head connection is assembled without air leaks. If you need to replace the gasket.

Pay attention to the ignition. Inspect the spark plugs and spark quality

In case of malfunction, install new spark plugs.

Carburetor adjustment should be carried out on a warm engine, and the carburetors should first be adjusted individually.

The first stage of adjusting carburetors on a Ural motorcycle

If you have carried out the above manipulations and are confident that all systems are working properly, we proceed to direct adjustment. You need to completely warm up the engine, it is advisable to drive for 10-15 minutes before tuning. Then we start the engine on one cylinder, having first removed the cap from the spark plug of the other cylinder.

1. Using the “quantity” screw (pictured No. 1), we lower the speed to the minimum stable.
2. Using the “quality” screw (pictured No. 2), we increase the speed until it stops growing.

Repeat points 1,2 – 2-3 times. We do the same on the other cylinder. We achieve the same operation of the cylinders individually by ear, ideally by the tachometer.

3. Connect both spark plug wires and synchronously turn the mixture quantity screws with both hands until the minimum idle speed is obtained. The engine should run smoothly and without jerking. The first part of the adjustment affects the stability of the launch of the Ural motorcycle, the correct operation of the carburetors at the initial opening of the throttle valves.

It is worth noting that: if you have an outdated model of carburetors, such as the K-65, the “quantity” screw No. 1 is located on top, on the carburetor cover.

Engine synchronization on a Ural and Dnepr motorcycle

Repairing a Dnepr engine is quite a difficult task. Insufficient synchronization in the operation of the Ural engine indicates that one of the cylinders is working more intensively than the second. This can lead to the fact that the cylinder that shows more powerful operation can wear out very quickly and fail.

The synchronization of the carburetors is clearly visible if you start the motorcycle at idle. Synchronization of Dnepr motorcycle carburetors occurs when the same operation of two cylinders is ensured. Simply put, motorcycle carburetor synchronization is achieved by lifting the throttle on both the left and right carburetors, switching between different modes.

Carburetor synchronization

We will describe the whole process of how to synchronize carburetors on a Ural or Dnepr motorcycle with your own hands. Let's start:

1. We position our bike so that the rear wheel can rotate well.
2. We start it, engage fourth gear and set the engine speed to the equivalent of 30 km/h.
3. Then we remove the tips from the spark plugs and screw them into ground, each in turn.
4. Now we carefully listen to the operation of each cylinder for differences and distortions.

Repairing a Dnepr motorcycle engine is a very important matter. Carburetors on a motorcycle are synchronized in a similar way, or you can use another method

Synchronization of motorcycle carburetors can be done by adjusting them, while assessing the speedometer readings. If the values ​​​​differ for two cylinders, then it is necessary to unscrew and screw in the adjusting screw at the throttles.

Engine repair Ural video

Tuning and synchronizing carburetors on the Dnieper/Ural

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Second phase

Now let's move on to the main second stage of carburetor adjustment in the Urals. Place the Ural motorcycle on the center stand, or in any way convenient for you, hang the rear of the motorcycle so that the rear wheel is in free rotation.

Start the motorcycle again and remove the spark plug wire from the right cylinder. Engage 4th gear, add a little gas, and the speedometer should show 55 km/h. Lock the throttle in any convenient way in this position (there is a small screw in the throttle for this). Then put the right spark plug wire back and remove the left one. Using the screws on the carburetor covers, we adjust the length of the cables so that when working on each cylinder, the speed on the speedometer does not change. This will ensure synchronized operation of the throttle valves during transient operating conditions.

Synchronization of two carburetors

After talking a little with people on the topic of carburetors, I realized that for most motorcyclists it is a very big problem to adjust two carburetors on a boxer engine...

To be honest, I also jumped around my K-65 quite a bit while I adjusted it and developed the adjustment technology. Namely, the whole difficulty lies in synchronizing the operation of carburetors in low, medium and maximum load modes. In other words, on incorrectly adjusted carburetors, one cylinder heats up more than the other when driving on the highway. The reason for this is the non-synchronous raising of the throttle valves; one carburetor is constantly open a little more than the other.

What we are asked to do according to the book:

• place the motorcycle on the stand;
• start the engine;
• engage 4th gear;
• turn off one of the cylinders by disconnecting the high voltage wire from the spark plug
• increase engine speed to speedometer reading 50 km/h
• wait a few seconds to make sure that the mode has stabilized, turn on the second cylinder and simultaneously turn off the first;
• raising or lowering the throttle by rotating the fittings on the carburetor caps, achieves the same speedometer readings for both cases. Since the adjustment can continue for quite a long time, it is necessary to monitor the thermal conditions of the engine and prevent overheating.

Personally, I have never used this method; it is a very complex and very low-tech method. I suggest taking it simpler. I adjusted Bing and K-65 using the method described below. After you have adjusted the idle speed, turn off the engine. Next you will need a second person, an assistant. Remove the air filter pipe from the carburetors (K-65). Using your left index finger, touch the throttle valve of the left carburetor. At the same time, touch the throttle valve of the right carburetor with the index finger of your right hand. At this point, the second person should pull the throttle very slowly. You will feel which throttle valve (left or right carburetor) will rise first. Achieve simultaneous lifting of the throttle valves by rotating the fittings on the carburetor covers. That's all the adjustment is. It seems to me that this is much simpler and more accurate than doing what is suggested in the book. This method can be used on any carburetors

(!)Note(!)

In this way, you need to adjust the carburetors only after they work normally at idle speed! If for some reason you touched the idle speed after synchronization, you will have to synchronize the carburetors

again.

Anonymous (pedestrian)

opposit.ru

Third stage

Let's move on to the final part - adjusting the carburetor of the Ural motorcycle. Now you need to adjust the main dosing system. It consists of throttle valves, needles and main fuel jets. The bottom line is that due to the variable cross-section of the carburetor needle, directly proportional dosing of fuel occurs depending on the amount of air passing through the carburetor diffuser. Make sure that the carburetor needles are straight and the holes for them in the throttle bodies are not worn out. Replace the spark plugs with new ones or clean the old ones. Ride a motorcycle at a constant speed of 70 km/h for 10 minutes. Stop, turn off the engine, unscrew the spark plugs and, according to the photo below, determine the correct adjustment:

1. This is the color of the candle when properly adjusted. As you can see, the brick color of the spark plug insulator is due to correctly tuned carburetors.
2. If the candle is black, this is a sign of a rich mixture. Therefore, we lower the needles in the carburetors by one notch (initially they should be installed in the middle position).
3. If the candle has white carbon deposits, raise the needles by one notch.

If, after moving the needles one notch, you cannot achieve a brick shade of the candle, try setting it 2 notches lower or higher, depending on the color of the insulator. As a result, we will get the correct mixture at constant engine speeds when driving along the highway.

It is important to know: if the spark plugs have black soot with a shine, perhaps the cylinder-piston group of the motorcycle is worn out, and the spark plugs are simply splashed with oil. It is worth thinking about repairs as soon as possible.

In this article we looked in detail at what it is to adjust the carburetor of a Ural motorcycle. Correctly setting the carburetors on a Ural motorcycle is the key to good engine performance.

Synchronization of two carburetors

After talking a little with people on the topic of carburetors, I realized that for most motorcyclists it is a very big problem to adjust two carburetors on a boxer engine...

To be honest, I also jumped around my K-65 quite a bit while I adjusted it and developed the adjustment technology. Namely, the whole difficulty lies in synchronizing the operation of carburetors in low, medium and maximum load modes. In other words, on incorrectly adjusted carburetors, one cylinder heats up more than the other when driving on the highway. The reason for this is the non-synchronous raising of the throttle valves; one carburetor is constantly open a little more than the other.

What we are asked to do according to the book:

• place the motorcycle on the stand;
• start the engine;
• engage 4th gear;
• turn off one of the cylinders by disconnecting the high voltage wire from the spark plug
• increase engine speed to speedometer reading 50 km/h
• wait a few seconds to make sure that the mode has stabilized, turn on the second cylinder and simultaneously turn off the first;
• raising or lowering the throttle by rotating the fittings on the carburetor caps, achieves the same speedometer readings for both cases. Since the adjustment can continue for quite a long time, it is necessary to monitor the thermal conditions of the engine and prevent overheating.

Personally, I have never used this method; it is a very complex and very low-tech method. I suggest taking it simpler. I adjusted Bing and K-65 using the method described below. After you have adjusted the idle speed, turn off the engine. Next you will need a second person, an assistant. Remove the air filter pipe from the carburetors (K-65). Using your left index finger, touch the throttle valve of the left carburetor. At the same time, touch the throttle valve of the right carburetor with the index finger of your right hand. At this point, the second person should pull the throttle very slowly. You will feel which throttle valve (left or right carburetor) will rise first. Achieve simultaneous lifting of the throttle valves by rotating the fittings on the carburetor covers. That's all the adjustment is. It seems to me that this is much simpler and more accurate than doing what is suggested in the book. This method can be used on any carburetors

(!)Note(!)

In this way, you need to adjust the carburetors only after they work normally at idle speed! If for some reason you touched the idle speed after synchronization, you will have to synchronize the carburetors

again.

Anonymous (pedestrian)

opposit.ru

Which carburetor is better to install on a Ural motorcycle?

Since 1985, the IMZ plant, Irbit, Sverdlovsk region, began to equip mass-produced Ural motorcycles with carburetors of the new K63 model. The K63 carburetor replaced the K301, K302 previously used. This carburetor is installed on the Ural motorcycle to this day. The machine is equipped with a two-cylinder engine, which is equipped with two K63 models of the same design.

Rice. 1. K63 carburetor for the Ural motorcycle

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The Ural is the most recognizable motorcycle with a boxer engine and a side-mounted trailer, which is known not only in the countries of the former USSR, but throughout the world. Today, these motorcycles are produced mainly for the foreign market with electronic fuel injection. But they used to have carburetors. This article will describe in detail the adjustment and tuning of various carburetors on a Ural motorcycle.

• Correct setting of the scooter carburetor

Carburetor design

The carburetor for the Ural motorcycle is a horizontal device designed to prepare the air-fuel mixture. The float chamber is located in the center of the assembly. The mechanism is equipped with a flat throttle valve with vertical stroke, two dosage systems - the main one, the idle one. They shape the volume and quality of the mixture.

The starting device is located separately, consisting of three main blocks, Fig. 2:

• building 8;
• chamber with float 38;
• cover 4.

Rice. 2. Schematic representation of the carburetor for 63. 1 - Fitting with lock nut; 2 - Throttle spring; 3 - Throttle lift limiter; 4 - Housing cover; 5 - Lock nut; 6 - Dosing needle bar; 7 - Throttle; 8 - Housing; 9-Air channel of the sprayer; 10 - Float lever axis; 11 - Spray body; 12 - Sprayer; 13 - Float chamber cover; 14 - Main fuel jet; 15 — Idle fuel jet; 16 - Lock washer; 17 — Channel for supplying the fuel mixture from the starting device; 18 - Float; 19 — Stop for adjusting the fuel level; 20 - Fuel valve; 21 - Drainage hole; 22 - Emulsion hole: 23 - Transition hole; 24 — The air channel of the jet is idle, running; 25 Dosing needle; 26 - Air channel of the float chamber; 27 — Fuel receiving fitting; 28 — Idle speed adjustment screw; 29 — Mixture quality adjustment screw; 30 - Air channel; 31 - Starting lever; 32 - Rod; 33 - Spring; 34 - Starter plunger; 35 — Float drowner; 36 - Plunger needle; 37 — Fuel jet of the starting device; 38 - Float chamber.

The float chamber communicates with the atmosphere through the vertical outer channel of the housing 26. The top cover of the chamber has a drainage hole 21. The carburetor of the Ural motorcycle is equipped with a lever float mechanism consisting of two floats 18. Both products have the shape of rectangles, connected together by a common lever made of the innovative material caprolactam as one piece.

Axle 10, pressed into the lever, presses the structure with floats against the two columns of the housing. The brass fuel valve 20 visually resembles a needle. There is an elastic washer on top of the cone. It is practically eternal, almost not subject to wear. Thanks to it, the Ural carburetor always has a stable level of gasoline in the float chamber. The valve has a groove at the bottom that connects it to the float. Therefore, it never gets stuck in the guide channel.

Preparation of the air-fuel mixture

From the starting device into the carburetor on the Ural motorcycle, the fuel mixture is directed through channel 17 to the mixing chamber.

The non-separable plunger 34 has built-in parts:

• conical needle 36;
• spring 33, which prevents needle 36 from jamming;
• the tip to which the rod is connected.

The nozzle of the main dosing system 12 is pressed into the housing 11, where 4 radial holes are made. The throttle, which has a U-shaped cross-section, is made of a sheet of brass. The throttle wall has a semicircular segment cut out. It faces the air purifier. This groove ensures that the carburetor in the Urals receives the specified vacuum above the nozzle while the engine is operating at low idle loads.

Adjusting the main carburetor systems in the Urals

Adjustment of carburetors on a Ural motorcycle is carried out after checking and adjusting the gaps between the spark plug electrodes, breaker contacts, valve stems, and the ends of the rocker arms. Each of the two carburetors is separately adjustable. It is necessary to begin adjusting the carburetor in the Urals after measuring the gap between the tip of the cable sheath and the fitting, which should be 2-3 mm.

Rice. 3a. The main elements of the carburetor: 1 - main air path: 2 - throttle valve; 3 - subsidizing haze; 4 — air nozzle; 5 - sprayer; 6 — air channel; 7 - well; 8 — main fuel jet; 9 — float chamber (central location).

Rice. 3b. Fuel corrector: 1 — air inlet channel: 2 — spool; 3 — spool needle; 4 — fuel jet: 5 — sprayer; 6 — output emulsion channel; 7 — spool return spring; 8 — corrector control cable.

If the gap does not correspond to the specified size, the union locknut is loosened. Turn to the right or left to set the required gap. After this, the fitting is re-locked with a lock nut and the carburetor of the Ural motorcycle is adjusted. By turning off the warm engine at a minimum engine speed without load, the basic settings are made. The idle system is adjusted for each of the two mechanisms separately. The Ural carburetor is adjusted with the second cylinder turned off.

Idle adjustment

By rotating screw 28, the crankshaft speed is set to the minimum stable engine speed. Screw 29 is slowly unscrewed gradually until the motor begins to malfunction. It also gradually, slowly twists until a calm, stable speed is achieved. Once again, use screw 28 to reduce the opening angle of the throttle valve until the minimum speed is reached.

At the same time, screw 29 adjusts the saturation of the mixture. Such operations are repeated until the minimum stable engine crankshaft speed is obtained. The carburetor of the Ural motorcycle is adjusted in the same way for the second cylinder. The test is carried out by sharply opening and closing the throttle. In this case, you must sharply turn the throttle towards yourself and release it to its original position.

Operating modes

Modes of medium loads are characterized by the position of the needle relative to the throttle. Adjustment is carried out by choosing its most optimal position. The settings must be repeated when seasonal conditions change (winter-summer), during the running-in of new vehicles, in order to increase engine power. In this case, the dosing needle 25 moves along the thread relative to the bar 6. The locknut 5 is loosened.

When screwed into the bar, the needle rises in relation to the nozzle hole. The mixture becomes richer. When unscrewing, the mixture becomes leaner. One revolution of the needle moves 0.5 mm. The quality of the adjustment is checked by sharply turning the throttle knob. The loud pops that the carburetor makes on a Ural motorcycle indicate that the mixture needs to be enriched. To do this, the needle rises.

When operating motorcycles, owners often wonder which carburetors are best to install on a Ural motorcycle. Now Chinese carburetors are widespread in the Urals. There are some good examples among them. Foreign-made Solex and Weber models performed well in operation. However, their prices are higher than domestic ones.

What carburetors should I put on the Ural IMZ motorcycle? In my opinion, a Russian-made K63 carburetor would be good for the Urals. This is a trouble-free mechanism, the professional adjustment of which allows it to last for several decades. Every 5 thousand km it is recommended to clean it, blow it out, and rinse it.

The jets must be washed with acetone. The parts are wiped with rags or soft vinyl. The throttle should be installed after servicing with the cutout facing the air filter. Regular maintenance will ensure long-term trouble-free operation of the K63 model.

How to properly adjust carburetors

This article begins a series of simple and understandable answers to frequently asked questions from the initiative group gathered here.

The instructions are often not at hand, or you simply cannot understand what is written there. Inside is a step-by-step algorithm for adjusting boxer carburetors.

In order to adjust carburetors, you need to know this: First of all, this work must be done after adjusting the valve clearances and ignition. Carburetors should not be worn out or different, otherwise it will be very difficult or even impossible to adjust them.

First we adjust the idle speed with the quantity and quality screws. This adjustment DOES NOT AFFECT driving modes! If there are problems while driving, there is no need to turn the screws. The quality screw regulates the ratio of gasoline and air in the mixture, the quantity screw raises the throttle valve, adjusting the idle speed. They need to be turned smoothly and slowly, 1/4 turn or even less, especially on carburetors K-301 and K-302. Now how to find these screws:

On the K-301 and K-302 carburetors, 1 is the quantity screw, 18 is the quality screw.

On the K-63, K-65, K-68, KARTECH carburetor: 28 is the quantity screw, 29 is the quality screw.

1. Loosen the cable so that it plays on the carburetor, set the needles on the carburetors to the middle position. 2. tighten the mixture quality screws all the way and unscrew them 1.5 turns. 3. Start and warm up the engine. 4. turn off the right cylinder by pulling the high-voltage wire from the spark plug. If the ignition is electronic, the wire must be shorted to ground, otherwise it will burn out. 5. On the left cylinder, lower the throttle valve (to the minimum stable operation of the engine) with the mixture quantity screw. If it stalls, start it on two cylinders, then turn off the right one again. 6. Unscrew the mixture quality screw and achieve maximum speed. 7. Reduce engine speed using the mixture quantity screw. 8. Repeat steps 5-7 until the valve is lowered to the very limit, usually 2-3 times.

9. Now turn on the right cylinder, turn off the left one and adjust the right carburetor (steps 5-8). 10. By alternately pulling the right and left high-voltage switches off the spark plug, you need to achieve the same audible speed from both boilers. 11. Connect both and by simultaneously tightening the mixture screws the same number of turns, we achieve the minimum stable idle speed. The motor should produce a uniform “thump-thump-thump” sound and should not jerk.

Well, we have adjusted the idle speed, now we will adjust the cables so that they raise the dampers at the same time and so that the cylinders work synchronously at operating modes.

12. Place the motorcycle on the center stand. 13. Start the engine and pull off the high-voltage wire from the right boiler. 14. Engage 4th gear and accelerate the engine according to the speedometer to 55 km/h. 15. Fix the throttle (there is a small screw on it for this purpose). 17. We attach the right high-voltage voltage, pull off the left one. 18. We adjust the RPM with the cable sheath screw so that the speedometer shows the same 55 km/h 19. We turn off the engine and lock the cable sheath screws.

Now our task is to adjust the main dosing system. I hope your carburetor needles are straight and your throttle bodies are not worn out!

20. We drive at a speed of 70 for 10-15 minutes. 21. look at the color of the candles. Brown/black - lower the needles one notch. White - raise one notch. Should be brick color. If it is a K-63 carburetor and the needles are threaded, then they need to be rotated 2-3 turns.

22. Repeat points 13-19

That's it, the adjustment is complete! If the motor overheats during this process, you need to let it cool down. Good luck on the roads!

The quality screw still affects traction from the very bottom. It is also advisable to check the level in the float before tuning. But the rest is written correctly and intelligibly. Even when the screw is not on the gas handle or is torn off, you can fix it with electrical tape.

interesting article! but with these settings at xx I sneeze into the carburetor and at a speed of 70 kmh the spark plugs are white and above 90 they don’t go at all (the needles are raised to the limit) and you have to touch the throttle carefully, otherwise it’s a failure, I want to buy a new K-65t and try with them. In general, recently the engine has started to struggle.

I set it up according to your diagram, and when the throttle is opened sharply, the engine choke, and if the unscrewed mixture quality screws are tightened so that it is approximately 0.5-1 turns from the tightened state, then the engine picks up speed very well when the throttle is sharply opened. How should it really be??

Possible malfunctions of motorcycle carburetors

The power and other qualities of motorcycles depend on how the carburetors work. It is on the correct adjustment of the carburetors that the way the motorcycle will start, its speed and control depends.

Many people mistakenly believe that a carburetor is a rather simple device. But it is a rather complex device. It is in it that various mixture formation processes take place. They are difficult to evaluate even in the laboratory. And if the metering systems or any carburetor component is faulty, it can be very difficult to determine the cause. Therefore, the performance of the carburetor is assessed by indirect signs. They evaluate the quality of the combustible mixture that is prepared in the carburetor. You can recognize this, but with experience. And at first, before adjusting the carburetors, the ignition system and the correctness of its installation are checked.

The combustible mixture can change its composition in order for the combustion process to be normal. This depends on many factors - time of year, engine operating mode and other factors. But for a specific case, its composition must be certain. And the smallest errors lead to increased fuel consumption, and the engine will not work well enough.

The resulting mixture of different composition equally slows down acceleration, reduces speed, and overheats the engine. How is the quality of the resulting mixture determined? To do this, you need to drive along the road and prepare the plate in advance. Moving at low speed, cover one-fourth the size of the inlet pipe with this plate. And watch the speed of your motorcycle change.

Possible options:

• Rich. With this composition, the speed of the motorcycle will decrease quite noticeably, and the engine speed will also decrease.
• Enriched. These figures will not decrease much.
• Depleted. Speed ​​increases slightly.
• Poor thing. This mixture will significantly increase the speed.

In what case is the composition of the mixture disrupted? When little air is supplied, or, on the contrary, a lot of fuel, the mixture turns out rich. This means that the carburetor adjustment was made incorrectly or the air filter is clogged. This mixture burns at a lower speed. Without having time to completely burn out in the cylinder, it burns out in the exhaust system. Hence the appearance of soot. And it, in the form of tarry deposits, can reduce engine power, and the cylinder overheats. As a result, excessive fuel consumption.

If a large amount of air enters the combustible mixture, but, on the contrary, there is less fuel, it turns out to be lean. There can be many reasons for this. The parts of the carburetor are not tightly connected, so foreign air enters. Fuel jets may become clogged, there may be several reasons. Such a mixture burns out at an even lower rate than a rich mixture. The result of using a lean mixture is increased fuel consumption, engine overheating, and a decrease in its power. Popping noises in the carburetor.

How to determine in which system a particular mixture is prepared? If you hear popping noises while driving downhill or when accelerating, it means the idle system is faulty. If popping noises occur when the engine picks up high speeds, you have a malfunction in the main metering system. You can change worn parts of the carburetor or the carburetor itself.

Synchronizing carburetors on a motorcycle

Synchronizing motorcycle carburetors is a precise procedure, but not very difficult. To carry out this action you will need a synchronizer. This is a set of meters that check for sparsity. And the meter itself is a vacuum sensor with a valve that smoothes out the oscillations of the needle. Sets with two or four heads are used. A four-head device is best.

Synchronization procedure:

• The motorcycle warms up to the required temperature.
• The tank is removed, then the filter.
• Now you need to choose the places where to connect the device heads. What is the essence of synchronization? It is necessary to set the same rarefaction formed in the collector. Because through it the combustible mixture enters the inlet cylinders from the carburetor. Therefore, connection points must be selected in the collectors.
• The device connects to the found collection points. It happens that it is difficult to get to these points, and then the carburetors can be raised. To do this, they are pulled out of the pipes, and after connecting the device, they are seated in place.
• The motorcycle starts. The valves of all sensors need to be adjusted. It is necessary that they react to any changes in sparseness, but do not fluctuate much. The valve is released if the arrow does not respond to any changes.
• Three screws can be seen on the carburetor. It is with their help that synchronization is carried out. One of them, the first, is located between the first two carburetors. We synchronize them. To synchronize the second pair of carburetors, the third and fourth, a third screw is used. He is between them. The central screw synchronizes all carburetors with each other.

First of all, the left screw and the right one, and only after that the central one.

• The first pair of carburetors is synchronized.
• The second pair of carburetors is synchronized.
• All readings are now aligned using the center screw.
• After the synchronization is completed, we apply gas, sharply raise the speed and reset again. All readings are synchronous.
• If this is not the case, the procedure, starting from the seventh step, must be repeated.

You can change the oil or carry out the synchronization procedure yourself. But adjusting a motorcycle carburetor is the more difficult part of the repair. And if you don’t have the skills to do this kind of work, it’s best to turn to professionals.

How to adjust the carburetor on a motorcycle

If the synchronization of carburetors is carried out so that the amount of the combustible mixture is adjusted, then they are adjusted to improve the quality of this mixture supplied to the cylinders from the carburetors.

The Keihin carburetor for a motorcycle is adjusted in the same way for different models and brands of motorcycle. It is best to adjust carburetors at the same time as cleaning the carburetors. Because most often a poor-quality combustible mixture is formed when the jets are not clean enough.

The carburetor for the Ural motorcycle and other domestic motorcycles has been used from St. Petersburg since ancient times. It was constantly modernized and changed. And today this is a completely new device, which is called K-68. Today the Ural is the only motorcycle in the world that uses carburetors with variable vacuum.

To keep your motorcycle running properly, you need to know how to adjust the carburetor. And this needs to be done under certain weather and a specific road. Carburetors installed on motorcycles differ slightly from each other.

Attention: Motorcycle carburetors are designed specifically, and all its systems must work in parallel. The slightest mistake in this type of work will lead to other errors occurring. Care is required here.

To the question of how to properly set up a carburetor, we will answer this way, only in strict sequence.

• The float chamber contains fuel. Its level needs to be adjusted. Read the instructions carefully. The required float height is indicated there. The tongue is bent for adjustment. This adjustment is only necessary for precise adjustment.
• Idling. In this case, the carburetor operates when the throttle valve is closed. Idle speed is adjusted. To do this, you need to use the idle system jet and screws that regulate the quantity and quality of the mixture formed.
• Transitional mode. Here the throttle valve opens to a quarter. It is very important to choose the right jet and adjust the idle system.
• The throttle valve is partially open, up to seventy-five percent. Here you need to pay special attention to the gap that forms between the needle and the tunnel where the needle moves. The composition of the mixture depends on the diameter of the needle. To access this needle, on most motorcycles the carburetors will need to be removed.
• The throttle valve is fully open. The size of the fuel jet used is important here. The spark plug insulator, or rather its color, will help you find out whether you have adjusted the carburetors correctly or not. When properly adjusted, its color is dark brown.

This work is complex and small. But the reliable operation of your motorcycle engine is entirely dependent on this work. Constant practice and experience will lead you to success.

Synchronizer - what kind of beast is it?

Unfortunately, it is impossible to synchronize the carbs with the “standard” set of bikers (keys, heads, grinders). You will still have to purchase a special tool - a synchronizer. It is produced at the factory, and is calculated at the factory in accordance with the vacuum corresponding to it in the pipes when the engine is idling.

There are synchronizers with mechanical and electronic displays. The latter are much easier to use, since there is no need to monitor several arrows at the same time.

The essence of the device is to measure the air pressure in the carburetor chambers. Therefore, its main parts are pressure gauges - one for each cylinder. Under each of them there is a fitting for adjustment - it will also have to be twisted during the process in order to stabilize the arrow.

Such things are very expensive, so many craftsmen make it themselves. The simplest synchronizer from twenty-cc syringes is assembled in half an hour, and works no worse than a store-bought one.

Algorithm

• To properly synchronize the carburetors, you will need to gain access to them. To do this, you need to remove the tank, air filter, and all other components that interfere with operation;
• In this case, it is necessary to connect an analogue of a gas tank to the carbs, up to a half-liter bottle suspended from the ceiling, since the procedure is carried out with the engine running and you cannot do without fuel;
• A hose from the synchronizer is connected to special outlets designed specifically for adjusting carbs;
• The engine starts, waits for time to warm up in order to achieve maximum stability in operation;
• Idle speed is set to the minimum value at which the engine does not stall;
• Based on the readings of the electronic display or arrows on the device, it becomes clear whether there is a need for synchronization. If the indicators are the same everywhere, then there is no need to do anything. If the data differs, then you will have to adjust the location of the throttle valve on individual carbs. In the case of a homemade synchronizer from syringes, it is important to achieve the same level of liquid in them;
• For four-cylinder bikes, the synchronous operation of the 1st and 2nd carbs is first adjusted, then the 3rd and 4th. And after that the first and second pair are already synchronized with each other.

Remember that if you own a two-cylinder boxer motorcycle Ural or Dnepr, with separate exhausts for each cylinder, then synchronization can be done by ear.