Excellent motorcycle performance begins with adjusting its carburetor. Carburetors K63 Carb adjustment in the Urals

Is it possible to install one carburetor on a Ural motorcycle? This question is asked by many owners of popular motorcycles in our country. The reason for this interest is obvious. Ural motorcycles, regardless of the year of manufacture, are standardly equipped with one carburetor for each cylinder. This provides better filling with the combustible mixture, but creates many problems during adjustment.

After all, synchronizing the operation of the cylinders is not an easy task even for an experienced specialist!

Everyone who has at least once adjusted the supply of a fuel mixture in the Urals knows this. Neither the latest domestic model K-68, nor the Japanese analogues from Mikuni are able to solve this problem. Moreover, the general condition of the engine also has an impact.

What needs to be done to install a monocarburetor

If you install one carburetor on a Ural motorcycle, this will largely solve this problem. This is a possible, although not ideal, solution. In bringing the plan to life, certain difficulties will have to be overcome. Necessary:

• Free up space above the engine crankcase. This is where it is most convenient to secure the intake tract and connecting flange.
• Make an intake collector.
• Find the right one according to carburetor parameters.

All this will require a significant investment of time and money.

Inappropriate installation option

What carburetors are suitable and what is better to install? We will have to disappoint those who plan to use available models from Oka or Zhiguli during the conversion. All car modifications are out of play in this case. There are several reasons:

• Vacuum inlet path of a motorcycle differs from the parameters characteristic of automobile engines. Because of this, correct adjustment of the carburetor on a motorcycle becomes almost impossible.
• Selection is carried out not just in terms of working volume, but in terms of the number of aspirations per unit of time. Aspiration can be roughly calculated by multiplying the engine displacement by the maximum speed.
• Car models pose a danger if the motorcycle falls, since fuel from them can splash out and ignite.

Automobile carburetors are not suitable for conversion!

So the idea of ​​using parts from Oka or other automotive equipment will have to be abandoned.

The agony of choice

There is more than enough advice on the Internet about which carburetor to install for a Ural motorcycle. But not all of them should be trusted unreservedly. Indeed, in the process of realizing your plans, you will encounter considerable difficulties. Here are some examples:

• Affordable An option can be considered the domestic K28G carburetor, which was equipped with the Tula-200 scooter produced during Soviet times. But there are no new ones on sale, and finding a used one in decent condition is very difficult. Unidentified defects will negate all expected benefits.
• Mikuni or Keihin models, borrowed from Japanese motorcycle models with a similar number of aspirations, cost a lot of money and will still require additional refinement. You will have to grind out new jets and change the factory settings.

Simply installing one carburetor instead of two without modification will not work!

Whatever option you prefer, simply installing one carburetor instead of two will not work. It will require major remodeling.

Need an intake manifold

A separate problem is the manufacture of the intake manifold. Since casting the part at home is not possible, you will have to use thick-walled stainless steel pipes. It is important to meet the following conditions:

• Inner diameter pipes must match the diameter of the inlet holes on the cylinders.
• Diameter, flow area and the bending of both branches of the collector must be the same.
• Connection areas should be made of thick, at least 5 mm, and even sheet. It would be good if all operations could be performed on a milling machine. In the absence of one, you will have to arm yourself with a good plumbing tool, be patient and do everything yourself.
• Internal welds, if any, they are carefully sanded. Irregularities and protrusions on the inner surface of the intake tract are unacceptable.

Change or leave, what do you prefer?

If you don’t do everything as expected, then selecting and installing a carburetor for a Ural motorcycle will only be a waste of time, effort and money. But even when all the conditions are met, it should be remembered that such a modification, although it will make it possible to easily adjust the supply of the fuel mixture, will create other problems:

• In the intake manifold, necessary to switch to one carburetor, condensation will accumulate in cold weather. This will make starting the engine more difficult.
• Converted Ural with one carburetor it will lose some power and will consume more fuel. After all, the filling of the cylinders will worsen.
• It will be necessary to decide where to attach a new, suitable air filter, which now will also only have one.

After studying the issue, many leave the option with two carburetors

Based on the above, many prefer to leave two carburetors on the Ural motorcycle, as before, replacing them with more advanced ones. Models with constant, rather than variable, discharge in diffusers are better suited for this. They allow you to get rid of failure during acceleration - a disease of many two-cylinder four-stroke engines.

On a note

We must not forget that before installing a new carburetor in the Urals, the power unit should be diagnosed, subjecting its components to the most thorough revision. Only after making sure that all parts are in good working order should you begin further work. After all, if there is something wrong with the engine, then it doesn’t matter how many carburetors there are on the motorcycle - 1 or 2.

Before installing a new carburetor, engine diagnostics are required.

The work ahead will not be easy. If you feel that you are not ready to handle it yourself, it is better to entrust the matter to specialists who already have experience in such alterations. But be careful not to give your pet into the hands of amateurs. Remember that it is very difficult to choose a suitable carburetor for a motorcycle, and especially for the Urals!

Brands, appearance, structure and parts in motorcycles change from year to year. Evolution also affects carburetors, the constant improvement of which does not take long to wait. Adjusting the carburetor on a Dnepr motorcycle is an important matter.
However, despite external and mechanical changes in the process of functioning of the latter, the principle of adjustment remains unchanged.

The carburetor as a structural element is designed to mix gasoline with air, as well as subsequently supply the appropriate amount of it to the carburetors of the Ural motorcycle engine cylinder. The adjustment affects the ease of starting and the stability of the engine. The process of regulating and tuning the carburetor can be presented in stages. Time to tune the carburetor on the Ural motorcycle. Just as important.

First stage

Before tuning and adjusting the carburetor on a Ural motorcycle, first of all pay attention to needle adjustment, which is responsible for mixing air and gasoline (in this case, it is necessary to understand that lower than the needle, the mixture is poorer) in the format of partial loads, when the throttle is not fully opened (the gas is not open to the maximum, but not idle either). We alternately release the needle downwards (first one way, then another) until “dips” occur in the acceleration of the motorcycle (shudders, twitching oscillations) at moments when the engine speed increases. At the moment, there is a noticeable loss of engine power, a kind of “sluggishness”, and popping noises are not uncommon. Afterwards, the needle is raised to the 1st groove and we head towards the road for a test check. When the needle is at the very bottom, and the previously mentioned reasons do not manifest themselves in the operation of the motorcycle, it is therefore worth checking the production of the atomizer in the needle-atomizer connection, which leads to an increase in fuel consumption. By changing the needle and sprayer everything should return to normal.

Second phase

Having dealt with adjusting the needle, we select the jets and proceed to the stage of adjusting the idle speed. This process is carried out by unscrewing or tightening the thrust screw, trying to achieve minimal stability of the speed, and with the screw we try to find the position of the maximum stable speed of the engine. Next, having stabilized the engine, we set the screw to the minimum stable speed. The next logical step would be to test the motorcycle again on the road. If jerks are sensitive due to over-leaning (a persistent lack of gasoline is noticeable), you will need enrichment on your part based on tightening the quality screw.
In this case, the composition of the mixture depends on the correctness of the carburetor adjustments, as well as the condition of the air cleaner. Thus, the task of repairing the carburetor on a Ural motorcycle is completed.

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 make 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. Adjust the RPM with the cable sheath screw so that the speedometer shows the same 55 km/h
19. Turn off the engine, lock the screws of the cable sheath.

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 by one division. 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!

Carburetor adjustment is an important skill for a motorcyclist to tune a motorcycle engine for optimal fuel consumption. Achieve maximum power while maintaining the excellent condition of the power unit for many years of operation.

The two-cylinder boxer engine has a carburetor for each cylinder, which increases the difficulty of tuning, especially the synchronization of the cylinders. When setting up each device, you must strictly follow the sequence of actions described in the instructions; this is the only way to achieve the best result.

First you need to understand the preparation of the fuel mixture. Find out what each part consists of, what each part is needed for, and what role it plays. With the help of which the device parameters are changed. What will happen if you turn the adjustment screws.

This K-37A device was installed on M-72 and K-750 motorcycles. Motorcycles with such a carburetor spent 100 kilometers:
- M-72 - 7 liters;
- K-750 - 6 liters;
- The fuel tank was enough for 310 kilometers.

Preparing for adjustment

Adjusting the K-37A carburetor of the Ural motorcycle has three stages of adjustment:
1. idle speed;
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.

Idle speed adjustment

The idle speed is adjusted in the following order:
1. Close the throttle completely.
2. Unlock the stop screw 19 (see figure) and screw it into a position so that the engine runs at slightly higher speeds.
3. Set the ignition timing shifter to late ignition.
4. Tighten the mixture quality screw 18 all the way.
5. Turn out screw 19 by 1-1.5 turns, the engine speed will decrease.
6. Listening to the operation, gradually turn out the mixture quality screw until the engine evenly develops a higher number of revolutions.
7. By unscrewing the thrust screw, reduce the speed to the minimum stable speed.
8. Lock both screws.

Adjustment at medium speed

Setting up the K-37A device of the Ural motorcycle at medium speeds is done as follows.

If, when the throttle valve is opened sharply, “sneezing” is observed in the carburetors and the engine stalls, then the mixture must be enriched by shortening the adjusting needle 12 by one or two holes.

If the “sneezing” stops and the engine revs well, then the adjustment has been made correctly. It is recommended to ride a few kilometers after this and make sure that the motorcycle pulls well.

Timing adjustment

Adjusting the uniformity of operation of both carburetors is quite difficult, especially since the synchronism is maintained for a relatively short time. However, it must be achieved and constantly maintained. Non-synchronous operation will lead to rapid wear of the connecting rod bearings and, when driving, will cause overheating of one of the cylinders and increased carbon formation.

The adjustment procedure is as follows:
1. Place the motorcycle on a stand so that the rear wheel can rotate freely.
2. Start the engine and engage fourth gear.
3. Remove the high voltage wire from the spark plug of one of the cylinders.
4. Bring the engine speed to a number corresponding to a speed of 30 km/h on the speedometer, and listen carefully to the operation of the cylinder.
5. Turn off the cylinder from operation by removing the high voltage wire from it, and at the same time put the wire on the spark plug of the not working cylinder.
6. Listen carefully to the operation of the second cylinder.
7. Comparing the operation of the cylinders by ear or according to the speedometer readings, you need to achieve synchronous operation of the devices by raising or lowering the throttle valve using the cable stop 26 (see figure).

Since such adjustment takes a relatively long time, you must be very careful not to overheat the engine, especially a new one, in which, if overheated, the pistons in the cylinder can easily jam.

To be honest, I also jumped around a lot with mine while I adjusted 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.

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.