Carburetors of motorcycles Izh-Planet 5, 4, 3, Sport - from design to adjustment

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Jupiter 5 is one of the most successful creations of Soviet motorcycle production. Today, like 30 years ago, the device is often found on the streets of both remote outbacks and large cities, and, in most cases, the owner prefers to handle its maintenance independently.

The carburetor, being one of the most important components of any motor vehicle, is subject to intensive use and increased wear. Considering the great age of some models, replacing this module very often becomes an inevitable condition for extending the life of the unit.

The motorcycle is equipped with Izhevsk carburetors K-62D, K-65D, K-68D , or the Czechoslovak model Jikov-2928SE . There are few differences between the first two options: the design of the top cover; enrichment jet diameter; needle fastening (K-65D comes with a nozzle). The K-68D differs from its predecessor:

• Enlarged diffuser.
• A round (not square, like the K-65) damper.
• Lateral (more convenient for optimization) location of the idle screw.
• Threaded (for quick needle adjustment) top cover.

Which carburetor is better to install on IZ Jupiter 5? As you can see, the 68th model is more convenient to maintain , however, experienced motorcyclists note that it often contains defects, for example, in the form of the absence of a hole that improves the formation of the fuel mixture.

Jikov-2928CE is considered a higher quality carburetor, but also more difficult to operate and repair. Therefore, when choosing this option, you should prepare for possible difficulties, for example, when searching for replacement jets, because their size is much smaller than those from Izhevsk.

Rice. Carburetor K-62:

1 — idle fuel jet, 2 — main fuel jet; 3 — float chamber, 4 — sprayer; 5 — float axis, 6 — float lever bushing; 7 — air channel, 8 — nozzle, 9 — dosing needle, 10 — body; 11 — throttle, 12 — needle lock; 13 — throttle spring; 14 — throttle lift limiter (removed after engine break-in); 15 — throttle control cable, 16 — rod with idle speed adjustment screw (lowering the throttle); 17 - cover; 18 — idle speed adjusting screw, 19 — fuel inlet fitting, 20 — adapter hole, 21 — idle speed emulsion channel; 22 — drainage hole, 23 — idle air channel, 24 — locking needle with washer, 25 — float, 26 — corrector emulsion channel; 27 — dosing needle; 28 — float stopper, 29 — plunger, 30 — plunger spring, 31 — corrector control cable

How to install a carburetor

Before installing the carburetor on IZ Jupiter 5, make sure it is completely clean and all parts are present. First, remove the carburetor cover with the three-hole throttle body. The round hole located in the center is intended for placing and fixing the needle, the shaped one, located on the side of the cutout, is for attaching the cable coming from the throttle handle, the T-shaped one is for installing the screw rod. The new carburetor on the IZH Jupiter 5 has a limiter located in the cover, which is removed after the break-in period.

After fixing the carburetor to the engine, a cable is attached to the shaped hole of the throttle and the cover is tightened. The throttle is checked for the ability to fully open the diffuser and not jam in all positions of the throttle stick.

• Design and adjustment of the K-62 carburetor

Next, the fuel line is connected to the fitting. The joints are checked for the slightest leak, after which the starting device is opened.

Apply a few light presses on the claw, then start the engine normally. After checking the functionality of the device and the uniformity of fuel distribution on a warm engine, the ignition can be turned off.

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Carburetor adjustment Izh Jupiter 5

Adjusting the IZ Jupiter 5 carburetor is the simplest, but at the same time the most important process. Whether it is K-62, K-65 or K-68, you must first warm up the engine to operating temperature, and then perform a sequential series of actions :

1. Set low but fairly stable engine speeds by rotating the screw that adjusts the throttle position.
2. By changing the position of the idle screw, set the engine to maximum speed.
3. Repeat these steps 4-5 times, gradually reducing engine speed.
4. Check with sharp jerks that the adjustment is correct.

The carburetor on the IZ Jupiter 5 should be adjusted so that there are no jerks and the engine does not stall in the event of sudden opening and closing of the throttle. In the first case, you should enrich the fuel mixture by turning the idle speed screw ¼-½ turn clockwise. In the second, turn the screw in the opposite direction.

You can also adjust the carburetor on IZ Jupiter 5 in operating modes. Depending on weather conditions and the technical condition of the engine, the metering needle can be moved up to enrich the mixture and down to obtain the opposite effect.

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Idle jet

If a jet of too large a capacity is installed, the engine begins to operate unstably, slowly picks up speed, and the exhaust sound becomes dull and weak.
If the jet has insufficient flow, the engine revs well, but when the throttle is closed sharply, the revs do not drop as quickly. The reduction in speed to idle occurs with a delay of up to several seconds. Too little throughput leads to unstable operation and frequent engine stops, both in low idle mode and when trying to raise the throttle. Operating the engine with an insufficient idle jet installed can result in the piston sticking to the cylinder wall when the throttle valve is closed. The risk is especially great if the engine has previously been running at full throttle for a long period of time. Under such conditions, after closing the throttle, the engine maintains high speed by inertia. If the idle system is running lean at this point, the heat load increases dramatically due to excessive lean combustion, increasing the risk of overheating and subsequent stalling.

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The K62 carburetor has two adjusting screws, with which you can change the idle speed, and a needle, by changing the position of which, you can change the property of the mixture (enrich or lean it). When we raise the needle, we enrich the mixture; when we lower it, we make it leaner. Adjusting the quality of the mixture is carried out by walking 2-3 km (at a speed of about 60-70 km/h) and looking at the spark plug. If the candle is covered with the working mixture (the candle is oily, dark brown or black), we lower the needle; if it is too dry (the color is white, light straw), we raise it. As a result, a light brown soot should appear. But this is just part of the adjustment; each time you need to set the carburetor idle speed. So we continue to adjust further:

• Basic rules for repairing a K65 carburetor

To adjust the idle speed on the K62 carburetor there is a “quality screw”. This screw supplies air even when the throttle is closed. We repeat, the propeller produces air, although some people think that this propeller is designed for fuel. Therefore, by tightening the quality screw, we close the air flow, that is, we enrich the mixture. If we unscrew the screw, the mixture becomes leaner. As was said, this screw provides air in all positions of the damper, and therefore at idle speed of the crankshaft. Therefore, the quality screw belongs to the idle air regulator. At this moment, it significantly affects the operation, but if the gas is at medium or high speeds, then the influence is not large, but it is present. So, it all comes down to the fact that the idle speed is adjusted, and this automatically affects all engine frequencies. Now, after a short introduction, let’s talk about the idle speed adjustment itself. To keep things simple, let’s talk about adjusting K62 K carburetors and similar ones for Minsk and Voskhod motorcycles. But by analogy, the adjustment of all types of carburetors is the same, so it will also work on IZH and other motorcycles.

Remember that carburetor adjustment always takes place on a warm engine. When the warm-up is done, we begin the adjustment. First, tighten the quality screw to the maximum and unscrew it halfway - one turn. Next, we start the motorcycle and lower the throttle completely with the upper idle screw, then, by unscrewing it, we achieve the minimum stable speed. Next, by unscrewing the quality screw little by little, we achieve maximum speed; when, after further unscrewing, the speed drops, we screw it back to the same maximum and stability. It turned out that we set a stable idle speed at these minimum speeds. But the idle speed is most likely too high, so we lower the throttle with the upper screw, achieving even lower speeds. We tighten it down to the very minimum, when at even lower crankshaft speeds the motorcycle begins to stall. Having established the minimum at which the motorcycle still works, we repeat the procedure again with the quality screw. By screwing in and unscrewing the screw we achieve stability. Then we lower the damper again, making a higher minimum of crankshaft revolutions and so on until the crankshaft begins to operate at the lowest frequencies. When we have completed the adjustment, we can check the idle for stability. To do this, take and sharply turn the throttle to maximum and look at the speed at which the revolutions increase. After increasing, we sharply lower the gas and listen to the engine again. If the idle speed adjustment is done correctly, then with such a sharp increase and decrease in gases, the motorcycle engine should listen to the throttle at the moment and also sharply increase and decrease the crankshaft frequencies. When the engine lags, it means the adjustment is slightly incorrect. In such cases, you can try to do everything all over again, but you can simply add or reduce air at idle. If, with a sharp increase in gas, the engine does not respond immediately or even stalls, it means that the screw should be tightened 1/4-1/2 of a turn. In case of poor performance in cases of sudden release of gas, the screw must be unscrewed 1/4-1/2 turn.

In principle, the adjustment can be completed here. As you can see, there is no particular difficulty here. The main thing is to do everything right.

Mostly motorcyclists suffer with carburetors due to complete misadjustment of the motorcycle. You should first carefully check the ignition and spark plug (it is advisable to install a new one). If the motorcycle is old, then worn out rings will affect performance and make it difficult to install the correct idle. If the whole point is in the development of engine parts, here you need to listen and adjust, since the specified rules will fit, but not completely.

You can also add that the K36 carburetors and other models are very similar in adjustment. The screws are basically the same, only their placement may differ. Therefore, having learned how to adjust the K62 carburetor, you will definitely be able to make adjustments in another model………

based on materials from blog-moto.ru

Single-cylinder two-stroke motorcycles Izh Planet 5,4,3 were equipped mainly with K-series float carburetors. In this article, the design of such carburetors, their malfunctions and adjustment will be described in detail.

Throttle valve

The throttle valve is stamped from brass, installed in the carburetor body and has a U-shaped cross-section. On the air intake side, the damper has a cutout designed to direct the air flow into the engine cylinder. The upper part of the damper is equipped with a rod with a limiter, with the help of which the degree of overlap of the diffuser is limited (to adjust the idle speed). A cable is connected to the damper and goes to the gas handle on the handlebars of the motorcycle. When the gas is released, the damper is returned by a spring.

What kind of carburetor is used on the Izh Planet-5 motorcycle

The latest Planet model was produced in several variations. Early transitional models were equipped with K-62I carburetors. Then they began to install the K-65I and the more progressive K-68I with a cylindrical throttle valve.

All three carburetors: top left - K62I, top right - K68I, bottom - K65I

All three carburetors have a similar operating principle. From the tank, through the fuel valve, fuel enters the float chamber. The floats are made of petrol-resistant lightweight material. As soon as gasoline fills the chamber, the floats will float up and the shut-off needle will block the fuel supply channel.

• Design and procedure for adjusting UAZ K126G carburetors

From the chamber, fuel enters the atomizer through the main fuel jet. In it, the fuel is mixed with air entering through a special hole in the atomizer body. The finished mixture enters the mixing chamber (diffuser) and then into the engine cylinder. This dosing system is called the main one. And it only works at medium and high engine speeds, when the throttle is raised more than 2/3 of its stroke.

To operate the engine at low speeds, the carburetor is equipped with an idle system. It consists of a fuel tube, mixture quantity and quality screws, a special air channel, transition and idle holes in the diffuser.

The fuel rises through the tube due to the vacuum in the mixing chamber and is mixed with air entering through the air channel. As a result, the resulting mixture, when the throttle is opened slightly, exits through the idle hole (it is specially located behind the throttle valve, at the end of the diffuser).

If you continue to raise the throttle, the vacuum will increase in the area of ​​the transition hole and the mixture will also begin to flow through it. In general, when you lift the throttle (turn the throttle lever), the mixture becomes leaner and the engine speed increases. The air flow speed increases and, by lowering the pressure in the mixing chamber, the fuel supply increases.

The carburetor of the Izh Planeta-5 motorcycle also contains an engine starting and warming up system (to facilitate engine starting in the cold season). The enrichment corrector is installed on the carburetor body or brought to the motorcycle handlebar using a cable. When it is lifted, 3 channels will open in the carburetor body. Through the fuel channel from the float chamber, the fuel will enter a special cavity, where it will mix with air coming from the air channel (this channel is usually located at the end of the diffuser on the air filter side).

As a result, the finished mixture will flow through a special channel to the outlet of the mixing chamber (behind the throttle valve). The channels are designed in such a way that the finished quality of the mixture is sufficient to warm up the engine.

Float stopper or additional starting device. When you press it, the floats lower and additional fuel enters the chamber. When starting, the mixture is richer and the engine starts easier. It is recommended to use the drowner only at temperatures of +5 C and below.

Float chamber

The float chamber is attached from below to the body using screws. The joint of the parts is sealed with a gasket made of special cardboard. The float consists of two elements mounted on a common axis. The fuel supply to the chamber is controlled by a needle. The lower part of the needle is connected to the plate on the float mechanism, and the upper part is connected to the fuel supply channel. The movement of the float is transmitted to the needle, which opens and closes the fuel supply to the float chamber. By changing the degree of bending of the plate, you can change the fuel level in the float chamber.

Additionally, the needle has three fixed positions for different operating conditions. At high ambient temperatures (plus 35 degrees and above) and at altitudes of 2000 meters above sea level, the needle is placed in the lower position. At low temperatures - to the upper.

Adjusting the K-68 carburetor on the IZH Planet-5 motorcycle

The K-68I carburetor was installed on the Izh Planet-5 motorcycle more often than others. With proper setup and proper care, the motorcycle starts quickly, runs smoothly and without complaints.

To adjust the K-68I carburetor you will need a flat-head screwdriver, pliers, and a ruler. For clarity and ease of adjustment, use the K-68 carburetor diagram.

Algorithm for adjusting the Izh Planeta-5 carburetor:

1. The first step is to check the fuel level in the float chamber. Unscrew the camera cover bolts with a screwdriver and remove it. Turn the carburetor over and use a ruler to measure the distance from the carburetor body to the top edge of the floats. It should be 26 ± 5 mm. If the parameters deviate, the tongue of the floats is bent in the appropriate direction using pliers. At the same time, in no case should the parallelism of the floats be disrupted.
2. Set a gap of 2 mm between the throttle valve and the bottom of the mixing chamber by adjusting screw 11. Then check the position of the throttle needle. The required needle position is the middle groove. The remaining grooves are made to move the needle lock and adjust the appropriate fuel quality depending on climatic conditions.
3. After all the above steps, we proceed to the most important stage - setting the idle speed. The idle quality adjusting screw 15 (located vertically on the left side of the carburetor) is screwed in until it stops, and then unscrewed 1-1.5 turns. Start the engine and warm up for 5 minutes. Using the mixture quantity adjustment screw 11 (located horizontally on the left side of the carburetor), we set the minimum stable engine speed. At the same time, slowly unscrew screw 15 until the engine speed stops increasing. It is the moment of reducing the crankshaft speed that will be optimal for determining the position of the adjusting screw 15. We again reduce the engine speed with screw 11 and unscrewing screw 15, we find a new optimal position of the throttle valve. This operation must be repeated until the minimum, but at the same time stable, engine crankshaft speed is established.
4. By sharply turning the throttle lever at idle, we check the correctness of the adjustment (the quality of the mixture). If, when the throttle is opened sharply, the engine stalls or picks up speed poorly, screw 15 needs to be tightened a little, thereby enriching the mixture. If the engine stalls when the throttle is closed, screw 15 should be unscrewed slightly.
5. You can also check the correctness of the adjustment by the color of the central insulator of the spark plug. After adjusting the carburetor, drive a motorcycle for a distance of 5-10 km and remove the spark plugs from the cylinder head. Dark carbon deposits indicate that the mixture is too rich. A light color (whitish or sandy) indicates that the mixture is poor. The normal recommended candle color is brown or brick.
6. It is also worth remembering that the free play of the throttle cable is 1-3 mm. If it is not there, the throttle adjustment will be incorrect. The free play is set by adjusting a special bolt located under cap 18.

The video below clearly shows the adjustment of the K-68I carburetor on the Izh Planet-5 motorcycle.

Checking the settings

After setting the minimum idle speed, you can check how the K-62 carburetor is configured. To do this, the speed is sharply increased and decreased by opening and closing the damper. A properly adjusted carburetor should react sharply to changes in the position of the throttle handle. If there are failures in operation or the engine stalls, then adjustments to the settings are required.

The first method of adjustment is to tighten or loosen the quality screw by one quarter or half a turn. In case of problems with gas supply, tighten the screw. If there are malfunctions in the engine when releasing gas, the screw is unscrewed. If this method does not help, then it is necessary to re-adjust the carburetor from the very beginning.

We examined the design of the K-62 carburetor and the main points regarding its adjustment. We hope this information was useful to you.

Carburetor repair

When using the motorcycle for a long time, you may encounter carburetor overflow (leakage from the drain hole). First of all, it is recommended to check the fuel level in the carburetor and the tight fit of the shut-off needle. By bending the locking needle brackets in the desired direction, we adjust the fuel level (the distance from the plane of the middle of the floats to the edge of the carburetor body is 13±1.5 mm). The tapered end of the locking needle is made of rubber. If it becomes leaky, it is recommended to replace it with a new needle from the repair kit. It also happens that the floats begin to leak gasoline due to fatigue of the material. It can also be treated by replacement.

Floats

Fuel nozzles become clogged due to low-quality fuel or when dirt gets in from the air through the filter. To clean gasoline, in addition to the mesh in the fuel tap, you need to additionally cut the fuel filter into the gas hose. The air filter must be tightly connected to the carburetor. At the same time, you cannot change its design, much less install a so-called zero.

The filter element must strictly comply with the throughput recommended by the motorcycle manufacturer. Never use needles or wire to clean the jets. It is enough to wash them in gasoline and blow them with compressed air.

Carburetor K-62 disassembled.

Sometimes it happens that when starting or running a motorcycle, the carburetor sneezes. This happens due to problems in the ignition system. The first step is to replace the spark plug. If this does not help, then the ignition has failed. Usually the carburetor shoots during early ignition. Sneezing can also be caused by a mixture that is too lean. The combustion process of such a mixture is slow and when the piston opens the inlet window, the mixture shoots into the diffuser.

The main reason for a lean mixture is air leaks in the following places:

• from under the crankshaft oil seals;
• cylinder heads;
• at the junction of the carburetor flange and the cylinder pipe.

We try to find and eliminate the cause of air leaks using the elimination method. You should start with inspecting and adjusting the ignition system.

Starting device

Almost all versions of the K-62 carburetor were equipped with a starting device. It was cable driven from a rotary lever on the motorcycle handlebar. Additionally, for starting at temperatures below minus 15 degrees, there is a push-button float suppressor. With its help, additional enrichment of the mixture is achieved, which is very important when starting cold two-stroke engines. Such a device was not installed on outboard motor carburetors.

To prevent the engine crankcase from being filled with fuel and getting it in liquid form into the cylinders, there is a drainage channel in the float chamber.

To limit the speed during the break-in period of the motorcycle, a throttle limiter is used in the carburetor. After running in it is removed. The landing flange of the K-62 carburetor is identical to previous models, which allows it to be installed instead of older models without modifications.

Which carburetor is better to put on Planet 5 instead of the original one?

If desired, imported Japanese Mikuni carburetors with diffuser diameters of 30 and 32 mm can be installed on Izh Planet-5 motorcycles. Naturally, you need to select jets recommended by the manufacturer. On Planet-5, the throughput of the main fuel jet corresponds to 270 ml/min, the corrector fuel jet is 255 ml/min.

You will also need to select an adapter to connect the carburetor flange to the cylinder. You can order an adapter from a turner or select one from other motorcycle models. The inlet window of the diffuser on Mikuni is wide, so the rubber pipe for connecting to the air filter will also need to be selected.

It is important to remember that all connections must be tight, without distortions.

The diameters of the diffuser and the cylinder inlet must be the same and have no steps that prevent the mixture from entering the combustion chamber.

This is what the installed Mikuni carburetor looks like on the Izh Planet-5 motorcycle.

All of the above also applies to the installation of a Chinese PZ 30 carburetor on the Izh Planet-5 motorcycle. Its special feature is the presence of a version with an accelerator pump, which helps enrich the mixture at high engine speeds. But to use it, you need an additional cable that will work in tandem with the motorcycle’s gas handle.

With minor modifications, the carburetor flange fits well with the mountings to the cylinder pipe. An important point is that you need to install a rubber or textolite gasket between the pipe and the flange so that the carburetor does not heat up when the engine is running.

This is what the installed PZ30 carburetor looks like on the Izh Planet-5 motorcycle.

Imported carburetors are good because they do not have the usual suction. To start the motorcycle, you do not need to fill the crankcase with gasoline; you just need to open the enrichment corrector. These carburetors also have regular drain holes instead of a drain hole, which are fitted with hoses that can be taken out to any convenient place. For example, under a motorcycle engine, so that if the carburetor overflows, nothing will get dirty.

Modifications

Various versions of the K-62 carburetor were used on two-stroke motorcycle engines of the Minsk and Izhevsk motorcycle plants, on boat engines of the Neptune series, and on Tulitsa scooters. Since the operating conditions and engine sizes of these machines are different, each carburetor had different diameters of the diffuser and fuel supply nozzles, which was reflected in the model index:

• K-62 with a 30 mm diffuser was used on the Jupiter 4 IZH.
• K-62B with a 32 mm diffuser was used on the Planet 4 IZH.
• K-62V with a 26 mm diffuser was used on Voskhod 3.
• K-62G with a 26 mm diffuser was used on Tulitsa scooters.
• K-62D with a 28 mm diffuser was used on the Jupiter 3 IZH.
• K-62E with a 30 mm diffuser was used on Serpukhov motorized strollers.
• K-62P with a 32 mm diffuser was used on the Planet 3 IZH.
• K-62L with a 26 mm diffuser was used on the Neptune 23 outboard motor.
• K-62M with a 32 mm diffuser was used on IZh PS.
• K-62S with a 26 mm diffuser was used on the Minsk 3.115 motorcycle.

Carburetor of Izh Planeta 3.4 motorcycles

Izh Planet-3 motorcycles were equipped with K-62P and K-36I carburetors. The latter had a unique design for its time. The throttle shape was U-shaped, which made it possible to significantly reduce the dimensions of the carburetor (in comparison with the K-28 and K-37 produced at that time). The corrector was moved out of the diffuser area and regulated not the air, but the fuel. This solution made it possible to reduce fuel consumption by 4-6% due to more stable mixture adjustment.

The mixing chamber cover was fastened with special locking springs, which made it possible to quickly and conveniently replace the throttle cable or rearrange the needle. The main fuel jet was screwed into the bottom of the carburetor next to the drain plug. To clean it, it was not necessary to dismantle the carburetor. The diameter of the diffuser of the K-36I carburetor at the outlet is 28 mm, and in the middle it is 26 mm. That is, the mixing chamber is a kind of aerodynamic profile, which has a beneficial effect on mixture formation.

Another feature of the K-36 carburetor is its operating principle, which is similar to a car carburetor. The screw for the amount of mixture in it regulates not the air, but the fuel emulsion entering behind the throttle. Due to this, the sensitivity of the carburetor settings at idle has increased. Adjustment is carried out with screw 1 for the quantity of the mixture (at an angle) and screw 2 for the quality.

The K-36 carburetor has one drawback. It is sensitive to road dust. The upper latches do not seal the lid of the mixing chamber tightly and dust particles get there, the valve begins to jam and wear out. That is why motorcycles on which such carburetors were installed (Kovrovets, Izh Planeta-3, etc.) were equipped with carburetor protective covers.

Later, new K-62 carburetors with the indices I, P, B began to be installed on the Izh Planet-3, 3-01 and 4 motorcycles. The power of two-stroke engines grew and there was a need to increase the diameter of the diffuser (now it was 32 mm), throughput jets, etc.

The new carburetor design made it possible to uninterruptedly supply the engine during sudden braking and acceleration, tilting and rolling of the motorcycle.

Setting up such a carburetor is carried out similarly to the K-68 setting described above. The quantity screw is not located on the side of the carburetor, but in the upper part.

Prerequisites for the creation of K-62

In the USSR, when producing any equipment, unification of components and parts was widely used. Carburetors were no exception. The K-62 carburetor began to be produced in the mid-1970s (Leningrad Carburetor and Valve Plant) named after V.V. Kuibyshev and replaced the K-36 series.

One of the main reasons for the creation of the new model was the increase in engine power. Such engines required enlarged air channels to prepare a larger volume of working mixture. The existing carburetor models did not allow for larger channels, and they also lacked many advanced solutions. The new K-62 carburetor was equipped with a centrally located float chamber, a flat throttle valve, and the float design was changed.

Thanks to such innovations, it was possible to reduce the dimensions of the carburetor and ensure stable engine operation during sudden changes in motorcycle driving conditions.