In Which Side Does The Sprocket Turn On The Chainsaw

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Algorithm for replacing the clutch drum

Chainsaw clutch closes the sprocket.

First of all, it should be noted that when buying spare parts for a chainsaw, you need to strictly observe the type of drum or use the advice of a specialist when it comes to modernizing it. As a rule, when changing the drum and saw chain at the same time, the drum bearings are also replaced.

Here you should purchase a special repair kit, which provides for the presence of both a drive sprocket and a bearing. Then you should prepare the tool and parts that will be required for the work:

  • universal wrench sold with chainsaw
  • mechanism piston stopper (plastic or metal in standard versions)
  • puller of the centrifugal mechanism or clutch (selected depending on the model of the chainsaw).

During the operation, the following actions are performed:

Chainsaw sprocket location diagram.

  • First, the saw headset is removed, the tire cover nuts are unscrewed with a universal wrench. The cover is removed, the bar and chain are removed.
  • After that, the air filter is removed.
  • The saw candle is unscrewed with the universal wrench. Instead, a prepared piston stopper is inserted, which will allow fixing the position of the piston in the cylinder.
  • The clutch remover fits into the universal wrench socket. Then, using the resulting device, the clutch is unscrewed. All actions must be carried out clockwise.
  • The clutch is removed, freeing access to the internal parts. Now you can remove the sprocket (clutch drum).
  • Depending on the type of drum, it is inspected or the crown is checked. The asterisk or crown is replaced with new ones. When installing new parts, the condition of the clutch separator must be carefully checked. Particular attention must be paid here to the springs of the centrifugal mechanism and the cams. If severe wear is detected, these parts also need to be replaced.
  • If the condition of the parts does not cause any complaints, all parts of the chainsaw are assembled in the reverse order. First of all, the piston stopper is unscrewed, the starter cord is pulled out, then the stopper is screwed in again. Such complex actions allow you to clamp the centrifugal mechanism of the chainsaw on the crankshaft.
  • Using a standard universal key, the clutch is clamped counterclockwise, that is, against the rotation of the chain.
  • After that, all nodes and parts can be successfully screwed into their original places.

In order to replace the sprocket on a chainsaw, all work must be done carefully and carefully.

Without special tools, repair work may end in failure: not only the star or centrifugal mechanism may break, but also the saw chain.

Replacing an asterisk on a chainsaw with your own hands

In the process of regular operation of the chainsaw, the sprocket shown in the photo is under heavy loads, and therefore it often fails. The sprocket, or otherwise the clutch drum, is an important and integral part of the chainsaw, which transfers the rotational energy from the drive to the chain.

Considering the safety of the drive sprocket and chainsaw chain, there are two ways to operate:

  • using only one chain
  • using two or more chains alternately.

In the first case, the chain can be operated until it is completely erased. However, there are a number of inconveniences here. Using only one chain, it is problematic to monitor its condition during intensive work. Hitting nails or other metal parts makes it necessary to adjust the chain, but since it is alone, the work is slowed down.

In the second case, the alternation of the chains allows uniform wear of both the sprocket and the chains.

In addition to the wear of the sprocket itself, do not forget about its bearing, which operates in idle mode. Therefore, very often they do not pay attention to it and forget to lubricate.

Usually, when replacing the drive sprocket, they immediately try to replace both the bearing and the chain. This is done due to the change in the chain pitch length as a result of intensive work.

Features of the clutch drum in chainsaws

The drum located at the base of the clutch of the mechanism is an integral part of the chain drive system. This detail resembles a star in its shape, due to which it got its name. Depending on the type of chainsaw, the part can be professional or household. Since a professional saw is used more often than a household saw, the drive sprocket also needs to be replaced regularly. If we talk about household tools, then everything here depends on the amount of work performed and the load that is on the circuit of the device.

The sprocket, crown and saw bearing most often require replacement.

In any case, the main reason for replacing a sprocket is chain wear on its teeth. In the event that a monolithic drum is installed in the device, the surface of the chain cuts it almost completely, which requires a complete replacement of the entire part. If the chainsaw has a drum with a replaceable crown, here you can limit yourself only to replacing the crown.

Usually, in order to remove the sprocket from the chainsaw, many people turn to specialized service centers, but if there is a need to save the family budget, you can do this work yourself. This activity does not look complicated, but it requires all the necessary parts and tools. The sprocket replacement process is the same for any device model.

Chainsaw Husqvarna 137. Replacing the clutch drum

The clutch drum of a chainsaw is one of the most common consumables in a chainsaw, because it is he who drives the cutting chain. The drums themselves are divided into two types. with a welded drive sprocket and with a replaceable rim, and in the second case only the replaceable rim wears out, the drum itself changes much less often.

When repairing the clutch of a chainsaw, they adhere to the rule. when two chains are completely worn out, the tire changes, when two tires are worn out, the clutch drum changes. The level of wear of the sprocket can be determined without special devices, it is enough to simply inspect it. the chain, moving at high speeds, eventually wipes the teeth along which it moves. If the wear is strong enough, then replacing the chainsaw clutch drum is inevitable.

The article will focus on the Husqvarna 137 chainsaw. Replacing the clutch drum is a simple procedure and takes place in several stages.

  • First you need to remove the tire and chain brake cover. For this, the combination key that comes with the chainsaw is suitable.
    Then remove the air filter cover, unscrew the spark plug, and lock the piston of the Husqvarna 137 chainsaw. For this procedure, it is recommended to use a regular rope, since when using a metal stopper there is a risk of puncturing the piston.

Replacing the sprocket on a Husqvarna chainsaw

Troubleshooting

Whatever one may say, but breakdowns still occur. But it is important not only to repair the device, but to determine the root cause.

The most common problems:

  • Oil leaks due to a violation of the integrity of the oil hose or its sealing at the attachment points.
  • Oil does not flow to the chain due to clogged feed channels with dust and chips.
  • The engine does not start or starts and immediately stalls due to an unregulated / malfunctioning carburetor, clogged sopun, air filter, muffler.
  • Chain wedges due to drive sprocket defects.
  • Engine clogged due to carburetor malfunction and high fuel supply.

How to remove an asterisk from a chainsaw: self-replacement

Today, almost every resident of a country house or summer resident has his own chainsaw. You cannot do without it during regular logging, gardening and municipal work. The demand for chainsaws is not falling, but even growing due to the fact that these devices do not require much knowledge and skills to work. The only thing that needs to be done regularly is to carry out technical inspections.

As with any tool, chainsaws require careful personal care. It is necessary to constantly check the oil supply to the chain, chain tension, brake operation, ignition system and other things. Fortunately, almost any malfunction can be solved at home on your own.

Chain direction and which side to wear

A chainsaw chain, if you look closely, has saw teeth pointing to one side. Therefore, it is very easy to determine the correct direction of the saw teeth on the guide bar: if you place the chainsaw itself in the plane in which it is in operation, then the row of teeth located on top of the guide bar, with sharp edges, should be directed to the end of the bar. While, the row of teeth, which is located at the bottom of the chainsaw, with sharp edges should point in the opposite direction, towards the drive sprocket.

It will not work to put the chain with the teeth inward to the grooves in the guide bar, it simply will not stick to the bar. Therefore, you need to put the chainsaw chain on the bar so that the guide ears of the saw blade links are directed towards the inside of the guide bar.

What to do if the chain sags

If the chain slack, there is a risk of injury to the operator. the saw blade could break or simply fly off the guide sprockets. Of course, modern chainsaws have safety and emergency stop systems, but these systems do not always work correctly.

It is important not to install a chain with defective or damaged saw links on the chainsaw, in addition to the danger of breaking at any time, such a chain will sharpen the guide grooves of the bar, which will lead to its distortion, uneven cut and failure of the guide bar.

Because of which the chain can sag during even short-term operation?

  • There may be problems with the guide bar. Sometimes, due to an oversight of the operator or due to severe wear on the threads of the fixing bolts at the point where the guide bar is attached, vibration can occur, which causes the chain to loosen. It is necessary to check the condition of the fixing bolts and, if necessary, replace them with new ones. When the bolts are sufficiently tightened, this problem does not arise.
  • If you handle your chainsaw with sufficient care, any chain can wear out over time. Trying to repair it or collect one from several is a useless exercise. If the chain headset has stretched due to natural causes, then it is best to get a new one.
  • The asterisk is skewed. Sagging can occur due to the misalignment of the sprocket teeth. In this case, it would be best to contact a service center to repair and adjust the position of the guide sprocket. It is quite difficult to fix the drive sprocket in the correct position, because you will have to dismantle a lot of small parts, remove the guide rail, and then assemble everything in the reverse order.

How to untangle a chainsaw chain

When removing an old chain or putting a new chain on the guide bar of the chainsaw, it can become tangled. It can also happen with careless transportation. When the chain is tangled, it folds into rings.

Due to the lack of flexibility in the transverse direction, it is very difficult to untangle it with bare hands, because when you try to untangle one ring in another place, a new ring is formed.

It is necessary to put the chainsaw chain on a horizontal surface and spin the rings in different directions, while pulling the blade in such a direction that the diameter of the rings increases. Sooner or later, the chain will unravel into its natural position.

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There is another way. you can rivet one link of the chain and straighten it, then connect it into a ring and rivet the riveted links back.

Chain tension

The chain of the chainsaw together with the guide bar is subjected to the greatest stress during operation, unlike other parts of the chainsaw. Over time, it lengthens in size due to boring gaps in the connecting links. This process occurs with absolutely any type of chain, therefore, when using a chainsaw, it is necessary to periodically monitor the correct chain tension and its wear.

The state of the chain depends on:

  • the length of her life;
  • safety of felling or lumbering;
  • ICE resource.

If the chain is overtightened, the efficiency of the sawing work decreases, and the motor and transmission are subjected to increased loads. The guide bar heats up a lot due to increased friction, the operating mode of the chainsaw goes into excessive consumption of the fuel mixture.

Step-by-step installation algorithm

Not all modern chainsaws are equipped with a setting wheel, which greatly simplifies the procedure for installing the saw blade. Systems with a setting wheel are generally a rarity among household chainsaws. Therefore, it is very important to know the technology and sequence of installing the chain on a chainsaw.

Key points to look out for:

  • Prepare a level surface on which you will assemble the chain and bar. This will minimize the chance of damage to the chainsaw or loss of small parts. A tire is laid out on the prepared surface and a parallel chain next to it.
  • Remove the sprocket protection, on modern chainsaws it is enough to unscrew the wing nut, on older models, you may need a spanner wrench of the appropriate size.
  • At the base of the guide bar, turn the idler sprocket all the way to the right. Only in this position is the chain installed.
  • Then the chain is successively placed link by link on the fixing groove on the guide rail. Install the chain from the top of the guide, gradually turn it so that the bar is always on top and the chain is on the bottom, this will allow it to always be taut and fit into the guide groove without problems. When doing this step, be sure to wear thick protective gloves, because your fingers will touch the cutting edge. Viewed from above, the cutter is always forward towards the end of the guide bar.
  • Put both the tire and the chain on the drive sprocket.
  • Secure the chain sprocket cover in place. Make sure all mounting pins line up with the holes. Incorrect installation with distortions or not completely can cause extraneous noise, rattling.
  • Make sure that the guides “go” into the special mounting chute.
  • After installation, check that the chain is secure on the chainsaw and on the bar. Everything must be securely fastened without backlash.

An important point is the degree of tension on the chain after installation. Setting the correct tension is easy and takes less than three minutes. First you need to loosen the nuts on the protective cover. Using the freely rotating adjusting screw, catch the correct tension so that the chain does not pull away from the edge of the guide bar more than 3-5 mm.

It remains only to tighten the nuts and check the tension. If correction is needed, adjust the tension again.

What is important to know: when the chain is in operation, due to frictional forces, its metal heats up and expands, and the length increases. Therefore, it is important to regularly check the tension and correct it in time.

How to install the bar and chain on the chainsaw, see the following video, which presents a clear algorithm of actions:

Why does the chain come off

Many, even the most experienced users of chainsaws, have encountered a situation in their life when the chain jumped off the guide bar during operation. The most common cause is insufficient chain tension or wear.

In 80% of cases, the stretched chain links slip from the teeth of the drive sprocket, and it flies out from the guide under the action of centrifugal force. Although sometimes the problem appears due to the incorrect position of the sprocket relative to the axis of rotation or a loose saw bar on the chainsaw.

How to install a chain on a chainsaw

The chainsaw chain is the element that is subjected to the greatest stress and overheating. From such influences, it can break, fly off the guide rail, or simply become dull from prolonged use. For timely maintenance or replacement with a new one, you need to know how to independently remove the saw chain from the chainsaw and install it back. The step-by-step algorithm of these operations will be shown below.

  • Chain direction and which side to wear
  • Chain tension
  • What to do if the chain sags
  • Step-by-step installation algorithm
  • How to untangle a chainsaw chain
  • Why does the chain come off
  • Output

Chainsaw sprocket and its purpose

The operation of a tool such as a chainsaw is carried out by means of a chain with cutting teeth on the outer surface. The number of cutting teeth on a chain differs depending on the model, which also affects the performance of the tool. The chain is driven by a specially designed drive sprocket that rotates from the engine crankshaft.

Chainsaw sprockets, like chains and bars, are consumables that tend to wear out over time. Wear is caused by frequent use of the tool. The time depends on the nature of the operation of the chainsaw, how long these materials and the tool itself will last. The replacement of the chain drive is usually carried out simultaneously with the bar and the chain.

Experts do not recommend using new chains on old sprockets that have obvious signs of wear. This is due to the fact that the tooth pitch of the new chain does not match with the grooves of the worn gear. Such a mismatch leads to the fact that at the initial moment of starting, the chain and the sprocket are subjected to strong dynamic loads. As a result, the chain mechanism with cutting teeth is subject to rapid wear.

When replacing a sprocket, a new roller bearing is required. With an excess of lubricant, the bearing also wears out quickly, which, as a result, negatively affects the functioning of the chain drive. Bearing cost is not high enough to miss out on replacement.

Chainsaw drive sprocket design

In the design of the chainsaw there is not only a leading, but also a driven sprocket. The chain saw drive sprocket is located in the tool structure, and the driven sprocket is located at the end of the bar. The purpose of the driven device is to equalize the tension and direction of movement of the chain device.

Leading devices are available in one piece and prefabricated. One-piece products consist of a hub with a pressed-on toothed rim. When replacing, the entire assembly is dismantled, since the gear structure is one-piece. Chainsaws of many well-known brands are equipped with solid gears from the factory.

Collapsible products are more perfect, since the process of replacing them is simplified through the simplest design of the mechanism. Only one crown is changed, the cost of which is 2 times less than the combined mechanism. You can determine the appropriate wear on the gear teeth by the following criteria:

  • The presence of large radii at the transition points of the teeth
  • Uneven tooth width
  • Detection of chips and metal chips on the top of the teeth
  • Seizure marks and scratches on the inner surface of the holes in the hub
  • Chain wedge detected when starting tool

If the master unit is worn out, it must be replaced. You can do this yourself, for which the tool is initially disassembled, and the version of the installed device is determined. Even if a non-separable gear is installed on the tool, then an assembly mechanism can be installed instead of it, which is more rational.

There are two types of installation of leading stars on chainsaws. The first method involves the location of the gear on the outside. Such designs are most common on Stihl chainsaws. The design of such a device is shown in the photo below.

The second option is inherent in instruments of Chinese origin. The gear teeth are not located on the outside, but on the inside, that is, the device is located the other way around.

Depending on the design of the tool, the process of dismantling the products in question will differ.

Features of replacing an asterisk on a chainsaw

The chainsaw chain is set in motion by means of a drive sprocket, which is connected to the gearbox of a gasoline two-stroke engine. During operation of the tool, wear of the sprocket splines is observed, which negatively affects the functioning of the tool. Sooner or later there comes a time when every sawyer wonders how to remove the sprocket from the chainsaw to replace it, and what this process is.

How an asterisk is removed and changed on a chainsaw

Before removing and replacing the star on the chainsaw, you need to make sure that the part is not subject to further use. To do this, you need to inspect the part, and a photo of a new and worn chainsaw sprocket is shown in the photo below.

To change the gear, you need to decide what type of device is on the tool, and what will be installed. For each type of mechanism, the sequence of actions will be different. Replacing an asterisk on a chainsaw of the first version of the non-separable type is as follows:

    Removing the guard, bar and chain

The assembly process is carried out in the reverse order. If you need to replace a collapsible type product, then the process will be almost the same, only in the end one crown is replaced without a drum.

If the replacement process is completed, you need to check. The tension force of the chain is checked, for which the hand brake is turned on, and the chain is pulled in the direction of its movement. The immobility of the product indicates the constriction of the mount. To loosen it, you will need to release the tensioner.

How to replace a star on a Chinese chainsaw yourself

If you come across a tool where the star is placed on the thread (fixed instead of the bracket), then the replacement process will be somewhat laborious. Let’s consider the sequence of actions in order:

  • First, you need to remove the casing, as well as the bar and chain, as in the first case.
  • After that, the protective pad is dismantled, under which the air filter and spark plug are located
  • Unscrew the spark plug. Either a special plastic insert must be screwed into the cylinder, or a cord must be inserted. This is done in order to block the movement of the piston. The cord is used with a woolen cord without protruding wire. The best option for such purposes is a wire from the iron.
  • The second option is preferred, as plastic inserts can damage the piston structure. The cord is inserted into the cylinder when the piston does not reach 2-3 mm to TDC
  • When the movement of the piston is blocked, you should use a special wrench, which is usually supplied with the tool. If there is no such key, you can use the one that is designed for an angle grinder or a regular open-end for “19”
  • You need to rotate the device sideways in a clockwise direction. As soon as the fastening is loosened, you can unscrew the device by hand, dismantle the gear with replacement, and in the same way install all the parts in place
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Finally, when the star is locked, the cord is removed from the cylinder and the plug is installed in place. A detailed description of the dismantling process is presented in the video.

After the work done, you will need to adjust the chain tension, and resort to checking the tool in action. At this point, the replacement process can be considered complete. How the chainsaw sprocket is replaced, and what this procedure is, is described in detail in the material. If you are faced with various problems, then seek help from specialists who will help you figure out the situation for free.

Recommendations: how to remove an asterisk from a chainsaw

Many tools require regular replacement of consumable parts. This also applies to drinking. That is why the question of how to remove the sprocket from a chainsaw, which is also often called a clutch disc or centrifugal mechanism, is very relevant for home craftsmen. In this regard, it is necessary to consider what is called an asterisk and why it is needed.

The clutch drum, called a sprocket, is an integral part of your chainsaw.

Features of the clutch drum in chainsaws

The drum located at the base of the clutch of the mechanism is an integral part of the chain drive system. This detail resembles a star in its shape, due to which it got its name. Depending on the type of chainsaw, the part can be professional or household. Since a professional saw is used more often than a household saw, the drive sprocket also needs to be replaced regularly. If we talk about household tools, then everything here depends on the amount of work performed and the load that is on the circuit of the device.

The sprocket, crown and saw bearing most often require replacement.

In any case, the main reason for replacing a sprocket is chain wear on its teeth. In the event that a monolithic drum is installed in the device, the surface of the chain cuts it almost completely, which requires a complete replacement of the entire part. If the chainsaw has a drum with a replaceable crown, here you can limit yourself only to replacing the crown.

Usually, in order to remove the sprocket from the chainsaw, many people turn to specialized service centers, but if there is a need to save the family budget, you can do this work yourself. This activity does not look complicated, but it requires all the necessary parts and tools. The sprocket replacement process is the same for any device model.

Algorithm for replacing the clutch drum

Chainsaw clutch closes the sprocket.

First of all, it should be noted that when buying spare parts for a chainsaw, you need to strictly observe the type of drum or use the advice of a specialist when it comes to modernizing it. As a rule, when changing the drum and saw chain at the same time, the drum bearings are also replaced.

Here you should purchase a special repair kit, which provides for the presence of both a drive sprocket and a bearing. Then you should prepare the tool and parts that will be required for the work:

  • a universal wrench sold with a chainsaw;
  • mechanism piston stopper (plastic or metal in standard versions);
  • puller of the centrifugal mechanism or clutch (selected depending on the model of the chainsaw).

During the operation, the following actions are performed:

Chainsaw sprocket location diagram.

  • First, the saw headset is removed, the tire cover nuts are unscrewed with a universal wrench. The cover is removed, the bar and chain are removed.
  • After that, the air filter is removed.
  • The saw candle is unscrewed with the universal wrench. Instead, a prepared piston stopper is inserted, which will allow fixing the position of the piston in the cylinder.
  • The clutch remover fits into the universal wrench socket. Then, using the resulting device, the clutch is unscrewed. All actions must be carried out clockwise.
  • The clutch is removed, freeing access to the internal parts. Now you can remove the sprocket (clutch drum).
  • Depending on the type of drum, it is inspected or the crown is checked. The asterisk or crown is replaced with new ones. When installing new parts, the condition of the clutch separator must be carefully checked. Particular attention must be paid here to the springs of the centrifugal mechanism and the cams. If severe wear is detected, these parts also need to be replaced.
  • If the condition of the parts does not cause any complaints, all parts of the chainsaw are assembled in the reverse order. First of all, the piston stopper is unscrewed, the starter cord is pulled out, then the stopper is screwed in again. Such complex actions allow you to clamp the centrifugal mechanism of the chainsaw on the crankshaft.
  • Using a standard universal key, the clutch is clamped counterclockwise, that is, against the rotation of the chain.
  • After that, all nodes and parts can be successfully screwed into their original places.

In order to replace the sprocket on a chainsaw, all work must be done carefully and carefully.

Without special tools, repair work may end in failure: not only the star or centrifugal mechanism may break, but also the saw chain.

As can be seen from the information provided, the question of how to remove the sprocket from the saw can be successfully solved on our own. Once performed, the operation will allow it to be carried out again and again, as soon as the need arises, and attention and accuracy will be the key to a well-performed work.

The device of a leading star on a chainsaw

Almost all models of modern chainsaws use a centrifugal clutch system. The specificity of this mechanism is that when the maximum number of revolutions of the gasoline engine is reached, the clutch drum starts automatically, transferring the rotation to the drive sprocket. This reduces stress on the base parts of the tool, extending life and maximizing productivity.

Figure 1. Diagram of the drive sprocket

The clutch drum, where the sprocket is located, can be located on the inside or outside of the chainsaw body. There is always a cover on top to protect the moving mechanisms from dirt, sawdust and dust. The clutch itself is a metal disc in the clutch drum. The entire mechanism is attached to the engine crankshaft by bolts with springs, along the edges of which there are friction linings. When the engine rpm exceeds a certain value, centrifugal force is generated, exerting strong pressure on the inside of the drum. After that, the sprocket starts up. the rotation of the chain saw begins.

Important! It is the sprocket that drives the chainsaw chain. All parts of this mechanism are closely interconnected, a breakdown of the headset leads to a malfunction of the instrument.

Features of replacing the star for chainsaws of different brands

When replacing or repairing a chainsaw, the design features of the model should be taken into account. The specifics of servicing the coupling drum of popular manufacturers:

  • Stihl (Stihl). The models of this brand have one-piece and collapsible types of sprockets. To unwind the clutch, you will need a 19 head and a knob. It should be noted that the thread is left-handed, and a reflective plate is installed behind the clutch (a consumable, often breaks when diagnosing a drum).
  • Partner (Partner). The peculiarity of this brand is that when replacing the sprocket it is recommended to change the bearing. If you ignore this step, after a scheduled repair there is a risk of chain malfunction, changing the pitch with active sawing.
  • Husqvarna (Husqvarna). Many Husqvarna models use an interchangeable sprocket. This simplifies scheduled replacement and repairs. When disassembling the tool, you will need a 13 wrench to fix the shaft from the impeller side.
  • Carver (Carver). Unlike other manufacturers, there are no specific design features of the clutch. Depending on the brand, the star can be solid or collapsible.

It is recommended that you carefully read the instructions before starting the scheduled repairs. It indicates the important design features of the saw, the frequency of replacing consumables.

How to assemble?

The assembly of the coupling mechanism should be carried out in the reverse order. First, install the sprocket on the needle bearing, then put on the drum, washer, gasket and the clutch itself. Tighten counterclockwise, lightly fix the piston.

If your chainsaw has an oil drive spring, it can be built into the drive sprocket. In most models, the correct position of this element is marked with a special color or notch. To get to the desired position, turn the sprocket until it clicks.

The last step in the assembly is to install the guide bar. During this process, it is required to release the handbrake and then check that the chain teeth fit into the corresponding grooves. After installation, mount the chainsaw chain until it is operational. Finally, remove the stopper, screw in the spark plug and replace the filter. The final step of the repair is to secure the protective cover of the case.

Expert advice: How to remove a sprocket from a chainsaw?

The chainsaw requires regular diagnostics and periodic replacement of worn parts. With regular use, not only the saw headset becomes unusable, but also the drive sprocket. In this tool, it acts as a clutch disc, which is why it has a significant load both during start-up and during operation. The asterisk on the chainsaw has a simple design, so repairs and maintenance are easy to do with your own hands. In this article, we will look at how to determine the degree of wear of this part and carry out a planned replacement.

  • The device of a leading star on a chainsaw
  • Types of stars
  • When replacement is needed?
  • How to change a star on a chainsaw?
  • How to unscrew?
  • How to assemble?
  • Features of replacing the star for chainsaws of different brands
  • How to reduce wear on the drive sprocket?

When replacement is needed?

The saw head and drive sprocket are subject to natural wear and tear during operation. This is not a breakdown, but a routine maintenance procedure for the tool. Reasons for replacing the sprocket:

  • intensive and long-term use of the saw;
  • mechanical shock of the headset;
  • using the wrong chain. Figure 2. Leading star on a chainsaw

Normal wear of the drive sprocket teeth is up to 0.5 mm. With regular work, this figure can reach up to 1 mm, but over time this will lead to a load on the engine, damage to other parts of the saw. You can determine the need for replacement or repair by the following signs:

  • there is mechanical damage to the guide sprocket;
  • the width of the teeth is disproportionate to their height;
  • there are asymmetric corners;
  • there are chips, grooves or large burrs on the hub.

If you do not timely diagnose and prevent the moving parts of the chainsaw, vibration increases and the impact on the crankshaft bearings increases. As a result, this leads to costly repairs, serious tool breakage.

Important! Manufacturers recommend inspecting the drawbar when the chain comes into contact with a metal object while cutting.

How to unscrew?

It is easy to remove and replace this part yourself. Work technology:

  • Secure the piston in the saw cylinder. First, remove the protective cover on the body, the air filter and unscrew the spark plug. Install a special piston stopper in the hole formed. instead, you can use a dense nylon cord or wire up to 15 cm long.If the piston interferes, you can slightly turn the sprocket or move the chain clockwise.
  • Unscrew the bolts on the cover that secures the tire, remove the protective cover. Loosen the chain tension or remove the saw attachment. At the same time, you can clean from dust, dirt and sawdust.
  • Depending on the model, the sprocket acts as an element of the clutch drum or be built in separately. In the second option, remove this part, replace it with a new one. The one-piece construction is difficult to repair. it is required to disassemble the unit. To do this, unscrew the coupling clockwise, remove the drum. Check structural parts for wear and deformation. Figure 4. Replacing the star with a new one
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If the sprocket is an element of the clutch drum, then the entire part will have to be changed. When replacing, you should pay attention to the conformity of the model. it must be similar to the factory one.

How to change the star on a chainsaw?

If the chain begins to vibrate even at low speeds, the chainsaw is operated for a long time without replacing parts. it is required

carry out diagnostics and, if necessary, change the components of the saw headset. For a planned replacement, you will need a new clutch drum or whisk, depending on the specific model, a basic set of tools:

  • candle key;
  • cable up to 15 cm long or piston stopper;
  • factory key for removing the clutch;
  • adjustable or wrench. Figure 3. Necessary tools for changing the star

It is recommended to have a round file, pliers, a vise and a knife to eliminate defects in the design from the chain set (if only tooth correction is required).

Tension check

To check the chain tension, the saw brake must be disengaged. Then manually pull the chain along the bus, if it runs smoothly and does not sag, then everything is fine. If the chain walks very tightly, then it needs to be slightly loosened, because there is a risk of rupture during work.

Why the chain flies, we find out the reasons

If you wondered why the chain on your chainsaw flies, then there is some kind of malfunction in the mechanism. There are three main reasons for this problem: bar malfunction, chain stretch, and loose sprocket. Let’s take a closer look at each of the possible causes of breakdown.

Chainsaw device features

The main part of a gasoline saw is the engine. In most modern devices, the engine is single-cylinder. Air cooling, two-stroke piston system. Oil in these types of engines is added directly to gasoline, and all due to the fact that the fuel is constantly flushing the crankcase. The oil-to-gasoline ratio varies from 1:20 to 1:50 depending on the manufacturer of the chainsaw.

The air filter on gasoline saws plays an equally important role. It needs regular cleaning. If the filter is heavily contaminated, dust from it will fall directly into the piston system, which will lead to engine damage.

If the filter is clogged, the saw loses speed and the engine starts to overheat, which can lead to burning of the piston rings.

The starter on gasoline saws is a rope with a handle that you pull on to activate the motor. When you pull on the rope, the teeth catch the ratchet, the flywheel starts to spin.

Many people complain that they have to pull the rope for a long time to ignite the engine. It depends on whether the carburetor is correctly aligned. If the carburetor produces the correct oil-gasoline mixture, then there should be no problems.

The main working mechanism is a tire with a chain.

The chain consists of three types of teeth: leading, cutting and connecting. They are riveted together. Cutting teeth are located on two sides: right and left.

How to Change the Chain and Bar on a Stihl MS170 Chainsaw | L&S Engineers

Chains are divided into two types: high profile and low profile. The first type includes chains, in which the teeth are located with a large gap, the second. with a smaller gap. Chains can also vary in shank thickness and link length. The chainsaw chain is attached to a bar that guides it in the correct direction. The end of the tire has a specific groove that holds the links and allows the chain to rotate. A driven sprocket is located at the front of the tire. The chain together with the bar is called a headset, since they are detachable parts of the chainsaw.

The gasoline saw has an automatic chain lubrication system. The tire supplies oil, which is then absorbed by the sawdust. If the saw is idling, the oil supply stops.

Chain tension

There are two ways to stretch the chain: fast and frontal. It is best to stretch in the frontal way.

If you carry out a frontal tension, then you need to unscrew the nuts that hold the tire and lift it over the edge. With a special bolt on the right, you need to tighten the chain until an acceptable tension is obtained, and then raise the tire even higher and clamp it.

If using the quick tightening method, first lift the wing nut handle and loosen it. Then tighten the chain tensioning screw clockwise as far as it will go. Then re-tighten the wing nut and lower the handle.

How to tension: installing the chainsaw cutting element

We have analyzed the main reasons for the sagging chain. How to install a chain on a chainsaw is described in the paragraph above. Now you need to correctly tighten the chain, and check if it will overtighten.

Poor drive sprocket

One possible chain slack on your device is a drive sprocket issue. Most often, everything happens due to the fact that the star is poorly fixed. Now we will tell you how to properly fasten the star and then put the chain on the chainsaw.

First you need to remove the engine protection cover. Next, remove the protective cover of the spark plug, pull out the air filter. Then you need to unscrew the candle with a special key. A special stopper is placed in its place, which fixes the piston in a certain position. With a special wrench (you can use a universal wrench for an angle grinder), turn the clutch disc clockwise until the piston reaches the uppermost position. If you look into the hole of the plug, then the piston should remain at the bottom. You can use a thick rope as a stopper; it is better to fold it several times. Once locked, you can clamp the drive sprocket by rotating the clutch disc counterclockwise.

After clamping, you need to do everything in the reverse order, that is, assemble the chainsaw. A chain is put on the tire; it must hit the drive sprocket that holds it. The tire is placed in special mounting holes and bolted. Then the defense is put.

The chain stretched

If your chain sags on a chainsaw, then this indicates a malfunction of some mechanism, one of the options is the wear of the chain itself.

Over time, the metal deforms and the chains become 0.5-1 cm longer. It is best to fix this problem by purchasing a new circuit, but there is a way to get the old one back. Experts say that this is very difficult and almost impossible, but we will tell you how it can be done at home.

For this we need:

  • vice;
  • file;
  • electric welding machine (not needed in all cases);
  • hammer;
  • pliers;
  • beard.

A regular chainsaw chain is made of strong steel, so it is difficult to disconnect. You need to disconnect the chain on the inside of the rivet, which serves as a connecting mechanism.

First, the chains need to be fixed in a vice, and then gradually grind off the protruding part. You need to grind with a file or a file. It is not recommended to use an angle grinder, as there is a risk of damaging the lateral parts of the links. After sewing, the rivets are knocked out with a beard. A knocked-out rivet should not be thrown away. You may not be able to find a replacement for it. Manufacturers of gasoline saws do not produce separate parts for the chain, as they do not assume that consumers will be able to repair the chain themselves. Most likely you will not be able to make a new rivet yourself, so you will have to install the old one.

In order to shorten the chain, you need to split it in two places. Remember, however, that the number of guide lugs on the inside of the chain and the distance between them must match the drive sprocket.

After removing one or more of the links (depending on the degree of chain stretch), the chains can be connected. We connect to old rivets, while pressing them tightly on the sides.

Next, we need a welding machine. The rivet must be welded to the lateral parts of the link. After that, with a file we grind off the excess that was formed during welding. The chain can be considered serviceable again.

Bus problems

When problems arise with the tire, the chain tension is almost always loosened. Usually this problem occurs at the place where the tire is attached.

This place is located in the groove between the outer plate, which is located on the chain guard and the inner plate, which is located on the motor housing. The casing together with the tire is fixed with a bolt. Such an attachment is referred to as an “engine assembly”. Drive sprocket and tire mount protected by special covers.

If the fixing bolts are loosened, the tire starts to move or vibrate. If the tire is in good condition, then the chain tension should be normal. After stretching, she will walk for at least five working days without suspenders. Therefore, you need to carefully tighten the bolts that hold the tire.

To understand how to tighten the chain on a chainsaw, you first need to find and release the chain brake. The tensioning screw is next to the bar and is turned until the chain is pulled over the bar. Then pull the chain in a clockwise direction. If it does not move, then it must be slightly loosened by turning the tension screw in the opposite direction.