How to Lubricate Husqvarna Chainsaw Needle Bearing
Replacing the drive sprocket on a chainsaw
Regardless of the class of the chainsaw and its operational characteristics, the design of removable saw sets is almost identical. The saw device kit includes a guide bar made of a special alloy and a chain, which is activated by the gear ring of the drive mechanism. To extend the life of the saw chain, timely replacement of the sprocket on the chainsaw is important.
The feasibility of timely replacement of worn parts of the drive chain
The design of its crown determines such an important parameter as the choice of chain by step.
- Installing a new part on a worn sprocket reduces its smoothness, accelerates wear, and initiates the risks of breakage and the creation of a traumatic situation.
- There is also an increase in operational loads on the engine and the elements of the kinematics of the tool.
- A similar process takes place when old extended chains are installed on the tire, the diameter of which is adjusted to the size of the tire by removing part of the links.
Experts also do not recommend arbitrarily changing the size of the stars. An experiment can adversely affect the engine resource and the kinematics of the instrument as a whole.
Safety of sawing operations of various degrees of complexity is ensured by the effective operation of the emergency stop brake and devices that block the expansion of the chain ends in case of an accidental break. In any case. the most reliable prevention of contingencies, maintaining the chainsaw in good condition.
A way to extend the leading sprocket resource
In practice, for uniform wear of the crown of the sprocket, a set of several chains of the same type is used, which alternately change as the cutting edges of the saw links become blunt. However, sooner or later, the user is faced with the need to replace a worn part.
Criteria for choosing a repair kit yourself
The desire of the owner to equip the headset with a saw chain with another step, leads to the need to change the asterisk to a part with a crown of the corresponding profile. This requirement applies to the entire range of European and Chinese chainsaws.
The operational reliability of a European-assembled saw, when operating in difficult conditions of increased loads, can significantly deteriorate if, instead of the original part, a Chinese asterisk is used.
Structural problems of different models
The problem is complicated by the design of branded chainsaws, which provides for the replacement of a worn drive only after the complete dismantling of the clutch mechanism and other components. In another embodiment, in order to remove the sprocket from the chainsaw, you must have a special key.
A design feature of a significant part of chainsaw imports is the placement of an asterisk on the clutch mechanism.
- With significant wear of the teeth, the drum is to be replaced, which is a single unit with the drive.
- The more progressive design of the drive sprocket allows you to restore the performance of the part by replacing the crown.
In the list of factory kits attached to the saws, such a tool is extremely rare. The problem is solved by replacing the parts that have exhausted the resource in the service workshop or by making the necessary fixtures at home.
The lack of prerequisites for the restoration of a worn star
The leading sprocket for a chainsaw of any power category is made of special steel, processed by a special technology, so repairing a part by welding by arc welding and subsequent milling is not possible.
The price of the part itself is several times lower than the cost of replacing it in service structures.
- The benefits of self-repairing a drive unit at a lower cost and time.
- If you have the appropriate tool, you can manage the work for a fairly short time interval.
The sequence of working moments is identical for almost all known models in the domestic market of chainsaw equipment. Experts advise using a branded part for replacement.
If we are talking about the modernization of this node, the feasibility of such a change should be clarified by consultation with an experienced specialist.
The best option is to buy a repair kit, which also includes a replacement bearing. In addition to the key, you may need an individual for each model puller of the clutch drum, a metal or plastic stopper to fix the piston in a predetermined position.
Algorithm for self-changing drum clutch with sprocket
Leading sprocket replacement technology provides for the implementation of the entire amount of work in a given sequence:
- dismantling the headset and air filter;
- installation of a piston retainer in the spark plug hole;
- the clutch and the gear drive made at the same time as the drum are removed by means of a puller; the sprocket can only be unscrewed clockwise.
If there is a lot of wear on the separator, breakdown of the springs of the centrifugal mechanism and cams, it is recommended to replace the entire kit.
If the condition of the removed parts is not in doubt, the whole mechanism is assembled in the reverse order. For reliable fixation of the clutch on the crankshaft, it is enough to unscrew the piston stopper, pull out the cord of the standard starter and return it to its original position.
It should be cautioned by amateur craftsmen from simplifying the requirements of repair technology and saving money on installing relatively cheap Chinese components.
The quality of the work done is guaranteed by attention, accuracy, compliance with the sequence of all dismantling and assembly operations.
Replacing the sprocket on a chainsaw. how to remove and change yourself
Gasoline chain saws, like most other tools, require periodic breakdown diagnostics and replacement of worn parts.
A significant part of them are connected with a leading chain saw for a chainsaw or clutch disc. one of the important elements of all chainsaws without exception.
Despite the relative simplicity of its design and the hints of the operating instructions, every year thousands of inexperienced craftsmen come to a standstill in this matter and spend money on service centers or do it wrong, which further aggravates the problem.
That is why we will dwell on this topic and understand the structure, functional features and repair of this working node of chainsaws.
Chainsaw sprocket device
An asterisk or centrifugal mechanism is a part resembling a star in shape. It takes over the engine torque and transfers it to the guide and saw chain. This guarantees the rotation of the cutting headset and the cutting process itself. It works in automatic mode, which depends on the magnitude of the engine speed.
The clutch drum can be localized both outside the chainsaw and on its inside under a separate cover.
It performs a protective function not only in relation to the material of which the sprocket is made, but also for the operator, who may be injured by it during operation.
In addition to the function of chain rotation, the leading star of the saw prevents the appearance of malfunctions of the motor system in those cases when the chain is jammed or stops rotating.
Classification of the leading chain saw chains
In accordance with the power class of the saws on which they are installed, the asterisk can be:
The main difference between them is the frequency of replacement and the rate of wear: in the Pro series, wear is faster and repairs are more frequent.
By design features, the leading chain saw stars are:
The latter consist of a hub with a stationary crown of a certain number of teeth. Their factory fitting does not allow to remove the crown separately from the hub. This situation is typical for many Chinese chainsaws, for example, from the Champion brand.
The situation with prefabricated sprockets is simpler: a removable crown quickly unscrews from the axis of the drum, so repair is not particularly difficult. This option is the advantage of most saws of European origin, for example, “Stihl” or “Husqvarna”.
When to change the chainsaw sprocket?
If the chain glues at low speeds, the saw is operated for a long time on the same chain and drive sprocket, and defects are detected during its inspection, its change is mandatory.
Externally, the state of the sprocket is determined by its teeth. They are considered worn out if:
- there are small chips or grooves from the guide;
- their width is disproportionate to height;
- the angles between the teeth and troughs are different;
- hub with seizures and other deformations due to lack of lubrication.
In each of the options described above. an asterisk is subject to repair.
What is needed to replace the sprocket on a chainsaw?
The main thing that is required is an understanding of the internal structure of the saws and a certain dexterity: if you are holding this power tool for the first time, it is better not to experiment with repairs and provide it to more experienced people.
If you are confident in your own technical literacy, to replace the sprocket on a chainsaw, you will need:
- a new clutch drum or its whisk. are selected in accordance with the model of a particular chainsaw;
- set of tools for repair.
How to remove an asterisk from a chainsaw: several options for different designs of the clutch drum
The method for a star with a stationary crown
To do this, produce:
- dismantling the protective cover and tire-cutting headset;
- locking of the piston of the motor;
- disconnecting the clutch from the motor system;
- recess from the saw body of the clutch and the centrifugal sprocket;
- visual inspection of the sprocket and its gear part;
- if defects are detected, replace the sprocket with a new clutch drum;
- diagnostics of clutch chainsaw elements for defects. worn centrifugal springs and cams can adversely affect the operation of the sprocket;
- if there are no malfunctions, we proceed to the assembly stage. To do this, you need:
- remove the stopper;
- to pull off the ignition cable;
- screw the stop to fix the centrifugal mechanism on the motor shaft;
- use a universal key in the direction against the chain stroke to tighten the clutch;
- return the remaining removed parts to their previous positions.
Method for star with collapsible clutch drum
The second method regarding how to unscrew the sprocket on a chainsaw with a collapsible clutch drum looks simpler than the previous one. The sequence of actions will be similar, but not the entire star will be subject to disassembly and reinstallation, but only a separate part of it. the ring gear.
Do not forget that the installation of a new chain on the tire chainsaw is one of the reasons to re-equip the saw with a new asterisk. Otherwise, the chain will stretch ahead of time or break during operation.
Less wear on the clutch drum results in alternate use of several chains and periodic maintenance of its bearing. This mechanism is used exclusively at idle: with an increase in speed, it is not involved in the work.
Experts recommend changing it simultaneously with a chain and an asterisk and systematically lubricating it with chain oil.
How to remove the asterisk from a Husqvarna chainsaw yourself: replacing the drive sprocket on a Stihl 180 and Partner chainsaw, video
The movement of the chain on the tire chainsaw is due to the drive sprocket connected to the engine gearbox.
Wear on the sprocket on the sprocket means that it needs to be replaced as soon as possible, otherwise it will not clutch with the chain and the chain will be damaged.
In this case, it must be taken into account that the drive sprocket has a number of features depending on the model of the saw and its type. In this article, we will highlight such a question as how to remove an asterisk from a chainsaw.
Feature of saw designs
Professional chainsaw brand STIHL
In operation, there are already several dozen chainsaws from different manufacturers, capacities, and most importantly special purposes. The saws are divided into:
- professional (for felling and construction);
- household (garden).
Accordingly, the drive gear will be different for them, as well as the sequence of actions. This is a feature of saw gearboxes. With most professional tools, the tire can change its location on the saw in two planes.
Chain sprocket, crown and bearing
The vast majority of household saws are sold under the brand name Partner. They simply change the star even at home, having bought a repair kit.
Since most often the asterisk in household saws is a prefabricated mechanism, it rotates due to the bearing. That is, changing the sprocket, you inevitably change the bearing and not the shaft.
In professional models (such as Stihl and Husqvarna), as well as in household ones, if it is not possible to have a specialized key for removing a star, use a soft cord with a diameter of 5-6 mm.
In all cases, the sequence of actions is as follows:
It looks like a chainsaw tire
- After the sprocket is free, you need to unscrew the spark plug to access the engine piston.
- Manually rotating the sprocket, bring the piston almost to the very top of the channel and fill the hole most tightly formed from the candle with a soft cord, thereby blocking the movement of the piston.
- Use the open-end wrench and unscrew the sprocket, depending on the model of the saw and the type of gearbox.
Note: Before starting to replace the sprocket, remember that there is a driven sprocket on the end of the bus. Each manufacturer prepares a saw with tires having the same slot pitch in advance. They must match, otherwise the chain cannot be put on the saw.
Thus, adhering to the recommendations given in the article, you can easily remove the sprocket from the chainsaw yourself.
How to remove and replace the drive sprocket on Husqvarna and Stihl chainsaws is described in detail in this. video:
How to remove and change the drive sprocket on a chainsaw?
When operating chainsaws, sooner or later there is a need to remove and replace the drive sprocket. This procedure is simple, so for it’s not necessary to contact the service. you can do everything yourself. In this article, we will look at how to remove and change the drive sprocket on a chainsaw.
Reasons for removal and replacement
Removing and replacing a star is usually done when a deep groove is formed in it. It appears due to friction from the chain, and when it becomes too deep, the chain can not always catch on a star.
It also happens that a chain that stretches out gradually grinds a groove under itself.
Then, when the teeth on the chain are completely worn out, the owner buys a new chain, but it does not stand on the old sprocket, since a groove is machined on it, which now fits only the previous extended chain.
That is why it is recommended to use three chains alternately. by the time all three chains are worn out, the sprocket will also wear out, and it will be possible to exchange all this together for new copies.
Also, the star is removed if it is necessary to carry out maintenance or repair of the clutch.
Removal and replacement process
The method of removing the sprocket will depend on the design of the chainsaw. Chainsaws can be divided into two types according to the location of the leading star:
- with the location of the sprocket basket closer to the engine;
- with the location of the basket closer to the side cover.
In the first case, the removal process is somewhat simpler. To do this, you just need to remove the snap ring with a screwdriver, after which the sprocket is easily removed.
In the second case, you first have to remove the clutch. To do this, stop the shaft on which it is located. There are two ways to do this:
- Or unscrew the candle and tighten the special piston stopper instead, which would prevent the latter from moving.
- Or, from the starter side, insert a suitable wrench or screwdriver into one of the available holes to lock the impeller there. True, this method is dangerous because often the sprocket is tightened quite strongly, because of which it is more likely to break the impeller blades than to unscrew the star. Therefore, if you do not have a stopper from the previous method, then use the alternative method from the next paragraph.
- The folk way is that instead of a special stopper, it is possible to push a piece of fabric into the combustion chamber through the hole where the candle is wrapped, leaving a part of the fabric so that it can then be pulled out. The fabric will occupy the entire space inside and prevent the piston from moving upward, due to which the shaft will stall. over, due to the fact that the fabric itself is soft, it will not cause any damage to the walls of the cylinder.
After the shaft is locked, you can unscrew the clutch. You need to use either a special puller, or you can do with a suitable open-end wrench by inserting it into the recesses on the clutch. Loosening is done clockwise, since the thread on the shaft is left.
Unscrewing the clutch, you can now easily remove the sprocket.
The installation of new parts must be done in the reverse order.
As you see, nothing complicated. everyone can handle it.
How to remove an asterisk from a Stihl, Husqvarna, Partner chainsaw and change it
Chainsaws produced by well-known manufacturers of special tools are characterized by high reliability and a long service life. This is due to the thoughtfulness of the design and the use of special grades of tool steel, from which all moving and rubbing parts are made. These include in the first place:
- chain with cutting edges;
- guide rail;
- chain drive sprocket driven in rotational motion due to the energy of a single-cylinder two-stroke gasoline engine.
They all work in intensive mode and wear out over time. Even a slight change in the geometric dimensions of these parts affects the performance and smoothness of the saw. If you needed to remove the sprocket from the chainsaw to replace it, you need to understand the principle of the clutch system, with which it has a direct connection.
Chainsaw clutch system
Centrifugal clutch is installed on Husqvarna, Stihl, Partner chainsaws and most models of other well-known brands. It turns on automatically when the engine enters a certain speed.
The clutch basket is disc-shaped. It has movable friction pads that can move in the radial direction. In the normal state, they are pressed by the built-in springs to the center, without touching the drum of the drive chain sprocket.
Elements with friction pads are shifted to the sides, clinging to the inner surfaces of the sprocket drum, which begins to rotate at the required frequency.
Such a system is able to protect the engine from serious damage in case of jamming of the chain.
Reasons to replace sprockets
Replacing the sprocket on a chainsaw with opening and revising the entire clutch assembly is carried out in the following cases:
- jamming the movement of the chain;
- physical wear of the sprocket to unacceptable limits.
The deviation of the geometric dimensions of the sprocket teeth from the nominal value must not exceed 0.5 mm. Otherwise, the work of the saw will be accompanied by increased vibration, which will lead to premature failure of the crankshaft bearings or the entire tool.
Typically, the sprocket’s operating life is approximately twice that of a single chain. In practice, 2-3 chains are often used alternately until their cutting edges are abraded, after which they acquire a new set and change the asterisk.
Sprocket Replacement Procedure
In the process of repairing any working unit of a chainsaw, it is possible to change the rejected part only to a similar one. Experienced craftsmen acquire the necessary parts in advance.
To open and repair a chainsaw you will need:
- universal wrench sold with saw;
- piston lock, which can be replaced with a thick cord 6-8 mm thick;
- special puller.
As an example, Husqvarna 137, a Japanese or Chinese chainsaw, in which the sprocket is located behind the clutch, can be considered. First, the protective cover of the clutch assembly is removed. To do this, you have to unscrew the two nuts with a universal key. After that, the guide bar and chain are easily dismantled.
- the air filter is removed;
- the spark plug is removed to provide access to the engine cylinder;
- by rotating the shaft clockwise, the cylinder piston rises to a vertical position, after which it is retracted a few millimeters back;
- the inner space of the cylinder above the piston is filled with a dense cord for accurate fixation of the piston, and with it the crankshaft.
After fixing the crankshaft, the puller is inserted into the holes of the coupling and rotates clockwise until it is completely dismantled.
Behind the clutch, an asterisk and a needle bearing are detected, ensuring smooth rotation. If unacceptable wear is detected, they should be replaced with new ones. Clutch inspection and repair consists of inspecting and replacing springs and cams.
All parts are installed in the reverse order. At the same time, to install the clutch, you will also have to fix the piston, but you need to do this with the left rotation of the crankshaft a few millimeters to the top point.
Video: How to Lubricate Husqvarna Chainsaw Needle Bearing
Work must be carried out carefully and accurately to avoid damage to the mechanism or its individual parts. Without at least basic knowledge of the design of the chainsaw, it’s not worth undertaking the replacement of the sprocket. it is better to entrust this task to professionals.
How to remove an asterisk from a chainsaw: change, replace, replace the lead, unscrew
The chainsaw sprocket is used to transmit engine torque through a centrifugal clutch to the saw chain. Sprocket teeth experience heavy loads during operation and therefore wear out gradually. It is easy to remove the sprocket from the chainsaw using a special tool, but you can do the work with improvised tools.
Design Features and Functions
The chain sprocket is functionally aligned with the clutch drum, inside of which there are cams compressed by a spring. A feature of the design device is that the engine shaft passes and rotates freely inside the clutch drum. Expanding cams are rigidly fixed at the end of the shaft.
When idling, the spring compresses the cams and they do not touch the drum. With increasing revolutions, the centrifugal force exceeds the stiffness of the spring and the cams come into contact with the walls of the drum. The latter begins to spin.
The teeth of the chain are meshed with the teeth of the drive sprocket. One of the functions of automatic centrifugal clutch is to protect the engine when the load on the circuit increases beyond the permissible limit. This may occur when the chain is jammed.
The outer part of the drum is covered by an emergency brake belt. When the handle is tilted, the tape is pressed against the drum and slows down its rotation. The effect is the same as when jamming the chain.
A feature of all chainsaws. the drum and clutch cams are mounted on the shaft with a nut with a left-hand thread, so that the mechanism does not unwind during operation.
Causes of malfunctions and how to determine the need for replacement
The wear of the teeth of the drive sprocket can occur for several reasons:
- natural wear together in the teeth of the chain;
- accelerated wear as a result of excessive tension or lack of chain lubrication;
- incorrectly selected chain;
- technological defect.
Metal wear can be determined visually when inspecting the sprocket without removing it from the saw. Dents and chips on the surface should not exceed 0.5 mm.
The need for replacement is determined by the increased noise during the movement of the chain, but this is characteristic only in the presence of deep potholes. Shallow production during operation is difficult to notice, but the chain will wear out a lot. When the teeth are broken, the chain can move in jerks, which is especially felt during operation.
How to remove an asterisk on a chainsaw
You can remove and change the asterisk at home, without resorting to the services of a service center. The procedure is as follows:
- we unscrew the mount of the saw set with a special key;
- unscrew and remove the headset cover;
- unscrew and remove the air filter cover and the filter itself;
- unscrew the spark plug.
To remove the sprocket, you need to fix the engine piston. To do this, gently pull the kick starter cord, lifting the piston up, but not bringing it to the end.
We push a long section of a thick cord into the candle hole until the combustion chamber space is filled. This is necessary in order to prevent the piston from reaching top dead center.
At the same time, the cord will serve as a damper, protecting the piston from possible damage. Part of the cord should come out of the hole so that it can then be removed.
To unscrew the sprocket, you need a special key, which rarely comes with a set of saws, especially cheap models. It is necessary to use a drift of soft metal. copper or aluminum.
The drift is leaned against the protrusions of the cams of the centrifugal mechanism and inflicted light blows with a hammer. The direction of impact should be almost parallel to the plane of the coupling, since with a large angle you can bend the cam mount and the clutch will have to be changed. The direction of impact is counterclockwise. Often the clutch is labeled “off” and an arrow showing the direction of impact.
After loosening the nut from its place, you can unscrew it by hand.
Some saw manufacturers use simple left-handed nuts to secure the clutch and sprockets. Then the task is simplified, because for removal you can take a simple open-end wrench of the right size.
Now remove the drive sprocket, being careful not to lose the plastic gear of the oil pump drive and the needle bearing.
How to install
After all the work is completed, the asterisk can be replaced with a working one. Assemble in the reverse order. Grease the needle bearing further.
When tightening the nut, there is no need to apply great efforts, since it will be tightened during operation.
How much is an asterisk and its replacement
The price of an asterisk for a chainsaw is highly dependent on the manufacturer and slightly lower than the cost of the saw chain. In order not to make a regular replacement, manufacturers recommend operating a saw with several chains and periodically changing their places. In this case, the wear of the sprocket teeth occurs more uniformly.
The replacement cost in service centers is commensurate with the price of the part itself, so it makes sense to do this work yourself, especially since no adjustments are necessary after that.
Replacing a Worn Chainsaw Sprocket
The drive chain sprocket or chain saw is one of the most important parts of the saw. The main function of the chainsaw sprocket is to transmit engine torque to the saw chain.
This transmission is through a centrifugal clutch. By type of sprocket, can be divided into professional and household, as well as chains.
During operation of the chainsaw and sawing wood, the drive sprocket, like the chain, gradually wears out.
Leading asterisk Husqvarna
Let’s find out in more detail why the replacement of a worn chain saw or chain saw sprocket is necessary and when it is better to perform such a change.
The main signs that an asterisk need to be changed:
- the chain was replaced twice on your chainsaw (one of the operating rules for operating the chainsaw and saw is that with frequent and active operation of the tool, after two chain changes, the drive sprocket should be replaced);
- sawing quality deteriorated, the chain began to need to be pulled more often;
- you have installed a new chain that the old drive sprocket does not fit (this part is not universal, and also has its own step, in addition, the steps of the drive and driven chain sprockets must match, otherwise the tool will not work);
- You are using another bus, shorter or longer.
Video about replacing asterisks on a chainsaw:
Why replace an asterisk?
Remove a worn star for the following reasons:
- with an old asterisk, the saw chain will stretch very quickly. after several applications the chain will hang, and the tension will not help;
- if you put a new chain on an old sprocket, the smoothness of the chain will decrease, the cut quality will deteriorate, the chain will lead to the side when cutting;
- general wear of the chainsaw will accelerate, the tool may fail at any time;
- the chain may break or the chain will jam during operation (dangerous by injuries to the hands and damage to the saw body, chainsaw);
- the tire will heat up faster, which will lead to quick overheating of the chainsaw;
- The load on the engine and housing will increase.
Video on how to change an asterisk on a chainsaw:
Are there any ways to extend the life of an existing star?
The main ways to extend the working life of the leading chain saw sprocket:
- use multiple chains (preferably three). This method is the most gentle and convenient for the owner of the chainsaw in that you do not need to constantly tighten the chain worn out by intensive work. Operation of three circuits in turn will save the sprocket’s life and delay its replacement;
- high-quality maintenance of the drive sprocket bearing. This part plays an important role in the operation of both the drive sprocket and the engine. A special lubricant is recommended for lubrication. The sprocket bearing is not always activated, but only at idle, therefore, it needs periodic lubrication. You can use tire grease, such as standard grease from Repsol or Husqvarna.
Is it wise to try to fix or sharpen an asterisk?
The cost of this spare part is small, and an independent repair or attempt to restore a worn part never leads to efficient operation of the chainsaw. It is recommended to replace the part with a new one with signs of wear.
How to unscrew an asterisk on a chainsaw:
What tools are needed to replace the sprocket
To replace the drive (drive) sprocket, you will need such tools and accessories:
- a special key for removing this part (usually supplied with expensive branded chainsaws, cheap saws are not equipped with such a key);
- drift from aluminum or copper (only from soft metals and only in the absence of a key);
- hammer (for striking a punch in the process of unscrewing the sprocket);
- flat screwdriver for tightening the nut;
- grease for sprocket bearing.
Construction problems, differences between different models
Branded chainsaws have a special design that does not allow replacing a worn-out drive without removing the clutch and other parts of the chainsaw. That is, the saw needs to be almost completely disassembled. modern models of expensive chainsaws are always equipped with a special key.
Chainsaw sprocket replacement
Also, the owner of the chainsaw may encounter such a nuance: on Chinese imported chainsaws or saws, the asterisk on the clutch mechanism can be located in an unusual way. On older models, when the teeth of the chain are worn, you need to unscrew and change the drum, one-piece with a drive. On newer models, you can replace the sprocket separately.
Algorithm for self-changing drum clutch with sprocket
How are the leading sprockets replaced on a saw or chainsaw. more on this in more detail.
For the sprocket replacement procedure, you need to do the following:
- remove the chain brake cover and pull it towards you (avoid contacting the brake band with the clutch parts);
- using a wrench, loosen the nuts that hold the chain tension and the chainsaw cover;
- remove the chain and then the tire by removing debris and sawdust from the mounting holes;
- we fix the piston in the cylinder using a normal lace, but if possible, use a piston stop or a special clamp;
- the clutch begins to rotate and do so until the piston touches the outlet;
- after which the stopper or cord is lowered into the candle opening and fixed there, tying several knots (the stopper will fix itself);
- unscrew the clutch nut (note. the thread of this nut is left, take this into account when unscrewing);
- hard tools must not be used so as not to break the soft metal clutch nuts;
- then the clutch is removed;
- after they remove the pinion gear itself;
- replace the old sprocket with a new one;
- reverse the assembly of the structure.
Video about replacing asterisks on a chainsaw or saw
“I’ve been sawing a Chinese chainsaw for five years, there’s a slight backlash in the sprocket, I think that because of this, large logs are given to saw very hard. The service center can’t really say anything, and I don’t know which star there should be, that is, which model to replace so that there is no play. Saw while on the move, no other complaints. "
Replacing a worn chainsaw sprocket Link to main publication
How to remove an asterisk from a chainsaw
The use of equipment is always closely associated with its maintenance and repair, and chainsaws are no exception. One of the common tasks is to replace the sprocket on a chainsaw. an element of one of the key nodes. Depreciation can be natural, associated with an incorrectly selected tire or poor part quality.
It is useful for each owner of such a tool to know how to remove the sprocket from the chainsaw correctly and replace it. Do-it-yourself repair can save both time and money. And also quickly bring the tool to working condition, because for this you do not need to wait for admission to the service, just purchase the necessary details.
How to remove an asterisk from a chainsaw. detailed description
The principle of operation of the clutch system
In most cases, a centrifugal clutch is used on Stihl, Partner, Husqvarna and other brands of chainsaw. When the engine picks up a certain number of revolutions, it turns on automatically, transmitting rotational movements to the sprocket.
The clutch is a disc located in the drum. The entire assembly is mounted on the shaft of the chainsaw engine. In the normal state, the clutch springs press the friction linings, preventing the transmission of movement to the drum, respectively, and to the sprocket.
When the speed reaches the set value, a centrifugal force is formed, under the influence of which the elements with friction pads are displaced, exerting pressure on the inner walls of the drum. Thus, the sprocket is driven by rotating the saw chain.
Why a sprocket replacement is necessary
Chainsaws have some parts that are subject to natural wear and tear; these include the chain, tire, and drive sprocket. This is not considered a tool breakdown because wear is a result of operation. Also, an inappropriate chain or mechanical shock may be a causal development. For example, after a chain meets a metal object, it is recommended to inspect the sprocket.
If you do not timely replace the part, the stability of the tool is violated. A worn part provokes excessive vibrations, which, in turn, have a negative effect on the bearings of the crankshaft.
Normal wear is considered to be up to 0.5 mm. However, often users bring the part to a deeper output of the order of 1 mm, not suspecting that the operation causes damage to other parts of the chainsaw. Naturally, later there is a breakdown of the bearings, which must be changed.
Step-by-step instructions for replacing the sprocket on a chainsaw
You can replace the asterisk on a chainsaw not only in the service, but also with your own hands. The whole process is relatively simple, for the repair will require:
- candle key;
- a wrench for removing the coupling (a regular grinder wrench for a nut is also suitable, but it is desirable that it be thicker);
- piston stopper (special tool, but it can be replaced with a tight cord);
- Adjustable wrench / wrench (may not be useful).
Step 1. Replacing the drive sprocket and chain begins with fixing the piston in the cylinder of the chainsaw. To do this, the upper housing cover, the air filter are removed, and the spark plug is twisted.
A special piston stopper is installed in this hole, but among the craftsmen it is not in great demand: a metal one can scratch a piston, and a plastic one can break and get inside. Most often, instead of it, they take an ordinary dense cord or wire about 10-15 cm long.
It is important that debris does not pour from it, metal wiring does not stick out. all this can get into the cylinder.
Step 2. Remove the cover on the side of the chainsaw where the tire is mounted. Usually it is held on two bolts and pressed with two nuts. You can unscrew them manually or with a wrench or universal wrench. The chain tension is released to immediately remove it and the saw bar. At the same stage, external cleaning should be carried out from accumulated dust and sawdust.
Step 3. Depending on the design of the chainsaw, the sprocket can be located under the clutch drum (separately or be part of it) or on top. In the second case, everything is simpler. remove the part and replace it with a new one.
In other circumstances, the assembly must be disassembled. The coupling is left-handed, so it is twisted clockwise with a special or Bulgarian key, the drum is removed, then the sprocket can be removed.
If the chainsaw has been used for a long time, the parts can become very sticky.
In such a situation, physical force will be required, but it is forbidden to use a hammer or chisel. this will render the entire part unusable.
Step 4. Remove all parts:
Perform an initial inspection of all elements for wear and deformation. Next, you can begin to repair and take up the replacement of the sprocket on a chainsaw. If it is part of the coupling drum, the entire part must be replaced. An important point will be the selection of a new part. it should be similar to the standard one.
Tool assembly order
The chainsaw is assembled in the reverse order. First, the sprocket is mounted on the needle bearing, then the clutch drum, the washer and the clutch itself. Twist it counterclockwise, but without unnecessary effort. The piston will also need to be fixed, but with a left rotation a few millimeters to the maximum high point.
Please note that sometimes the oil actuator is equipped with a spring that transmits movement from the sprocket to the pump. If the mustache of the spring does not fall into place, the oil will not be supplied to the chain. Usually the correct position is marked by color, risks, in the absence of those, you need to slowly rotate the part until a characteristic click.
Next, you need to install the saw bar on the chainsaw. To set the chain, you need to release the hand brake by pulling the lever towards you (towards the handle). It is important here that the teeth of the chain fall into the grooves of the sprocket.
Inattentiveness, this moment can be missed, which will lead to a quick damage to the chain. Its correct direction is indicated on the case with characteristic pictograms.
After installation, it must be pulled to a working condition.
At the end, you need to remove the piston stop, install the spark plug, air filter in its place. Fasten the top case cover.
Watch the video how to remove an asterisk from a chainsaw
In order for the chainsaw mechanism to serve longer, you must adhere to certain rules. Experienced craftsmen recommend:
- Always lubricate the needle bearing after changing the sprocket.
- Correctly select the saw chain and bar. Sprocket pitch and chain must match (e.g. 3/8 or 0.325). If you use the wrong consumables, then the sprocket flares up, quickly and unevenly wears out.
- Many try to replace the drive sprocket and chain at the same time. The fact is that as the chainsaw is used, the chain inevitably stretches, accordingly, the length of its step also changes. And this already negatively affects the sprocket itself, in particular, a wide step will wear out faster, breaking grooves along the edges.
- Be sure to regularly clean the chainsaw. Periodically, you need to remove the side cover and remove accumulated sawdust, which inevitably fall through the hole near the chain and mix with the grease.
- Watch the "behavior" of the circuit when working. If it starts to wedge. this is an occasion to conduct an initial inspection of the drive sprocket.
The algorithm of actions during the repair work of the chainsaw is quite simple and based on the experience and knowledge of qualified craftsmen. Therefore, it is not recommended to neglect certain nuances.
The instruction presented by us will help to remove the star from the saw with your own hands, without resorting to the help of specialists, on most types of chainsaws. In private, any deviations, non-standard designs are not excluded.
Sometimes it is very useful to read the user manual for the tool, it may contain the necessary information about the features of the design, detailing of spare parts with a description.
Chainsaw sprocket. designation, breakdowns and replacement
In any chainsaw, one of the key parts is the drive sprocket for the chainsaw.
It is also called a clutch drum. this causes confusion when people who are poorly informed in the device of this unit do not understand that replacing a clutch and replacing an asterisk on a chainsaw is one and the same.
To prevent further confusion, let us consider in more detail the purpose of this mechanism, its device and how to replace the asterisk on a chainsaw.
What is the chainsaw sprocket for?
In a chainsaw there are several main components: engine, housing, tire, chain, drive and driven sprockets. A driven sprocket and chain are installed on the chainsaw tire.
A chain equipped with cutting tools serves to cut wood, but for this it must be set in motion. The chainsaw drive sprocket is located near the engine and is driven by the engine through a centrifugal clutch.
The driven sprocket is located on the other end of the tire and serves as a supporting and tensioning element.
Leading sprockets for chainsaws, their types and design
There are two types of chain saw sprockets. combined and one-piece. One-piece is a monolithic element installed behind the clutch. the so-called sprocket with a stationary crown. The crown is fixedly attached to the clutch drum associated with a centrifugal clutch.
A similar design is used in most chainsaws, including those made in China. There is nothing complicated in how to remove an asterisk from a Chinese chainsaw, but you must completely remove the entire asterisk.
With more expensive models, the situation is even simpler. Their chainsaw sprockets have a prefabricated design with a replaceable crown. The crown is put on the drum shaft and transmits torque to the chain. Therefore, replacing the sprocket on a chainsaw is very quick and easy. the crown is removed, and the drum can be left in place.
When to change the chainsaw sprocket: types of malfunctions
The main problem with the leading sprockets is tooth wear. In normal operation, the drive sprocket for the chainsaw has minimal wear. subject to operating rules and normal chain lubrication. But if during cutting the blade comes across a solid object (stone, nail, etc.)
d), that tooth, which at this moment was moving the chain, will receive a very strong dynamic blow. So strong that the tooth can easily break. As a result, during operation, the chain will slip and may fall off the tire. this will result in personal injury or damage to other elements.
Despite the constant lubrication of the web, the chain moving at great speed still has an abrasive effect on the sprocket. Therefore, over time, in any case, it will wear out. in order to know when to replace the sprocket on the chainsaw tire, regularly inspect this unit.
Bearing failure is unlikely under the condition of proper operation. If it is well lubricated on time, then the sprocket will be erased much faster than the bearing. However, if this happens, then you need to unscrew the sprocket on the chainsaw, replace the bearing, having previously missed it well, and then install it back.
How to remove an asterisk from a chainsaw
The very first and most important advice. if you do not know how to remove the chainring on a chainsaw, it is better to contact the service. If you understand the technique, you can do it yourself, especially if you need to do it in the field or make repairs as quickly as possible. Consider both options: with removable and stationary crown
How to unscrew an asterisk on a chainsaw
Stationary crown option
The procedure for removing the sprocket from the chainsaw may vary slightly depending on the model, but in general it is:
The assembly order is performed in the reverse order, while twisting the coupling is done counterclockwise.
Such a general procedure is how to remove an asterisk from a Chinese or any other production chainsaw in the version with a stationary crown.
Variable crown option
In this case, the procedure is completely similar to the above method, with the only exception. in case of failure of the teeth on the crown, only the crown changes. But the asterisk will still have to be removed, because otherwise access to it will be impossible to obtain.
How to Remove a Leading Sprocket From a Chainsaw
Leading asterisk of a chainsaw. An interesting video with a step-by-step analysis of a chainsaw. Like any you need to remove from. Correct selection and substitution
The chain transmission of a chainsaw of any design determines the operability of the tool. over, in the process of use the chain is stretched, and the teeth leading asterisk wear out. Illiterate sprocket selection will drastically reduce tooth longevity chainsaws, and its incorrect adjustment will lead to premature wear.
A little about the rules of operation of the node
Regardless of the brand of the manufacturer (Stihl, Husqvarna, Partner, Patriot, Makita) chainsaws subdivided into household, semi-professional and prof.
The difference, however, is not in the quality of the assembly or the manufacture of components, but in the class of tasks performed, performance and long-term drive power.
This intends the selection of the material of the drive sprocket for the chainsaw, its implementation and the design of the saw chain.
The tool’s operability will be determined by the method of operation of the chain-sprocket pair. In most cases, users use one of two options:
- The chain is operated right up to the complete wear of the teeth, and then both the saw blade and the sprocket are immediately replaced;
- Repeated chain swapping, having a different step, and each will need its own driving sprocket.
The choice of option is often determined by the attitude of the owner to his own instrument. Many owners of gasoline chainsaws after a device breakdown are concerned about how to remove the chainsaw sprocket.
If you don’t care what to saw (wood or iron staples stuck in it, screws, etc.), then you can slow down on the first option.
The chain, however, will have to be corrected from time to time, thereby reducing the performance of working on a chainsaw.
It is categorically not recommended to leave an old chain with the latest starlet and vice versa. If the saw blade is worn out, the possibility that the tooth pitch does not match is practically one hundred percent. How to replace i.e. thread left and easily change the drive sprocket.
Unscrew the asterisk with. Therefore, at the initial moment of launch, both components of the chain transmission will be subjected to significant dynamic loads.
As a result, either the chain will be stretched in advance, “adjusting” to the sprocket, or one of the teeth on the leading sprocket will burst upon impact.
In addition, it is worth focusing on the operation of the shaft bearing assembly leading asterisk. When the saw is in the operating speed mode, only the crankshaft rotates. How to remove an asterisk from a chainsaw and repair.
But all chainsaws function periodically at idle, when the bearing rotates. With a lack of lubrication, wear of the seat occurs, and. as a result. additional beating of the teeth of a still quite functional chain gear.
Replacing the sprocket on a Chinese chainsaw
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How to change an asterisk on a chainsaw easily without effort and troubles
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From this it follows that when replacing the chain and the drive sprocket for a chainsaw, it is not bad to simultaneously replace the bearing.
Design features of leading stars
Any manufacturer in the instruction manual indicates the tooth pitch. Considering that the driven sprocket (designed to create the necessary tension) is also installed on the saw bar, the pitch here and there should be the same.
The leading chain saw sprockets can be solid and prefabricated. In the first case, the sprocket includes a hub on which a gear ring is pressed.
This is how the details in Champion chainsaws are arranged.
The product should be removed when replacing it completely, since at home it is almost impossible to comply with the preload value set at the manufacturer. And to buy a crown separately is also a problem.
In chainsaws from Stihl or Husqvarna, the replaceable crown is located directly on the drum shaft, and therefore its replacement does not present any difficulties.
The wear of the teeth is determined by the following criteria:
If at least one of the above factors is present, the drive sprocket must be replaced.
Before starting work (especially if the chainsaw has worked relatively little), it is worth checking the fastening of the saw bar. The tensioner screw has moved away or the fastening nuts have been unscrewed. the guide is already not aligned with the longitudinal line of the saw blade.
How to remove and replace the sprocket with the characteristic of the chain and its tension on the chainsaw. He begins to contact not with the center, but with the periphery of the teeth of the drive sprocket, causing their intense wear.
After tightening the specified elements, the operation of the chainsaw is checked: if the play is not eliminated, then the sprocket will have to be changed.
how remove the lead an asterisk with a chainsaw?
As already noted, the sprocket can have a separate and pressed crown. Therefore, the sequence of actions will be different.
For a stationary crown located sequentially produce:
- Dismantling the casing;
- Removing the saw bar with chain;
- Disconnecting the clutch from the engine (the piston should first be locked);
- Removing the clutch together with the drum;
- Removing the crown from the drum using an ordinary open-end wrench (some manufacturers also attach a puller to the spare parts kit).
Assembly of the unit is carried out in the reverse order. For some models, before dismantling the crown, take off also an air filter.
When disassembling the drive sprocket for a chainsaw, which has a removable crown, the procedure will be almost the same, but at the final stage it is only necessary to replace the crown.
After completion of work, it is necessary to check the effectiveness of the replacement. To do this, check the chain tension: if the brake is released and an attempt is made to pull the chain in the direction of its movement, it is stationary, then the fastener is “tightened” and the tensioner should be slightly released.
The success of the work is determined by the presence of a special repair kit purchased for a particular brand of chainsaw. To push the carburetor off, you now need to remove the Stihl 180 chainsaws, as well. Otherwise, you should know exactly the size of the saw and the pitch of the teeth.