✅ Replacing the sprocket on a Husqvarna chainsaw

Chainsaw drive sprocket device

An asterisk or centrifugal mechanism is a part shaped like a star.
It takes on the engine torque and transmits it to the guide and saw chain. This guarantees the rotation of the cutting set and the sawing process itself. It operates automatically, which depends on the amount of engine speed. The clutch drum can be located both outside the chainsaw and on its inside - under a separate cover. It performs a protective function not only in relation to the material from which the sprocket is made, but also for the operator, who may be injured by it during work. In addition to the function of chain rotation, the saw drive star prevents the occurrence of malfunctions of the motor system in cases where the chain jams or stops rotating.

The owner’s desire to equip the headset with a saw chain with a different pitch leads to the need to replace the sprocket with a part with a crown of the corresponding profile. This requirement applies to the entire range of chainsaws made in Europe and China.

The operational reliability of a European-assembled saw, when working under difficult conditions with increased loads, can significantly deteriorate if a Chinese-made sprocket is installed instead of a branded part.

A little about the rules for operating the node

Regardless of the manufacturer’s brand (Shtil, Husqvarna, Partner, Patriot, Makita), chainsaws are divided into household, semi-professional and professional. The difference, however, lies not in the quality of assembly or manufacturing of components, but in the class of tasks performed, performance and long-term drive power. This determines the choice of material for the drive sprocket for the chainsaw, its design and the design of the saw chain.

The performance of the tool will be determined by the way the chain-sprocket pair is used. In most cases, users use one of two options:

The chain is used until the teeth are completely worn out, and then both the saw blade and the sprocket are replaced at the same time;
Periodic replacement of chains that have different pitches, and each will require its own drive sprocket.

The choice of option is often determined by the owner’s attitude towards his instrument. If it doesn’t matter what to cut (wood or steel staples, screws, etc. stuck in it), then you can go with the first option. The chain, however, will have to be adjusted periodically, thereby reducing the performance of the chainsaw.

It is strictly not recommended to leave the old chain with the new sprocket and vice versa. If the saw blade is worn out, the probability that the tooth pitch will not match is almost one hundred percent. Therefore, at the initial moment of start-up, both components of the chain drive will be subject to significant dynamic loads. As a result, either the chain will stretch prematurely, “adjusting” to the sprocket, or one of the teeth on the drive sprocket will burst upon impact.

In addition, it is worth focusing on the operation of the bearing assembly of the drive sprocket shaft. When the saw operates at operating speed, only the crankshaft rotates. But all chainsaws periodically operate at idle speed when the bearing rotates. If there is a lack of lubrication, wear of the seat occurs, and - as a result - additional runout of the teeth of a still fully functional chain drive.

It follows from this that when replacing the chain and drive sprocket for a chainsaw, it is a good idea to simultaneously replace the bearing.

Replacing the drive sprocket on Husqvarna 154, 254, 262 chainsaws

For Husqvarna chainsaw models 154, 254, 262 series

, equipped with
8-tooth
chains with
a 0.325

a Rezer SP 38071
drive sprocket is used .
The part differs from the previous all-metal construction
. This means that there is no such element as a replaceable crown.

On the one hand, such a detail loses

in operational life, on the other hand, it has a more
attractive cost
.
The price is almost two times lower
compared to sprockets with a replaceable crown.
Husqvarna 154, 254, 262
models by clicking on the following link.

Drive sprocket replacement process for Husqvarna 154, 254, 262
has a slightly different algorithm. Let's look at it in more detail.

Remove the side of the chainsaw to gain access to the saw group
.
Read also: Choosing the right trimmer line

Using a combination key
loosen
the chain
and remove it together with
the bar
.

Remove the rope starter
from the opposite side.
Use hex wrenches
.

Fix the shaft on the impeller side with a 13mm wrench
.

Using a special key
remove
the clutch
.
Unscrewing should be done clockwise
.

Dismantle

sprocket and needle bearing.

Assembly is carried out in reverse order

.
The clutch should be tightened counterclockwise
.
The force should not be too high
, since the coupling
self-tightens
when rotating.

In fact, the replacement process is not very difficult.

and it is quite possible to produce it
yourself
.
Buy quality drive sprockets
for
Husqvarna 154, 254, 262
in our TUKINGARDEN store.

Required Tools

Once we have diagnosed the faulty clutch system and drive sprocket, we need to purchase spare parts. Here it is important to know and match the parameters of the chainsaw and chain. If you decide to install a chain with a different pitch, then the sprocket must be replaced with a new one.

We also do not recommend installing Chinese components on European-made chainsaws. In this case, the reliability of your saw will decrease significantly.

This requirement applies to all models, no matter where they are produced and no matter what class they belong to.

Repair kit for chainsaw

The drive sprocket is often sold complete with a replacement bearing, but it can also be purchased separately. If we talk about the price of the sprocket and the entire repair kit, then you need to take into account the brand of chainsaw and its model. For a Chinese chainsaw, the drive sprocket will cost about 5-7 dollars. Prices for repair kits for chainsaws from European manufacturers start at $20.

Important: You should consider the model of your chainsaw and the class to which it belongs. Household and professional tools have different drive gears.

Before visiting the store, it is best to photograph the components that you are going to replace and show the photo to the seller.

Replacing the clutch drum with sprocket

All modern chainsaws are equipped with a chain brake device and in most models its operation is carried out by means of a belt located on the tire cover and a chain that goes around the clutch drum.

When the chain brake is engaged and the gas trigger is pressed, the clutch disc continues to rotate, and the drum is clamped by the brake band. If you do not turn off the brake in time and continue to press the gas trigger, the tire cover and chains will begin to melt, and the clutch drum may burst.

To replace the clutch drum you must:

Remove the air filter cover;
Stop the engine and unscrew the nuts;
Pull out the clutch disc;
Stop the engine;
Install the new disc, press the washer and nut.

Drive sprocket for chainsaw

A chainsaw sprocket or clutch plate serves to transmit rotational motion and power to the saw chain. Structurally, there are three types of drive sprockets;

1. The sprocket is solid. In such a sprocket, the clutch plate is rigidly welded to the drive ring. In case of wear, the entire sprocket is replaced.

2. The sprocket is collapsible. It is a clutch plate with splines onto which the crown drive sprocket fits. The clutch plate wears out very little and a replacement hub is cheap. The collapsible sprocket is very beneficial for large volumes of work and is used mainly by professionals.

3. The sprocket is a replaceable crown. This sprocket is used to replace on collapsible sprockets.

The selection of the drive sprocket is carried out according to the chainsaw model. If you are in doubt about your choice, call us and we will try to suggest the correct spare part.

Causes of malfunctions and how to determine the need for replacement

Wear on the drive sprocket teeth can occur for several reasons:

natural wear and tear along the chain teeth;
accelerated wear as a result of excessive chain tension or lack of lubrication;
incorrectly selected chain;
technological defect.

Metal wear can be determined visually by 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 increased noise when the chain moves, but this is typical only in the presence of deep potholes. It is difficult to notice shallow wear during operation, but the chain will wear out greatly. When the teeth are broken, the chain may move jerkily, which is especially noticeable during operation.

How to change a sprocket on a chainsaw?

To replace a worn element, you will need to buy a part of the same type and with the same dimensions as the standard element. In most cases, the factory chainsaw bearing must also be replaced during repairs.

It is best to initially buy a repair kit, which includes both a bearing and a sprocket. To remove the sprocket from the chainsaw and install a new part in its place, you will also need to prepare tools. Their list includes:

a universal key, which is supplied with the chainsaw;
removable key for dismantling the centrifugal clutch. When choosing it, you need to take into account the model of the chainsaw;
mechanical piston stopper. A metal or plastic tool is suitable for removing the piston.

Replacing the sprocket on the chainsaw tire should be done in the following order:

First, you will need to remove the saw blade assembly. Using a universal key, you need to unscrew the protective covers;
Next, you need to remove the standard air filter of the instrument;
After this, using a universal key, you will need to unscrew the spark plug. In its place, you need to install a mechanical piston stopper - it is necessary to fix the piston in a stationary position;
Then you will need to install a removable key in the universal key slot to dismantle the clutch mechanism. Using the resulting device, you need to carefully dismantle the standard saw clutch. To do this, the factory assembly should be turned clockwise;
After removing the coupling, passage to the internal elements is free. This will make it possible to unscrew the sprocket of the household chainsaw;
The removed drum will need to be carefully inspected. If necessary, the ring or sprocket should be replaced. During replacement, you will need to check the separator. If necessary, you need to replace worn springs and cams of the centrifugal mechanism;
After replacing all faulty elements, you can begin reassembling the chainsaw. To do this, you first need to unscrew the previously installed piston corkscrew, and also pull out the factory trigger cable. After this, the stopper will need to be screwed back in. This will make it possible to reliably press the centrifugal clutch of the tool onto the engine crankshaft;
Next, using the universal key, you will need to press the clutch counterclockwise;
At the end, all previously dismantled parts can be installed back on the chainsaw.

Types of clutch malfunctions and ways to eliminate them

Here the list of possible breakdowns is not so long, the most common cases are:
Damaged spring , it can be stretched or burst, in both cases the clutch will not work and repairs are necessary. Depending on the brand of chainsaw, you will have to replace the spring or the entire clutch. So, for example, on Stihl saws it is possible to replace the spring, but on Husqvarna and Echo you will have to completely change the clutch.

Clutch drum , on which the chainsaw drive sprocket is located. Wear of the drum and sprocket also impairs the performance of the clutch mechanism; it is determined quite simply; wear inside the drum and on the sprocket is visible to the naked eye. The problem can be eliminated by installing a new clutch drum.

Another type of failure is a faulty bearing inside the clutch drum; its wear is also natural, although not as frequent as compared to the cases described above. On many models of chainsaws, this bearing is replaced, and there is no need to change the entire clutch.

Recommendations: how to remove a sprocket from a chainsaw

Many instruments require regular replacement of consumables. It touches it and drinks it. This is why the question of how to remove a chainsaw sprocket, often called a clutch disc or centrifugal mechanism, is very important for DIYers. In this regard, it is necessary to consider what is called an asterisk and why it is necessary.

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

Features of the clutch drum in chains

The drum, which underlies the clutch mechanism, is an integral part of the chain drive system. This detail resembles a star in its shape, from which it gets its name. Depending on the type of chainsaw, the part can be professional or home. Since a professional saw is used more often than a home saw, the drive chain also requires regular replacement. If we are talking about household tools, everything here depends on the amount of work performed and the load that is on the device circuit.