Replacing the crankshaft on a Chinese chainsaw

The main signs that the asterisk needs to be changed:

  • on your chainsaw, the chain was replaced twice (one of the current rules for operating a chainsaw and a saw. with frequent and active use of the tool, after two changes of the chain, the drive sprocket should be replaced);
  • the quality of sawing has worsened, the chain needs to be tightened more often;
  • you installed a new chain, which does not fit the old drive sprocket (this part is not universal, and also has its own pitch, in addition, the steps of the drive and driven chain sprockets must match, otherwise the tool will not work);
  • you are using a different bus, shorter or longer.

Chainsaw sprocket replacement video:

replacing, crankshaft, chinese, chainsaw

Also, the owner of a chainsaw may encounter such a nuance: on Chinese imported chainsaws or saws, the sprocket on the clutch mechanism may be located in an unusual way. On older models, when the chain teeth are worn out, 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-replacement of the clutch drum with an asterisk

How is the drive sprocket replaced on a saw or chainsaw. more on this in detail.

For the sprocket replacement procedure, you need to do the following:

  • remove the chain brake cover and pull it towards you (avoid contact of the brake band with the clutch parts);
  • using a wrench, loosen the nuts holding the chain tension and the chainsaw cover;
  • remove the chain and then the bar, removing debris and sawdust from the holes for the fasteners;
  • we fix the piston in the cylinder using a regular cord, but if possible, you need to use a piston stopper or a special lock;
  • the clutch begins to rotate and do this until the piston touches the outlet;
  • after which the stopper or lace 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-handed, take this into account when unscrewing);
  • it is forbidden to use hard tools so as not to break the soft metal of the clutch nut;
  • then the clutch is removed;
  • then remove the sprocket gear itself;
  • replace the old asterisk with a new one;
  • assemble the structure in reverse order.

What tools are needed to replace the sprocket

To replace the drive (drive) sprocket, you will need the following 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);
  • a punch made of aluminum or copper (only from soft metals and only in the absence of a key);
  • hammer (for striking the punch while unscrewing the sprocket);
  • flat screwdriver for tightening the nut;
  • sprocket bearing grease.

Is it wise to try to fix or sharpen the star?

The cost of this spare part is small, and self-repair or an attempt to restore a worn-out part never leads to the efficient operation of the chainsaw. It is recommended to replace the part with a new one if there are signs of wear.

How to unscrew an asterisk on a chainsaw:

Are there ways to extend the life of an existing sprocket?

The main ways to extend the working life of the chain saw drive sprocket:

  • use several chains (preferably three). This method is the most gentle and convenient for the owner of the chainsaw in that it is not necessary to constantly tighten the chain worn out by intensive work. Operation of three chains in turn will save the resource of the sprocket and postpone its replacement;
  • quality maintenance of the bearing of the drive sprocket. This part plays an important role in the function of both the drive sprocket and the engine. It is recommended to use a special lubricant for lubrication. The sprocket bearing is not constantly engaged, but only at idle, therefore it needs periodic lubrication. Tire nose grease can be used, such as standard grease from Repsol or Husqvarna.

Dismantling a Chinese chainsaw

In the video, a detailed replacement of the piston group of a chainsaw, How to do it correctly, in stages and without.

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Repair of assembly or assembly of a prefabricated Chinese part Part 3

Broken chain brake system

The braking system may malfunction or not function at all, causing problems in the operation of the power unit due to clogging of the surface hidden under the protective cover. Another possible cause is a worn out brake band. The tape is replaceable and if clogged, clean it thoroughly.

In order to less frequently encounter various problems in the operation of the saw, check various parts of the device for wear, including the anti-vibration unit, the guide, all sprockets, including the main.

Trimmers and Chainsaws

Do-it-yourself first repair of a chainsaw: the retaining ring fell (during the repair of a Chinese chainsaw, it is necessary to completely disassemble the engine, change all gaskets, change the piston pin retaining rings, piston compression rings, remove the pistons on the piston and on the cylinder mirror or on the chrome or nikosil coating of the inner surface cylinder).

DIY chainsaw repair: hot chainsaws at idle speed and during the passage of gas (the reason is fuel problems, to troubleshoot a chainsaw malfunction, see carburetor and fuel line).

Unscrewed flywheel and broke the shaft (another do-it-yourself chainsaw repair).

Parted jam-silencer key.

The drive of the oil pump is out of order (Plastic).

Needle “Flying” drum.

Chainsaw malfunction: brake disc burned out (and melted the cover).

Cracks appeared on the plastic covers of the cylinder and starter (the Chinese chainsaw needs to be repaired).

Part breaks Drum in starter where spring engages.

Burned gasket under the muffler.

DIY chainsaw repair: rusty needle bearing inside the clutch drum (it must be cleaned, washed and lubricated so that the chain does not rotate at idle speed, the clutch rotates clockwise).

See also  How to Remove Clutch on Any Brand Chainsaw

Causes of piston chainsaw malfunctions

There are many reasons for the failure of the CPG, which are usually divided into two main categories: natural wear and tear and artificial malfunctions. The first type of malfunctions, as the name implies, is the physical wear of the rubbing parts of the piston group. The second category is more extensive and implies:

Elements of a piston chainsaw

  • strong overheating of the internal combustion engine and, as a result, the appearance of thermal seizures on the surface of the piston;
  • breakage of the lower part of the piston (skirt) due to the duration of the chainsaw operation at maximum speed;
  • ingress of foreign particles into the combustion chamber and the occurrence of mechanical damage to the CPG;
  • breakage of the compression (piston) ring due to severe wear or exceeding the permissible saw speed;
  • inconsistency of the recommended portions of gasoline and oil when preparing the fuel mixture.

Worn chainsaw piston

Experts do not recommend disassembling the CPG for no particular reason. However, if the tool has significantly lost power, there is a metallic ringing in the internal combustion engine, or the crankshaft does not turn when the starter jerks, the piston chainsaw should be diagnosed. First of all, to identify engine malfunctions, it is necessary to measure the compression in the cylinder. With a significant deviation from the values ​​recommended by the manufacturer, we can safely say that there are scratches, wear and tear on the surface of the cylinder or piston. It is the drop in compression that is the basis for the complete disassembly and repair of the piston group of the chainsaw.

For the prompt diagnosis of the CPG for a breakdown of the chainsaw compression ring or scuffs in the cylinder, professionals advise to remove the muffler and assess their condition through the outlet window.

Features of the Chinese chainsaw

Before you figure out how to adjust a Chinese chainsaw, set it up, fix it and make it work correctly, you need to consider the design of the tool. Basically, Chinese-made models have:

  • 2-stroke carburetor type engine;
  • one air cooling system;
  • one cylinder of different volume.

Please note that often the chainsaw fails due to contaminated air entering the engine. Ideally, there should be a lot of dust in it, but operating the tool in such conditions is very rare. For this reason, the piston group can wear out. To prevent this from happening, it is recommended to clean the air filter from time to time. Some chainsaws have a special air pre-purification system for this.

Let’s go back to the design of the chainsaw. How does the engine start? For this, a starter system is provided, which can be improved for easy starting with the following details:

  • a special booster pump, which is called a primer;
  • steel spring, scrolling the crankshaft as sharply as possible;
  • a decompression valve connecting the cylinder to the atmosphere, regulating the pressure on its walls.

Additionally, depending on the model of the power unit, it can be equipped with different vibration damping systems, saw sets and lubrication systems.

Chainsaw piston group

The dimensions of the cylinder-piston group are determined primarily by the diameter of the piston made of heat-resistant aluminum alloy. Regardless of the model, the CPG of the chainsaw consists of a cylinder, a piston, a retaining pin and two retainers.

Chainsaw cylinder mirror

When buying a piston chainsaw, you should pay attention to the inner surface of the cylinder, which must be polished and have a glossy shine. In the presence of damage, scratches, experts do not recommend installing such a cylinder.

In order to increase compression in the working unit and, as a result, increase power, many manufacturers install two piston rings each. Chainsaw compression rings made of special cast iron adhere tightly to the cylinder, which ensures the tightness of the combustion chamber.

disassembly of the Chinese (Gypsy) chainsaw. Disassemble the chainsaw casually.

Defective ignition system

When a Chinese chainsaw stalls, inspect the spark plug. If it is completely dry, then this indicates that no fuel has entered the cylinder, which means that the cause of the malfunctioning of the tool must be looked for in another unit. If the candle is filled with oil, then you need to adjust the carburetor.

In addition, you need to thoroughly clean the spark plug, shut off the fuel blend supply, ventilate the chamber after removing traces of fuel, and then start the starter system. When the plug is installed in place, check the engine.

If you notice black carbon deposits, change the oil to a quality one or adjust the ratio of consumables. In this case, the candle is also cleaned (in some cases, a needle or awl will be needed), as well as its cleaning with the electrode skin.

Remember to set the electrode gap correctly when reinstalling the spark plug. Optimal width. 0.5 millimeters.

Important! In some cases, a new candle is needed, but first check for a spark using a method convenient for you.

Difficult replacement of a piston on a Chinese chainsaw Photo report

How to repair a chainsaw cylinder block?

For restoration, the master completely disassembles the motor and examines its working parts. Measurements are made that allow you to accurately assess the condition of the equipment and understand what repair procedures need to be performed. During overhaul, it is possible to bore parts if they are made of suitable materials.

Also, the recovery process includes other stages:

  • evaluation of the efficiency of the piston stroke, measurement of the generated compression in the working chamber;
  • checking the integrity of the equipment, searching for mechanical damage, scratches;
  • analysis of the condition of the piston fasteners, elimination of backlash and other problems;
  • checking other equipment that affects the operation of the piston group.

In order for the restoration of the chainsaw cylinder to be successful, the master conducts a series of checks after assembling the equipment

It is important that the power corresponds to the factory parameters, and during idle work and under load, the saw demonstrates stable rpm. Only after such checks can the equipment repair be considered complete.

Why motor parts break?

Breakdowns can be planned and emergency. The planned failure depends on the manufacturer, the materials of the group, the intensity of operation. The saw resource is usually calculated in hours. After working out the prescribed number of engine hours, the tool should be returned for repair to prevent the engine.

  • operation at increased loads, incomparable with the power of the tool;
  • lack of normal maintenance, which leads to dry operation of the motor and increased wear;
  • the use of low-quality fuel, which does not provide stable engine operation;
  • the large age of the saw, despite the low intensity of use.

Each start of the tool puts a certain stress on the piston and cylinder. Therefore, the resource of the device also depends on the number of starts. If you notice extraneous sounds from the motor, a decrease in power, an increase in consumption, it’s time to send the equipment for preventive repair to a service center.

How to increase the life of your chainsaw

You need to have a couple of tires and at least four chains in reserve. For a uniform wear process, the chain must be turned 180 ° after three hours of operation, after the same period of time, the chain must be replaced with another.

See also  How To Spin A Clutch On A Chainsaw

Timely cleaning of the tool ensures that the various holes are not clogged, which can lead to difficulty or even stop the flow of the fuel mixture, which will affect the working condition of the chainsaw.

If you are not confident in your abilities and are afraid to spoil the unit, then it is better to contact the professionals. They, by virtue of their experience, will always be able to correctly diagnose the problem and qualitatively fix the problems in your chainsaw.

How to properly run a chainsaw. the main threats

What, in fact, are the problems of many councils. Let’s figure it out in order.

P / p No. Meeting council Arguments for” Arguments against”
one The chainsaw must be run in at idle speed. Lowest idle. The most harmful advice I come across. A great way to kill a cylinder-piston group. Idling, even in cars, is allowed only for a short time: in this mode, the fuel burns out in a suboptimal proportion, the ability to lubricate surfaces sharply deteriorates, heat dissipation deteriorates sharply, carbon deposits appear, and seizures occur in long-term operation.
2 For the chainsaw, you need to prepare a special mixture of oil and gasoline. In a special proportion (some sites write. more oil, some. more gasoline). Arguments “For” are offered by both. What exactly to stop at is up to the one who listens to the advice of “experts”. Deviation from the instructions of the instructions developed by the manufacturer entails inevitable problems either from oil starvation or from an overabundance of lubricant. In either case, nothing good will come of it.
3 It is necessary to carefully study the instructions, prepare a mixture, pour oil into a container for lubricating the chain and work carefully. “For”. because it is recommended by the manufacturer. There are no arguments against. But why do many sites chew on this banality for a dozen paragraphs? To make the article voluminous?
four Using the adjusting screw “H” you need to lower the minimum speed of the chainsaw and make the mixture richer. At low revs, the lubricity of the surfaces is improved. This is recommended by the “leading saw manufacturers”. It’s a lie. No manufacturer will recommend pouring oil into their saw, thereby trying to shift the imperfection of their own production onto the shoulders of the consumer.

There are other options for advice. Do not list everything.

How to put the piston on a chainsaw correctly

The work on replacing the piston for most models of modern chainsaws is carried out according to the following algorithm:

  • Top and side covers are removed.
  • Unscrew the candle.
  • The handle is removed from the shock absorbers and the handle is detached from the body.
  • The leading sprocket and starter are removed.
  • A piston stopper is installed in the spark plug hole and the nut that fixes the flywheel and clutch is unscrewed.
  • The flywheel, the clutch, the worm drive of the oil pump, located immediately behind the clutch mechanism, is removed.
  • The screws securing the carburetor and air filter are loosened, after which these units are removed together with the engine control lever.
  • The ignition coil is removed, as well as the muffler.
  • The saw is turned upside down and, by unscrewing the screws fastening to the body, the engine is disconnected.
  • The pallet is unrolled and the piston is removed.
  • Since the piston is removed only together with the crankshaft, it is necessary to remove the circlip to disconnect it.
  • The old piston is replaced with a new one, but as carefully as possible. This is due to the high fragility of the compression rings.
  • The crankcase is put in place, and a sealant is used instead of a gasket.

All subsequent actions are carried out according to the reverse algorithm of disassembly.

Chainsaw does not idle

In this case, you should start looking for a malfunction with the filter elements. For the most part, it is due to the decrease in the throughput of the air and gasoline filters that the idle speed begins to “float”.

If everything is in order with the filters, then it is necessary to check the components of the gas supply system, and also to make sure that there is no spontaneous change in the carburetor settings.

Gasoline does not flow into the cylinder of the chainsaw

There are several reasons why the fuel mixture stopped flowing into the cylinder:

  • Clogged air filter.
  • Carburetor settings went off.
  • The carburetor membrane is no longer integral.
  • The channels through which gasoline is transported are clogged.

Recoil when starting the chainsaw

For the most part, recoil at the moment of starting signals the clamping of the decompressor. If the instrument is not equipped with a decompressor, then, most likely, the ignition system is out of order.

Fuel system

Fuel system malfunctions are also quite often the main reason that prevents a chainsaw from working as efficiently as possible. First of all, you need to check the quality of the fuel mixture.

Some owners prefer to use a non-recommended brand of gasoline, but alcohol-based solutions or add more oil than is required.

Necessary skills and tools for repair

Most of the malfunctions of gasoline chain saws can be fixed by hand. True, this requires an understanding of the chainsaw device and how the nodes function among themselves. As for the tool, most often you need:

  • screwdrivers (slotted and power);
  • the combination wrench included in the kit or conventional wrenches with different head sizes.

Chainsaw loses power under load

If in the process of work the saw power disappeared somewhere, then the problem should be looked for in the following places:

  • In the muffler. He, as you already understood, tends to clog.
  • Clogged fuel filter.
  • In a poorly functioning fuel pump.

Fuel supply system repair

Fuel may not enter the cylinder for the following reasons:

  • Dirty fuel filter. Remove the fuel hose and check how the fuel flows. If the jet is weak, the filter may need to be cleaned. It is taken out through the filler hole of the fuel tank and cleaned; in case of severe contamination, it is replaced with a new one. As a preventive measure, it is recommended to replace the fuel filter every three months.
  • Clogged breather (holes in the fuel tank cap). Check also by disconnecting the hose, in case of blockage, clean with a needle.
  • Lack or insufficient amount of fuel. There may be several reasons for the malfunction. The first reason is a clogged air filter. Air ceases to flow into the carburetor in the required amount, in this regard, due to a too rich fuel mixture, engine operation is disrupted. The contaminated filter is carefully removed, cleaned and washed in water, then dried and reinstalled.

Another reason is improper adjustment of the carburetor. Adjustment is made with three screws.

Timely replacement of the fuel filter ensures full fuel supply

The fuel hose and choke actuator must fit snugly against the fittings

See also  How to Clean a Breather In a Chainsaw

The throttle lever cable must be in place

During work, you must use the instructions, otherwise you can only make it worse.

And the last reason is a violation of the integrity of the membrane or clogging of the carburetor channels.

To repair the carburetor yourself, you need to get acquainted with all its parts.

All parts must be clean, dry and in good condition.

Dismantling and cleaning the muffler

If the engine works fine at low speeds, and at high speeds it starts to stall, the reason may lie in the spark arrester of the muffler, clogged with combustion products.

  • remove the muffler;
  • disassemble (there are also non-separable models);
  • remove carbon deposits using detergents;
  • dry with a hairdryer;
  • put in place.

Dry cleaning is unacceptable, as the soot contains carcinogens, the inhalation of which is hazardous to health. After removing the muffler, the outlet is closed with a clean cloth.

Interruptions in the operation of the chainsaw signal a possible clogging of the muffler

To avoid clogging of the muffler, it is necessary to monitor the composition of the fuel mixture. The amount of oil should not exceed the standards recommended by the manufacturer. Poor oil quality also negatively affects engine performance.

Do-it-yourself chainsaw repair: analysis of major breakdowns and methods for their elimination

It would seem, why does a chainsaw need a summer resident who grows vegetables and fruits, or the owner of a country house who has a small garden and several flower beds? The question disappears when there is a desire to build a bathhouse, update a greenhouse, knock down an old business, or just make a bench for relaxation. Unfortunately, any mechanism periodically needs prophylaxis and replacement of spare parts, and for this you need to be well versed in the device of the product, in addition, repairing the chainsaw with your own hands will save time and money.

Assessment of the state of the cylinder-piston group

Often the engine will not start or run at full capacity due to low cylinder pressure. It can be caused by piston or cylinder wear, piston ring sinking, bearing wear. You can partially examine the state of the cylinder-piston group (CPG) by removing the muffler and looking into the opened hole.

A compressor placed in the spark plug hole will help to measure the compression in the engine. according to the measurement results, you can also talk about the state of the CPG. Accurate data is obtained only after complete disassembly of the mechanism. If the piston is chipped or scratched, it must be replaced. The piston ring must be clean, free of carbon deposits, and be exactly in its place.

Piston and crank mechanism wear is considered a serious problem.

According to the results of measuring the compression, one can judge the condition of the parts of the CPG

Checking the ignition system

The first thing to do if a chainsaw breaks down is to inspect the spark plug by disconnecting the wire and carefully unscrewing it with a special key.

The components of the chainsaw ignition system: 1. flywheel with magnets, 2. ignition module, 3. spark plug, 4. high voltage wire

Unscrew the spark plug to check its condition.

Her appearance says a lot:

  • Dry. Most likely, the fuel mixture does not enter the cylinder. It’s not about the ignition system, so the plug is screwed back.
  • Strongly splashed with fuel. The reason for the excess fuel mixture lies either in a violation of the starting rules, or in an incorrect adjustment of the carburetor. The spark plug is carefully wiped, shut off the fuel supply and turn on the starter. to remove excess fuel and ventilate the combustion chamber. Then the candle is placed in place and the mechanism is started again.
  • Covered with black carbon. This may indicate the use of low-quality oil, an incorrectly adjusted carburetor, or an incorrectly calculated gasoline to oil ratio. The candle should be washed, cleaned of carbon deposits with a sharp object (awl or needle), wipe the electrodes with a sandpaper and put in place.

When checking the candle, you need to pay attention to the gap between the electrodes: from 0.5 to 0.65 mm is considered normal. A damaged or worn gasket must be replaced.

A large amount of black carbon on the spark plug indicates a malfunction of the engine.

Best Chinese Clone Chainsaw

To be sure, you should also check for a spark. To do this, put the ignition cable on the spark plug, connect the plug nut and the cylinder with pliers, start the starter and watch for the spark. If it is missing, the plug must be replaced. If the new spark plug also does not emit sparks, the problem is in the high-voltage wire or in the broken connection with the spark plug.

Chainsaw structural components

All chainsaws are similar in structure, regardless of whether they are European (ECHO, Stihl, Husqvarna) or domestic (Kedr, Ural). The main elements are located inside the body. the fuel tank and the engine, and outside the starter, the handle, the saw part (tire) with the chain. A sharp jerk of the cable starts the engine, and that one. the saw blade.

To begin with, we suggest that you familiarize yourself with the video clips that show how the chainsaw works and how it works:

From time to time, the saw malfunctions, which require disassembly to eliminate. What can happen to such a simple mechanism as a chainsaw? At least the following:

  • Stops to start;
  • Starts up, but soon stops;
  • Ceases to function in the cut;
  • Loses its power;

Most of the malfunctions are associated either with interruptions in the operation of the engine (fuel supply system, exhaust system, ignition, cylinder-piston part), or with malfunctions of other systems and assemblies (clutch, chain brake, tire, lubrication system). Consider the most common breakdowns and techniques for their elimination.

A serviceable chainsaw starts with one jerk and does not fail in the cut

Repairing the chain lubrication system

Let’s consider three main faults:

  • Oil leakage. Check that the pipes are tightly connected to the pump unions and that they are not cracked. Problem tubes are sealed with sealant or replaced.
  • Insufficient oil supply. Most likely, the lubrication channels are clogged.
  • Cracks in the oil pump housing. Part needs to be replaced.

Here’s how to diagnose the lubrication system:

Adjusting the chain brake

The chain brake often does not work due to clogging of grease or sawdust in the brake band and the space under the cover. All parts should be cleaned from blockages. Perhaps the tape is simply worn out, then it needs to be replaced.

The chain brake is restored by mechanical cleaning

Some parts of a chainsaw will wear out faster than others. These include the drive sprocket, tire, chain, anti-vibration elements. For quick replacement, it is best to always have spare parts on hand Chain sharpening should not be neglected.