Chainsaw DIY tire repair

In detail: do-it-yourself chainsaw tire repair from a real master for the site my.housecope.com.

A chainsaw is a very useful thing in the household. After all, it quickly and relatively easily solves a lot of problems of home construction, gardening and landscaping. Chainsaws are a rather capricious tool, but if handled correctly, they are an indispensable tool. Which has one weak point: the guide rail. It is she who accounts for most of the operational loads. And this means that knowing why tires fail more often than other parts of chainsaws and how to replace them correctly if necessary will help you more than once to save money and time during seasonal or project work with a tool.

3 Replacing the chainsaw tire and its fasteners
4 Replacing the tire and chain headset of the chainsaw with your own hands, video

The tire and its fastening elements are consumable parts. The wear of this assembly occurs both under work loads and as a result of improper operation. You will immediately determine the presence of faults in this area. The tire will not be able to provide normal tension, lubrication and smooth running of the chain, and its fastening - fixing the saw axis relative to the tool body.

It is not safe to operate a saw with a faulty tire. Therefore, at the first sign of a breakdown of the unit, you need to turn off the motor and find out what is wrong. Knowing the design features of the tire and its attachment to your chainsaw will help you to successfully eliminate the cause of the malfunction.

The bar determines the axis and length of the cut by guiding the chain. But the basis of the mechanism is still the fastening. It fits into the groove between the inner plate on the motor housing and the outer plate located on the chain guard. The busbar and the casing are fixed with a bolt connection. This part of the mount is called the "engine unit" and its shape and design depend on the model of the chainsaw. The tire mount and drive sprocket are covered with a separate cover.

Video (click to play).

Chainsaw bar mounting studs

The drive links of the saw chain fit into a guide groove on the edge of the bar and mesh with a drive sprocket connected to the PTO shaft. The bar can move when the fixing bolts are loosened. The chain tension can be adjusted manually or, as on professional chainsaws, automatically. Finally, a stop is located at the front of the bar mount. It serves to securely fix the cutting axis when the moving chain comes into contact with the tree.

Chainsaw drive sprocket version: with removable and stationary crown

A good tire should provide adequate chain tension. To check it, you need to release the chain brake and pull the chain by hand in the direction of its movement. If the chain does not move, then the attachment is too tight. It needs to be slightly released, and then again check the free movement of the chain.

Adjusting the chain tension with a wrench

The main parts of the tire are the body and the groove. The width of the latter is called the gap. The front of the guide bars is made of heavy-duty steel. The tire body is also hardened.

Currently, there are various types of saw bars on the market, which differ in:

body length and width;
the size of the gap;
the presence of a nozzle of increased strength on the front;
the presence and type of driven sprocket hidden in the front of the tire body.

Various types of saw bars

The shape of the shank and the location of the technological holes in the tires are standard for most amateur and professional chainsaws, but structurally they can be divided into open and closed. Obviously, the former are inferior to the reliability of attachment to the body of the latter, i.e. the busbar cover and bolt connection are subject to increased loads. You also need to monitor the integrity of the teeth of the sprocket - if it is blunt or chipped, it will quickly deteriorate the driving links of the chain.

Your chainsaw tire needs regular maintenance. After each session of work, its grooves must be cleaned of dirt and sawdust, otherwise the lubricant will not flow to the chain. The wear of the tire groove should be uniform, therefore it should be turned over from time to time. In addition, before starting work, always check for the presence of oil on the chain body and in the gap.

Checking the operation of the lubrication system

It is not recommended to use more than three chain sets with one bus. During operation, the gap, despite all the strength of the metal of the tire body, expands, which leads to the appearance of backlash during the movement of the chain and its sagging even with the extreme forward position of the tire.

The driven sprocket located at the front of the tire is lubricated separately. Oil does not get there, unlike the rest of the guide groove. It is poured into special holes in the front of the tire, and if there is no sprocket, it is applied to the toe of the tire.

Separate sprocket lubrication system

To replace the fastening elements, the bar and the chain set, it is necessary to disassemble the entire fastening mechanism. It will not hurt to prepare a rectangular piece of cloth or cardboard in advance, as well as free space on the table for disassembling the tool and temporarily placing the removed parts.

Chainsaw tire fastening diagram

Replacing the fasteners and tires of the chainsaw is necessary when:

Critical wear of the seat or shank elements.
Damage to the casing.
Failure to fix the fastening bolts.
Damage or deformation of the tire body.
Abrasion or breakage of the drive and driven sprocket teeth.
Damaged chain lubrication grooves.
Worn chain tensioner.
Wear of the groove and tire retainer.

That is why the guide bar and fasteners are consumable parts - only one universal wrench supplied with the tool is needed to replace them. And, of course, knowledge of the algorithm for disassembling, assembling and adjusting the mechanism.

Chainsaw with tire removed

To disassemble the tire mount, you should:

put the engine upright and, by unscrewing the corresponding nuts, remove the drive sprocket cover;
lift the bar by the front end and turn the chain clamping screw, freeing it from the groove of the bar;
pull the chain from below and, turning the clamping screw, release it from the groove;
remove the chain from the drive sprocket and pull it out from under the casing, then put it aside;
if there is damage or signs of wear, the casing and mounting gaskets should be replaced;
remove the chain bar to be repaired or replaced from the groove mount.

After that, the chain must be put on a new tire and the last one must be installed in the groove to be installed. Next, the headset is brought into engagement with the drive sprocket and closed with a lid. Just before starting work, do not forget to check the absence of slack in the chain and the quality of its tension.

If the new tire is attached and the headset is installed correctly, the chainsaw is ready for use again. By the way, just in case, you should make sure of this by sawing several thin branches.

Read also: DIY repair of water pumps

Perhaps, in your case, the ratio between gasoline and oil in the mixture is disturbed, the carburetor is not adjusted, or low-quality oil is used. Rinse the candle in gasoline, clean the carbon deposits with a needle or an awl, clean the electrodes with a fine sandpaper and reinstall. Even when repairing a goodluck chainsaw with your own hands, which consists in checking the spark plug, there is good reason to believe that the faults are in the fuel system, you need to check the spark plug for the presence of a spark.

If there is no spark, you just need to replace the spark plug. The reasons for the absence of a spark can also be hidden in a faulty ignition module or in violations of the gap between the flywheel magnetic circuit and it. The distance should be 0.2 millimeters.A gap violation is especially likely if you disassembled the saw before removing the ignition module and flywheel. The gap must be set using a gasket that is 0.2 mm thick, placed between the ignition module and the flywheel boss. The defective ignition module must be replaced.

If it has been established by inspection of the spark plug that no fuel enters the cylinder, all the reasons for this must be considered. In particular: non-flow of fuel from the tank due to the clogged hole in its lid, while a vacuum is created in the tank, which prevents fuel from flowing out; insufficient flow or non-flow of fuel from the carburetor into the cylinder; contamination of the fuel filter, which is installed in the tank.

Insufficient fuel supply or the absence of the correct ratio between air and fuel, which are mixed in the carburetor, occurs for the following reasons: due to an unregulated carburetor, clogged air filter, clogged filter mesh or carburetor channels.

Chainsaw repair, as a rule, is not complete without cleaning the air filter, since it becomes dirty quickly enough. When this happens, the ingress of air into the carburetor is reduced, at the outlet the fuel mixture is too rich, and this in turn disrupts the normal functioning of the engine. The dirty filter must be removed for cleaning very carefully so that dirt does not get into the carburetor from it. Clean the filter or wash in water and detergent, dry and reinstall.

Correct the misalignment of the carburetor by adjusting it. This can be done with three screws - minimum and maximum speed. Carry out the adjustment in strict accordance with the instructions for repairing the chainsaw, non-observance of which often leads to engine damage. Some chainsaw manufacturers leave one adjusting screw to exclude unwanted intervention by inexperienced users in the functioning of the carburetor.

If the carburetor adjustment did not help, it is recommended to clean the filter mesh and channels, and also check the membrane for integrity. The carburetor is one of the most complex chainsaw devices, therefore, it is necessary to start disassembling and cleaning it with an understanding of the responsibility of this operation. This unit consists of a large number of small parts that have the unpleasant feature of jumping out of their places unnoticed and getting lost irretrievably, so after disassembling this capricious device it may not be possible to assemble it.

The cause of a motor malfunction, especially if it functions normally at low speeds and stalls under load, is the clogging of the spark arrester of the muffler with combustion products, which prevents normal exhaust. In this case, do-it-yourself repair of a Husqvarna chainsaw consists of removing the muffler, if it is collapsible, then disassembling it, and wet cleaning the unit from carbon deposits using a detergent.

After washing, dry the non-separable muffler with a hairdryer. Remember that soot contains substances that are carcinogenic, and dry cleaning, after which they may be inhaled, is unacceptable. When removing the muffler, plug the engine outlet with a clean cloth.

The muffler can become clogged for the following reasons: due to the use of a fuel mixture with a large amount of oil (the oil level is recommended by the manufacturers), the use of low-quality oil or oil, which is not intended for two-stroke engines.

The most serious are damage to the cylinder-piston group of the chainsaw. This is the worn out piston and cylinder, scuffs and scratches on their surfaces, sinking in the piston ring grooves and their wear, as well as wear on the crankshaft bearings.In the usual way, these malfunctions provoke a drop in the pressure level in the cylinder and the impossibility of starting the engine in the future, or its inability to deliver full power.

There are several ways that help assess the condition of the cylinder-piston group. Remove the muffler and look out the window where you can see part of the side of the unit. Despite the limited overview, a general understanding of the CPG can be obtained.
Turn the crankshaft using an electric motor with a flexible shaft or a starter by hand, while monitoring the pressure on the pressure gauge.

For a workable chainsaw, the last indicator should be in the range of 0.8-0.9 MPa. With its fall, the power of the engine also decreases. At a pressure level of 5 atm, the engine can and will work, but at idle speed.It will be possible to accurately assess the state of the CPG only after repairing the saw-free parterre with your own hands, which consists in disassembling the engine - disconnecting the crankcase from the cylinder and removing the piston. If the latter has seizures, deep scratches or chips, it must be replaced. If the cylinder surface is damaged or worn out, there is a chance to bore it to the repair size. Low compression is caused by coking and piston ring wear. Serviceable rings are always clean from carbon deposits, sit loosely in the piston groove and press tightly against its inner surface.Rare do-it-yourself Ural chainsaw repair manuals do without mentioning the breakdowns of the chain lubrication system, which are quite common. They usually manifest themselves as insufficient or non-supply of lubricant to the chain and in the formation of oil leaks. If the chain is dry, first of all, it is necessary to inspect the channels through which the oil is supplied to the tire and clean them. Their clogging is not uncommon. Image - Chainsaw DIY tire repair

If there is a significant leakage of oil (a small level of leakage is considered normal), it is recommended to check the tightness of the connection to the pipe fittings of the pump. They can crack or fall off. In addition to smudges, a violation of the tightness of the oil line can also provoke insufficient lubrication of the chain. The pump will suck in air, which will definitely affect its performance. It is customary to eliminate such violations by sealing the tubes with a sealant or replacing them. The most serious malfunction of the lubrication system is cracks that form in the oil pump housing. It needs to be replaced in this case.

Some parts of the chainsaw, which are subject to natural wear and tear, must be replaced after a certain period of useful life. Their breakdown is a regularity and not at all a malfunction. Wearing parts include a tire, a chain, a drive sprocket, anti-vibration system units and others.

If you do not repair your husqvarna chainsaw with your own hands and replace wearing parts in time, then their excessive wear will affect other parts of the chainsaw in the most negative way. In particular, if the drive sprocket and tire are not changed in time, then the increased vibration will badly affect the crankshaft bearings. The limit for the depth of the sprocket teeth must be up to 0.5 millimeters.

Although sprockets in practice often operate until wear of 1 millimeter or more, without suspecting that this causes an increase in the loads on the crankshaft bearings, accelerated failure. When three or four chains are worn out, you need to change the tire directly, if its wear reaches its limit by this time.

Chainsaw bar wears especially in the areas where cutting occurs most often, usually on the underside of the guide bar. Any time the chain is changed, the bar must be flipped 180 degrees around the horizontal axis for even wear.

Now you know that you can troubleshoot a chainsaw with your own hands.To do this, you should always have a manual for the repair of chainsaws at hand. And in order to finally understand this difficult matter, we invite you to watch a video about repairing a chainsaw, which will help to consolidate all the acquired knowledge in practice.

DIY chainsaw repair

All chainsaw malfunctions can be divided into two main groups: engine problems with all its components and systems (ignition, fuel supply system, cylinder-piston group, exhaust system) and malfunctions of other components (chain brake, lubrication system, clutch, tire etc.).

the engine won't start;
starts, but stalls;
works unstable;
does not develop power, i.e. works normally at idle, but stalls under load.

When repairing a chainsaw with your own hands, it is necessary to act in an exclusionary way - to inspect alternately all the probable prerequisites for a malfunction, starting with those whose verification and elimination takes the least time (about the device and operation of a two-stroke motor, see here).

Ignition system... Almost all types of engine problems listed above can be caused by faulty ignition systems. Therefore, when they occur, it makes sense to start troubleshooting with a candle. This is all the more justified since the state of the latter can provide useful information about the operation of the fuel system. So, if a problem occurs, you need to unscrew the candle and inspect it.

The wire is disconnected and the candle is unscrewed with a special key.

If the plug is dry, this means that the problem is most likely not in the ignition system, but in not entering the cylinder. fuel mixture... You can wrap the spark plug back and start the fuel system. If the spark plug is heavily splashed with a fuel mixture, then there is an excess of it. This can occur from a misalignment of the carburetor or a violation of the starting rules. The spark plug is wiped and dried, the cylinder is drained by shutting off the fuel supply and operating with the starter to ventilate the combustion chamber and remove excess fuel. Then put the candle in place and repeat the start.

The presence of a large amount of black carbon also indicates a malfunction in the fuel system.

The ratio between oil and gasoline in the mixture may be disturbed, the carburetor is not adjusted, or poor-quality oil may be used. The candle is washed in gasoline, cleaned with a needle or an awl from carbon deposits, the electrodes are cleaned with a fine sandpaper and installed in place.

In all these cases, it will not be superfluous to check the gap between the spark plug electrodes. Depending on its brand, it should be in the range of 0.5-0.65 mm. It is also necessary to check the spark plug gasket. If it is worn out or damaged, the tightness of the combustion chamber may not be ensured, which leads to a decrease in compression in the cylinder and problems in the operation of the engine.

Even if, when checking the spark plug, there is good reason to believe that the problem is in the fuel system, you need to check the spark plug for the presence of a spark. If only to be sure that everything is in order with it. For this:

put the ignition cable on the spark plug;
using pliers with insulated handles, apply the thread or nut of the candle to the cylinder;
pull the starter handle and see if there is a spark or not.

If there is no spark, you just need to replace the spark plug. If the new spark plug does not have a spark either, you need to check the condition of the high-voltage wire for an open circuit and contact with the spark plug.

The reason for the absence of a spark may also lie in a faulty ignition module or a violation of the gap between it and the flywheel magnetic circuit. It should be 0.2 mm. A gap violation becomes especially likely if the saw was disassembled before the flywheel and ignition module were removed. The gap is set with a 0.2 mm spacer between the flywheel boss and the ignition module.The defective ignition module must be replaced.

Having checked the ignition system in this way and not finding a malfunction, you can go to the supply system fuel mixture.

Fuel supply system... If by inspection of the spark plug it was found that fuel does not enter the cylinder, all possible reasons for this need to be considered. This could be:

no fuel flow from the tank due to a clogged hole in its lid (breather), while a vacuum is created in the tank, which prevents fuel from flowing out;
contamination of the fuel filter installed in the tank;
non-admission or insufficient admission fuel mixture from the carburetor to the cylinder.

To diagnose the first two reasons, it is enough to disconnect the fuel hose from the carburetor and see if fuel is leaking from it or not. If it flows with a full stream, the breather and filter need not be checked, if it does not flow or flows weakly, we can assume that the cause of the malfunction has been found. The breather is cleaned with a needle. The fuel filter is removed through the filler opening of an empty fuel tank, with a wire hook, together with a suction hose from which the filter is disconnected and cleaned or replaced with a new one. Chainsaw manufacturers recommend changing the fuel filter every 3 months.