The CV joint, the half-axle, the half-shaft, the axle, or even the drive shaft are some of the many names of this mechanical part. It is a very important part in a motor vehicle, but it is also, in fact, a very simple mechanism. Let’s demystify this mechanical assembly.
First thing first, let’s agree on a name. In reality, we are talking about a half-wheel axle. A few joint variants are used in the assembly of a half-axle. Two mechanical principles are the most often used: the universal joints and the constant velocity joints.
The universal joint (U-joint)
The universal joint is extremely simple and is an excellent economical choice. The Italian inventor M. Cardano perfected this technique to couple two rotating shafts that are not aligned or when the angular positions relative to each other vary. In the ATV industry, it is mainly used on drive shafts and more rarely on half-axles.
Composed of a cross-section and yokes that are very economical to replace, this mechanism also has a downside. Its operation results from a non-linearity of rotation. To counter this phenomenon, a second U-joint must be installed on the same shaft, at the same angle, and synchronized by a quarter turn. Another dark facet is its vulnerability to water which will disintegrate it.
Example of non-linearity of the universal joint
The constant velocity joint (CV joint)
The constant velocity joint is a much more advanced mechanism. Its linearity is almost perfect, which results in smoother operation. As it is more complex, it is also much more expensive. Its design requires grease to lubricate it as well as to dissipate heat. A simple intrusion of water or sand into the assembly will contaminate the grease and inflict fatal punishment on the joint. As it is protected by a flexible bellow or boot, you can easily guess the importance of it being kept in good condition.
Periodic check of your half-axle boots
A simple visual inspection of the CV joint boots can tell you if you need to take action.
The presence of grease outside the boot indicates that immediate repair is needed. Traces of wear or cracks on the bellows are signs of repair intervention in a near future.
Choice of replacement boots
There are four choices of replacement CV boots on the market. That of the manufacturer of your ATV (OEM), the replacement “jobber” boot (aftermarket), the universal boot, and the replacement kit sold in two parts to be bonded together.
The latter is a real joke and I don’t recommend it. This replacement boot is split into two parts which must be assembled around the constant velocity joint and then bonded with glue. Cleanliness and very good dexterity are a must in this case. Repairing a CV boot with this kit is, indeed, really not as easy as it seems.
The third solution, the universal boot, can be interesting. This bellow does not require disassembly of the constant velocity joints. You have to stretch the boot and pass it over the joint. The boot composition is usually very flexible, but is also more fragile to the impact of branches and other objects encountered on the trails
The OEM and aftermarket replacement boots are, in my opinion, the best choices.
Those are the ones I recommend.
Replacement boot assembly
Replacing a half-axle boot
ATV used: CFMoto CForce 1000
Required tools
Removal of the wheel and disassembly of the brake caliper will be necessary. Unscrew the nut from the end of the half axle. Remove the retaining bolts from the ball joint suspension links on the steering knuckle. Release the assembly and set aside the knuckle.
Remove the half axle from the differential by pulling it firmly. It may be necessary to use a lever between the differential and the half-axle. Take care not to damage the differential seal.
Remove the clamps from the boot to be replaced using sharp wire cutters. Cut the old boot and set it aside. Inspect the grease in the CV joint. If the grease is not contaminated with water, sand, or dust, that is good news: the CV joint may still be in good condition.
If, on the other hand, the grease is discolored or contaminated, the joint is likely damaged. In other words, even if the boot is replaced, a premature CV joint failure is to be expected.
To separate the CV joint from the half-axle, it will be necessary to use a hammer to hit it with a few light strokes. Use a brass punch and strike only in the central part near the half-axle. Note its installation position, it should not be reversed. Once the parts are separated, remove as much of the old grease as possible. Inspect the condition of the CV joint. If there are scratches or traces of abrasion, unfortunately, the joint will have to be replaced.
Damaged CV joint
Reassembly of the CV joint
First, put the small clamp on the half-axle. Then slip the CV boot. Pour some of the grease supplied with the replacement boot onto the constant velocity joint. Now reinstall the joint on the half axle. Make sure that it is properly locked in place.
Pour the rest of the grease into the boot and put it in place over the CV joint. Install both clamps and tighten them using the boot clamp pliers.
CV Boot clamp pliers
Now you just have to reinstall the half-axle by reversing the procedure. Position the C-lock in the center of the half-axle, this will facilitate its insertion into the differential. If some oil has leaked out of the differential during repair, simply fill up the oil level. Make sure to respect the tightening torque of the wheel bearing nut.
In conclusion, a CV boot repair is a relatively simple operation. If there is any doubt as to the condition of your CV joint, it is possible to get a replacement unit without replacing the whole half-axle. However, in most cases, the cost of both parts (boot and CV joint), will exceed that of a full replacement half-axle assembly. Check the two options.
Your CV boot is the most vulnerable part of your axle.
The soft rubber boot seals great against water, dust, and debris without compromising the full flexibility of your CV joint. But sticks, rocks, or even improper installation can lead to tears. A torn boot leads to lost grease, and lost grease leads to a broken axle. That’s why it’s so important to know how to change the CV boot on your Polaris Ranger.
It’s a cheap fix that doesn’t take too long. Do it right by following these 10 steps, and you’ll save a bundle of cash.
Materials Needed to Replace a CV BootChanging a boot is relatively easy, and with a little practice, you should be able to do it in thirty minutes or so.
And that’s how you change the CV boot on your Polaris Ranger! Just reinstall your axle and suspension and you’re ready to ride!
But WAIT, there’s more.
Yes, you’re installed and ready to ride. But it’s important to keep up with routine maintenance so you’re not having to pull some big bills out of your wallet in a couple of weeks.
Inspect Your CV Boots FrequentlyThe rule of thumb is to check your CV boots for tears before and after every ride. It’s easier to spot dust and dirt sticking to the grease that’s leaking out of your joint rather than seeing the tear itself.
When you find a tear, pick up a Polaris Ranger CV boot repair kit and fix it ASAP.
There’s no reason to put off replacing a torn boot. It’s a small and cheap fix (SuperATV sells them for $25-$30) that can quickly turn into a more expensive fix if left unchecked. A torn boot can let water and dirt into the CV. If you keep riding on it, your CV will break. As soon as you see a tear in a boot, replace it!
In this article, we'll cover the maintenance features of 125cc 4-stroke gasoline engine ATVs for kids and teens. see the MOTAX family, using the MOTAX T-REX SUPER LUX ATV as an example.
To change the engine oil you will need:
1.
A container for draining used oil (can be made from an old plastic canister by cutting off the side).
2. Four-stroke ATV engine oil (we recommend using oil of the MOTUL line).
Please note that it is not permissible to use oil intended for automobile engines, since the gearshift mechanism and clutch are in the same oil bath with the engine and for their proper operation a certain set of additives is required, which are not found in automobile oil.
3. 17mm socket wrench or wrench.
The 125cc MOTAX T-REX SUPER LUX power pack has a 0.7L oil fill tank.
The ATV engine must be warmed up to operating temperature before changing the oil. Since the oil sump of the gearbox and engine is combined, it is recommended to ride the ATV forward and in reverse gear. This must be done so that the oil becomes more liquid and fluid, and the wear products that may have been deposited on the inner walls of the crankcase and the mechanism become suspended and mixed with the oil.
Don't be alarmed if the oil you drained from the ATV's power unit is dark in color. During operation, the oil darkens, which indicates that it works and protects the engine from wear.
In order to drain the oil, it is necessary to unscrew the drain plug located at the very bottom of the engine crankcase. Do not confuse this plug with the chain tensioner bolt, which is installed next to it, in the left side cover of the motor.
It must not be unscrewed during this operation.
Unscrew the drain plug (in our case, the drain plug is green, see the photo above), having previously moved a container under the ATV to drain the used oil. Let the oil drain completely.
While the oil is draining, unscrew the oil dipstick, which simultaneously functions as an oil filler plug and leave it in place without removing it
below
In this case, the used oil will drain off without residue.
After the old oil is completely drained, screw back the oil drain plug
Be careful not to use too much force when tightening the plug, as this could damage the threads in the aluminum crankcase of the ATV engine.
New oil can now be added. The ATV's engine is equipped with both a dipstick and a viewing window on the bottom of the engine.
It is better to focus on the viewing window. The oil level should be approximately at the top of the oil.
The engine is splash lubricated, too much oil is better than too little. The ATV engine is equipped with a breather at the top, the excess will come out through it without damaging the gaskets and seals. Of course, you should not get involved in overflowing oil into the engine either. Oil should be poured through the hole in which the oil dipstick is installed
After the oil has been filled, screw the dipstick back into place. Start the engine and let it idle for about 30 seconds. Stop the engine, let the ATV stand still on level ground for about 30 seconds. If the oil level has dropped, the oil must be topped up.
If the level is correct, you can proceed to the next stage of maintenance work.
Almost all 2017-2019 ATVs a serviceable foam rubber filter is installed for cleaning the air entering the carburetor.
If the filter element is intact, not torn, then it is allowed to simply rinse it without changing it to a new one.
The first thing to do is disconnect the filter from the ATV carburetor.
Filter, worm-drive clamp, Phillips screwdriver required for removal
Loosen the clamp and tighten the air filter
The MOTAX uses two types of filters. Foam rubber, as in the photo above and a filter with a metal mesh. The principle of their maintenance is similar, the used ATV filter must be washed and then impregnated with a special oil, such as MOTUL.
To wash the filter element, you can use both special liquids (for cleaning carburetors) and ordinary liquids - gasoline, kerosene, diesel fuel, water from Fairy for washing dishes.
The filter must be washed carefully to avoid damaging the filter element.
After the filter has been washed, it must be dried and soaked in oil. Oil penetrates through the pores of the filter element, lingering in them, thereby helping to trap the smallest particles of dust and dirt.
It is necessary to impregnate the filter evenly, without gaps. Any, even the smallest gap, is a weak point through which dirt and dust will surely get into the engine, subjecting it to premature wear
After oil is applied to the filter, you need to take a regular plastic bag, put it on the filter and rub the applied oil on the surface of the filter element.
The oil is now evenly distributed over the surface of the filter element. No gaps or voids.
Reinstall the filter, leaving the filter bag in place for now to avoid getting your hands dirty. Before installation, it is recommended to lubricate the rubber seat with engine oil
Tighten the clamp with a screwdriver
Remove the bag from the filter. Done - the air filter has been serviced, you can proceed to the next stage of the ATV maintenance work.
NGK C7HSA Spark Plug
Requires 16 Spark Plug to ignite mixture on MOTAX ATVs with 125cc engine
MOTAX T - REX SUPER LUX0003 Remove the spark plug cap from the spark plug, put the cap on the spark plug and turn it counterclockwise. Install the new spark plug in reverse order. We tighten the candle with sufficient force, but at the same time carefully so as not to break the threads in the head of the engine block. The applied force on the key should be smooth and moderate. After the spark plug has been replaced, it's time to service the ATV's suspension. The MOTAX ATV's suspension joints are equipped with grease fittings that are designed to force grease into the ball joint using a special grease gun. The same grease fittings are provided to lubricate the steering shaft and rear swingarm ATV's suspension requires a special grease gun and grease for the pivot joints. Any type of grease gun can be used, but we find the most convenient gun with a flexible nose, designed to work with hard-to-reach suspension grease points MOTUL Tech Grease 300 is an excellent lubricant.0003 Once the syringe is ready for use, put its head on the grease fitting of the suspension assembly to be lubricated injected with a syringe can damage them. Wipe off excess grease with a rag or rag and put a protective cap on the grease fitting All suspension units equipped with grease fittings are sprayed in this way. To lubricate the steering shaft, put the syringe head on the grease fitting it is equipped with. passed through the entire node and is no longer required. To service the ATV's drive chain, jack up the rear axle of the ATV so that the wheels turn freely in the air, but the ATV maintains a stable position. mud. For this work, you can use the special tool MOTUL or regular gasoline and a brush. It is better to install a pan under the ATV so that the remnants of the old grease and cleaning agent flow into it. The chain should be thoroughly rinsed from the inside and the outside by turning the ATV wheel and thereby shifting it Apply new lubricant only on a dry, clean surface, so after washing the chain should be wiped with a rag or rag Please note that the ATV during the performance of these works, for safety reasons, it must be de-energized. Be careful not to get your hands between the drive chain and the star. ATV chain can be lubricated with any lubricant specifically designed for this purpose. Chain lubricant is sold in aerosol cans. We recommend using MOTUL C3 off Road Lubrication should be applied on the inside and outside of the chain, on both rows of links. A chain tensioner is installed on MOTAX ATVs. This assembly is flushed and lubricated during maintenance along with the chain Pull the roller down and loosen the chain with one hand, check for slack with the other by pressing the chain from the bottom up If the chain slack is more than 1. To adjust the tension of the chain, loosen the rear bottom bracket at the top and bottom using the 17 and 14 wrenches. Next, tighten the chain with tensioners. Chain tensioners are installed on both sides of the carriage and it is necessary to adjust the chain tension both simultaneously and evenly. Otherwise, the axle of the ATV will be skewed That is, if the nut was tightened three turns on one tensioner, then the same must be done on the second tensioner. Retract the roller and check the chain tension. After the chain tension is adjusted, tighten the nuts securing the rear carriage of the ATV. Pay special attention to the position of the speed sensor, which is mounted on one of the bottom bracket bolts. Please note that the sensor must be installed flush with the holes in the driven star into which the magnets are inserted. These magnets during movement transmit signals to the sensor, which converts them and transmits them to the dashboard of the ATV From time to time the quad is acting up and not behaving as you would like. Nothing beautiful lasts forever, right? One of the most common faults you may encounter is the ATV suddenly pulling to the left or right. If you are lucky, your problem may have a simple solution) The most common problem that causes the ATV to pull to one side is the difference in rolling resistance due to different tire pressures. Also, the problem may be associated with natural wear or damage to various components of the chassis of the ATV and, as a result, a violation of the angle of the wheels. So how do you determine what is causing problems when riding an ATV? As you probably already understood, there can be several reasons. To understand why an ATV wants to pull off the road and dive into a ditch when you really don't want to, you need to do a number of checks. In my experience, the most common cause, and by far the easiest problem to check and fix, is uneven ATV tire pressures. A flat tire has a larger area of contact with the road surface than a normally inflated wheel, as a result of which the friction force, and hence the rolling resistance force, applied to such a wheel will be higher. The wheel will roll more slowly. The opposite wheel will run ahead and try to turn the ATV around the slow wheel. That is, if the ATV pulls, for example, to the left side, most likely, the fact is that the left wheel is lowered. To solve this problem, you need to equalize the air pressure in the ATV tires. At the same time, you should be aware that due to the design features and weight distribution of the ATV, the tire pressure on the front and rear axles may differ. Check with a good tire pressure sensor. Most manufacturers are equipped with ATVs with a set of tools and a sensor for checking air pressure in wheels, for example, ATVs Yacota SELA 200 , Yacota SELA 150 , Yacota Cabo 200024, Yacota Cabo 20023 , , MOTAX 200 , MOTAX GRIZLIK and MOTAX RAPTOR . ATVs MOTAX and YACOTA have these sensors in the standard tool kit. The air pressure should be checked in both the front and rear tires. True, uneven pressure in the rear tires, most likely, will not be the reason for the withdrawal of the ATV from a straight path. Different pressure in the rear tires can provoke another malfunction - premature wear of the rear differential, due to the increased load on it. But this is a story for a separate review. I always keep this inexpensive instrument in my tool kit, its accuracy is good enough to use. Also make sure that the maximum tire pressure is not exceeded. To check if the front wheel diameters are the same, you can do a simple check: place the ATV on a level surface and use chalk to make a mark on the sidewall of each front tire at the lowest point. Wheels must be pointing straight ahead, gear lever in neutral position. Roll the ATV forward until one of the wheels has made two or three revolutions and the mark you just made is back to the very bottom, to its original position. Look at the mark on the opposite tire. Ideally, it should also be at the very bottom. If this is not the case, the wheel circumferences do not match. If the reason for the ATV pulling to the side lies in the difference in wheel circumference, then when driving to the right, the right tire should have a smaller circumference, and when driving to the left, the left one. The circumference of the wheels can differ not only due to uneven wear, but also due to the difference in air pressure in the tires. The wheel is like a balloon, the higher the pressure, the larger its diameter and vice versa. For this operation, you need to lift the ATV, put it steadily on the supports so that all the wheels are in a suspended state. It is very convenient to use a motorcycle stand to lift the ATV. If you do not have them yet, and you plan to service the ATV yourself, I recommend purchasing them. They are relatively inexpensive. Tackles will greatly simplify the ATV maintenance process. Check that there is no excessive play in the ATV suspension and steering joints. Start with the tie rods and steering rack. This operation is more convenient to carry out with an assistant. Have an assistant move the ATV handlebars to the right and left, often and with a small range of motion. And you, in turn, keep your hand on the swivel, which are subject to verification. Check the steering tips and tie rods one by one. You will feel the excess play in the hinge with your hand. If the ATV steering wheel has excessive play, but the tie rod and steering tip are in order, then the steering rack itself or the steering shaft bushing may have play, which can also be checked by hand. The steering column bushing usually wears out over time. Tighten any loose bolts and replace worn parts. Worn parts can break soon, so replacing them won't be a waste of money, even if their wear isn't the reason your ATV pulls to one side. In addition, the wheel bearings must be checked for excessive play. To do this, have a helper grab the top and bottom of the wheel and shake it while you check for play in the ball joints and wheel bearings. Check how easy the wheels turn. The wheels should rotate freely, without noise and crackling. The presence of noise indicates wear on the hub bearing. And the tight running of the wheel is about bearing wear or souring of the brake pads. As we said, if one of the ATV's wheels is spinning at a slower speed than the other wheel, the ATV will pull towards the slow wheel. If necessary, replace the bearings and service the front brake calipers. Sometimes the caliper is easy enough to clean, and sometimes you can’t do without replacing the brake cylinders or the caliper bracket itself. Control check three: checking the running gear for geometry violations. If you use the ATV for active riding or sports, then it is possible that you have bent some part of the suspension on the next jump. ATV front suspension A-arms are especially prone to damage if you hit a stump or rock while riding. "Fast-growing" trees suddenly appearing in front of the ATV as you drive, a common story!) A-arms are designed to absorb heavy suspension shocks and, through their integrity, retain more expensive and hard-to-find ATV parts that are more difficult, more expensive or even impossible to repair, for example, an ATV frame.
In order to control the supply of oil to the lubricated unit, we recommend that you keep your fingers free from the syringe on the rubber boot. Thus, it will be possible to feel when the lubricant passes through the swivel and its excess begins to come out. At this point, the injection of lubricant into the joint must be stopped 
To do this, you can use the same canister that was used to drain the used oil from the engine. 
5 cm, the chain tension must be adjusted. ATV » ATV pulls to the side? What malfunctions can provoke such behavior of the ATV and how to fix them.
Why is the ATV pulling to the side?
Let's take a look at some of the most common causes of ATV pulling to the side, and of course, here we'll talk about how to get rid of these problems. 
Although I don't have exact statistics to tell you which malfunction occurs most often, I still recommend that you start with what is easiest to check and fix before spending time and money on more unusual and potentially more complex searches. Control test one: ATV tire pressure check.
Let's look at what happens when ATV tires have different pressures. It is best to refer to the operating instructions, which must indicate the required air pressure in the wheels recommended by the manufacturer. The pressure in the wheels installed on the same axle of the ATV must be the same.
If there is no such device in your kit, I recommend that you definitely purchase it. A very slight difference in air pressure in the tires may well be the reason that the ATV pulls to the side when driving in a straight line.
ATV wheels can wear differently over time, resulting in the diameter of one wheel being different from the diameter of another wheel. This can also cause the ATV to pull to the side. 
Control check two: checking the wear of the tie rods, ball joints, bushings and bearings
The same goes for the ball joints on the tie rods.
Complete the work with suspension lubrication. The running gear of ATV brands YACOTA , MOTAX , AVANTIS is equipped with special grease fittings through which you can easily lubricate the desired suspension unit. We have already told, in one of the reviews, using the example of a gasoline 125 cc ATV MOTAX T-REX , about the features of maintenance of the ATV suspension. Regular maintenance of your ATV will definitely prolong its life. 
