How an ATV Clutch Works: Operation and Maintenance


quad with clutch

The clutch system in your ATV is the main connection between your vehicle and the wheels’ controls. It’s an important constituent of the overall transmission system that doesn’t get much attention when everything works well. How does a clutch work?

An ATV clutch works by ensuring stability in the power generated from the ATV engine to work with a transmission. The mode of operation in a clutch will vary depending on whether it is a sheave clutch or a centrifugal clutch. It can also use a multi-plate clutch design.

The rest of the article will look at the different types of clutches you may find in an ATV and how they work.

Why Does an ATV Need a Clutch?

A clutch is an integral unit in any vehicle’s power transmission, and an ATV is no different. When your ATV is on, the engine spins all the time, but the wheels do not.

The clutch ensures smooth engagement between the spinning engine and the transmission, ensuring that there’s no slippage between them.

What Are the Types of Clutch ATVs?

There are three main types of clutch you can find in any ATV model today. They are the sheave clutch, centrifugal clutch, and multi-plate clutch.

Sheave ATV Clutch

These clutches are mostly used in ATV models fitted with automatic CVT (continuously variable transmissions) systems. They are built to ensure the engine is constantly running at the best RPM needed to generate the highest power possible at any speed level.

This system consists of a primary and secondary clutch. These are also known as the drive/driven clutch.

How Does It Work?

The ATV engine’s crankshaft is linked to the primary clutch, which is joined to the secondary clutch through the drive belt. Finally, the ATV’s secondary clutch is linked to its transmission.

The primary and secondary clutches have movable and stationary sheaves where the drive belt fits.

The moveable sheave is fitted with a spring for compression and some flyweights. The weights are useful because they help the stationary and movable sheaves to maintain an appropriate distance.

When your engine is running and the driveshaft spins, centrifugal sources move the flyweights and the stationary and movable sheaves around to force a gear change and deliver higher speeds when you need it.

Here’s a video showing the install of a sheave clutch:

Centrifugal ATV Clutch

The centrifugal ATV clutch gets its name from the fact that it relies on the centrifugal force generated while it is rotating to activate or deactivate the clutch system.

How Does It Work?

Different manufacturers have different designs and layouts for centrifugal clutches, but the operation mode is similar across the board.

The ATV engine’s crankshaft is hooked to the central or main drive shaft inside the clutch system. While the crankshaft rotates, the drive shaft spins with it. The entire clutch system is contained inside an external clutch drum linked to the ATV transmission.

A collection of springs linked to the ATV drive shaft nestles between the outer or exterior clutch drum and the central drive shaft. Some clutch shoes (weighted) are affixed to the other extreme of the springs.

These shoes don’t interact with the clutch drum’s inner side due to the tension delivered by the springs.

The ATV’s drive shaft spins both the shoes and the springs as the crankshaft spins. With an increase in the speed of rotation, the shoes’ centrifugal force also increases. The force pushes the shoes outward, so they can come in contact with the clutch drum’s inner face and bind against it.

As soon as the shoes come in contact with the ATV clutch drum, the drum will spin, providing drive or power from the ATV engine into the transmission and the rear wheels.

Here’s a video showing how a centrifugal clutch works:

Multi-Plate ATV Clutch

A multi-plate clutch is a popular option found in many ATV models. It receives power from an engine and channels it to the input shaft of the transmission. From here, the power moves to the rear wheels through the gearbox.

How Does It Work?

The crankshaft coming from the ATV engine is linked to a drive gear joined to the outer clutch basket. The clutch basket rotates as the crankshaft spins. Inside the outer basket, a clutch boss (a smaller inner basket) is linked to the ATV transmission.

A set of friction clutch plates (also known as clutch discs) separate the inner and outer baskets. A section of the plates is joined to the outer basket while some drive clutch plates hook up to the inner clutch basket.

The clutch plates are protected from the top by a set of springs and the pressure plate. The pressure plate is designed to hold down the clutch plates to ensure the friction plates are bound tightly to the drive plates for a clean lock.

As the crankshaft rotates the outer basket connected to it, the tightly locked clutch plates trigger rotation in the inner basket as well. The result is rotation in the ATV transmission input shaft, which drives the ATV’s gearbox and rear wheels.

Here’s a video showing the operation of a multi-plate clutch:

Maintenance for Your ATV Clutch

We’ve seen a peek into what happens under the hood with the main types of ATV clutches. The convoluted nature of the systems means that your clutch needs regular maintenance.

If you take your ATV to a maintenance shop, you’ll likely get clutch maintenance by default. However, if you’re doing the job on your own, there are a few things you should know:

  • If you ride dry ground with your ATV, remove the clutch cover and inspect it visually every time you change the oil. Check for any underlying problems.
  • If you regularly ride across mud terrains, you should remove the clutch cover after every couple of weeks of riding.
  • If you ride across swamps, the clutch needs to be cleaned and inspected for structural damage after every ride out in the swamp.
  • Do you race with your ATV? The clutch will be under more significant strain. Therefore, you should check it immediately after the race day.

Here are some things to watch out for when inspecting your ATV clutch:

  • Check the belt to confirm that it is in good condition and change it when necessary.
  • Check the weights (if you have a sheave clutch) to ensure they are clean. Clean everything thoroughly if dirty, including the shims.
  • Check the bushings to see if they are worn. You’ll need to replace the clutch completely in this scenario.

These are some of the major maintenance tips to keep in mind for your ATV’s clutch. If you don’t ensure regular maintenance for the vehicle, there is a high possibility that it will develop any of the common problems associated with ATV clutches.

These include clutch slipping, clutch creeping and the attendant pungent smell, and a jerky feel in the lever. Repair these problems will cost more than maintenance in most cases, so give the clutch the desired attention.

Don’t forget to practice sensible clutch use while out riding to reduce the chances of damage. Don’t use your clutch as an aid for braking, and don’t leave your foot on it half the time.

Basically, any scenario that doesn’t make sense with your standard car or motorcycle clutch should be avoided with your ATV as well.

Conclusion

The clutch operation in an ATV is a very elaborate process regardless of the ATV clutch type in your model.

Understanding how each type of clutch works makes it easier for you to deliver regular maintenance if you have the DIY skills. If you don’t have the skill to handle the maintenance, outsource it to avoid more serious damage.

Rob

That's me sinking another ATV. I love to ride no matter what it is, snowmobiles, four wheelers, dirt bikes, and anything else off-roading. I've experienced my fair share of machines, and like to share that experience here.

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