What is a Jackshaft on a Go Kart? Everything Explained

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Ever wondered about go-kart jackshafts? They’re a DIY game-changer, replacing the traditional chain system for efficient energy transmission. No more fuss with engine-to-axle alignment issues!

Picture it as a dual-pulley system, syncing power between the main shaft and axle. Perfect for DIYers, it’s a lifesaver for hassle-free go-kart assembly.

In this article, we dive into jackshafts—components, assembly, significance, and explore handy jackshaft kits. Stick around to demystify this vital go-kart element!

What is a Jackshaft on a Go Kart? Everything Explained

What is JackShaft on a Go-Kart?

A jackshaft is a mechanical component used in go-karts to transfer energy between the engine’s shaft and the rear axle. The assembly looks like a dual crankshaft and axle system with a dual gear system on it. It’s also commonly known as a countershaft because of the presence of the main engine’s shaft.

go kart jackshaft

Its primary purpose is to transmit the energy to the rear axle regardless of the alignment issues. The reason is that it’s challenging to get the right alignment if you build a go-kart at home. So, it works best even if the axle and the engine crankshaft are not properly aligned.

In a nutshell, it’s a simple pulley-like assembly with two gear systems attached, handling two systems simultaneously for energy transfer.

Is Jackshaft on a Go-Kart Worthwhile?

The purpose of the jackshaft on a go-kart is to deliver the rotational energy of the engine to the rear axle with the help of a chain and gear system. It plays an intermediate role, remains at the center, and transfers the mechanical power easily without the alignment problems of the two sprockets.

If I talk about the working, it relies on two different sections. First, the engine’s power is transmitted to the jackshaft In sprocket. Secondly, the out sprocket further delivers it to the axle. Most importantly, the sprocket and gear sizes transfer the energy in a certain ratio according to the requirements of your homemade go-kart.

Let’s explain some other factors depicting the jackshaft’s importance. Primarily, it’s like a torque converter where the speed of the engine is converted to the main shaft. After that, the available gear and sprocket sizes decide the final torque and speed output. Therefore, it’s also known as a torque converter in a go-kart.

On the other hand, It’s used in classic vehicles like go-karts, where you can relocate the power source and axle depending on the final design. It’s helpful where you can’t align the axle and shaft properly for mechanical energy transfer. The overall assembly is connected via a belt or chain to make it an overall robust system. So, if you ask: Should I install a jackshaft for my go-kart? Indeed, it’s a useful component.

Jackshaft Assembly on a Go-Kart

As it transmits the mechanical assembly from the engine shaft to the rear axle. It acts like a pulley or the overlapping point to neglect the alignment of the shaft and axle. It distributes the torque, spreading the load on different components. So, what is the jackshaft assembly on a go-kart?

The overall assembly consists of four components instead of two because it contains two sprockets. The engine’s shaft is connected to the outer sprocket on the jackshaft, and the second (behind) sprocket is connected to the rear axle for mechanical energy transfer. Yeah, they are not perfectly aligned, causing little power loss but keeping you away from the accurate alignment. Therefore, I always suggest that DIYers use the Jackshaft kit instead of buying the separate components, which further causes issues.

Jackshaft Kit for Go-Kart and Its Benefits

As mentioned above, always buy the jackshaft kit instead of a single component to prevent sizing and other issues while setting them up. It consists of two bearing hangers, two bearings, two sprockets, a key stock, and a collar.

So, what if you don’t buy the Jackshaft kit? Surely, the components’ size and dimensions will not match each other, and it will create an issue while setting up your go-kart. The jackshaft kit’s components are compatible with each other, having the same dimensions to set it easily without issues.

What is Jackshaft Bearing?

The jackshaft’s core component? Bearings. They dictate the rotational motion, ensuring it’s smooth and frictionless. This synchronized force then hooks up with the engine’s shaft speed, transmitting it to pulleys and other components. Bearings are the unsung heroes, found throughout—on the main shaft and axle. In a nutshell, a go-kart jackshaft is a compact powerhouse with bearings, orchestrating seamless rotations.

What is a Go Kart Jackshaft Plate?

The whole jackshaft assembly is contained on a plate known as a jackshaft plate. It is directly bolted on the engine’s shaft and effortless to install. Previously, they came without bolts, and the DIYers had to weld it with the engine’s outer cover. In actuality, it was hard to replace. Nowadays, the plate comes with a bolt assembly to make it easier to install, replace, and repair.

Go Kart Jackshaft Calculator

Remember that another primary purpose of this component is to maintain the required ratio of the overall gear system. Calculating the jackshaft ratio is easier as you have to look at the overall setup.

The calculator calculates the ratio among all four sprockets instead of two sprockets.

How To Calculate Jackshaft Ratio?

The ratio is calculated by multiplying Ratio A by Ratio B, which is explained as:

  • Ratio A: Teeth of Jackshaft’s In-Sprocket / Teeth of Crankshaft Sprocket
  • Ratio B: Teeth of Axles On-Sprocket / Teeth of Jackshaft’s Out-Sprocket

When you get both ratios, multiply them to get the overall go-kart jackshaft ratio. It’s also known as the final ratio of the system.

jackshaft components

What is a Jackshaft on a Go Kart Yamaha?

Yamaha always stands out from other companies in terms of quality and mechanical parts for vehicles like go-karts. It’s still leading by providing high-quality jackshaft go-karts in different sizes and dimensions. Choose from a 40/41/420 chain and jackshaft kit. The kit is useful for Go-karts and mini-bikes. Exceptional quality and perfect dimensions make them reliable for all go-kart lovers.

Important Go-Kart Jackshaft Maintenance Tips

Its maintenance is necessary for its longevity; otherwise, it may not be able to transfer rotational energy accurately due to energy losses. Make sure to check the tightness of the sprockets so it is not damaged. Clean it with a bristle brush or soft cloth if you find debris and dirt on it. Moreover, keep it lubricated with high-quality chain lubricant for go-karting.

How to maintain a go-kart jackshaft? Let’s look at some pro’s tips:

  • Check for the wear and tear after a week.
  • Check the tightness; the chains on the sprockets should run smoothly.
  • If worn, replace the sprockets and chain at the same time.\
  • The bearings should run smoothly, and you can use grease or lubricant for it.
  • The bearings should not make noise.
  • The teeth of the sprockets should be in good shape.

Final Words

In short, the go-kart’s jackshaft is vital for transferring rotational energy, eliminating alignment issues. It offers benefits like torque control, reduced stress on sprockets, and easy installation—a must-have for DIY go-kart builders.


What is the purpose of the jackshaft?

It is responsible for rotational energy transfer from the engine to the axle, regardless of the alignment. It controls the torque, reduces stress on the chains, and offers several other benefits to the DIYers.

What are the components of a go-kart jackshaft?

It consists of four main components, mainly crankshaft sprocket (attached with the engine), jackshaft in-sprocket, jackshaft out-sprocket, and axle sprocket. However, the two sprockets are directly attached to the assembly.

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