Go-karts are fairly simplistic machines that are cheap and easy to maintain. However, oftentimes you need to have stronger parts installed on faster karts. The faster your kart is, the more strain the clutch will take, which is why it helps to know how to adjust your kart’s torque converter.
The 4 steps to adjust your go-kart’s torque converter are:
- Remove the face cam from the driver pulley
- Adjust the spring position
- Replace the face cam
- Preload the torque converter
Torque converters can be an important part of your kart, so it’s crucial that you understand them before you start making adjustments. Below, we go into more detail about kart torque converters, and provide you with more advice on how to properly adjust yours.
What Is A Torque Converter On A Go-Kart?
Go-karts normally use a centrifugal clutch. On karts, these clutches connect the engine to the sprockets and the rear axle, which drives the kart forwards. They are excellent at high speeds, but at lower RPMs they tend to struggle, and they also don’t like idling. Centrifugal clutches are sensitive and can break when the gas and brake pedals are used at the same time.
The alternative to using a centrifugal clutch is a torque converter. Torque converters use a Continuously Variable Transmission system (CVT). This means that it can constantly adjust the gear ratio depending on the speed of the kart, or the engine’s RPM. This makes them the better choice for karts that will be driving at lower speeds and require more torque in lower RPM ranges.
Torque converters are commonly found on cars alongside the transmission. Torque converters are large and heavy parts, so it’s hard to imagine these being placed on a kart. However, the karting and mini bike versions of torque converters are much smaller, lighter, and more compact than the ones found on cars, so it’s easy to fit them onto a smaller vehicle like a kart.
So, the main difference between a torque converter and a centrifugal clutch performance-wise is where they produce maximum torque. The centrifugal clutch produces most torque at higher speeds, and it loves to stay in motion. This makes it ideal for racing karts. The torque converter is ideal for low RPM ranges and it produces more power at slower speeds, making it more suited to off-road karts.
How Does A Go-Kart Torque Converter Work?
A go-kart’s torque converter has several important moving parts. The main parts that we’ll be focusing on are the two pulleys (round plates) and the belt that runs in between these pulleys. Much like with a chain, one pulley is attached to the engine, which is what gets the torque converter to start rotating and turning, this is also known as the driver pulley.
Inside the driver pulley is a weight and spring system, which will be the main focus when it comes to making adjustments later on. The spring is responsible for the tension inside the driver pulley. Adjusting this spring will change the amount of torque that the torque converter has, and where in the RPM range the torque converter starts to kick in.
There is a belt that runs from the driver pulley to another one, which in turn is attached to the chain. When the engine is switched on, the pulley will begin to rotate and cause the weights to experience centrifugal force, much like your standard karting clutch.
Forces In Action
The faster the weights move, the more their weight will be pushed outward, but the spring system holds them in place, and acts with more force to keep them there.
Another section of the driver pulley moves based on these forces, and this causes the belt to move as well. As the belt changes angle, and as this angle changes, so does the diameter of the belt.
In other words, the higher the engine RPM, the more the belt expands, which constantly changes the gear ratios. As the rear pulley is connected to the chain, it causes the chain to spin faster, but in a more controlled way.
KEY POINTS• Go-kart torque converters are an alternative to using a centrifugal clutch
• Torque converters are more suited to lower-speed karts
• They work using a system of belts and pulleys
What You’ll Need To Adjust Your Kart’s Torque Converter
Adjusting the torque converter on your kart is incredibly simple and can be done in just four steps. The only tools you’ll need are a pair of long nose pliers, as well as a pair of tongue-and-groove point pliers. If you’re planning on replacing the spring inside the torque converter, you’ll need a new one of these as well.
Different spring colors can also affect how the torque converter performs. The red spring is standard, while the yellow springs tend to provide less tension (and torque) and the green springs tend to produce more tension (and more torque). The difference between these springs is minor, so it’s often not worth going out of your way to change them.
4 Steps To Adjust Your Kart’s Torque Converter
1. Remove The Face Cam From The Driver Pulley
The first step is to remove the nut and washer on the fixed cam on the driver pulley. Underneath that is a snap ring, which you need to remove using the long nose pliers. Make sure to hold onto the driver pulley as it is spring loaded and could jump off the plate. If you’re not holding onto it, the cam face (the plate that holds the spring) could be damaged if it drops onto the ground.
2. Adjust The Spring Position
With the cam separated from the torque converter, you can adjust the spring as needed. As we mentioned earlier, you can switch out the springs for different types, but the main adjustment that you’ll likely be making is to the spring’s position. The spring can be adjusted quickly and easily.
The spring will likely be in the middle of the three positions on the fixed cam. This is the standard position, and you can move the spring to either the first or the third hold to make your required adjustment. Some torque converters come with labels on each hole, but in general the higher the number (from left to right), the more torque your kart will have.
3. Replace The Face Cam
You can replace the face cam by reversing the order or taking it apart, but it’s a bit more tricky than that because you will need to preload the torque converter. The spring inside the torque converter needs to be wound up and needs to have tension on it, which is what makes this process a bit trickier.
The first step is to place the spring in the position you want it to be in, both on the fixed cam and the cam face. Then you need to align the flat sides on both the fixed cam and the cam face when you slot them back together.
4. Preload The Torque Converter
Preloading the torque converter is the next step. All you need to do is keep pressing the cam face against the fixed cam and turn it counterclockwise until it hits a stop. From there, you need to keep the pressure on the plate as you put the snap ring back in place. The snap ring will hold the torque converter in place, and all that’s left to do from there is to screw the nut back in place.
Common Go-Kart Torque Converter Problems
Torque converters are more complicated than the usual centrifugal clutches that you would usually find on a kart. Torque converters also have some extra moving parts, which means that they are more susceptible to problems and broken parts. Below are some of the most common problems that go-kart torque converters have.
Torque Converter Belt Slipping
Just like the chain on your kart’s sprocket that keeps falling off, you may find that the belt on a torque converter may also slip off the pulleys from time to time. This is mostly caused by three common problems, including the wrong belt size, the pulleys being out of alignment, or the pulleys being worn out.
The first check you should do is on the belt. You’ll need to check out your torque converter’s manual or manufacturer’s guide to get an idea of the type and size of belt that you should be using. The next step is to check if the pulleys have been properly installed and that they are aligned correctly.
If none of these fix the issue, then it’s likely that some of the parts could be worn out. You can check the driven parts of the pulley to see if the surface has worn smooth. If the damage is too severe you will need to replace these parts.
Kart Jerking Under Acceleration
Your kart should have smooth acceleration even at the highest torque settings. If your kart is not accelerating smoothly and you experience a jerking motion when pressing down on the throttle, you definitely have an issue. The most likely problem is that you’re using the wrong belt for your torque converter, or that the driver unit needs to be cleaned and lubricated.
Torque Converter Won’t Disengage
If you take your foot off the throttle the pulleys should return to idle. If this does not happen, or if there is a delay in the kart going back to idle then you may have a problem with the torque converter.
A quick clean and check of the torque converter could solve this problem. You will need to take the pulleys apart and ensure that none of the elements inside the torque converter are damaged. You can lubricate the internal parts of the moveable clutch to ensure that it runs smoother, but make sure not to lubricate any area that touches the belt.
Kart Moves At Idle
If you find that your kart is moving when the engine is idling, you may need to make some adjustments to either the torque converter or your engine. Your kart should be able to idle without the rear axle spinning when the kart is lifted onto a stand. The problem is that the clutch is engaging at idle RPM, when it should be slightly higher.
In terms of the torque converter, you can change the weight spring system. You will need to replace the spring for a tighter one and use lighter weights, as this would require higher engine speed to get the clutch to engage. The other solution is to lower the idle speed of your engine using the idle screws (loosening them will decrease the idle speed).
Torque converters aren’t frequently used in karting, especially in racing. However, they can be helpful in some instances such as in off-road karting or if you’ve got kids driving your karts. Torque converters are much stronger than centrifugal clutches, and they produce more torque at lower RPM than the standard clutch you would find on your racing kart.
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