When I started karting, I was unaware of the importance of exhaust maintenance. I noticed my kart’s engine sounded a lot ‘unhealthier’ than the rest of my competition. If you want to avoid these problems, you need to know how to maintain your kart’s exhaust.
Our 5 tips for maintaining your kart exhaust are:
- Look for cracks
- Check your exhaust mounts
- Check your exhaust matting
- Inspect the manifold seal
- Paint it regularly
These tips range from quick solutions to more thorough maintenance procedures, but they will all ensure that your engine is running at the optimum level of performance. We go into more detail on each of them below, but first we discuss why kart exhaust maintenance is so important.
Why Is Kart Exhaust Maintenance Important?
The exhaust is a key part of the 2-stroke engine unit. Many kart exhausts are very reliable systems, but they do wear out with use, as any part on a kart does. High wear on your exhaust can cause you major engine problems in the long run, especially if you are racing.
My kart was always struggling on the straights, and I could never understand why, until I started to properly maintain my exhaust. An exhaust must be regularly maintained to keep your engine running at its peak performance.
5 Winning Tips For Maintaining Your Kart Exhaust
1. Look For Cracks
Regularly checking the outside of the entire exhaust pipe is crucial. You should make this a habit when cleaning your kart, as this will be the easiest time to spot any cracks that may be hidden by dirt or grease. It will save you a lot of time and a lot of money in repairs and replacements.
Replacing your kart’s exhaust system is not cheap, so check the pipe for cracks that might start to show over time. This should not be happening if your kart’s exhaust is correctly mounted, which means you should ensure it is to prevent potential issues (see the next tip for more detail on this).
Some common places for cracks to appear on your kart’s exhaust include:
- The exhaust chambers and silencer
- Chassis mounting brackets
- Welded areas
- Engine outlet connection
Do keep in mind that as per some regulations (including Rotax), you are permitted to repair cracks on your exhaust through welding, but modifying the exhaust system is illegal.
2. Check Your Exhaust Mounts
Exhaust mounts are often overlooked during routine maintenance. As we mentioned above, cracks can form on these exhaust mounts, which can lead to more extreme problems over time. These mounts are out of sight, and therefore they are usually checked less often than they should be.
One of my old karts didn’t have the rubber bumpers that absorb the vibration from the chassis. This became an issue for me in Round 5 of my national karting championship. My exhaust loosened off the chassis mounting during one of the heats, and I couldn’t fix it between rounds, so I had to race on with a loose exhaust.
This was heavily detrimental to my kart’s handling ability, and a loose exhaust can cause further damage to the exhaust unit itself. The rubber bumpers that cushion your exhaust are crucial and will add to the reliability of the entire unit. They are not too expensive, but they can save you a lot of trouble in the long run – and a lot of money!
3. Check Your Exhaust Matting
This will likely (and hopefully) be the majority of your exhaust maintenance. The matting inside the exhaust silencer has a recommended service life of 6 to 10 hours. This can easily be overlooked because of its short lifespan, and because you can’t actually see the matting from the outside of the exhaust pipe.
When the matting starts to burn away your kart will lose engine performance, and it will start to sound louder and ‘unhealthier’ than the other karts around you. When it burns away too much you will start to see hotspots on the exhaust. These can easily be seen if your exhaust is clean and painted because of the hotspots burning through the exhaust paint.
Removing The Rivets
To replace your kart’s exhaust matting, drill the rivets off the end of the exhaust muffler, starting with the top one. We will be replacing these with a different solution in a later step. If you have trouble removing the rivets, try to angle your drill slightly differently or use a set of locking pliers to hold the rivets in place.
In order to access the other two rivets, use the pliers or a spring puller to remove the exhaust springs that hold the muffler in place where it attaches to the main exhaust chamber. This will allow you to rotate the muffler and gain easy access to the other rivets that need to be removed.
Once the rivets are all removed, put the springs back to hold the muffler in place. This will make your job much quicker and easier than removing the whole system. The next step is to remove the stinger (the perforated tube inside the exhaust).
Removing The Old Matting
You will see the old, burnt wool matting inside the exhaust. Use your pliers to remove it. Grab the matting with the pliers and rotate it (like how you would wring water out of a towel) and try to pull as much of the matting out as you can. The more careful and methodical you are in this step, the more work you will save yourself in the next step.
Now you need to ensure that all of the old matting residue has been removed inside the exhaust. There are two methods you can use to do this. The first is to use a torch and a long steel rod and pull out all the excess and burnt off matting. Depending on the state of your matting, this could take some time. The other method is to start the kart up, so that all of the excess matting is blown out of the exhaust.
Warning: This will be extremely loud, so always ensure that you and everyone around you is wearing adequate ear protection!
Adding The New Matting
Roll up the new matting around the stinger as tight as you can. You may have to roll it multiple times to get a good fit on the stinger. Wear gloves when working with the exhaust matting as it can cause skin irritation due to the fibreglass.
Put the stinger with the new matting rolled around it back into the exhaust. This can be quite a tight fit, so try to rotate it while pushing it into the exhaust. You can use a soft hammer towards the end to tap the stinger into place. Finally, use M4 x 10mm or M5 bolts in place of the rivets. These will be easier to undo the next time you need to replace your exhaust matting!
4. Inspect The Manifold Seal
Having your manifold sealed tightly is key for maximum engine performance. Sometimes the exhaust doesn’t fit perfectly on the gasket due to rust or the exhaust itself being slightly bent or damaged. If the seal is broken, you can suffer a loss of exhaust pressure and therefore engine performance.
You can get away with using a high temperature silicone sealant. Apply the sealant to the outside of the exhaust where it connects to the outlet. Be careful not to apply too much of the sealant though, as it can leak over into the exhaust and restrict the outlet.
5. Paint It Regularly
Finally, you should also regularly paint your go-kart’s exhaust. The only colour permitted by regulations is black, so unfortunately you can’t make it match your livery and helmet design. Using high temperature exhaust paint, you should paint it as often as you replace your matting (every 6-10 hours of run time).
This will help you to identity the hotspots we mentioned earlier when your exhaust matting starts to burn away. You will easily be able to recognize when it’s time to replace it.
Exhaust maintenance is a vital part of overall kart care, but it is so often overlooked. Some people are intimidated by having to work on the exhaust because they do not understand it, while others are simply unaware of the fact that the exhaust requires maintenance at all! However, follow our tips above and you’ll never run into any major exhaust problems with your go-kart.
I created and have been writing on this site since 2019, collaborating with drivers, coaches, engineers and manufacturers to provide you with the most reliable information about motorsport. Find out more about me here.