Free Modifications To Make Your Go Kart Faster

-So you’ve got a go kart and you want to make it faster. But maybe you just bought it and don’t want to spend a bunch of money on parts? Maybe you’ve had it for a while, and still don’t want to spend a bunch of money on parts? Either way, you’re in luck! 

An engine needs more air and fuel in and more exhaust out to make more power, plain and simple. Past that we’ll un-limit the engines’ potential and allow it to spin faster. Lastly, we’ll see what we can do with a little bit of air.

Free Engine Upgrades

Perhaps the biggest limiting factor is your engine’s required factory limitations. By default engine manufacturers have to think in terms of reliability and emissions and by doing so sacrifice horsepower. We’ll attempt to reverse those decisions.

• Intake – When you remove the air filter cover you should see a paper accordion filter and a foam filter behind that. We need to keep the foam filter in tack, but give it a good wash and make sure it’s fully dry. Anything that was stuck in there can restrict flow. Second, we need to retain the rubber surround on the paper filter to keep the foam in place. What we can do though is to cut out the paper in the middle leaving about 10% at either end to hold it in place. Lastly, drilling holes in the outer cover will maximize the amount of air we’re pulling in. 
• Fuel – First off, make sure you have fresh gas. Now I know this isn’t free, but you have to put in gas to start with, so might as well make sure you have all fresh gas. Next, we want to make sure we’re getting as much fuel into the carb as we can to match the new, hopefully, larger, amount of air that we’re allowing through our filters. To do this we will remove the bowl of the carb and pull the jet out of the middle. There is a hole in the middle and we want to drill it one drill size larger than it currently is. Beware that this will require very small drill bits, so technically not free if you don’t already have the bits. Definitely a worthwhile modification though. Borrow some bits if you have to, this is a must.
• Exhaust – This one will be a bit tricky and relies on what you have on hand, and if you have a welder. Most factory exhausts have a night little tube coming off before going into the exhaust box. This can be cut off and you can weld on a tube to extend it and make your own header. Granted this requires a welder and the existence of a tube already. You can also metal hose clamp a tube on if you lack a welder, just make it really really tight. Again, ask a friend on this one if you have one with a welder. 
• Compression – This one is probably the most skipped, but very easy. Basically, you need to remove the head and sand it down ever so slightly. It’s best to do this on a belt sander if you have one. If not you can attempt to go smaller on your head gasket. I have heard of soda cans being used in place of the head gasket. The idea here is just to allow less volume inside the combustion chamber. Make sure to torque your head bolts down in a star pattern, just like you should with wheels on a car.
• Port and Polish – While you have the head off, it’s a perfect time to get some work done on the exhaust side. You want the exhaust to flow as quickly and smoothly as possible. Depending on the design of the exhaust you may file away some of the material to allow more exhaust to escape faster. Just be careful not to file too far. Small changes make a big difference on these little engines. Lastly, do a good bit of polishing of the exhaust port. If you have a Dremel, they were made for this! Get out your low grit for porting and your high grit for the polishing. Polishing takes a long time but any bit helps. If you get to the point that it’s a mirror shine, you’re done. Also, make sure to leave the intake side alone, you want a little rougher in there to make sure the air and fuel mix up nicely against the rough sidewalls. 
• Governor – This one will come with a disclaimer. Removing the governor is at your own risk. That is because the purpose of the governor is to keep the engine running at a certain RPM, most of the time around 3,600 RPMs. This is because that’s where the engine is most reliable and rated at for heat dissipation and other parts rotating allowances. Once you start spinning the whole assembly faster you are going to start creating a lot more heat, and you are going to be stressing the parts more. Namely, the flywheel and connecting rod. 

Now that we’re past the reasons why the governor exists, let’s talk about the benefits. Well obviously if you were reading along you’ll know that it allows the engine to spin faster. The higher the RPMs, the faster the engine is. Also, with the added air and fuel we’re getting into the engine, the higher RPMs will allow the engine to take full advantage of that extra mixture. Basically, all of these modifications complement each other, and RPMs fit really well into this formula. 

A note of caution with a removed governor, because the engine is spinning faster, it is also creating a lot more heat. Because of that reason, you need to be aware of how long you are spinning the engine at max RPM’s. It’s recommended to not max out the engine for longer than a couple of minutes at a time. Personally, I like to stick to much smaller amounts, like 30 seconds at a time, and then allowing the RPMs to come back down and the engine to cool itself off. There are definitely consequences to removing the governor and you need to be fully aware of what could happen if you don’t treat the engine correctly. Worst case the flywheel could break apart and come flying off. Metal projectiles are never something you want to deal with. There is a cover over the flywheel, but it is plastic on most parts so it’s not going to stop it too much. Also, you risk blowing a connecting rod out the side of the engine. Bottom line, just be careful and don’t run your go kart at full throttle constantly. 

On to the removal, you will need to remove the crankcase cover to do this. Be very careful when removing it and see if you can get it off without tearing the gasket. Depending on how old your go kart engine is, this might not be possible. You can reseal it with RTV sealant or gasket maker, but much easier if you can retain the factory seal. Once you have access to the crankcase you are looking for a little plastic gear wheel that’s the size of a half dollar. Different manufacturers affixed them in different fashions, but you just need to find a way to get it off of there. While you’re in there cutting and chipping away at it, just be very aware of the pieces. You will need to make sure you get every last piece back out or else it will get caught up inside your engine and cause you more problems. Also, make sure you check for washers behind the gear, most of the time there are a couple so check with a screwdriver and make sure you get them all out. You will see an arm on top of the gear, just move it to the side and leave it once you have the gear out. You can technically remove it, but you’d have a hole in the side of the engine you’d need to plug. If you go this route you could tap the case and thread a bolt in there with some sealant. 

• Full Throttle – Sometimes there are adjustment screws on carbs that are set to not allow full throttle. A good way to check this is once you have the intake and filters off you’ll be able to see the butterfly inside the carb. Push your throttle pedal all the way down and hold it. Then see if your butterfly can go any further with you pushing on it manually. If it moves open further, you have room to improve. Next, I would try to push the throttle linkage manually without the pedal and see if that gets you full throttle. If that does, you can simply reach back while driving the push the throttle further open. If you’re still not able to get full throttle you’ll need to do some adjusting of screws that might hold back the linkage, or bending of the brackets to allow full throttle. Just watch what happens when you push the pedal and you’ll know which direction you need to allow the linkage to go further. 

Other Free Upgrades

• Weight Reduction – This seems pretty self explanatory. Remove anything you don’t need or don’t want. There’s not much to improve on with the frame and drilling holes in it will go further towards wrecking the structural rigidity than it will with weight. Just be smart with what you remove and don’t take off anything basic you need to operate the go kart.
• Fuel – If you have some isopropyl alcohol or household rubbing alcohol laying around you can add that to your gas. This is a trick that can raise the octane level in your gas and give you slightly more horsepower. As an added bonus it will also allow your engine to burn at a colder temperature which will help counteract the heat created from removing the governor and spinning at higher RPMs. Just don’t overdo this, you should never have more than a 50/50 mix, and I would recommend staying more towards the 75 gas/25 alcohol. Too much alcohol and you’ll start to get a negative effect. Start with a little and test to see where the sweet spot is. 
• Tires – In the effort of every last bit helps, make sure your tires are fully inflated. Bigger tires will make your go kart faster since they will spin at a faster rate. So having them inflated really well will give you just a slight bit of edge. Also if you go a little further over-inflated, less of the material should tough the ground giving you less rolling resistance. 

This is the most complete list I have for getting the most out of your go kart with free modifications. Keep in mind some of these will reduce the lifespan of your go kart parts, so proper care needs to be taken to make sure you don’t have a failure while driving. As with most things, there are going to be better alternatives to some of these suggestions, but they’ll cost money. In our next post, I’ll be outlining the upgrades that are available and outlining which ones are the best upgrade for the money. Hopefully, these changes will allow you to have a ton more fun with your go kart!