How to rebuild
a gokart
By Jakub Nowicki
Restoring a Gokart or any other basic, mechanical vehicle is difficult with no experience. There are many unexpected challenges that make your life more difficult along the way. I have learned this during the last 6 months of working on my project. I will try to guide you through your process of restoring in 4 parts: preparation, disassembly, replacing and assembly. The goal of this tutorial is to prepare you for the problems you didn’t expect, and minimize the time wasted on them.
1 Preparation
1.1 Choosing the right gokart
There are different types of gokarts, all built with different intentions and for different purposes. Here, I will not speak about professional racing karts or off road buggies but rather, old racing gokarts, meant purely for fun. There is a surprisingly big amount of these to buy online. Wherever you go, whether it’s OLX or Craigslist, you will find a surprisingly big amount of vintage racing karts that usually cost less than 250$ or 1000zł. Another place to buy these types of machines is to get in contact with someone getting out of professional karting. These people are also a good place to look for parts like tires, as professional karting takes a lot of these. Once you find the gokart you are interested in, it’s time to check its condition. The obvious thing is making sure the engine works. The other thing you would want to know is if the frame or back axle has any cracks or bends. Cracks can often lead to the frame breaking which can result in a big accident while driving. It is also crucial to know if replacing the brakes will be needed. Once you have checked that, check if the bearings work well and if you can spot any parts that are loose. The one component that you really want to focus on, is the steering column that takes the biggest amounts of force when cornering. It, having any flaws, could result in snapping, and losing control at a high speed.
1.2 Workplace
To start the project, you need to have a space to work on it. Around 15 square meters of surface you are not scared of destroying are needed to work comfortably. This space will mostly serve as a warehouse for the disassembled parts and frame, but it should also have a table for cleaning parts and taking care of the smaller ones such as the brake system. The area you will be working in also needs good lighting, around 400 lumens per square meter.
1.3 Tools
You can’t start doing anything without the proper tools. The two main pieces of equipment you are going to be using, is a regular brushless drill and an impact wrench. There is a huge difference between these two devices. Unlike the drill that needs to get momentum in order to unscrew a screw, the impact wrench delivers the power immediately with rapid hits. You should do fine with the impact wrench with 400 nm of force. To be able to use an impact wrench, you should get a decent quality wrench box (if the quality will be insufficient, the wrenches could break while trying to unscrew some parts). If you plan on using a brushless drill, get yourself a set of bits. Apart from these, a set of open-end wrenches and a drill brush are necessities. You need to remember that while buying, think about whether the size of the impact wrench adapter is the same as the size of the wrenches themselves (usually ½ inch)
2 Disassembly
2.1 Main parts
The most important thing to remember while taking apart, is to document where everything was originally. You should do it by making detailed pictures with your phone that you will use later on. I recommend starting your disassembly with the biggest parts, such as the seat, steering wheel and wheels that you will likely face problems with. To remove the tyre from the wheel you need a lot of force, which you most likely lack at your workplace. Therefore I recommend taking the wheels to the closest vulcanizer who should take care of them in about 15 minutes. The disassembled parts and screws should be kept in boxes by categories such as steering system, engine attachment or seat to keep track of where components are going. There are also several parts that are covered in grease and rust, and don’t want to move. While dealing with them I used WD-40 and a rubber hammer.
2.2 Back axle
The back axle will be another challenge. It is heavily based on being kept together by pressure. The main pressure suppliers are the two bearings stuck on the axle itself. You don’t have to replace them, but it is a thing I highly recommend doing if you want better performance. I tried treating them with a hammer which didn’t go well. The effects I ended up with were very small and the axle was damaged. To remove the bearings, you need to go to a car shop which has a special tool for that. The tool works on incredibly high pressure and will do its job with no problem. Now your go kart should be in pieces.
3 Replacing
3.1 Brakes
The brakes are the only part of the gokart that actually keep you safe, and that’s why they are crucial to the build. The type of brakes you will most likely encounter are hydraulic brakes. The common problem for this type of brake is the piston getting stuck because of being old. To get the piston out, I connected a bicycle pump, and just pushed it once. If you want to remove the pistons this way, be careful since the pistons can jump out of the cylinder with a high velocity. I suggest you take the brakes apart and clean them. The parts that will need replacing for your safety are the lines. The lines are working on 800psi, to 2000psi in the case of maximum effort, so when you buy one, choose one with over 2000. After several years of being used they are pretty vulnerable for cracking which is undesired at high speeds. To replace a part like this you just take it to a hydraulic shop and order a new one of the same size. When you put it all back together, remember to add brake fluid, not water or any other substance. You can get brake fluid on pretty much any gas station.
3.2 Sanding
You will surely want to make your gokart look like it’s brand new, and the first step to doing that is sanding. Sanding is a process of blasting small pieces of material (usually glass) on the old and dirty surfaces to remove the unnecessary coat and get the parts ready for painting. You want to sand only the major pieces made of metal like the steering system or frame, not the smaller ones like screws. One more important thing to remember is not to treat moving pieces that are in constant friction with other elements with sand. Doing that can result in destroying the parts and having to get new ones. I was pretty lucky to have a sandblaster that I had access to personally, however, most people don't, so I advise you to give the parts away to a professional who will take care of it. This will spare you time but cost you some money. It’s important to note that sanding is not a necessity. If you don't have equipment for it, you can use method 3.3 which will be much more time consuming.
3.3 Using the brush
There are some parts that you don't really want to sand. Using a wire brush compatible with your drill, will clean heavily painted parts and will produce a really cool looking effect of brushed steel. You will not want to paint all surfaces because the paint easily comes off in areas that are often hit, like the floor, rims or back axle.
3.4 Painting
To make your project look ideal, you have to customize it by painting it. This is the part in which I committed the biggest mistake because of using the wrong paints and painting parts I shouldn’t have. The effect is still satisfying but once the paint is scratched, it goes off. It is a process that cost me a lot of time and money. Therefore, If you are not a big fan of spending time doing a continuous and boring job, it can be painted by a professional. The amount of financial resources I invested in paints would be similar if I had given it to be painted. If you are willing to do it by yourself, the first thing you should think of is the paint you want to use. Regardless of the color you should use automotive spray paint you can buy anywhere online. The paint should be applied from around 20cm, in a quick way, making thin layers. At least 3 coats of paint are needed to bring the desired effect. You ought to use a primer beforehand to add a layer of depth to the paint. Depending on whether you use light or dark colors, you would want to choose a light or dark primer. You need to know that if you wait >7 days after sanding, the metal might start getting a ginger color, which doesn't really disturb the paints, but can damage the metal to some extent. The only parts that should be painted are the ones that don't move. Paining any bearing mounted in the chassis will create huge problems while steering, and you will likely have to replace them.
3.5 Blackening the bolts
If you wish to make your bolts black, and make them look fresh, a bit of chemistry is needed. The first step is to wire brush them. You can also use a sandblaster if you are looking for a more matte finish. The next step is making a black oxide concentrate and distilled water mixture in the proportion of 9 (boc) to 1 (dw). The concentrate you can buy online and to
distill the water, you just boil it. After keeping the bolts in the mixture for about 20 seconds, you ought to dry them and put in distilled water. To add an extra layer of protection, applying WD-40 and waiting for it to soak in will help. It is important not to paint the bolts and nuts, as then, you will face problems while trying to screw them in.
a gokart
By Jakub Nowicki
Restoring a Gokart or any other basic, mechanical vehicle is difficult with no experience. There are many unexpected challenges that make your life more difficult along the way. I have learned this during the last 6 months of working on my project. I will try to guide you through your process of restoring in 4 parts: preparation, disassembly, replacing and assembly. The goal of this tutorial is to prepare you for the problems you didn’t expect, and minimize the time wasted on them.
1 Preparation
1.1 Choosing the right gokart
There are different types of gokarts, all built with different intentions and for different purposes. Here, I will not speak about professional racing karts or off road buggies but rather, old racing gokarts, meant purely for fun. There is a surprisingly big amount of these to buy online. Wherever you go, whether it’s OLX or Craigslist, you will find a surprisingly big amount of vintage racing karts that usually cost less than 250$ or 1000zł. Another place to buy these types of machines is to get in contact with someone getting out of professional karting. These people are also a good place to look for parts like tires, as professional karting takes a lot of these. Once you find the gokart you are interested in, it’s time to check its condition. The obvious thing is making sure the engine works. The other thing you would want to know is if the frame or back axle has any cracks or bends. Cracks can often lead to the frame breaking which can result in a big accident while driving. It is also crucial to know if replacing the brakes will be needed. Once you have checked that, check if the bearings work well and if you can spot any parts that are loose. The one component that you really want to focus on, is the steering column that takes the biggest amounts of force when cornering. It, having any flaws, could result in snapping, and losing control at a high speed.
1.2 Workplace
To start the project, you need to have a space to work on it. Around 15 square meters of surface you are not scared of destroying are needed to work comfortably. This space will mostly serve as a warehouse for the disassembled parts and frame, but it should also have a table for cleaning parts and taking care of the smaller ones such as the brake system. The area you will be working in also needs good lighting, around 400 lumens per square meter.
1.3 Tools
You can’t start doing anything without the proper tools. The two main pieces of equipment you are going to be using, is a regular brushless drill and an impact wrench. There is a huge difference between these two devices. Unlike the drill that needs to get momentum in order to unscrew a screw, the impact wrench delivers the power immediately with rapid hits. You should do fine with the impact wrench with 400 nm of force. To be able to use an impact wrench, you should get a decent quality wrench box (if the quality will be insufficient, the wrenches could break while trying to unscrew some parts). If you plan on using a brushless drill, get yourself a set of bits. Apart from these, a set of open-end wrenches and a drill brush are necessities. You need to remember that while buying, think about whether the size of the impact wrench adapter is the same as the size of the wrenches themselves (usually ½ inch)
2 Disassembly
2.1 Main parts
The most important thing to remember while taking apart, is to document where everything was originally. You should do it by making detailed pictures with your phone that you will use later on. I recommend starting your disassembly with the biggest parts, such as the seat, steering wheel and wheels that you will likely face problems with. To remove the tyre from the wheel you need a lot of force, which you most likely lack at your workplace. Therefore I recommend taking the wheels to the closest vulcanizer who should take care of them in about 15 minutes. The disassembled parts and screws should be kept in boxes by categories such as steering system, engine attachment or seat to keep track of where components are going. There are also several parts that are covered in grease and rust, and don’t want to move. While dealing with them I used WD-40 and a rubber hammer.
2.2 Back axle
The back axle will be another challenge. It is heavily based on being kept together by pressure. The main pressure suppliers are the two bearings stuck on the axle itself. You don’t have to replace them, but it is a thing I highly recommend doing if you want better performance. I tried treating them with a hammer which didn’t go well. The effects I ended up with were very small and the axle was damaged. To remove the bearings, you need to go to a car shop which has a special tool for that. The tool works on incredibly high pressure and will do its job with no problem. Now your go kart should be in pieces.
3 Replacing
3.1 Brakes
The brakes are the only part of the gokart that actually keep you safe, and that’s why they are crucial to the build. The type of brakes you will most likely encounter are hydraulic brakes. The common problem for this type of brake is the piston getting stuck because of being old. To get the piston out, I connected a bicycle pump, and just pushed it once. If you want to remove the pistons this way, be careful since the pistons can jump out of the cylinder with a high velocity. I suggest you take the brakes apart and clean them. The parts that will need replacing for your safety are the lines. The lines are working on 800psi, to 2000psi in the case of maximum effort, so when you buy one, choose one with over 2000. After several years of being used they are pretty vulnerable for cracking which is undesired at high speeds. To replace a part like this you just take it to a hydraulic shop and order a new one of the same size. When you put it all back together, remember to add brake fluid, not water or any other substance. You can get brake fluid on pretty much any gas station.
3.2 Sanding
You will surely want to make your gokart look like it’s brand new, and the first step to doing that is sanding. Sanding is a process of blasting small pieces of material (usually glass) on the old and dirty surfaces to remove the unnecessary coat and get the parts ready for painting. You want to sand only the major pieces made of metal like the steering system or frame, not the smaller ones like screws. One more important thing to remember is not to treat moving pieces that are in constant friction with other elements with sand. Doing that can result in destroying the parts and having to get new ones. I was pretty lucky to have a sandblaster that I had access to personally, however, most people don't, so I advise you to give the parts away to a professional who will take care of it. This will spare you time but cost you some money. It’s important to note that sanding is not a necessity. If you don't have equipment for it, you can use method 3.3 which will be much more time consuming.
3.3 Using the brush
There are some parts that you don't really want to sand. Using a wire brush compatible with your drill, will clean heavily painted parts and will produce a really cool looking effect of brushed steel. You will not want to paint all surfaces because the paint easily comes off in areas that are often hit, like the floor, rims or back axle.
3.4 Painting
To make your project look ideal, you have to customize it by painting it. This is the part in which I committed the biggest mistake because of using the wrong paints and painting parts I shouldn’t have. The effect is still satisfying but once the paint is scratched, it goes off. It is a process that cost me a lot of time and money. Therefore, If you are not a big fan of spending time doing a continuous and boring job, it can be painted by a professional. The amount of financial resources I invested in paints would be similar if I had given it to be painted. If you are willing to do it by yourself, the first thing you should think of is the paint you want to use. Regardless of the color you should use automotive spray paint you can buy anywhere online. The paint should be applied from around 20cm, in a quick way, making thin layers. At least 3 coats of paint are needed to bring the desired effect. You ought to use a primer beforehand to add a layer of depth to the paint. Depending on whether you use light or dark colors, you would want to choose a light or dark primer. You need to know that if you wait >7 days after sanding, the metal might start getting a ginger color, which doesn't really disturb the paints, but can damage the metal to some extent. The only parts that should be painted are the ones that don't move. Paining any bearing mounted in the chassis will create huge problems while steering, and you will likely have to replace them.
3.5 Blackening the bolts
If you wish to make your bolts black, and make them look fresh, a bit of chemistry is needed. The first step is to wire brush them. You can also use a sandblaster if you are looking for a more matte finish. The next step is making a black oxide concentrate and distilled water mixture in the proportion of 9 (boc) to 1 (dw). The concentrate you can buy online and to
distill the water, you just boil it. After keeping the bolts in the mixture for about 20 seconds, you ought to dry them and put in distilled water. To add an extra layer of protection, applying WD-40 and waiting for it to soak in will help. It is important not to paint the bolts and nuts, as then, you will face problems while trying to screw them in.
