Build a Go Kart
Nothing channels the inner speed-demon like tearing around on a go-kart. Building one yourself from a kit or from scratch can be a highly-addictive project, a fun garage activity for amateur mechanics of all ages. Depending on your access to the necessary tools, you can learn to plan a cool go-kart design for yourself, weld together the right kind of chassis, and make the beast move. See Step 1 for more information.
Contents
Steps
Planning Your Project
- Draw up detailed plans for the go-kart you want to make. Go karts can be many different sizes, shapes, and designs. These homemade vehicles are amenable to any design elements you want to throw into it. The basic essentials are a chassis, a simple engine, and a steering/braking system.
- Get creative in your planning for the project and produce detailed diagrams to make sure you get enough materials to complete the job. Look at other go-karts for inspiration and learn from kart-makers who've been there before.
- Alternatively, you can find schematics and plans online for many different types of models, if you'd rather let someone else do the planning. Use a template and modify it as you see fit.
- Size the go-kart appropriately. The size of the go-kart should depend on the age and size of the driver. For young drivers, about 30 inches (0.76 m) wide by 50 inches (1.3 m) long will work, while adults will want about 40 inches (1 m) wide by 72 inches (1.8 m) long.
- It's important to plan the go-kart accurately, using specific measurements, otherwise it'll be difficult to get the right materials and the right amount of them.
- Gather your materials. If you're short on cash, visit a scrap yard and see if you can pick up any low-cost parts. Or, you may be able to salvage parts from an old riding lawnmower or a junk go kart found at a yard sale. Ask lawn mower repair services for spare parts or junked out riding lawnmowers and used 4 cycle engines in the 10 to 15 horsepower range, with horizontal shaft and a drive clutch assembly. Here's what you'll need:
- For the chassis:
- 30 feet (9.2 m) of 1-inch (2.5 cm) square tubing
- 6 feet (1.8 m) of 0.75-inch (2 cm) round steel barstock
- 6 feet (1.8 m) of 0.5-inch (1.5 cm) bar stock
- 3/16-inch (0.5 cm) thick steel plate in a width and length slightly larger than your engine
- Plywood or metal (for seat and floorboards)
- Seat
- For engine:
- Engine (try an old lawnmower engine)
- Chain that fits the sprocket
- Bolts, washers
- Gas tank
- For the drive train:
- Wheels
- Steering wheel
- Gear and handbrake
- Drive shaft
- Bearings
- Steering shaft
- Brake pedal
- Throttle/go pedal
- For the chassis:
- Obtain a welder. If you've got no experience welding, you will have to hire a welder for this project. The most essential part of the go-kart is a solid chassis that'll hold you onto it while driving and house the engine. If you're going to weld it together out of pieces of barstock, the welds should all be made with the proper heat, weld depth/penetration and uniform weld-beads. Otherwise, the welds may be weak, brittle, bubbly, cracked and/or only surface deep, making your go-kart a death trap.
- If you don't have experience welding, don't start by putting together a go-kart. Start with other smaller projects if you want to learn.
- Consider buying a go-kart kit. If you're not interested in welding and designing your own go-kart, purchase a no-weld kit that you can put together with simple tools, featuring detailed instructions and schematics to make the job a snap.
- Available widely for about $550 dollars, you can have the satisfaction of putting together a go-kart yourself without the hassle of designing it and buying all the materials separately.
Building the Chassis and Steering Column
- Cut the metal tubing. Cut your lengths of tubing to the appropriate lengths, given your design or schematics.
- For most designs, the front end will feature a camber angle, narrower than the rear, which will allow the wheels room to turn, allowing the chassis to twist slightly. To do this, mount a King Pin at the front corners where the wheels will be, to allow for easy twist.
- For an easy eye-guide, consider marking up the floor of the garage or the area you're working with sidewalk chalk of the appropriate measurement, to keep you from having to remeasure repeatedly. You could even draw out the whole design on the ground and start laying it on top.
- Weld the frame together according to your design. Use concrete blocks to keep the frame elevated while you work, making sure all your connection points are solid and the chassis is secure. It needs to be strong enough to hold your weight and the weight of the engine, so it's not the time for a shoddy weld job. For more strength, use gussets at all corners.
- Assemble the front stub axles. Build your axle with a straight piece of 0.75-inch (2 cm) steel rod, and two bushings attached to your frame. Use washers and cotter pins drilled through the axle to keep the assembly in position.
- Install the front stubs that'll allow you to turn easily before messing with the steering column and attach your King Pin, to the steering arm. You'll need to have at least 110 degrees of angle on the front wheels, so plan accordingly.
- Install your rear axle and wheel assembly. You'll likely need to assemble an axle carrier with a bearing bracket for the rear axle, meaning that the axle itself can be welded to the frame while also spinning freely and snugly. Weld a steel plate onto the chassis, securing the pressure plate outside with high-tensile bolts and lock nuts, to squeeze the bearing.
- Rather than making your own, you can also purchase these assemblies, sometimes called "Pillar Bearing Units."
- Build your seat out of plywood and bolt it to the frame. Drill holes in the plywood and install T nuts within the holes to provide support when bolting the seat to the frame. Cover the plywood with 2" high density foam, then cover the foam with marine vinyl. Secure the vinyl to the seat by stapling it to the underside or back portion of the plywood. Alternatively, you can try to salvage an old go-kart seat or an appropriately-sized car seat from the junk yard to save money. Leave enough room for the steering, engine, and other controls.
Mounting the Engine and Steering Column
- Install the engine mount. Weld a flat piece of 3/16-inch (0.5 cm) thick steel plate to the rear frame to mount your engine. Place the engine on the plate, and mark the holes for the mounting bolts so that the engine pulley lines up with the drive pulley on your axle.
- Attach the drive pulley on the axle prior to mounting the axle in the bushings. You can either use a set screw to hold it in position, or weld it directly to the axle, but it should be aligned with the pulley on your engine.
- Assemble your steering linkage. Use the 0.5-inch (1.5 cm) steel rod for linkages, and the 0.75-inch (2 cm) for your axles. To make the 90-degree bends in the 0.75-inch (2 cm) rod, you may have to use a torch to heat the steel.
- Provide adjustable links for aligning steering, because it is very important to have the proper caster and camber: front-wheel vertical and steering tilt.
- Install the wheels and brakes. Get some small racing wheels to give your kart the optimum acceleration and control. Fix them onto the axles with hubs and start working on the brakes, so the go-kart will be safe.
- For the brakes, fix a disc onto the rear axle and a caliper assembly onto the chassis for the most professional system possible. Often, you can acquire these assemblies in relatively good shape from junked motorbikes. They're the appropriate size and will be easy to work with.
- Install a brake pedal to operate with your foot, regardless of what kind of acceleration you have. Don't leave too much to do with your hands other than steering.
- Attach the throttle cable to the hand throttle. Depending upon your experience and the kind of engine you're working with, you may be able to put together a foot pedal, or you may just need to make it easy and throttle-up like you would a lawnmower.
- Double check your brakes and suspension system before test-driving. Even if you're going at relatively slow speeds, it's important to make sure you're not going to slip an axle on your first go-around. Double check your welds, your brakes, and the engine's mounting. Then take 'er for a spin!
Tips
- Try to add the extras at the end, so you can do all the big, more important, mechanical parts first.
- The assembly does have an accelerator, which also can be added using a simple throttle cable assembly from a discarded push mower, or a more sophisticated foot operated gas pedal.
- Get a go kart manual, as it will help and you can also get driving and tuning tips.
- This go cart assumes the use of a centrifugal clutch, but a modification can incorporate a drive belt idler system and either a hand applied or foot controlled gas pedal/clutch.
- The notes above reference the fact that it is assumed the builder will be using "junk" parts from discarded mowers and other sources. It is likely that it would be cheaper to buy a manufactured go cart than it would to buy certain pre-engineered parts to build it.
- Some people recommend buying a set of well-engineered and designed plans that incorporate some of the tried and tested automotive principles: like Ackermann steering, Castor, King pin inclination etc. You will be much more likely to finish and enjoy your kart if you build it from good plans.
- Use motorbike engine with a limiter so you don't go as fast as a motorbike.
- The costs for a simple kart can easily run to $600.00 - $700.00 USD, if not more. You can get a good set of plans for around $40.00 USD, some plans are even less than that. The cost of the plans is slightly under $80.00 USD. This is probably not a bad idea unless you're a pro.
Warnings
- Test the go kart before going on the track, as the parts could detach or fail.
- Wear protective gear when driving go carts: helmets, pads, etc.
- This is not a real car and should not under any circumstances be driven on the road!
- Because this is a simple project without high-tech engineering and design considerations, it is not recommended that a high gear ratio or large engine is used on this go kart. Speeds over {{safesubst:#invoke:convert|convert}} can cause failure of insufficiently engineered components.
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Sources and Citations
- Video provided by KartFab
