To make a go kart that corners on rails like a Porche, looks like a Ferrari and turns all your neighbor's heads we need to back up the truck and go to the beginnings.
In short hand, there are five steps to development a straightforward frame. First of all the following steps are:
Razor Ground Force Electric Go-Kart
1. Machine And Passenger Layout
2. Drive Train System
3. Steering System
4. Brake System
5. Throttle System
Let's get into it now....
1. Machine And Passenger Layout
First of all the assumption, either this go-kart is made out of wood or is made out of steel is that you have some sort of layout in mind. Typically the Machine is behind, and the man sits in front of the engine. A good safe layout is to have a seat safe the passenger from the engine.
So a buildings of some sort is needed to hold the seat in place. You can use a seat off of a chair, but a more protective seat is a ½ piece of plywood angled back and supported. Outside the piece of wood is optional, but it is more comfortable with basically a piece of heavy cloth Outside a cushion. The cloth is stapled typically into the board (on the backside).
The buildings supporting the seat can be wood, or steel.
The frame work can be wood or steel as well. If using wood, use two by fours settled vertically, so that the drive of the wood is optimized.
If you are using steel for the frame, use a tubing that is at least .070 wall or thicker. The length of the frame is really dictated by how big the man is. Have a man sit conveniently in the leaned back position with a steering wheel in their hands. That is the man compartment. Part this length.
Add the Machine drive section and the man compartment lengths together and that is the length of the gokart. Cut your frame tubes (or tack tubes together) to this length. You will need at least two parallel lengths of tubing.
Space the tubes apart the width of the seat you made (20 inches is a good width).
Cut at least four (4) tubes to the 20 inch length. Lay all the pieces on the floor. Place the 20 inchers at the following locations: Machine Plate area, seat back section, seat forward section, front main bumper tube, and rear main bumper tube. (The bumper tubes can be wider than the frame by 12 inches (6 inches per side).)
Tack the tubes in place using a welder. If you do not have a welder, then you can fasten them together using plates and bolts. (Trust me, buy a 0 welder and save yourself wood chips and drill bits, busted knuckles and exasperation!)
What you have put together now is what I term a "flat-go kart." You will soon find out that flat gokart frames are weak and wish extra stiffening. You may want to put some struts into the principles to bolster the frame design. Typically what I use is the seat back as reference. This works very well as an integral frame support, side seat holder, and Machine protector.
2. Drive Train System
The next sequence is to place your Machine and drive train principles in place. At the same time put your seat in position to make sure the seat and Machine are not hitting each other. Be sure to make the seat detachable so that you can really work on the Machine principles when needed.
When placing your Machine typically a plate is needed to hold the Machine onto the frame. Some designers use tubes with holes drilled in them for Machine placement. I prefer the plate option, because it gives me greater options as far as Machine choices in the future.
For example on the Phi-Alpha-10 and the Phi-Alpha-9 (go karts I designed) the Machine plate served well in allowing me to use distinct engines, either Briggs and Stratton, Tecumseh or even Honda. All Machine types could be really mounted just by drilling the holes in the motor mount plate.
Most go karts use a slot principles to keep the chain tight. In other words, the Machine is mounted not using holes but slots. That works, but honestly, drilling slots is intensive works and requires some patience and thought. So I prefer tensioning the chain, it works great on multiple fronts. (I can go on and on about engines, drive trains and such...but we have got to keep provocative here...)
A word about drive systems: A live axle principles is really the way to go. All you have to do is mount two bearing brackets and away you go. On a one wheel drive system, you need to have extra rims that contain bearings, extra drive sprockets that connect to the tires, and the axle if it gets bent, you have to cut it out of the frame and start over....so use a live axle...
But, that is not all true. You can get away with using old lawnmower wheels if they have bushings in them. They work great for acting as bearings. Grease snot out of the axel-hub interface and away you go. Be sure to retain the wheel with a cross bolt that is at least grade 5.
3. Steering System
So after having mounted the rear axle (with brake disc (or brake drum) and sprocket), and having settled the Machine and chain principles in place, tour to mounting the front steering system.
Before we did some measurements of the man sitting in the comfortable position, make sure you remember the estimation (relative to the go kart frame) of the steering wheel. That is the target point for the steering wheel.
The actual position of the front wheels is a bit more involved though. You will need a scale. Place the scale first of all under the rear wheels. I typically use a board settled across the rear frame rails underneath the wheel area. Have man sit in the go kart. (Be sure to a have the front wheels, steering wheel and steering buildings on the go kart when you weigh it)
Now tour to the front of the go kart and place the board in the normal area that you want the steering system. Again weigh the go kart.
Take the two weights and add them together. That is the total weight. The front weight ideally should be with-in 5 to ten pounds of the rear weight. This is called 50/50 weight distribution. The more weight you have on the rear, the more the go kart will under-steer. Meaning, when you turn the wheel the go kart will tend to keep going straight. The more weight you have on the front wheels, the more the go kart will over steer. Most drivers are used to under-steer, it is easier to recover from.
But I digress...
Once you have settled the front wheels in place then fix the front steering principles in place there. I typically use plates, so that I can move the steering principles back or forward. So I weld mating plates on the frame and the steering system, then bolt them together.
For wood go karts, you can really organize a very garage wood go kart using the carriage style steering as long as the steering is supported an not aloud to twist.
A word on steering systems: You can buy from the store steering assemblies that you tack onto tubes. These work real well, with one exception, they typically come in .750 inch diameter shafts, where most high speed bearings use .625 diameter shafts. The shafts may need replacement. Look for .625 shafts... Additionally, there are ways to make the steering more tractable and more user friendly, these involve geometric relationships such as camber, caster, Ackerman and so forth.
4. Brake System
Now that you have the steering principles in position, you can button up the hole project by Outside the lowest of the go kart. Sheet metal (like furnace guys use) is the best option. Buy some tech screws (the ones with drills on their ends) and zip straight through the sheet metal into the tubing. Once you have that in place, you don't have to worry about your feet hitting the ground!
Now it is time to place the brake system. You consideration we settled the brakes in place on the live axle, now the actual braking mechanism needs to be mounted to the frame work. You can either weld it, or bolt it to the frame. I prefer bolting, it is more forgiving and easier to repair.
A word on brake float: The brake principles should float. What that means is that the disc either needs to be mounted freely on the shaft, or the brake caliper needs to float. If the neither is floating, you will get a binding, and prematurely worn out brakes, and fast! So keep that in mind. Something has to float, the disc or the brake caliper (1 of the 5!)
For your brakes it is foremost to have the brake off while driving. A good spring is needed to keep the pedal back when the brake is not being used.
On a wood go kart be sure to use the same belief into the brake system. A lot of force is going into the brake boards so be sure to list for this in the brake mechanism which regularly involves force multiplier linkages.
5. Throttle System
This seems like the most inane or over looked principles on the go kart. It shouldn't be though. A good association between the throttle and the pedal is needed and a good range of appeal is needed too. Most pedals give you distinct holes to work with, allowing your several options in throttle actuation.
Again, like the brake, a good spring is needed. Do not use a spring on the carburetor, but use the spring in the pedal, or pedal system.
A word about throttles: most engines come with governors. It is a good idea to use the governor system, because it helps keep the Machine at even speeds and from over revving.
How to Build a Go Kart - 5 Go Kart building Secrets
