196CC Custom Go Kart
About This Project
I had been thinking about building a go kart from scratch for quite some time and decided that because I was at home for my first coop, this was a better time than any to get started. I had a hard deadline to finish the project before I moved back to Waterloo for my study term which drove me to dedicate lots of time to it.
Planning & Procurement
I began by modeling out the chassis and main components of the kart in SolidWorks to get a feel for how it should look and to catch any interference within components. After this was complete, I started obtaining the different powertrain parts I needed such as the engine, rear axle and wheels as well as the wood for the frame.
The chassis was based off of a backbone chassis frame for added torsional rigidity as well as stability.
Assembly
I started by building the frame with pieces of 2x4 and a 6' long piece of 12x2x8 to build off of. I then began installing the live rear axle by mounting the pillow block bearings to the frame. After this, I installed the steering system and front wheels which consisted of angled spindles that created a negative camber on the front wheels. I decided to go with this setup because it increases handling and gives the kart a sportier look. When I completed this, I installed the engine and mocked up the seat placement to get a rough idea of the kart's overall look.
Throughout this process I reduced the width of the rear end due to the rims I purchased which left me with some extra wood on the sides next to the rear wheels. I wanted to keep the extra wood sticking out as wheel wells but the tires I ended up getting were quite large so I had to cut them off.
Assembly Issues
During assembly, I found that the rear axle that I had ordered had been manufactured poorly. The axle must have had poor cylindricity tolerances (or inadequate quality control) as the pillow block bearings did not slide along the entire shaft. After reaching approximately 2" into the shaft, they would stick and could not be pushed further. This was an issue as the bearings had to reach 6" into the shaft to allow for the axle to enter the rims. To alleviate this problem, I began filing down the axle to remove some of the extra material on it as well as designing a jig to aid in installing the bearings. I FDM 3D-printed a jig that would allow me to evenly apply force to the bearing. With this, I was able to slowly but surely install the bearings to the correct distance on the shaft without damaging them.
Brake & Throttle System
While developing the brake and throttle system, I wanted to reuse what I had lying around in my garage as much as possible. As a result of this, I came up with a system that utilized brake cable from an old bike we had. This led me to building a throttle pedal attached to the throttle control arm with brake cable. The cable for the throttle pedal was screwed into the side of the pedal which was bolted to a hinge.
Originally, I wanted to build a brake pedal as well but as I did not have enough cable, I built a handbrake with a wooden dowel and parts I stripped from the bike. The bike had rim brakes which utilized springs to pull the pads in and slow down the wheel. I took these and designed a 3D-printed part to hold the spring and allow it to attach to the dowel. This allowed the handbrake to remain stiff but still have a springy aspect to it so it could return to its original position when let go. The brake itself was a mechanical brake caliper system bought off the shelf. It was activated by a lever that I connected to the brake cable.
Engine Prep & Testing
When I got the engine mounted I also had to break the chain to the correct size. As the engine was built for a power washer, I had to modify it to allow for manual throttle control which was done by installing a throttle control arm. When this was complete, I was able to run the first engine fire in the chassis! After this, I just needed to mount the rear wheels and the kart was ready to go.
In terms of timeline, this was about 1.5 months into the build.
Final Product
Results, Improvements & Challenges
My original goal for this build was to be able to run the kart at a top speed of at least 30 kph. After completing some rounds of testing, I was able to clock it at 42 kph! This was a great feeling after spending months working on this kart and at times even doubting if I could complete it in time.
To improve on this build, I would increase the size of the front wheels. The smaller front wheels make the kart look more visually pleasing, but it reduces the front clearance by a significant amount. I would also add a supporting beam to the steering column as the current design has a bit too much play.
Despite the wonderful outcome, there were many challenges with this project. One of the biggest challenges was my lack of experience in woodworking. I've worked with metal and have experience in sheet metal bending, MIG welding, etc. but hadn't spent much time with wood. In addition to this, I had a relatively small space to work in which made maneuvering the kart quite difficult. Another challenge was the temperature. Most of this kart was built in sub-zero temperatures - often around -10° C. After working all day, going into the garage to work on the kart in the cold was quite difficult to convince myself to do. Even with these challenges however, I was motivated to get this build done so I could enjoy driving it!