What you need:
Cardboard and lots of it
Black poster board
White poster board or paper
Red spray paint
Black spray paint
Silver spray paint
Styrofoam cones (4)
Black tape (we used electrical tape because that's what we had)
It's been 4 years since I made this costume....but I'm going to do my best to explain the building process from memory. The first thing we did was cut our design from cardboard. I usually cut the sides first and then add a piece of cardboard at the front and another at the back. I use hot glue to attach all the pieces so that I have one solid body. Later we cut a piece of cardboard to go on front of the kart...kinda like the front bumper with the sides. Again using hot glue to hold everything. The front bumper was attached to the main body of the kart. We also made a spoiler using a long rectangular piece of cardboard with square pieces on each end. That completed the body of the kart. I painted it red. I painted a foam ring black for the steering wheel and used zip ties to attach it to the frame of his kart.
The styrofoam cones were painted silver to be the exhaust pipes in the back. Later I hot glued red tissue paper to them to look like flames. To attach the cones, we just cut holes into the back of the kart frame and shoved the cones through. I used hot glue to make sure they were secure. We cut a small hole in the spoiler so that Caleb's handlebar would fit through. We didn't attach the spoiler to the actual kart, it was just held on by the handle bar.
We used black electrical tape to add our racing stripes down the kart. I traced a number "5" out of paper and added that to the spoiler. Caleb was 5 at that the time. I also cut out a letter "M" for the front of the kart. The wheels were just black poster board with a white circle added to the center. I also added smaller black pieces of paper to the white circle to make it look more like a wheel.
The entire kart fit right over Caleb's chair. We didn't really have to do anything to attach it because it fit so nicely.
If you have any questions or need more specific instructions, feel free to contact me using the button on the right side.