Here is a pic of my go cart it has a 4 cylinder mercury outboard boat motor power head on it. The engine is 65 HP producing about 75 hp at 7200 RPM running on 90% gas plus 10% alcohol. The engine is water cooled using 2 heater cores from junk yard cars as radiators and a Toyota water pump belt driven off the rear axle. Disc brakes and positive traction rear axle. Gear ratio is 3.7 to 1 direct drive with #40 chain. It idles at about 5 mph and will reach top speed 87 mph in about 3 seconds. Total weight of the entire go cart is 218 lbs. G force is unreal I have to accellerate in the curve with 1 eye closed because the G force causes my eyes to cross. Punch the gas pedal to the floor you better be handing on tight G force will pull your hands off the stearing wheel. This is the most fun toy I have ever built. This is not something you give to your grandson to play with if he isn't at lease 15 years old with some good common sense he doesn't need this toy.
If anyone wants to build one let me know I will help you all I can. This is the second one I have built. Do not PM me all help needs to be where everyone can read and use the informations.
There is a good amount of machine work here. I build the disc brake caliper out of aluminum. #40 sprocket has a lot of metal removed to make it light weight. Motor mounts are machines, bearing mounts, water pump mounts, homemade V belt aluminum pully, brake pedal and linkage, stearing and linkage, front wheel stearing system and axles. It all has to be made 1 piece at a time. You need a lathe and a milling machine. The engine has to be rebuilt too. I don't care what kind of condition the motor is in I can make it run. I bought a motor that was on the bottom of the lake for almost a year and got it running good. Carburators have to be turned 90 degrees so 2 adptors have to be machined. Old carburators will work but road vibration makes the fuel foam and it screws up the float. 2 cycle diaphram carburetors work great. If you have a model airplane engine built a larger copy of the carburetor for the 65 hp engine.
I am getting read to build another one soon. Just as soon as I can clear out a few of my other projects and make some room I will be ready to build another go cart. I have 2 engines that are built and ready to bolt to the frame.
If the gear ratio was changed to about 2 to 1 this thing would go over 160 mph. Speed is not as much fun as power. My son use to talk about speed all the time it took me a long time to prove to him power is way more fun than speed.