Yamaha has designed an engine specifically for go-karts. Responding to the concerns of karters, the company has developed this engine to provide the power output and the configuration requested. It is a simple engine, but can be adapted to provide power for just about any kind of go-kart.
The KT100 is an air-cooled two-stroke engine. This means it has only two cycles: compression/ignition and exhaust. The combustion chamber produces power, or "fires," every time the piston reaches the top. When the piston travels down, it is the exhaust stroke. This is more efficient than a four-stroke engine, since these fire on only every fourth stroke.
Displacement and Weight
The size of the engine is 97.6 cc, rounded up to 100 cc. The bore, or diameter of the piston, is 52 mm. The stroke, or how far the piston travels in the cylinder, is 46 mm. The engine weighs 21 lb.
Because it is a two-stroke engine the oil must be mixed in with the gasoline. The recommended oil by Yamaha is Yamalube 2R. The ratio of the mix is 20:1. This means for every 20 parts of gasoline, one part of oil is added to the gasoline. For example for 20 quarts of gasoline, you would add in one quart of oil. If you use 20 pints of gasoline, mix in one pint of oil.
Carburetor and Ignition
The carburetor is a Walboro WB-3A unit. This is a very simple carburetor and separates the oil out from the fuel in the carburetor process. The ignition is called TDI. This means it is a solid state ignition, developing the high voltage by using transistors and capacitors. It is also a simple system, but effectively produces a high voltage to "fire" the spark plug.