Greg Pickens motorcycle image from Fotolia.com.
A carburetor is a mechanical device that combines air and fuel in an internal combustion engine. The carburetor controls the flow of air to an engine. The speed of the air entering the engine determines the amount of air pressure in the engine. Air pressure affects the amount of fuel that is introduced into the jet stream and ultimately enters the engine. A Mikuni carburetor is a specific type of carburetor that is made in Japan and is used on a variety of Japanese motorcycles, including Yamaha, Honda, and Kawasaki. It is a good idea to occasionally adjust a Mikuni carburetor to ensure optimum engine performance and to ensure that your motorcycle does not put unnecessary pressure on the engine.
Remove the air filter from its mounting with the flat-head screwdriver. Make sure the air filter is free of debris and put it back in place. If the air filter is damaged or corroded, it must be replaced.
Locate the air screw on the back of the carburetor and tighten the screw with the Phillips screwdriver. Turn the screw clockwise to decrease the amount of air entering the carburetor and make the motorcycle engine burn more fuel (as the air-fuel mixture will be made up of more fuel). This setting will make the engine more powerful but will consume fuel more quickly.
Adjust the pilot jet, located under the air screw, using the adjustable wrench. The pilot jet regulates the amount of fuel entering the carburetor. Turning the pilot jet clockwise reduces the amount of fuel entering the carburetor; turning it counterclockwise increases the amount of fuel going into the carburetor.
Adjust the throttle slide valve, which regulates the amount of fuel-air mixture entering the motorcycle engine through the carburetor. The throttle slide valve has numbered settings, and sliding the valve to a higher numbered setting means that more mixture will enter the engine, causing the engine to produce more power.
Tighten or loosen the jet of the needle with the adjustable wrench. The needle jet also controls the flow of the fuel-air mixture exiting the carburetor and must be adjusted to correspond to the same numbered setting as the throttle slide valve.
Adjust the carburetor choke valve by tightening or loosening its screw with the Phillips screwdriver. To increase engine power, loosen the screw.
- Make a note of the factory setting of the Mikuni carburetor before adjusting it.
- Always wear protective clothing, including gloves and eye protection, when working with engines.
Articles will need
- flat head screwdriver
- Phillips screwdriver
- Adjustable wrench