A carburetor is a mechanical device that combines air and fuel in an internal combustion engine. The carburetor controls the flow of air into an engine; the speed of the air entering the engine determines the amount of air pressure in the engine. The air pressure impacts the amount of fuel being drawn into the jet stream and ultimately, entering the engine. A Mikuni carburetor is a major line of carburetors that is used primarily in motorcycles and Japanese cars, including some Toyotas and Hondas. Rebuilding a Mikuni carburetor can save you money if you know how.
1. Remove the air filter from the top of the carburetor. If the filter is corroded, pry it loose with the flathead screwdriver. Scrub the area around the filter with the wire brush, and pop the new air filter into place.
2. Unscrew the choke valve using the Phillips-head screwdriver, and remove the old screw. Oil the choke valve in the area around the screw with the oil can. Re-fasten the choke valve to the inside of the carburetor, using the new swivel screw. Tap the choke valve a few times to make sure that it rotates freely.
3. Open the fuel delivery compartment, and remove the metering rod, using the adjustable wrench. Discard the old bolt that was used to attach the metering rod to the mechanical linkage.
4. Clean the metering rod thoroughly, using the dry cloth to remove oil and other residue.
5. Oil the mechanical linkage that attaches to the top of the metering rod. Make sure that the mechanical linkage moves freely by tapping it a few times.
6. Re-attach the top of the metering rod to the mechanical linkage, using the new 6-inch steel bolt and the adjustable wrench.
7. Unscrew the float valve using the adjustable wrench, and check the attachment area for corrosion. You may be able to clean the attachment area using the dry cloth, but if there is too much corrosion, the float valve will need to be replaced.
8. Scrub the inside of the fuel nozzle with the wire brush to ensure that the nozzle’s pathway to the air intake area is clear. Also scrub the inside of the float chamber using the wire brush. Re-attach the float valve to the inside of the float chamber using the adjustable wrench.