MIKUNI 1 38MM TMX SERIES FLAT SLIDE CARBURETOR. The vendor part number is 1. Read title to know what you are getting. 38MM MIKUNI TMX SERIES FLAT SLIDE CARBURETOR. The TMX features a flat slide design in a smooth bore venturi to provide improved throttle response and wider powerband. The float system with independently moving floats, working with a main jet enclosed in a baffle chamber, allows the TMX to perform smoothly without hesitation on the roughest terrain. TMX series carburetors are available in 35mm bore sizes for 125cc race engines, and in 38mm bore sizes for use in 250cc race engines.