carburetor racing jet, #90, #95, #100, #105, #110, carburetors jets, carb jets, GY6 Carburetor 139QMB, GY6 4-Stroke Engine Performance Parts, Mod kits for gas scooters, GY6 engine, scooter performance upgrade For GY6 engines . Allows more fuel to be fed into the engine to create proper fuel/air mixture. To be used in conjunction with an air filter upgrade and/or other mods that increase air flow into the engine. Fits all GY6 buggies & motorscooters.