About this product
Fine-tune your scooter or small engine build with this 10-piece M4 Carburetor Main Jet Set. Engineered specifically for GY6 50cc and 139QMB engines, as well as a wide range of popular aftermarket carburetors including Mikuni, Keihin, PWK, CVK, and PZ19 models, these round-head brass jets offer the precision you need for optimal fuel delivery and peak engine performance.\n\nEach jet is CNC-machined from high-grade solid brass to resist fuel corrosion and maintain exact tolerances under high-heat engine bay conditions. Whether you are re-jetting for high-flow air filters, aftermarket exhaust pipes, elevation changes, or routine maintenance, this multi-pack gives DIY mechanics and motorsports enthusiasts the reliability and versatility needed to dial in the perfect fuel-air mixture. Keep your scooter, moped, or pit bike running smooth, responsive, and efficient with direct-fit M4 replacement jets.