NIMTEK 50cc Scooter Carburetor GY6 Four Stroke with Jet Upgrades Scooter Moped ATV Brand New High Quality Aftermarket Carburetor. Carburetor with accelerator pump for many 50cc GY6 4-stroke engines QMB139 Upgraded jets for better starting, idling and performance. 85 main, 32 pilot jet. 18mm ID (Intake side), 40mm OD air filter side