Prima's main jet kit for 17.5mm carbs using 6mm Dellorto main jets, including Yamaha 2T Zuma 50cc bikes. Are you dialing in your scooter to accommodate for that new air filter, exhaust, cylinder kit, elevation or season change? Save yourself some of the headache during the trial and error process by picking up one of our jetting kits! Jetting is something that takes trial and error. See our blog of jetting instructions for more info. Specifications: For stock-17.5mm carbs 10-piece set The kit includes #80 to #125 6mm jets Compatibility: 50cc bikes running 17.5mm carbs using 6mm Dellorto main jets, including Yamaha 2T Zuma 50cc bikes