Yamaha - Jet, main (#50) - 7CU-E414J-50-A0Yamaha Main Jet #50 Carburetor Fuel Metering Component 7CU E414J 50 A0 Overview Main jets are where I start when an engine feels off at higher throttle. If its clogged or worn, youll notice it when the motor struggles to pull or just doesnt feel as strong as it should. Ive seen engines wake right back up with the correct jet in place. When its dialed in, you get smooth power all the way through the throttle range. Key Features High Speed Fuel Control