Yamaha GYTR Heavy Flywheel YZ250Genuine Yamaha GYTR Flywheel YZ250 2021 By smoothing out the YZ250s power delivery the GYTR Heavy Flywheel delivers a less aggressive hit when you twist the throttle. Its increased inertia mass helps to keep momentum through corners and makes the bike more usable especially in muddy and sandy conditions. Smoother power delivery Less aggressive hit Enhances power character Easy to fit Heavy flywheel, adds 227 grams for an interia mass of 5. 76kg cm2