Moose Racing Dynojet Jet Kits provide a simple and affordable solution to carburetor tuning problems. Kits increase power and smoothness throughout the rev range while maintaining optimum fuel economy. Jets Included for Kits Below: STAGE 1 Kit: Designed for machines with stock engines using the stock airbox, air filter and stock or aftermarket exhaust. Fully adjustable to allow for the use of well-designed aftermarket exhausts and stock replacement air filters. Improve throttle response and drivability. Power increases of approximately 5% throughout the entire power range. STAGE 2 Kit: Designed for machines with stock or mildly modified engines using well-designed stock or aftermarket exhausts with a modified airbox and a stock or replacement air filter. For applications where airbox modifications improve overall engine performance, a power increase of 8% can be achieved in most cases. Note: NOT compatible with California-spec bikes.