Stage 1 Kits. Designed for motorcycles with a stock engine using the stock airbox, air filter, and stock or aftermarket pipe. Stage 1 kits are fully adjustable to allow the use of well- designed aftermarket pipes and K&N stock replacement air filters. Stage 1 kits are designed to improve throttle response and driveability. In most cases power increases of approximately 5% throughout the entire power range can be achieved.
Stage 3 Kits. Designed for motorcycles with stock or mildly modified engines using K&N individual air filters and a stock or aftermarket pipe. In most cases power increases of 10-15% can be achieved. However, driveability may be compromised particularly with short stroke high RPM motors. On some modern engine and airbox designs, individual filters and proper jetting offer no performance improvement, yet compromise driveability. In such cases stage 3 kits are not available.