Boyesen 644 Boyesen Power Reeds Yamaha Dirt Bike Yamaha-FZ-1-2013 2013-2021 Polaris Indy 600 SP

2013-2021 Polaris Indy 600 SP 129in

1987-1988 Yamaha Champ 100 YFM100

17 hour talk time

2017-2019 Polaris Rush 600 XCR

Race-proven power is what you get with an EVO S series exhaust

Boyesen 644 Boyesen Power Reeds Yamaha Dirt Bike Yamaha-FZ-1-2013 2013-2021 Polaris Indy 600 SPBoyesens revolutionary dual stage reed design delivers more usable power than stock. Your original one stage reed operates most effectively only within a narrow RPM range. Boyesens one soft reed on top of one firm flow through reed gives you a wide range of intake control, plus increased intake velocity. Your original reeds cant possibly duplicate that performance. Dual stage reeds Minor change gives major H. P. improvements Faster opening and closing