Description

Your Yamaha 640’s intake efficiency directly impacts power delivery across the entire RPM range. Boyesen’s dual-stage reed design increases flow velocity and pressure consistency, translating to sharper throttle response and stronger acceleration from idle to redline. If you’re serious about extracting every bit of performance from your engine, upgrading from restrictive OEM reeds is one of the highest-ROI modifications available.

Laboratory flow analysis proves Boyesen racing reeds outperform standard units by permitting greater flow velocity across all operating pressures. The result is measurable gains in responsiveness and sustained power delivery that you’ll feel on every run.