Description
Stock reeds limit your Kawasaki 639’s potential across the entire power band—from initial throttle response to peak acceleration. Boyesen’s dual-stage reed design increases flow velocity at every operating pressure, unlocking measurable performance gains without sacrificing reliability. If you’re serious about maximizing your engine’s output, this is a foundational upgrade that delivers real results.
- Dual-stage reed design
- Laboratory flow-tested
- Increased flow velocity
- Improved start-up response
- Enhanced top-end acceleration
- Kawasaki 639 specific
- Bolt-on installation
- MPN: 639









