Screw-damper cover on a motorcycle primary-chain cover

A simple low-cost vibration damper (a loose extension nut) was designed to dampen out the cover’s breathing mode. Historically, a large cover was the dominant mechanical noise radiator in the powertrain. This vibration damper has proven effective in reducing the cover’s breathing mode of vibration, thus reducing the noise radiated by the cover. In a noise pass-by test, the damper showed a measurable noise reduction. An FEM analysis was used to identify the anti-node at the cover’s breathing mode. A proposed analytical model (Lanchester damper) was used to understand the damping mechanisms.