Mercury - Quicksilver 5W Motorcycle Shock Oil Suspension Fluid Medium-Light Viscosity 8M0128405. Overview. Anyone who rides regularly knows the difference a good suspension makes. It's not just about smoothing out the bumps - it's about feeling connected to the road or trail in a way that builds confidence. When your shocks are working the way they should, the bike feels steady beneath you, predictable in corners, and controlled even when the terrain gets rough. Quicksilver 5W Motorcycle Shock O