S&S Cycle Street Performance .585 Valve Spring Kit for 1984-2004 Harley-Davidson Big Twin

S&S Cycle Street Performance .585 Valve Spring Kit for 1984-2004 Harley-Davidson Big Twin

The valve spring governs every combustion event – too soft and the valve floats at speed, too stiff and power is wasted fighting the spring rather than turning the wheel. S&S Cycle street performance springs strike a tested balance between control and efficiency, giving the engine a cleaner throttle response and more consistent power delivery across the rpm range without sacrificing reliability.

Key Features

• .585-inch lift capacity for performance camshaft upgrades on Evolution and Twin Cam 88 engines
• Single-wire conical spring design provides progressive rate for smooth valve actuation
• Rated 325-pound open pressure for reliable high-rpm valve control
• Fits 1984-1999 Evolution Big Twin and 1999-2004 Twin Cam 88 engines
• Complete kit includes springs, retainer collars, shims, and keepers

Technical Specifications

• Lift Capacity: .585 inch
• Open Pressure: 325 lb
• Spring Type: Single-wire conical
• Includes: Springs, retainer collars, shims, and keepers
• Application: 1984-2004 Big Twin (Evolution and Twin Cam 88)

Fitment Notes

• Fits 1984-1999 Evolution Big Twin and 1999-2004 Twin Cam 88 engines
• Compatible with performance camshafts requiring up to .585-inch valve lift
• Rated for street performance applications; verify compatibility with competition or race cam specifications
• Review the Fitment tab for complete year and model breakdown