S&S Cycle Manifold Conversion Kit for 1984-1999 Harley-Davidson Evolution Big Twin

S&S Cycle Manifold Conversion Kit for 1984-1999 Harley-Davidson Evolution Big Twin

The stock rubber compliance manifold on an 80-inch Evolution Big Twin is engineered for flexibility, not performance, allowing it to flex under load and leak over time. This S&S Cycle kit replaces it with a rigid precision-machined aluminum manifold, including all flanges, O-rings, and spacers for a complete installation that eliminates flex-related intake leaks.

Key Features

• Replaces stock rubber compliance manifold on 1984-1999 80-inch Evolution Big Twin engines
• Rigid precision-machined aluminum construction eliminates flex and intake leaks
• Machined with 1-7/8-inch throat compatible with most S&S and stock carburetors
• Fits stock Keihin butterfly carbs and S&S 1-3/4″ and 1-7/8″ carburetors
• Includes mounting flanges, two specially molded S&S O-rings, and two 0.350-inch aluminum spacers
• Not for use with S&S G series carburetors

Technical Specifications

• Manifold Material: Precision-machined aluminum
• Throat Diameter: 1-7/8 inches
• Application: 1984-1999 80-inch Evolution Big Twin
• Compatible Carburetors: Stock Keihin butterfly, S&S 1-3/4″ and 1-7/8″ carbs (not G series)
• Includes: Manifold, mounting flanges, two S&S O-rings, two 0.350-inch spacers
• Country of Origin: USA

Fitment Notes

• Fits 1984-1999 Harley-Davidson 80-inch Evolution Big Twin engines
• Compatible with stock Keihin butterfly carburetors and S&S 1-3/4″ and 1-7/8″ carburetors
• Not compatible with S&S G series carburetors
• S&S O-rings must be used – they are slightly thinner than OEM to accommodate the larger S&S port diameter
• Review the Fitment tab for complete year and model breakdown