1985 Harley Davidson Evolution 80ci (Dyna / Softail / FXR / Touring) Suspension Hydraulics, Fork Fluids & Sag Tuner

OEM hydraulic capacities, air-gap measurement standards, clicker baselines, and mathematical rider sag tuning.

Front Preload Baseline

Fixed OEM spacer

Rebound Damping Baseline

Fixed orifice hydraulic damping

Compression Damping Baseline

Fixed orifice hydraulic damping

Target Free Sag (Unladen)

25 - 30 mm

Enter 3-Point Sag Measurements (mm)

Suspension Sag Diagnosis & Geometry Status

Enter your extended, static, and rider measurements on the left (or select a preset) to compute exact sag percentages and spring preload recommendations.

Spectro Heavy Duty Type E 20W Fork Oil

Formulated with anti-foam agents and shear-stable viscosity index improvers to prevent damping fade under aggressive riding heat.

James Gasket 39mm/41mm Fork Seal Kit

Features directional triple-lip rubber seal profile and external garter springs engineered to withstand heavy stanchion flex without weeping.

140 mm (5.5 in) compressed without spring

Trapped air column acts as a progressive spring in final 30% of stroke. Adding +5mm oil increases bottoming resistance without stiffening small bump compliance.

U.S. Department of Transportation compliance database (Title 49 U.S.C. Chapter 301).

No Active Federal Safety Recalls Reported

The U.S. DOT National Highway Traffic Safety Administration (NHTSA) records zero open safety recall campaigns for the 1985 Harley Davidson Evolution 80ci (Dyna / Softail / FXR / Touring) platform. Always check your individual 17-digit VIN at an authorized dealership or via NHTSA.gov for individual recall completions.