Harley Davidson Motor Sprocket Shaft Seal – Left Side Big Twin 1970–1999 (OEM 12026)

This Harley Davidson motor sprocket shaft seal (left side) is a direct replacement for leaking or worn factory seals on Big Twin engines. Designed to properly seal the left side motor sprocket shaft, this part replaces Harley-Davidson OEM 12026, 12026A, 12026B. this is Number 28 in the parts diagram, and is highlighted in yellow.

A failing sprocket shaft seal can quickly turn into a mess—and bigger problems if ignored. Whether you’re handling routine maintenance or doing a full drivetrain or engine service, this seal helps keep oil where it belongs and your Big Twin running clean.

Correct fit, no nonsense, and exactly what you need for long-term reliability on classic Harley motors from 1970–1999.

Fitment

Harley-Davidson Big Twin models

1970–1999

Left side motor sprocket shaft

Replaces Harley-Davidson OEM 12026