S&S Breather Gear for Big Twin (1977–1999)

This is the Breather Gear for Big Twin (1977–1999) — a stout little cog that ensures your crankcase breathing stays honest and reliable. In engines of that era, the breather gear plays a subtle but critical role: it forces gases and vapours out of the crankcase rather than letting them build pressure and sneak past seals. If your breather gear is worn, loose, or the wrong size, you risk oil dribble, crankcase pressure, or even foaming.

S&S’s version is a standard-size replacement intended for cases where the original breather hole hasn’t been modified. It fits OEM Big Twin gear systems as well as S&S SH-Series and V-Series engines.

In other words: drop it in, and it behaves exactly like the original — but built with S&S’s expectations of quality.

Design & Quality Notes

• Precision manufacture — made to tighter tolerances than many stock parts, ensuring a better “fit and forget” condition.

• High strength materials — built to resist fatigue under repeated stress.

• OEM-sized replacement — intended to drop in to original breather gear spacing, without requiring case modifications.

• Fitment — covers Big Twins from 1977 through 1999, making it suitable for most late-era classic and cruiser Big Twin engines.