Breather reed valve assembly for 1999–up big twins with S&S Oil Pumps. Besides offering improved oil scavenging and reduced oil carryover, S&S crankcase breather reed valves make your bike run better and provide a more enjoyable riding experience.
The functional part of S&S crankcase breather reed valves consists of steel reeds that are normally in the closed position. When the pistons travel downward in the cylinders, pressure in the crankcase below the pistons causes the reeds to open, allowing the air and oil mist in the crankcase to escape into the cam chest. When the pistons change direction and begin traveling back upward in the cylinders, a vacuum is created in the crankcase. The vacuum causes the reeds to close, preventing air from entering the crankcase. The effect is that a slight vacuum is maintained in the crankcase, and oil scavenging is greatly improved.
Fits Twin Cam 88® and S&S® T-Series engines
For Engines with S&S Oil Pumps
1999-'02. . . . . . 31-2070
2003-up . . . . . . 31-2071
S&S special application crankcases. . . . . . 31-2086