2337ST Steel breather valve. STD. Elongated

This standard-size JIMS steel breather valve features an elongated rear oil hole designed to improve crankcase vacuum, which is particularly beneficial for large-capacity performance engines. CNC machined from aerospace-quality steel, it offers superior durability compared to stock plastic or cast breathers. This valve fits late 1977 to 1999 Big Twin models, excluding Twin Cam engines, and is a direct replacement for OEM part number 25313-77C. It is also compatible with late 1979 to 1999 style steel breather valve thrust washers. Upgrading to a steel breather is a smart move for any Evolution-era engine build, ensuring consistent performance and better oil scavenging under high-load conditions.