S&S, reed breather valve. STD O.D.

For head vented models. Similar in function to the S&S Reed valve for Twin Cam models. Unlike the regular rotating breather valve which is opened and closed by crankshaft rotation and pre-set timing, the Reed valve uses actual pressure to open and close on the right moment, at different RPM's this ideal moment varies. This means an advantage for the Reed valve over the regular mechanical timed breather valve in reducing oil carry over, especially in high RPM conditions. Note: Not suitable for use with crankcase vented models.

Fits: > 93-99 Evo Big Twin (NU)