Keep it original with the genuine Beta BETA RETAINER, UPPER (OEM 28.16823.000) — the factory Cylinder/Cylinder Head/Valvetrain component for the EVO 250 4T, EVO 300 4T, REV 250 4T (2007–2010). It keeps your Beta performing exactly as the factory intended. Replace it as part of normal maintenance or after wear. Original parts install withou...