For your 2013 F6b, it looks like this is the OEM 90 degree valve stem -

VALVE, RIM (BS)
44753-MCA-003 In Stock$7.75
$7.57

Mine is still the original. If it were a full rubber unit I'd have long since replaced it. It just has the one seal. I'm a bit surprised that they don't seem to sell a "rebuild" kit with the o ring and valve stem itself...